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Atherosclerosis Independence: Genetic Polymorphisms of Ion Channels Role in the Pathogenesis of Coronary Microvascular Dysfunction and Myocardial Ischemia (Coronary Artery Disease (CAD))

Reviewer and Co-Curator: Larry H Bernstein, MD, FCAP

and

Curator: Aviva Lev-Ari, PhD, RN

The role of ion channels in Na(+)-K(+)-ATPase: regulation of ion
transport across the plasma membrane has been studied by our Team in 2012 and 2013. This is article TWELVE in a 13 article series listed at the end of this article.

Chiefly, our sources of inspiration were the following:

1.            2013 Nobel work on vesicles and calcium flux at the neuromuscular junction

Machinery Regulating Vesicle Traffic, A Major Transport System in our Cells 

The 2013 Nobel Prize in Physiology or Medicine is awarded to Dr. James E. Rothman, Dr. Randy W. Schekman and Dr. Thomas C. Südhof for their discoveries of machinery regulating vesicle traffic, a major transport system in our cells. This represents a paradigm shift in our understanding of how the eukaryotic cell, with its complex internal compartmentalization, organizes the routing of molecules packaged in vesicles to various intracellular destinations, as well as to the outside of the cell. Specificity in the delivery of molecular cargo is essential for cell function and survival. 

http://www.nobelprize.org/nobel_prizes/medicine/laureates/2013/advanced-medicineprize2013.pdf

Synaptotagmin functions as a Calcium Sensor: How Calcium Ions Regulate the fusion of vesicles with cell membranes during Neurotransmission

Larry H Bernstein, MD, FCAP and Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2013/09/10/synaptotagmin-functions-as-a-calcium-sensor-how-calcium-ions-regulate-the-fusion-of-vesicles-with-cell-membranes-during-neurotransmission/

2. Perspectives on Nitric Oxide in Disease Mechanisms

available on Kindle Store @ Amazon.com

http://www.amazon.com/dp/B00DINFFYC

https://pharmaceuticalintelligence.com/biomed-e-books/series-a-e-books-on-cardiovascular-diseases/perspectives-on-nitric-oxide-in-disease-mechanisms-v2/

3.            Professor David Lichtstein, Hebrew University of Jerusalem, Dean, School of Medicine

Lichtstein’s main research focus is the regulation of ion transport across the plasma membrane of eukaryotic cells. His work led to the discovery that specific steroids that have crucial roles, as the regulation of cell viability, heart contractility, blood pressure and brain function. His research has implications for the fundamental understanding of body functions, as well as for several pathological states such as heart failure, hypertension and neurological and psychiatric diseases.

Physiologist, Professor Lichtstein, Chair in Heart Studies at The Hebrew University elected Dean of the Faculty of Medicine at The Hebrew University of Jerusalem

Reporter: Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2013/12/18/physiologist-professor-lichtstein-chair-in-heart-studies-at-the-hebrew-university-elected-dean-of-the-faculty-of-medicine-at-the-hebrew-university-of-jerusalem/

4.            Professor Roger J. Hajjar, MD at Mount Sinai School of Medicine

Calcium Cycling (ATPase Pump) in Cardiac Gene Therapy: Inhalable Gene Therapy for Pulmonary Arterial Hypertension and Percutaneous Intra-coronary Artery Infusion for Heart Failure: Contributions by Roger J. Hajjar, MD

Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2013/08/01/calcium-molecule-in-cardiac-gene-therapy-inhalable-gene-therapy-for-pulmonary-arterial-hypertension-and-percutaneous-intra-coronary-artery-infusion-for-heart-failure-contributions-by-roger-j-hajjar/

5.            Seminal Curations by Dr. Aviva Lev-Ari on Genetics and Genomics of Cardiovascular Diseases with a focus on Conduction and Cardiac Contractility

Aviva Lev-Ari, PhD, RN

Aviva Lev-Ari, PhD, RN

Aviva Lev-Ari, PhD, RN and Larry H. Bernstein, MD, FCAP

Justin Pearlman, MD, PhD, FACC, Larry H Bernstein, MD, FCAP and Aviva Lev-Ari, PhD, RN

Other related research by the Team of Leaders in Pharmaceutical Business Intelligence published on the Open Access Online Scientific Journal

http://pharmaceuticalintelligence.com

See References to articles at the end of this article on

  • ION CHANNEL and Cardiovascular Diseases

https://pharmaceuticalintelligence.com/?s=Ion+Channel

  • Calcium Role in Cardiovascular Diseases – The Role of Calcium Calmodulin Kinase  (CKCaII) and Ca(2) flux
  • Mitochondria and Oxidative Stress Role in Cardiovascular Diseases

Thus, the following article follows a series of articles on ion-channels and cardiac contractility mentioned, above. The following article is closely related to the work of Prof. Lichtstein.

These investigators studied the possible correlation between

  • Myocardial Ischemia (Coronary Artery Disease (CAD)) aka Ischemic Heart Disease (IHD) and
  • single-nucleotide polymorphisms  (SNPs) genes encoding several regulators involved in Coronary Blood Flow Regulation (CBFR), including
  • ion channels acting in vascular smooth muscle and/or
  • endothelial cells of coronary arteries.

They completely analyzed exon 3 of both KCNJ8 and KCNJ11 genes (Kir6.1 and Kir6.2 subunit, respectively) as well as

  • the whole coding region of KCN5A gene (Kv1.5 channel).
The work suggests certain genetic polymorphisms may represent a non-modifiable protective factor that could be used
  • to identify individuals at relatively low-risk for cardiovascular disease
  • an independent protective role of the
    • rs5215_GG against developing CAD and
    • a trend for rs5219_AA to be associated with protection against coronary microvascular dysfunction

Their findings are a lead into further investigations on ion channels and IHD affecting the microvasculature.

Role of genetic polymorphisms of ion channels in the pathophysiology of coronary microvascular dysfunction and ischemic heart disease

BasicResCardiol(2013)108:387   http//dx.dio.org/10.1007/s00395-013-0387-4

F Fedele1•M Mancone1•WM Chilian2•P Severino2•E Canali•S Logan•ML DeMarchis3•M Volterrani4•R Palmirotta3•F Guadagni3

1Department of Cardiovascular, Respiratory, Nephrology, Anesthesiology and Geriatric Sciences,Sapienza University of Rome, UmbertoI Policlinic, Rome, Italy  e-mail:francesco.fedele@uniroma1.it
2Department of Integrative Medical Sciences, Northeastern Ohio Universities College of Medicine, Rootstown,OH
3Department of Advanced Biotechnologies and Bioimaging, IRCCS San Raffaele Pisana,Rome,It
4Cardiovascular Research Unit, Department of Medical Sciences, Centre for Clinical and Basic Research, Raffaele Pisana, Rome, Italy (CBFR)

BasicResCardiol(2013)108:387   http//dx.dio.org/10.1007/s00395-013-0387-4
This article is published with open access at Springerlink.com

Abstract

Conventionally,ischemic heart disease (IHD) study is equated with large vessel coronary disease (CAD). However, recent evidence has suggested

  • a role of compromised microvascular regulation in the etiology of IHD.

Because regulation of coronary blood flow likely involves

  • activity of specific ion-channels, and
  • key factors involved in endothelium-dependent dilation,

genetic anomalies of ion-channels or specific endothelial-regulators may underlie coronary microvascular disease.

We aimed to evaluate the clinical impact of single-nucleotide polymorphisms in genes encoding for

  • ion-channels expressed in the coronary vasculature and the possible
  • correlation with IHD resulting from microvascular dysfunction.

242 consecutive patients who were candidates for coronary angiography were enrolled. A prospective, observational, single-center study was conducted, 

  • analyzing genetic polymorphisms relative to

(1) NOS3 encoding for endothelial nitric oxide synthase (eNOS);
(2) ATP2A2 encoding for the Ca/H-ATP-ase pump (SERCA);
(3) SCN5A encoding for the voltage-dependent Na channel (Nav1.5);
(4) KCNJ8 and in KCNJ11 encoding for the Kir6.1and Kir6.2 subunits
of genetic K-ATP channels, respectively;and
(5) KCN5A encoding for the voltage-gated K channel (Kv1.5).

No significant associations between clinical IHD manifestations and

  • polymorphisms for SERCA, Kir6.1, and Kv1.5. were observed (p[0.05),

whereas specific polymorphisms detected in eNOS, as well as in Kir6.2 and Nav1.5 were found to be correlated with

  • IHD and microvascular dysfunction.

 Interestingly, genetic polymorphisms of ion-channels  seem to have an important clinical impact

  • influencing the susceptibility for microvascular dysfunction and (IHD,
  • independent of the presence of classic cardiovascular risk factors: atherosclerosis   

http//dx.dio.org/10.1007/s00395-013-0387-4

Keywords: Ion-channels, Genetic polymorphisms, Coronary microcirculation, Endothelium, Atherosclerosis Ischemic heart disease

 Introduction

Historically, in the interrogation of altered vascular function in patientswith ischemic heart disease (IHD), scientists have focused their attention on the correlation between

  • endothelial dysfunction and
  • atherosclerosis [11, 53, 6567].

The endothelium-independent dysfunction in coronary microcirculation and its possible correlations with  

  • atherosclerotic disease and
  • myocardial ischemia has not been extensively investigated.

In normal conditions, coronary blood flow regulation (CBFR) is mediated by several different systems, including

  • endothelial,
  • nervous,
  • neurohumoral,
  • myogenic, and
  • metabolic mechanisms [2, 10, 14, 15, 63, 64, 69].

Physiologic CBFR depends also on several ion channels, such as

  • ATP-sensitive potassium (KATP) channels,
  • voltage-gated potassium (Kv) channels,
  • voltage-gated sodium (Nav) channels, and others.

Ion channels regulate the concentration of calcium in both

  • coronary smooth muscle and endothelial cells, which
  • modulates the degree of contractile tone in vascular muscle and
  • the amount of nitric oxide that is produced by the endothelium

Ion channels play a primary role in the rapid response of both

  • the endothelium and vascular smooth muscle cells of coronary arterioles
  • to the perpetually fluctuating demands of the myocardium for blood flow
    [5, 6, 13, 18, 33, 45, 46, 51, 52, 61, 73, 75].

Despite this knowledge, there still exists an important gap about 

  • the clinical relevance and 
  • causes of microvascular dysfunction in IHD

By altering the overall

  • regulation of blood flow in the coronary system,
  • microvascular dysfunction could alter the normal distribution of shear forces in large coronary arteries

Proximal coronary artery stenosis could

  • contribute to microvascular dysfunction [29, 60]. But
  • ion channels play a critical role in microvascular endothelial
  • and smooth muscle function.

Therefore, we hypothesized  that alterations of coronary ion  channels could be the primary cause in a chain of events leading to

  • microvascular dysfunction and 
  • myocardial ischemia

independent of the presence of atherosclerosis.

Therefore, the objective of our study was to evaluate the possible correlation between

  • IHD and single-nucleotide polymorphisms  (SNPs) for genes encoding several regulators involved in CBFR, including
  • ion channels acting in vascular smooth muscle and/or
  • endothelial cells of coronary arteries.

Discussion

Implications of the present work. This study describes the possible correlation of polymorphisms in genes encoding for CBFR effectors (i.e., ion channels, nitric oxide synthase, and SERCA) with the susceptibility for microcirculation dysfunction and IHD.

Our main findings are as follows: (Group 3 – Normal Patients – anatomically and functionally normal coronary arteries).

  • In Group 3, the genotype distribution of SNP rs5215 (Kir6.2/KCNJ11) moderately deviates from the HW equilibrium (p = 0.05).
  • In Group 1 (CAD), the polymorphism rs6599230 of Nav1.5/SCN5A showed deviation from HW equilibrium (p = 0.017).
  • The genotypic distribution of rs1799983 polymorphism for eNOS/NOS3 is inconsistent with the HW equilibrium in groups 1, 2, and 3 (p = 0.0001, p = 0.0012 and p = 0.0001, respectively).

Haplotype analyses revealed that there is no linkage disequilibrium between polymorphisms of the analyzed genes. There was no significant difference in the prevalence of T2DM (p = 0.185) or dyslipidemia (p = 0.271) between groups, as shown in Table2. In regards to genetic characteristics, no significant differences between the three.

1. A marked HW disequilibrium in the genotypic distribution of rs1799983 polymorphism for eNOS/NOS3 was observed in all three populations. Moreover, this SNP seems to be an independent risk factor for microvascular dysfunction, as evidenced by multivariate analysis;
2. The SNPs rs5215_GG, rs5218_CT, and rs5219_AA for Kir6.2/KCJ11 could reduce susceptibility to IHD, since they were present more frequently in patients with anatomically and functionally normal coronary arteries;
3. In particular, with regard to rs5215 for Kir6.2/KCJ11, we observed a moderate deviation from the HW equilibrium in the genotypic
distribution in the control group. In addition, this genotype appears to be an independent protective factor in the development of IHD, as evidenced by multivariate analysis;
4. Furthermore, the trend observed for the SNP  rs5219_AA of Kir6.2/KCNJ11 may suggest an independent protective factor  in the development of coronary microvascular dysfunction
5. The rs1805124_GG genotype of Nav1.5/SCN5A seems to play a role against CAD;
6. No association seems to exist between the polymorphisms of SERCA/ATP2A2, Kir6.1/KCNJ8, and Kv1.5/KCNA5 and the presence of IHD;
7. All groups are comparable regarding the cardiovascular risk factors of T2DM and dyslipidemia, illustrating a potentially important implication of genetic polymorphisms in the susceptibility to IHD.

It is important to underline that the control group (Group 3) is a high-risk population, because of their cardiovascular risk factors

  • hypertension = 17 %,
  • T2DM = 34.1 %,
  • dyslipidemia = 41.4 %,

with an appropriate indication for coronary angiography, in accordance with current guidelines. Nevertheless, these patients were demonstrated to have both anatomically and functionally normal coronary arteries. Moreover, as shown in Tables 2 and 3, we observed that

  • rs5215_GG, rs5218_CT and rs5219_AA for Kir6.2/KCNJ11 had a higher prevalence in this group,compared to patients with CAD
  • and patients with microvascular dysfunction.

Moreover, as shown in Table 4, the presence of the rs5215_GG polymorphism for the Kir6.2 subunit was

  • inversely correlated with the prevalence of cardiovascular risk factors and CAD,whereas
  • rs5219_AA of the Kir6.2 subunit trended towards an inverse correlation with coronary microvascular dysfunction.

On the other hand, the SNP rs1799983_GT of eNOS was

  • confirmed to be an independent risk factor for microvascular dysfunction.

Our data suggest that the presence of certain genetic polymorphisms may represent a non-modifiable protective factor that could be used

  • to identify individuals at relatively low-risk for cardiovascular disease,
  • regardless of the presence of T2DM and dyslipidemia.

Current Clinical and Research Context

In normal coronary arteries, particularly the coronary microcirculation, there are several different mechanisms of CBFR, including

  • endothelial, neural, myogenic, and metabolic mediators [2, 8, 10, 12, 14, 15, 37, 55, 63, 64, 69].

In particular, endothelium-dependent vasodilation acts mainly via eNOS-derived nitric oxide (NO) in response to acetylcholine and shear stress.

  • NO increases intracellular cyclic guanosine monophosphate. It also causes vasodilation via
  • activation of both K-Ca channels and K-ATP channels.

Recent data suggested a pathophysiologically relevant role for the polymorphisms of eNOS/NOS3 in human coronary vasomotion [40–43]. Our data suggest that rs1799983_GT at exon 7 (Glu298Asp, GAG-GAT) of eNOS/NOS3 represents

  • an independent risk factor for coronary micro-vascular dysfunction, which agrees with a recent meta-analysis reporting an
  • association of this SNP with CAD in Asian populations [74]. In addition,
  • this SNP has been associated with endothelial dysfunction, although the mechanisms are not well defined [30].

Consistently, a recent study performed on 60 Indian patients with documented history of CAD reported a significantly higher frequency of rs1799983 (p.05) compared to control subjects, indicating that

  • variations in NOS3 gene may be useful clinical markers of endothelial dysfunction in CAD [54].
Interestingly, another association between rs1799983_GT and impaired collateral development has been observed in patientswith a

  • high-grade coronary stenosis or occlusion [19].
As is well known, the significance of the mechanisms of CBFR is partly determined by the location within the coronary vasculature. For instance, for vessels with a diameter of < 200 µm—which comprise the coronary microcirculation—metabolic regulation of coronary blood flow is considered the most important mechanism [24, 63]. Importantly, many of these mediators of metabolic regulation act through specific ion channels. In particular, in both coronary artery smooth muscle cells and endothelial cells
  • potassium channels determine the resting membrane potential (Em) and serve as targets of endogenous and therapeutic vasodilators [9, 27].
Several types of K+ channels are expressed in the coronary tree.
  • The K-ATP channels couple cell metabolic demand to conductance, via pore-forming (Kir6.1 and/or Kir6.2) subunits and regulatory
    [sulphonylurea-binding (SUR 1, 2A, or 2B)] subunits.
  • Kir6.x allows for channel inhibition by ATP, while SURx is responsible for channel activation by ADP and Mg2+.
K-ATP channel activation results in an outward flux of potassium and

  • consequent hyperpolarization, resulting in
  • voltage-gated calcium channel closure,
  • decreased Ca2+ influx, and ultimately
  • vasodilation [1, 5, 18, 20, 21, 33, 61, 62, 73, 75].

Our data do not support any significant difference regarding the Kir6.1 subunit of the K-ATP channel. On the other hand, this study suggests

  • an important role of specific SNPs for the Kir6.2 subunit (Tables 2, 3)—i.e., rs5215, rs5219, and rs5218—

in the susceptibility to IHD and microvascular dysfunction. These SNPs are among the most studied K-ATP channel polymorphisms, especially in the context of diabetes mellitus. In fact, in both Caucasian and Asian populations, these three SNPs as well as other genetic polymorphisms for the KCNJ11 gene have been associated with diabetes mellitus [34, 35, 44, 50, 57, 58, 70].

Nevertheless, the precise

  • structure–function impacts of the various amino acid substitutions remain unclear.

The rs5215 and rs5219 polymorphisms, also known as I337V and E23K, respectively, are highly linked with reported

  • concordance rates between 72 and 100 % [22, 23, 56].

The high concordance between rs5219 and rs5215 suggests that these polymorphisms

  • may have originated in a common ancestor, further indicating a
  • possible evolutionary advantage to their maintenance in the general population [49].

In our study, multivariate analysis suggests both an independent protective role of the

  • rs5215_GG against developing CAD and
  • a trend for rs5219_AA to be associated with protection against coronary microvascular dysfunction (Table 4a, b).
  • The variant rs5215_GG is a missense SNP located in the gene KCNJ11 at exon 1009 (ATC-GTC) and results in
    the substitution of isoleucine (I) residue with valine (V) [23].

Future studies are necessary to better understand the influence of this single amino acid variant on the function of the channel.

In humans, vasodilation of the coronary microvasculature in response to hypoxia and K-ATP channel opening
  • are both impaired in diabetes mellitus [39].
It is also described that gain-of-function mutations of the KCNJ11 gene cause neonatal diabetes mellitus, and loss-of-function mutations lead to congenital hyperinsulinism [43]. Our study is not discordant with previous studies about the correlation of SNPs of the Kir6.2 subunit and diabetes mellitus. Rather, our findings show that these SNPs are correlated with anatomically and functionally normal coronary arteries,
  • independent of the presence of either diabetes mellitus or dyslipidemia.
These data suggest the possibility that these particular SNPs may identify individuals with decreased risk for coronary microcirculatory dysfunction and IHD,
  • regardless of the presence of T2DM and/or dyslipidemia.

However, further studies are necessary to confirm these findings. In this context, to better investigate the implications of genetic variation in the K-ATP channel,

  • future studies should include ion channel’s functional modification due to the SNPs and analysis of SUR subunits.

More than 40-kV channel subunits have been identified in the heart, and sections of human coronary smooth muscle cells demonstrate Kv1.5 immunoreactivity [16, 17, 27, 38]. Through constant regulation of smooth muscle tone, Kv channels contribute to the control of coronary microvascular resistance [4, 7]. Pharmacologic molecules that inhibit Kv1.5 channels such as

  • pergolide [25],
  • 4-amino-pyridine [32], and
  • correolide [17]

lead to coronary smooth muscle cell contraction and block the coupling between

  • cardiac metabolic demand and
  • coronary blood flow.

However, no significant differences were identified between the study groups in terms of the particular polymorphisms for Kv1.5 that were analyzed in this study. Expression of

  • the voltage-dependent Na+ channel (Nav) has been demonstrated in coronary microvascular endothelia cells [3, 66].

Our analysis reveals a possible implication of the polymorphism rs1805124_GG for Nav1.5 channel with the presence of anatomically and functionally normal coronary arteries. This SNP leads to a homozygous 1673A-G transition, resulting in a His558-to-Arg (H558R) substitution. It is important to underline that

  • our data are the first to correlate the polymorphism rs1805124_GG with IHD.

Further research is necessary to confirm the observed implication.

Finally, we have analyzed the sarco/endoplasmic reticulum calcium transporting Ca2+-ATPase (SERCA), which is fundamental in the regulation of intracellular Ca2+ concentration [6].

SERCA is an intracellular pump that

  • catalyzes the hydrolysis of ATP coupled with the
  • translocation of calcium from the cytosol into the lumen of the sarcoplasmic reticulum.

Although this pump plays a critical role in regulation of the contraction/relaxation cycle, our analysis did not reveal any apparent association between

  • genetic variants of SERCA and the
  • prevalence of microvascular dysfunction or IHD.

Conclusions

This pilot study is the first to compare the prevalence of SNPs in genes encoding coronary ion channels between patients
  • with CAD or microvascular dysfunction and those with both anatomically and functionally normal coronary arteries.
Taken together, these results suggest the possibility of associations between SNPs and IHD and microvascular dysfunction, although

  • the precise manners by which specific genetic polymorphisms affect ion channel function and expression
have to be clarified by further research involving larger cohorts.

Limitations and future perspectives

Notable limitations of this pilot study are as follows:

1. Due to the lack of pre-existing data, the power calculation was performed in advance on the basis of assumptions of allele frequencies and the population at risk.
2. The sample size for each group is small, mainly due to both the difficulty in enrolling patients with normal coronary arteries and normal microvascular function (group 3) and the elevated costs of the supplies such as Doppler flow wires.
3. There is a lack of ethnic diversity of our cohort.
4. Currently, there is an absence of supportive findings in another independent cohort or population. However, our pilot study included patients within a well-defined, specific population and was aimed to identify the presence of statistical associations between selected genetic polymorphisms and the prevalence of a specific disease.
5. There is a lack of functional characterization of the described genetic polymorphisms.
6. We have not identified any correlation between novel SNPs and IHD. Nevertheless, we completely analyzed exon 3 of both KCNJ8 and KCNJ11 genes (Kir6.1 and Kir6.2 subunit, respectively) as well as the whole coding region of KCN5A gene (Kv1.5 channel).  Moreover, we examined previously described SNPs since there are no data in the literature regarding the possible association of the prevalences of those polymorphisms in the examined population.More extensive studies are necessary to confirm our  findings, possibly with a larger number of patients. Future investigations are also required to confirm the roles of ion  channels in the pathogenesis of coronary microvascular dysfunction and IHD. These studies should involve analysis of both other subunits of the K-ATP channels

  • sulfonylurea receptor, SURx and further coronary ion channels (e.g., calcium-dependent K channels), as well as
  • in vitro evaluation of ion channel activity by patch clamp and analysis of channel expression in the human cardiac tissue.

Moreover, to better address the significance of microvascular dysfunction in IHD, it could be interesting to analyze

  • typical atherosclerosis susceptibility genes (e.g., PPAP2B, ICAM1, et al.).

Methods

In this prospective, observational, single-center study – 242 consecutive patients admitted to our department were enrolled with

  • the indication to undergo coronary angiography .

All patients matched inclusion criteria

  1. age [18];
  2. suspected or documented diagnosis of acute coronary syndrome or stable angina
  3. with indication(s) for coronary angiography, in accordance with current guidelines [36, 68], and
  4. the same ethno-geographic Caucasian origin) and

Exclusion Criteria

  1. previous allergic reaction to iodine contrast,
  2. renal failure,
  3. simultaneous genetic disease,
  4. cardiogenic shock,
  5. non- ischemic cardiomyopathy

All patients signed an informed consent document  –

prior to participation in the study, which included

  • acknowledgement of the testing procedures to be performed
    (i.e., coronary angiography; intracoronary tests; genetic analysis, and processing of personal data).

The study was approved by the Institution’s Ethics Committee.
All clinical and instrumental characteristics were collected in a dedicated  database.

 Study Design

(a)  Standard therapies were administered, according to current guidelines [36, 68].
(b) An echocardiography was performed before and after coronary angiography
(c)  Coronary angiography was performed using radial artery or femoral artery
Judkins approach via sheath insertion.
(d) In patients showing normal epicardial arteries, intracoronary functional tests
were performed through Doppler flow wire to evaluate

  1. both endothelium-dependent microvascular function
    [via intracoronary (IC) infusion of acetylcholine (2.5–10 lg)] and
  2. nonendothelium-dependent microvascular function
    [via IC infusion of adenosine (5 lg)] [31]. 

(e) In all enrolled patients, a peripheral blood sample for genetic analysis was taken. 

On the basis  of the  coronary angiography and the intracoronary functional tests, 

  • the 242 patients were divided into three groups (see also Fig. 1).
  1. Group 1: 155 patients with anatomic coronary alteration
    (comprising patients with acute coronary syndrome and chronic stable angina).

    • microvascular dysfunction defined as coronary flow reserve (CFR) \ 2.5
    • after IC infusion of acetylcholine and adenosine].
  2. Group 2: 46 patients with functional coronary alteration
    [normal coronary arteries as assessed by angiography, and

    • as assessed by angiography and with normal functional tests
      (CFR C 2.5 after intracoronary infusion of acetylcholine and adenosine) (Fig. 1).
  3. Group 3: 41 patients with anatomically and functionally normal coronary arteries


BRC 2013 fedele genetic polymorphisms of ion channels.pdf_page_2

Fig. 1 Study design: 242 consecutive not randomized patients matching inclusion and exclusion criteria were enrolled.
In all patients, coronary angiography was performed, according to current ESC/ACC/AHA guidelines. In patients with
angiographically normal coronary artery, intracoronary functional tests were performed. In 242 patients
(155 with coronary artery disease, 46 patients with micro-vascular dysfunction, endothelium and/or non-endothelium
dependent, and 41 patients with anatomically and functionally normal coronary arteries) genetic analysis was performed.

Genetic Analysis

In conformity with the study protocol, ethylenediaminetetraacetic acid (EDTA) whole blood samples were collected according
to the international guidelines reported in the literature [48]. Samples were transferred to the Interinstitutional Multidisciplinary
BioBank (BioBIM) of IRCCS San Raffaele Pisana (Rome) and stored at -80 C until DNA extraction. Bibliographic research by
PubMed and web tools OMIM (http://www.ncbi.nlm.nih.gov/omim), Entrez SNP (http://www.ncbi.nlm.nih.gov/snp), and
Ensembl (http://www.ensembl.org/index.html) were used to select variants of genes involved in signaling pathways

  • related to ion channels and/or reported to be associated with
  • microvascular dysfunction and/or myocardial ischemia and/or
  • diseases correlated to IHD, such as diabetes mellitus.
Polymorphisms for the following genes were analyzed:
  1. NOS3 (endothelial nitric oxide synthase, eNOS),
  2. ATP2A2 (Ca2+/H+-ATPase pump, SERCA2),
  3. SCN5A (voltage-dependent Na+ channel,
  4. Nav1.5),
  5. KCNJ11 (ATP-sensitive K+ channel, Kir6.2 subunit),
  6. KCNJ8 (ATP-sensitive K+ channel, Kir6.1 subunit) and
  7. KCNA5 (voltage-gated K+ channel, Kv1.5).

In particular, we completely analyzed by direct sequencing

  • exon 3 of KCNJ8 (Kir6.1 subunit), which includes eight SNPs, as well as
  • the whole coding region of KCNA5 (Kv1.5 channel), which includes 32 SNPs and
  • four previously described variants [26, 47, 71, 72].
We also examined
  • the whole coding region of KCNJ11 (Kir6.2 subunit), for which sequence variants are described [26, 28].

All SNPs and sequence variants analyzed—a total of 62 variants of 6 genes—are listed in Table 1.

BRC 2013 fedele genetic polymorphisms of ion channels_page_004
BRC 2013 fedele genetic polymorphisms of ion channels_page_005

DNA was isolated from EDTA anticoagulated whole blood using the MagNA Pure LC instrument and theMagNA Pure LC
total DNA isolation kit I (Roche Diagnostics, Mannheim, Germany) according to the manufacturer’s instructions. Standard
PCR was performed in a GeneAmp PCR System 9700 (Applied Biosystems, CA) using HotStarTaq Master Mix
(HotStarTaq Master Mix Kit, QIAGEN Inc, CA). PCR conditions and primer sequences are listed in Table 1.

In order to exclude preanalytical and analytical errors, all direct sequencing analyses were carried out on both
strands using Big Dye Terminator v3.1 Cycle Sequencing kit
(Applied Biosystems), run on an ABI 3130
Genetic Analyzer (Applied Biosystems), and repeated on PCR products obtained from new nucleic acid extractions.
All data analyses were performed in a blind fashion.

Statistical Analysis

This report, intended as pilot study, is the first to compare

  • the prevalence of SNPs in genes encoding  several effectors (including ion channels)
  • involved in CBFR between these groups of patients.

No definite sample size could be calculated to establish a power analysis. groups of patients. However, assuming

  • a 15 % prevalence of normal  macrovascular and microvascular coronary findings in unselected patients
    undergoing coronary angiography,

we estimated that

  • a sample size of at least 150 patients could enable the computation of two-sided 95 % confidence intervals for
    • such prevalence estimates ranging between -5.0 and + 5.0 %.

The significance of the differences of observed alleles and genotypes between groups, as well as

  • analysis of multiple inheritance models for SNPs were also tested
    (co-dominant, dominant, recessive, over-dominant and log-additive)
  • using a free web-based application (http://213. 151.99.166/index.php?module=Snpstats)
  • designed from a genetic epidemiology  point of view to analyze association studies.

Akaike Information Criterion (AIC) was used to determine the best-fitting inheritance model for analyzed SNPs,

  • with the model with the lowest AIC reflecting the best balance of  goodness-of-fit and parsimony.

Moreover,  the allelic frequencies were estimated by gene counting, and the genotypes were scored. For each gene,

  • the observed numbers of each genotype were compared with those expected for a population in Hardy–Weinberg (HW) equilibrium
  • using a free web-based application  (http://213.151.99.166/index.php?module=Snpstats) [59].

Linkage disequilibrium coefficient (D0) and  haplotype analyses were assessed using  the  Haploview 4.1 program.
Statistical analysis was performed using SPSS software package for Windows v.16.0 (SPSS Inc., Chicago, IL).

All categorical variables are expressed as percentages, and all continuous variables as mean ± standard deviation.
Differences between categorical variables

  • were analyzed by Pearson’s Chi-SQ test.

Given the presence of three groups, differences  between continuous variables, were calculated using
(including the number of SNPs tested),

  • one-way ANOVA; a post-hoc analysis with Bonferroni correction was made for multiple comparisons.

Univariate and multivariate logistic regression analyses

  • the independent impact of genetic polymorphisms on
    • coronary artery disease and microvascular dysfunction,

were performed to assess the independent impact of

  • genetic polymorphisms on coronary artery disease
    and microvascular dysfunction
    ,

while adjusting for other confounding variables.  The following parameters were entered into the model:

  • age,
  • male gender,
  • type 2 diabetes mellitus (T2DM),
  • systemic arterial hypertension,
  • dyslipidemia,
  • smoking status, and
  • family history of myocardial infarction (MI).

Only variables with a p value < 0.10 after univariate analysis were entered

  • into the multivariable model as covariates.

A two-tailed p < 0.05 was considered statistically significant.

Definition of Cardiovascular Risk Factors

Patients were classified as having T2DM if they had

  • fasting levels of glucose of >126 mg/dL in two separate measurements or
  • if they were taking hypoglycemic drugs.

Systemic arterial hypertension was defined as

  • systolic blood pressure  > 140 mmHg / diastolic blood pressure > 90 mmHg
  • in two separate measurements or
  • if the patient was currently taking antihypertensive drugs.

Dyslipidemia was considered to be present if

  • serum cholesterol levels were>220 mg/dL or
  • if the patient was being treated with cholesterol-lowering drugs.

Family history of MI was defined as a first-degree relative with MI before the age of 60 years.

Results

Sixty-two polymorphisms distributed among six genes coding for
  • nitric oxide synthase,
  • the SERCA pump, and
  • ion channels
    • were screened for sequence variations using PCR amplification and
    • direct DNA sequencing analysis

in the population of

  • 155 patients with CAD (group 1),
  • 46 patients with microvascular dysfunction (group 2), and
  • 41 patients with normal coronary arteries and
    • normal endothelium dependent and endothelium-independent vasodilation (group 3).
In Group 3, the genotype distribution of

  • SNP rs5215 (Kir6.2/KCNJ11) moderately deviates from the HW equilibrium (p = 0.05).
In Group 1 (CAD), the polymorphism

  • rs6599230 of Nav1.5/SCN5A showed deviation from HW equilibrium (p = 0.017).
The genotypic distribution of groups in terms of polymorphisms for
  • eNOS/NOS3, SERCA/ATP2A2, Nav1.5/SCN5A, Kir6.1/KCNJ8, or Kv1.5/KCNA5
were noticed. However, significant differences (p.05) for the SNPs
  • rs5215_GG, and
  • rs5219_AA of Kir6.2/KCNJ11 were observed,
as shown in Table 2. 

Table 3 displays 
significant differences between normal subjects (group 3) and
  • patients with either CAD (group 1) or microvascular dysfunction (group 2).

BRC 2013 fedele genetic polymorphisms of ion channels_page_006

When correcting for other covariates as risk factors, the rs5215_GG genotype of Kir6.2/KCNJ11 was found to be 

  • significantly associated with CAD after multivariate analysis (OR = 0.319, p = 0.047, 95 % CI = 0.100–0.991), evidencing
  • a ‘‘protective’’ role of this genotype, as shown in Table 4a.

Similarly, a trend that supports this role of Kir6.2/KCNJ11 was also observed

  • in microvascular dysfunction for rs5219 AA. In contrast,
  • rs1799983_GT for eNOS/NOS3 was identified as an independent risk factor

following multivariate analysis (Table 4b), which agrees with literature findings as described below. 

BRC 2013 fedele genetic polymorphisms of ion channels_page_007

SOURCE for TABLES

BasicResCardiol(2013)108:387   http//dx.dio.org/10.1007/s00395-013-0387-4

Conflict of interest On behalf of all authors, the corresponding author states that there is no conflict of interest.
Open Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.

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2. Baumgart D, Naber C, Haude M, Oldenburg O, Erbel R, Heusch G, Siffert W (1999) G protein beta3 subunit 825T allele and enhanced coronary vasoconstriction on
alpha(2)-adrenoceptor activation. Circ Res 85:965–969. doi:10.1161/01.RES.85.10.965
3. Belardinelli L, Shryock JC, Fraser H (2006) Inhibition of the late sodium current as a potential cardioprotective principle: effects of the late sodium current inhibitor
ranolazine. Heart 92:6–14. doi:10.1136/hrt.2005.078790
4. Berwick ZC, Moberly SP, Kohr MC, Morrical EB, Kurian MM, Dick GM, Tune JD (2012) Contribution of voltage-dependent K+ and Ca2+ channels to coronary pressure-
flow autoregulation. Basic Res Cardiol 107:264. doi:10.1007/s00395-012-0264-6
5. Brayden JE (2002) Functional roles of KATP channels in vascular smooth muscle. Clin Exp Pharmacol Physiol 29:312–316. doi:10.1046/j.1440-1681.2002.03650.x
6. Brini M, Carafoli E (2009) Calcium pumps in health and disease. Physiol Rev 89:1341–1378. doi:10.1152/physrev.00032.2008
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Basic Res Cardiol (2013) 108:387   http://dx.doi.org/10.1007/s00395-013-0387-4

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Erythropoietin (EPO) and Intravenous Iron (Fe) as Therapeutics for Anemia in Severe and Resistant CHF: The Elevated N-terminal proBNP Biomarker

 

Co-Author of the FIRST Article: Larry H. Bernstein, MD, FCAP

Reviewer and Curator of the SECOND and of the THIRD Articles: Larry H. Bernstein, MD, FCAP

and

Article Architecture Curator: Aviva Lev-Ari, PhD, RN

This article presents Advances in the Treatment using Subcutaneous Erythropoietin (EPO) and Intravenous Iron (Fe) for IMPROVEMENT of Severe and Resistant Congestive Heart Failure and its resultant Anemia.  The Leading Biomarker for Congestive Heart Failure is an Independent Predictor identified as an Elevated N-terminal proBNP.

NT-proBNP schematic diagram-Copy.pdf_page_1

FIRST ARTICLE

Anemia as an Independent Predictor of Elevated N-terminal proBNP

Salman A. Haq, MD1, Mohammad E. Alam2, Larry Bernstein, MD, FCAP3,  LB Banko 1, Leonard Y. Lee, MD, FACS4, Barry I. Saul, MD, FACC5, Terrence J. Sacchi, MD, FACC6,  John F. Heitner, MD, FACC7
1Cardiology Fellow,  2  Clinical Chemistry Laboratories, 3 Program Director, Cardiothoracic Surgery, 4 Division of Cardiology,  Department of Medicine, New York Methodist Hospital-Weill Cornell, Brooklyn, NY

(Unpublished manuscript)  Poster Presentation

SECOND ARTICLE

The effect of correction of mild anemia in severe, resistant congestive heart failure using subcutaneous erythropoietin and intravenous iron: a randomized controlled study

Donald S Silverberg, MDa; Dov Wexler, MDa; David Sheps, MDa; Miriam Blum, MDa; Gad Keren, MDa; Ron Baruch, MDa; Doron Schwartz, MDa; Tatyana Yachnin, MDa; Shoshana Steinbruch, RNa; Itzhak Shapira, MDa; Shlomo Laniado, MDa; Adrian Iaina, MDa

J Am Coll Cardiol. 2001;37(7):1775-1780. doi:10.1016/S0735-1097(01)01248-7

http://content.onlinejacc.org/article.aspx?articleid=1127229

THIRD ARTICLE

The use of subcutaneous erythropoietin and intravenous iron for the treatment of the anemia of severe, resistant congestive heart failure improves cardiac and renal function and functional cardiac class, and markedly reduces hospitalizations

Donald S Silverberg, MDa; Dov Wexler, MDa; Miriam Blum, MDa; Gad Keren, MDa; David Sheps, MDa; Eyal Leibovitch, MDa; David Brosh, MDa; Shlomo Laniado, MDa; Doron Schwartz, MDa; Tatyana Yachnin, MDa; Itzhak Shapira, MDa; Dov Gavish, MDa; Ron Baruch, MDa; Bella Koifman, MDa; Carl Kaplan, MDa; Shoshana Steinbruch, RNa; Adrian Iaina, MDa

J Am Coll Cardiol. 2000;35(7):1737-1744. doi:10.1016/S0735-1097(00)00613-6

http://content.onlinejacc.org/article.aspx?articleid=1126474

Perspective

This THREE article sequence is related by investigations occurring by me, a very skilled cardiologist and his resident, and my premedical student at New York Methodist Hospital-Weill Cornell, in Brooklyn, NY, while a study had earlier been done applying the concordant discovery, which the team in Israel had though was knowledge neglected.  There certainly was no interest in the problem of the effect of anemia on the patient with severe congestive heart failure, even though erythropoietin was used widely in patients with end-stage renal disease requiring dialysis, and also for patients with myelofibrosis.  The high cost of EPO was only one factor, the other being a guideline to maintain the Hb concentration at or near 11 g/dl – not higher.  In the first article, the authors sought to determine whether the amino terminal pro– brain type natriuretic peptide (NT-pro BNP) is affected by anemia, and to determine that they excluded all patients who had renal insufficiency and/or CHF, since these were associated with elevated NT-proBNP.  It was already well established that this pro-peptide is secreted by the heart with the action as a urinary sodium retention hormone on the kidney nephron, the result being an increase in blood volume.  Perhaps the adaptation would lead to increased stroke volume from increased venous return, but that is not conjectured.  However, at equilibrium, one would expect there to be increased red cell production to maintain the cell to plasma volume ratio, thereby, resulting in adequate oxygen exchange to the tissues.  Whether that is always possible is uncertain because any reduction in the number of functioning nephrons would make the kidney not fully responsive at the Na+ exchange level, and the NT-pro BNP would rise.  This introduces complexity into the investigation, requiring a removal of confounders to establish the effect of anemia.

The other two articles are related studies by the same group in Israel.  They surmised that there was evidence that was being ignored as to the effect of anemia, and the treatment of anemia was essential in addition to other treatments.  They carried out a randomized trial to determine just that, a benefit to treating the anemia.  But they also conjectured that an anemia with a Hb concentration below 12 g/dl has an deleterious effect on the targeted population.  Treatment by intermittent transfusions could potentially provide the added oxygen-carrying capacity, but the fractionation of blood, the potential for transfusion-transmitted disease and transfusion-reactions, combined with the need for the blood for traumatic blood loss made EPO a more favorable alternative to packed RBCs.  The proof-of-concept is told below.  Patients randomized to receive EPO at a lower than standard dose + iron did better.

 

Introduction

In this article, Erythropoietin (EPO) and Intravenous Iron (Fe) as Therapeutics for Anemia in Severe and Resistant CHF: The Elevated N-terminal proBNP Biomarker we provides a summary of three articles on the topic and we shading new light on the role that Anemia Hb < 12 g%  plays as a Biomarker for CHF and for

  • prediction of elevated BNP, known as an indicator for the following Clinical Uses:
Clinical Use
  • Rule out congestive heart failure (CHF) in symptomatic individuals
  • Determine prognosis in individuals with CHF or other cardiac disease
  • Maximize therapy in individuals with heart failure by the use of Subcutaneous Erythropoietin (EPO) and Intravenous Iron (Fe)
Evaluation of BNP and NT-proBNP Clinical Performance
Study Sensitivity(%) Specificity(%) PPV(%) NPV(%)
Diagnose impaired LVEF3
BNP 73 77 70 79
NT-proBNP 70 73 61 80
Diagnose LV systolic dysfunction after MI2
BNP 68 69 56 79
NT-proBNP 71 69 56 80
Diagnose LV systolic dysfunction after MI12
BNP 94 40 NG 96
NT-proBNP 94 37 NG 96
Prognosis in newly diagnosed heart failure patients: prediction of mortality/survival1
BNP 98 22 42 94
NT-proBNP 95 37 47 93
Prognosis post myocardial infarction: prediction of mortality2
BNP 86 72 39 96
NT-proBNP 91 72 39 97
Prognosis post myocardial infarction: prediction of heart failure2
BNP 85 73 54 93
NT-proBNP 82 69 50 91
PPV, positive predictive value; NPV, negative predictive value; LVEF, left ventricular ejection fraction; NG, not given.
Reference Range
BNP: < 100 pg/mL13
proBNP, N-terminal: 300 pg/mL
The NT-proBNP reference range is based on EDTA plasma. Other sample types will produce higher values.
Interpretive Information
Symptomatic patients who present with a BNP or NT-proBNP level within the normal reference range are highly unlikely to have CHF. Conversely, an elevated baseline level indicates the need for further cardiac assessment and indicates the patient is at increased risk for future heart failure and mortality.BNP levels increase with age in the general population, with the highest concentrations seen in those greater than 75 years of age.14 Heart failure is unlikely in individuals with a BNP level <100 pg/mL and proBNP level ≤300 pg/mL. Heart failure is very likely in individuals with a BNP level >500 pg/mL and proBNP level ≥450 pg/mL who are <50 years of age, or ≥900 pg/mL for patients ≥50 years of age. Patients in between are either hypertensive or have mild ischemic or valvular disease and should be observed closely.15BNP is increased in CHF, left ventricular hypertrophy, acute myocardial infarction, atrial fibrillation, cardiac amyloidosis, and essential hypertension. Elevations are also observed in right ventricular dysfunction, pulmonary hypertension, acute lung injury, subarachnoid hemorrhage, hypervolemic states, chronic renal failure, and cirrhosis.NT-proBNP levels are increased in CHF, left ventricular dysfunction, myocardial infarction, valvular disease, hypertensive pregnancy, and renal failure, even after hemodialysis.Although levels of BNP and NT-proBNP are similar in normal individuals, NT-proBNP levels are substantially greater than BNP levels in patients with cardiac disease due to increased stability (half-life) of NT-proBNP in circulation. Thus, results from the two tests are not interchangeable.
References
  1. Cowie MR and Mendez GF. BNP and congestive heart failure. Prog Cardiovasc Dis. 2002;44:293-321.
  2. Richards AM, Nicholls MG, Yandle TG, et al. Plasma N-terminal pro-brain natriuretic peptide and adrenomedullin. New neurohormonal predictors of left ventricular function and prognosis after myocardial infarction. Circulation. 1998:97:1921-1929.
  3. Hammerer-Lercher A, Neubauer E, Muller S, et al. Head-to-head comparison of N-terminal pro-brain natriuretic peptide, brain natriuretic peptide and N-terminal pro-atrial natriuretic peptide in diagnosing left ventricular dysfunction. Clin Chim Acta. 2001;310:193-197.
  4. McDonagh TA, Robb SD, Murdoch DR, et al. Biochemical detection of left-ventricular systolic dysfunction. Lancet. 1998;351:9-13.
  5. Mukoyama Y, Nakao K, Hosoda K, et al. Brain natriuretic peptide as a novel cardiac hormone in humans: Evidence for an exquisite dual natriuretic peptide system, ANP and BNP. J Clin Invest. 1991;87:1402-1412.
  6. Hunt PJ, Richards AM, Nicholls MG, et al. Immunoreactive amino-terminal pro-brain natriuretic peptide (NT-PROBNP): a new marker of cardiac impairment. Clin Endocrinol. 1997;47:287-296.
  7. Davis M, Espiner E, Richards G, et al. Plasma brain natriuretic peptide in assessment of acute dyspnoea. Lancet. 1994;343:440-444.
  8. Kohno M, Horio T, Yokokawa K, et al. Brain natriuretic peptide as a cardiac hormone in essential hypertension. Am J Med. 1992;92:29-34.
  9. Bettencourt P, Ferreira A, Pardal-Oliveira N, et al. Clinical significance of brain natriuretic peptide in patients with postmyocardial infarction. Clin Cardiol. 2000;23:921-927.
  10. Jernberg T, Stridsberg M, Venge P, et al. N-terminal pro brain natriuretic peptide on admission for early risk stratification of patients with chest pain and no ST-segment elevation. J Am Coll Cardiol. 2002;40:437-445.
  11. Richards AM, Troughton RW. Use of natriuretic peptides to guide and monitor heart failure therapy. Clin Chem. 2012;58:62-71.
  12. Pfister R, Scholz M, Wielckens K, et al. The value of natriuretic peptides NT-pro-BNP and BNP for the assessment of left-ventricular volume and function. A prospective study of 150 patients.Dtsch Med Wochenschr. 2002;127:2605-2609.
  13. Siemens ADVIA Centaur® BNP directional insert; 2003.
  14. Redfield MM, Rodeheffer RJ, Jacobsen SJ, et al. Plasma brain natriuretic peptide concentration: impact of age and gender. J Am Coll Cardiol. 2002;40:976-982.
  15. Weber M, Hamm C. Role of B-type natriuretic peptid (BNP) and NT-proBNP in clinical routine.Heart. 2006;92:843-849.

SOURCE

B-type Natriuretic Peptide and proBNP, N-terminal

http://www.questdiagnostics.com/testcenter/testguide.action?dc=TS_BNP_proBNP

FIRST ARTICLE

Anemia as an Independent Predictor of Elevated N-terminal proBNP

Salman A. Haq, MD1, Mohammad E. Alam2, Larry Bernstein, MD, FCAP3,  LB Banko 1, Leonard Y. Lee, MD, FACS4, Barry I. Saul, MD, FACC5, Terrence J. Sacchi, MD, FACC6,  John F. Heitner, MD, FACC7
1Cardiology Fellow,  2  Clinical Chemistry Laboratories, 3 Program Director, Cardiothoracic Surgery, 4 Division of Cardiology,  Department of Medicine, New York Methodist Hospital-Weill Cornell, Brooklyn, NY

(Unpublished manuscript)  Poster Presentation:

Anemia as an Independent Predictor of Elevated N-Terminal proBNP Levels in
Patients without Evidence of Heart Failure and Normal Renal Function.

Haq SA, Alam ME, Bernstein L, Banko LB, Saul BI, Lee LY, Sacchi TJ, Heitner JF.

Table 1.  Patient Characteristics

Variable No Anemia(n=138) Anemia(n=80)
Median Age (years) 63 76
Men (%) 35 33
Creatinine (mg/dl) 0.96 1.04
Hemoglobin (g/dl) 13.7 10.2
LVEF (%) 67 63
Median NT-proBNP (pg/ml) 321.6 1896.0

Poster-ProBNP_final[1]

A series of slide showing the determination of the representation of normal NT-proBNP range
after removal of patient confounders.

Slide1

Slide10

Slide5

Slide8

ABSTRACT

Introduction

N-terminal proBNP (NT-proBNP) has emerged as a primary tool for diagnosing congestive heart failure (CHF). Studies have shown that the level of

  • NT-proBNP is affected by renal insufficiency (RI) and age, independent of the diagnosis of CHF.

There is some suggestion from recent studies that

  • anemia may also independently affect NT-proBNP levels.

Objective

To assess the affect of anemia on NT-proBNP independent of CHF, RI, and age.

Methods

We evaluated 746 consecutive patients presenting to the Emergency Department (ED) with shortness of breath and underwent evaluation with serum NT-proBNP.

All patients underwent a trans-thoracic echocardiogram (TTE) and clinical evaluation for CHF. Patients were included in this study if they had a normal TTE (normal systolic function, mitral inflow pattern and left ventricular (LV) wall thickness) and no evidence of CHF based on clinical evaluation. Patients were excluded if they had RI (creatinine > 2 mg/dl) or a diagnosis of sepsis. Anemia was defined using the World Health Organization (W.H.O.) definition of

  • hemoglobin (hgb) < 13 g/dl for males and hgb < 12 g/dl for females.

Results

Of the 746 consecutive patients, 218 patients (138 anemia, 80 no anemia) met the inclusion criteria. There was a markedly significant difference between

  • NT- proBNP levels based on the W.H.O. diagnosis of anemia.

Patients with anemia had a

  • mean NT- proBNP of 4,735 pg/ml compared to 1,230 pg/ml in patients without anemia (p=0.0001).

There was a markedly

  • significant difference in patients who had a hgb > 12 (median 295 pg/ml) when compared to
  • both patients with an hgb of 10.0 to 11.9 (median 2,102 pg/ml; p = 0.0001) and
  • those with a hgb < 10 (median 2,131 pg/ml; p = 0.001).

Linear regression analysis comparing hgb with log NT-proBNP was statistically significant (r = 0.395; p = 0.0001). MANOVA demonstrated that

  • elevated NT- proBNP levels in patients with anemia was independent of age.

Conclusion

This study shows that NT-proBNP is associated with anemia independent of CHF, renal insufficiency, sepsis or age.

INTRODUCTION

B-type natriuretic peptide (BNP) is secreted from the myocardium in response to myocyte stretch. 1-2 BNP is released from the myocytes as a 76 aminoacid N-terminal fragment (NT-proBNP) and a 32-amino acid active hormone (BNP). 3 These peptides have emerged as a primary non-invasive modality for the diagnosis of congestive heart failure (CHF). 4- 7 In addition, these peptides have demonstrated prognostic significance in patients with invasive modality for the diagnosis of

  • congestive heart failure (CHF). 4- 7
  • heart failure 8-9,
  • stable coronary artery disease 10, and
  • in patients with acute coronary syndromes. 11-14

Studies have shown that the level of NT- proBNP is affected by

  • age and renal insufficiency (RI) independent of the diagnosis of CHF. 15,16

There is some suggestion from the literature that

  • anemia may also independently affect NT-proBNP levels. 17-20

Willis et al. demonstrated in a cohort of 209 patients without heart failure that anemia was associated with an elevated NT- proBNP. 17 Similarly, in 217 patients undergoing cardiac catheterization, blood samples were drawn from the descending aorta prior to contrast ventriculography for BNP measurements and

  • anemia was found to be an independent predictor of plasma BNP levels. 18

The objective of this study is to assess the effect of anemia on NT-proBNP independent of CHF, sepsis, age or renal insufficiency.

METHODS

Patient population

The study population consisted of 746 consecutive patients presenting to the emergency room who underwent NT-proBNP evaluation for the evaluation of dyspnea. Transthoracic echocardiogram (TTE) was available on 595 patients. Patients were included in this study if they had a normal TTE, which was defined as normal systolic function (left ventricular ejection fraction [LVEF] > 45%), normal mitral inflow pattern and normal LV wall thickness. CHF was excluded based on thorough clinical evaluation by the emergency department attending and the attending medical physician. Patients with disease states that may affect the NT- proBNP levels were also excluded:

  1. left ventricular systolic dysfunction (LVEF < 45%),
  2. renal insufficiency defined as a creatinine > 2 mg/dl and
  3. sepsis (defined as positive blood cultures with two or more of the following systemic inflammatory response syndrome (SIRS) criteria: heart rate > 90 beats per minute;
  4. body temperature < 36 (96.8 °F) or > 38 °C (100.4 °F);
  5. hyperventilation (high respiratory rate) > 20 breaths per minute or, on blood gas, a PaCO2 less than 32 mm Hg;
  6. white blood cell count < 4000 cells/mm3 or > 12000 cells/mm³ (< 4 x 109 or > 12 x 109 cells/L), or greater than 10% band forms (immature white blood cells). 21

The study population was then divided into two groups, anemic and non- anemic. Anemia was defined using the world health organization (W.H.O.) definition of hemoglobin (hgb) < 13 g/dl for males and < 12 g/dl for females.The data was also analyzed by dividing the patients into three groups based on hgb levels i.e. hgb > 12, hgb 10 to 11.9 and hgb < 10.

Baseline patient data

Patient’s baseline data including age, gender, ethnicity, hemoglobin (hgb), hematocrit (hct), creatinine, NT- proBNP were recorded from the electronic medical record system in our institution. Chemistry results were performed on the Roche Modular System (Indianapolis, IN), with the NT- proBNP done by chemiluminescence assay. The hemogram was performed on the Beckman Coulter GenS. All TTE’s were performed on Sonos 5500 machine. TTE data collected included LVEF, mitral inflow pattern and LV wall thickness assessment.

Statistical analysis

The results are reported in the means with p < 0.05 as the measure of significance for difference between means. Independent Student’s t-tests were done comparing NT proBNP and anemia. Univariate ANOVAs and multivariate ANOVA (MANOVA) with post hoc tests using the Bonferroni method were used to compare NT- proBNP levels with varying ranges of hgb and age using SPSS 13.0 (SPSS, Chicago, IL). A linear regression analysis was performed using SYSTAT. Calculations included Wilks’Lamda, Pillai trace and Hotelling-Lawley trace. A GOLDMineR® plot was constructed to estimate the effects of age and anemia on NT- proBNP levels. The GOLDMineR® effects plot displays the odds-ratios for predicted NT-proBNP elevation versus the predictor values. Unlike the logistic regression, the ordinal regression, which the plot is derived from, can have polychotomous as well as dichotomous values, as is the case for NT-proBNP.

RESULTS

Of the 746 consecutive patients, 218 patients met the inclusion criteria (fig 1). Baseline characteristics of patients are listed in table 1. The median age for anemic patients was 76 years and 63 years for patients without anemia. One third of patients in both groups were men. The mean hemoglobin for

  • anemic patients was 10.2 g/dl as compared to 13.7 g/dl for non-anemic patients.
  • The mean LVEF of patients with anemia was 64% as compared to 67% for non-anemic patients.

Based on the WHO definition of anemia, 138 patients were determined to be anemic while 80 patients were diagnosed as non-anemic. There was a markedly  significant difference between NT-proBNP levels based on the WHO diagnosis of anemia.

Patients with anemia had a

  • mean NT-proBNP of 4,735 pg/ml compared to 1,230 pg/ml in patients without anemia (p = 0.0001).

Of the 218 patients in the study, 55 patients had a hgb of < 10 g/dl. Analysis using

  • hgb < 10 g/dl for anemia demonstrated a statistically significant difference in the NT-proBNP values.

Patients with a hgb < 10 g/dl had a mean NT- proBNP of 5,130 pg/ml

  • compared to 2,882 pg/ml in patients with a hgb of > 10 g/dl (p = 0.01)

The groups were also divided into three separate categories of hgb for subset analysis:

  • hgb > 12 g/dl,
  • hgb 10 to 11.9 g/dl and
  • hgb < 10 g/dl.

There was a markedly significant difference in

  •  the NT- ProBNP levels of patients who had a hgb > 12 g/dl (median 295 pg/ml) when
  • compared to those with a hgb range of 10.0 g/dl to 11.9 g/dl (median 2,102 pg/ml) (p = 0.0001),

and also a significant difference in

  • NT- proBNP levels of patients with a hgb > 12 g/dl (median 295 pg/ml) when
  • compared to a hgb of < 10 g/dl (median 2,131 pg/ml) (p = 0.001).

However, there was no statistically significant difference in NT-proBNP levels of patients with hgb 10 g/dl to 11.9 g/dl

  • when compared to those with a hgb of < 10 g/dl (p = 1.0).

A scatter plot comparing hgb with log NT-proBNP and fitting of a line to the data by ordinary least squares regression was significant (p = 0.0001) and demonstrated

  • a correlation between anemia and NT-proBNP levels (r = 0.395) (fig. 2).

MANOVA demonstrated that elevated NT- proBNP levels in patients with anemia was independent of age (Wilks’ Lambda [p = 0.0001]). In addition, using GOLDMineR® plots (figure 3a and 3b) with a combination of age and hb scaled as predictors of elevated NT-proBNP,

  • both age and hgb were required as independent predictors.

What about the effect of anemia? The GOLDminer analysis of ordinal regression was carried out in a database from which renal insufficiency and CHF were removed. The anemia would appear to have an independent effect on renal insufficiency. Figure 4 is a boxplot comparison of NT – proBNP, the age normalized function NKLog (NT- proBNP)/eGFR formed from taking 1000*Log(NT- proBNP) divided by the MDRD at eGFR exceeding 60 ml/min/m2 and exceeding 30 ml/min/m2. The transformed variable substantially makes the test independent of age and renal function. The boxplot shows the medians, 97.5, 75, 25 and 2.5 percentiles. There appears to be no significance in the NKLog(NT pro-BNP)/MDRD plot. Table II compares the NT-proBNP by WHO criteria at eGFR 45, 60 and 75 ml/mln/m2 using the t-test with unequal variance assumed, and the Kolmogorov-Smirnov test for nonparametric measures of significance. The significance at 60 ml/min/m2 is marginal and nonexistent at 75 ml/min/m2. This suggests that the contribution from renal function at above 60 ml/min2 can be ignored. This is consistent with the findings using the smaller, trimmed database, but there is an interaction between

  •  anemia, and
  •  eGFR at levels below 60 ml/min/m2

DISCUSSION

The findings in this study indicate that

  • anemia was associated with elevated NT-proBNP levels independent of CHF, renal insufficiency, sepsis or age.

These findings have been demonstrated with NT-proBNP in only one previous study. Wallis et al. demonstrated that after adjusting for age, sex, BMI, GFR, LVH and valvular disease;

  1. only age,
  2. valvular disease and
  3. low hemoglobin

were significantly associated with increased NT-proBNP. 18.

In our study, CHF was excluded based on both a normal TTE and a thorough clinical evaluation. In the only other study directly looking at NT- proBNP levels in anemic patients without heart failure

  • only 25% of patients had TTEs, with one patient having an LVEF of 40%. 17

BNP, the active molecule released after cleavage along with NT- proBNP, has also been studied in relation to blood hemoglobin levels. 18 In 263 patients undergoing cardiac catheterization  blood samples were drawn from the descending aorta prior to contrast ventriculography to determine the value of BNP. Anemia was present in 217 patients. Multivariate linear regression model adjusting for

  1.  age,
  2.  gender,
  3.  body mass index,
  4.  history of myocardial infarction,
  5.  estimated creatinine clearance, and
  6.  LVEF
  • found hgb to be an independent predictor of BNP levels.

In our study, patients with anemia were slightly older than those without anemia. However, both MANOVA and GOLDMineR® plot demonstrated that

  • elevated NT-proBNP levels in patients with anemia was independent of age.

Other studies have found that BNP is dependent on renal insufficiency and age. Raymond et al. randomly selected patients to complete questionnaires regarding CHF and

  1. then underwent pulse and blood pressure measurements,
  2.  electrocardiogram (ECG),
  3.  echocardiography and
  4.  blood sampling. 15

A total of 672 subjects were screened and 130 were determined to be normal, defined as

  • no CHF or ischemic heart disease,
  • normal LVEF,
  • no hypertension,
  • diabetes mellitus,
  • lung disease, and
  • not on any cardiovascular drugs.

They found

  1. older age,
  2. increasing dyspnea,
  3. high plasma creatinine and a
  4. LVEF < 45%

to be independently associated with an elevated NT-proBNP plasma level by multiple linear regression analysis. In another study, McCullough et al. evaluated the patients from the Breathing Not Properly Multinational Study

  • looking at the relationship between BNP and renal function in CHF. 16

Patients were excluded if they were on hemodialysis or had a estimated glomerular filteration rate (eGFR) of < 15 ml/min. They found that the BNP levels correlated significantly with the eGFR, especially in patients without CHF, suggesting

  1. chronic increased blood volume and
  2. increased left ventricular wall tension as a possible cause. 16

Our study was designed to exclude patients with known diseases such as CHF and renal insufficiency in order to demonstrate

  • the independent effect of anemia on elevated NT-proBNP levels.

The mechanism for elevated NT-proBNP levels in patients with anemia is unknown. Some possible mechanisms that have been reported in the literature include

  • hemodilution secondary to fluid retention in patients with CHF 18,
  • decreased oxygen carrying capacity with accompanying tissue hypoxia which
  • stimulates the cardio-renal compensatory mechanism leading to increased release of NT-proBNP. 17

The findings from our study suggest that

  •  NT-proBNP values should not be interpreted in isolation of hemoglobin levels and
  • should be integrated with other important clinical findings for the diagnosis of CHF.

Further studies are warranted

  1.  to assess the relationship between anemia and plasma natriuretic peptides, and
  2. possibly modify the NT-proBNP cutoff points for diagnosing acutely decompensated CHF in patients with anemia.

CONCLUSION

This study shows that elevated NT-proBNP levels are associated with anemia independent of

  •   CHF,
  •  renal insufficiency,
  •  sepsis and
  •  age.

NT-proBNP levels should be interpreted with caution in patients who have anemia.

 REFERENCES

1. Brunea BG, Piazza LA, de Bold AJ. BNP gene expression is specifically modulated by stretch and ET-1 in a new model of isolated rat atria.Am J Physiol  1997; 273:H2678-86.

2. Wiese S, Breyer T, Dragu A, et al. Gene expression of brain natriuretic peptide  in isolated atrial and ventricular human myocardium: influence of angiotensin II and diastolic fiber length. Circ 2000; 102:3074-79.

3. de Lemos JA, McGuire DK, Drazner MH. B-type natriuretic peptide in cardiovascular disease. Lancet 2003; 362:316-22.

4.   Dao Q, Krishnaswamy P, Kazanegra R, et al. Utility of B-type natriuretic  peptide in the diagnosis of congestive heart failure in an urgent care setting. J Am  Coll Cardiol 2001; 37:379-85.

5. Morrison LK, Harrison A, Krishnaswamy P, Kazanegra R, Clopton P, Maisel A. Utility of rapid natriuretic peptide assay in differentiating congestive heart failure from lung  disease in patients presenting with dyspnea.
J Am Coll Cardiol  2003; 39:202-09.

6.  Maisel AS, Krishnaswamy P, Nowak RM, et al.  Rapid measurement of B-type natriuretic peptide in the emergency diagnosis of heart failure. N Engl J Med 2002; 347:161-67.

7. Januzzi JL, Camargo CA, Anwaruddin S, et al. The N-terminal Pro-BNP investigation of dyspnea in the emergency department (PRIDE) study. Am J  Cardiol 2005; 95:948-954.

8.  Tsutamoto T, Wada A, Meada K, et al.   Attenuation of compensation of  endogenous cardiac natriuretic peptide system  in chronic heart failure: prognostic role  of plasma  brain natriuretic peptide concentration in patients with chronic  symptomatic  left ventricular dysfunction.
Circulation 1997; 96(2): 509-16.

9.  Anand IS, Fisher LD, Chiang YT, et al. Changes in brain natriuretic peptide and norepinephrine over time and mortality and morbidity in the Valsartan Heart Failure Trial (Val-HEFT). Circulation 2003; 107:1278-1283.

10. Omland T, Richards AM, Wergeland R and Vik-Mo H. B-type natriuretic peptide and long term survival in patients with stable coronary artery disease.
Am J Cardiol 2005; 95:24-28.

11. Omland T, Aakvaag A, Bonarjee VV. et al. Plasma brain natriuretic peptide as an indicator of left ventricular systolic dysfunction and long term prognosis after acute myocardial infarction. Comparison with plasma atrial natriuretic peptide and N-terminal proatrial natriuretic peptide.
Circulation 1996; 93:1963-1969.

12. de Lemos JA, Morrow DA, Bently JH, et al. The prognostic value of B-type natriuretic peptide in patients with acute coronary syndromes. N Engl J Med 2001; 345:1014-1021.

13. Richards AM, Nicholls MG, Espiner EA, et al. B-type natriuretic peptides and  ejection fraction for prognosis after myocardial infarction. Circulation 2003; 107:2786-2792.

14. Sabatine MS, Morrow DA, de Lemos JA, et al.  Multimarker approach to risk  stratification in non-ST elevation acute coronary syndromes: simultaneous  assessment of troponin I, C-reactive protein and B-type natriuretic peptide.
Circulation 2002; 105:1760-1763.

15. Raymond I, Groenning BA, Hildebrandt PR, Nilsson JC, Baumann M, Trawinski   J, Pedersen F.  The influence of age, sex andother variables on the plasma level of N-terminal pro brain natriureticpeptide in a large sample of the general  population. Heart 2003; 89:745-751.

16. McCollough PA, Duc P, Omland T, McCord J, Nowak RM, Hollander JE, et al. B-type natriuretic peptide and renal function in the diagnosis of heartfailure:  an analysis from the  Breathing Not Properly Multinational Study.
Am J Kidney Dis 2003; 41:571-579.

17. Willis MS, Lee ES, Grenache DG. Effect of anemia on plasma concentrations of  NT-proBNP.
Clinica Chim Acta 2005; 358:175-181.

18. Wold Knudsen C, Vik-Mo H, Omland T. Blood hemoglobin is an independent  predictor of B-type natriuretic peptide.
Clin Sci 2005; 109:69-74.

19. Tsuji H, Nishino N, Kimura Y, Yamada K, Nukui M, et al. Haemoglobin level influences plasma brain natriuretic peptide concentration. Acta Cardiol 2004;59:527-31.

20. Wu AH, Omland T, Wold KC, McCord J, Nowak RM, et al. Relationship  of B-type natriuretic peptide and anemia  in patients withand without heart failure:  A substudy from the Breathing Not Properly(BNP) Multinational Study.
Am J  Hematol 2005; 80:174-80.

22. Bone RC, Balk RA, Cerra FB, Dellinger RP, Fein AM, et al.  Definitions for sepsis and organ failure and guidelines for theuse of innovative therapies in sepsis.  The ACCP/SCCM Consensus Conference Committee. Chest. 1992;101(6):1644-55.

Table Legends

Table I. Clinical characteristics of the study population

Table II. Comparison of NT- proBNP means under WHO criteria at different GFR

Table I
Variable No Anemia(n=80) Anemia(n=138)
Median age (years) 63 76
Gender
    Men (%) 27 (34) 47 (34)
    Women (%) 53 (66) 91 (66)
Weight (kg) 82.9 80.1
Chest Pain 21 (26) 3 (2)
Hemoglobin (g/dl) 13.7 10.2
Hematocrit (%) 40.5 30.5
Mean Corpuscular Volume 97 87
Creatinine (mg/dl) 0.99 1.07
Median NT-proBNP (pg/ml) 321 1896
Medical History
    HTN (%) 12 (15) 51 (37)
    Prior MI (%) 11 (14) 5 (4)
    ACS (%) 16 (20) 3 (2)
    CAD (%) 2 (1) 3 (2)
     DM (%) 18 (22) 11 (8)
Medication
   Clopidogrel 58 (72) 15 (11)
   Beta Blockers 68 (85) 27 (20)
   Ace Inhibitors 45 (56) 18 (13)
   Statins 57 (71) 17 (12)
   Calcium Channel Blocker 17 (21) 8 (6)
LVEF (%) 67 64

HTN: Hypertension CAD: Coronary Artery Disease
MI: Myocardial Infarction DM: Diabetes Mellitus
ACS: Acute Coronary Syndrome LVEF: Left Ventricular Ejection Fraction

Table II
GFR WHO Mean P (F) N NPar
> 45 0 3267 0.022 (4.33) 661
1 4681
> 60* 0 2593 0.031 (5.11) 456 0.018
1 4145
> 60r 0 786 0.203 (3.63) 303 0.08
1 3880
> 75 0 2773 > 0.80 320 0.043
1 3048

*AF, valve disease and elevated troponin T included
r AF, valve disease and elevated troponin T removed

FIGURE LEGENDS

FIGURE 1. Study population flow chart. (see poster)
FIGURE 2. Relationship between proBNP and hemoglobin. (see above)
FIGURE 3. NT-proBNP levels in relation to anemia (see above)

Supplementary Material

Table based on LatentGOLD Statistical Innovations, Inc., Belmont, MA., 2000: Jeroen Vermunt & Jay Magidson)

4-Cluster Model

Number of cases                                   408
Number of parameters (Npar)             24

Chi-squared Statistics
Degrees of freedom (df)                          71                     p-value
L-squared (L²)                                    80.2033                    0.21
X-squared                                            80.8313                     0.20
Cressie-Read                                        76.6761                     0.30
BIC (based on L²)                          -346.5966
AIC3 (based on L²)                        -132.7967
CAIC (based on L²)                       -417.5966

Model for Clusters
 Intercept                Cluster1      Cluster2     Cluster3     Cluster4     Wald     p-value
————–           0.1544           0.1434        0.0115        -0.3093     1.1981     0.75
Cluster Size           0.2870          0.2838       0.2487          0.1805
(across)

LogNTpr
< 1.5                       0.0843           0.2457       0.0006          0.0084
1.6-2.5                   0.6179            0.6458       0.0709          0.2809
2.5-3.5                  0.2848           0.1067         0.5319          0.5883
> 3.5                      0.0130           0.0018         0.3966         0.1224
MDRD
> 90                     0.1341             0.7919         0.0063         0.6106
61-90                  0.6019            0.2040          0.1633         0.3713
41-60                  0.2099            0.0041          0.3317         0.0175
< 41                     0.0542            0.0001         0.4987        0.0006
age
under 51           0.0668           0.5646          0.0568        0.0954
51-70                 0.3462            0.3602          0.3271         0.3880
over 70             0.5870            0.0752          0.6161         0.5166
WHO
No anemia      0.7518             0.6556          0.2041         0.0998
Anemia            0.2482             0.3444          0.7959         0.9002

———          Cluster1          Cluster2      Cluster3      Cluster4
Overall           0.2870            0.2838         0.2487        0.1805
(down)

LogNTpro
< 1.5                0.2492              0.7379           0.0013         0.0116
1.6-2.5            0.4163               0.4243           0.0427        0.1167
2.6-3.5           0.2296               0.0887          0.3723        0.3095
> 3.5              0.0328                0.0023          0.7982        0.1666
MDRD
> 90              0.1001                0.5998           0.0043        0.2958
61-90           0.5198                 0.1716           0.1136         0.1950
41-60           0.3860                 0.0055          0.5847         0.0238
< 41             0.1205                  0.0002          0.8785         0.0008
 age
< 51            0.0720                 0.7458           0.0910          0.0912
51-70         0.3036                 0.3084           0.2013          0.1867
over 70     0.3773                  0.0409          0.3633           0.2186
 WHO
No anemia 0.4589              0.3957           0.1076           0.0378
Anemia     0.1342                 0.1844            0.3742           0.3073

Hemoglobin on NT proBNP 3

SECOND ARTICLE

The effect of correction of mild anemia in severe, resistant congestive heart failure using subcutaneous erythropoietin and intravenous iron: a randomized controlled study

Donald S Silverberg, MDa; Dov Wexler, MDa; David Sheps, MDa; Miriam Blum, MDa; Gad Keren, MDa; Ron Baruch, MDa; Doron Schwartz, MDa; Tatyana Yachnin, MDa; Shoshana Steinbruch, RNa; Itzhak Shapira, MDa; Shlomo Laniado, MDa; Adrian Iaina, MDa

J Am Coll Cardiol. 2001;37(7):1775-1780. doi:10.1016/S0735-1097(01)01248-7

http://content.onlinejacc.org/article.aspx?articleid=1127229

OBJECTIVES

This is a randomized controlled study of anemic patients with severe congestive heart failure (CHF) to assess the effect of correction of the anemia on cardiac and renal function and hospitalization.

BACKGROUND

Although mild anemia occurs frequently in patients with CHF, there is very little information about the effect of correcting it with erythropoietin (EPO) and intravenous iron.

METHODS

Thirty-two patients with moderate to severe CHF (New York Heart Association [NYHA] class III to IV)
who had a left ventricular ejection fraction (LVEF) of 40% despite maximally tolerated doses of CHF medications and
  • whose hemoglobin (Hb) levels were persistently between 10.0 and 11.5 g% were randomized into two groups.
Group A (16 patients) received subcutaneous EPO and IV iron to increase the level of Hb to at least 12.5 g%. In Group B (16 patients) the anemia was not treated. The doses of all the CHF medications were maintained at the maximally tolerated levels except for oral and intravenous (IV) furosemide, whose doses were increased or decreased according to the clinical need.

RESULTS

Over a mean of 8.2 +/- 2.6 months,
  • four patients in Group B and none in Group A died of CHF-related illnesses.
  • The mean NYHA class improved by 42.1% in A and worsened by 11.4% in B.
  • The LVEF increased by 5.5% in A and decreased by 5.4% in B.
  • The serum creatinine did not change in A and increased by 28.6% in B.
  • The need for oral and IV furosemide decreased by 51.3% and 91.3% respectively in A and increased by 28.5% and 28.0% respectively in B.
  • The number of days spent in hospital compared with the same period of time before entering the study decreased by 79.0% in A and increased by 57.6% in B.

CONCLUSIONS

When anemia in CHF is treated with EPO and IV iron, a marked improvement in cardiac and patient function is seen,
  • associated with less hospitalization and renal impairment and less need for diuretics. (J Am Coll Cardiol 2001;37:1775– 80)

Anemia of any cause is known to be capable of causing congestive heart failure (CHF) (1). In patients hospitalized with CHF the 

  • mean hemoglobin (Hb) is about 12 g% (2,3),

which is considered the lower limit of normal in adults (4). Thus, anemia appears to be

common in CHF. Recently, in 142 patients in our special CHF outpatient clinic, we found that

  • as the CHF worsened, the mean Hb concentration decreased, from 13.7 g% in mild CHF (New York Heart Association [NYHA] class I) to 10.9 g% in severe CHF (NYHA 4), and
  • the prevalence of a Hb 12 g% increased from 9.1% in patients with NYHA 1 to 79.1% in those with NYHA 4 (5).
The Framingham Study has shown that anemia is an
  • independent risk factor for the production of CHF (6).
Despite this association of CHF with anemia,
  • its role is not mentioned in the 1999 U.S. guidelines for the diagnosis and treatment of CHF (7), and
  • many studies consider anemia to be only a rare contributing cause of hospitalization for CHF (8,9).
Recently, we performed a study in which the anemia of severe CHF that was resistant to maximally tolerated doses of standard medications
  • was corrected with a combination of subcutaneous (sc) erythropoietin (EPO) and intravenous iron (IV Fe) (5).
We have found this combination to be safe, effective and additive
  • in the correction of the anemia of chronic renal failure (CRF) in both
  • the predialysis period (10) and the dialysis period (11).
The IV Fe appears to be more effective than oral iron (12,13). In our previous study of CHF patients (5), the treatment resulted in
  • improved cardiac function,
  • improved NYHA functional class,
  • increased glomerular filtration rate,
  • a marked reduction in the need for diuretics and
  • a 92% reduction in the hospitalization rate
compared with a similar time period before the intervention. In the light of these positive results, a prospective randomized study was undertaken
  • to determine the effects of the correction of anemia in severe symptomatic CHF resistant to maximally tolerated CHF medication.

Abbreviations and Acronyms

CABG coronary artery bypass graft
CHF congestive heart failure
CRF chronic renal failure
EPO erythropoietin
%Fe Sat percent iron saturation
GFR glomerular filtration rate
Hb hemoglobin
Hct hematocrit
IU international units
IV intravenous
LVEF left ventricular ejection fraction
NYHA New York Heart Association
PA pulmonary artery
sc subcutaneous
SOLVD Studies Of Left Ventricular Dysfunction

MATERIALS AND METHODS

Patients.Thirty-two patients with CHF were studied. Before the study, the patients were treated for least six months in the CHF clinic with

  • maximally tolerated doses of angiotensin-converting enzyme inhibitors, the beta-blockers bisoprolol or carvedilol, aldospirone, long-acting nitrates, digoxin and oral and intravenous (IV) furosemide.

In some patients these agents could not be given because of contraindications and in others they had to be stopped because of side effects. Despite this maximal treatment

  • the patients still had severe CHF  (NYHA classIII), with  fatigue and/or shortness of breath  on even mild exertion or at rest.  All had levels of
  • Hb in the range of 10 to 11.5 g%  on at least three consecutive visits over a three-week period.
  • All had a LVEF of 40%.

Secondary causes of anemia including hypothyroidism, and folic acid and vitamin B12 deficiency were ruled out and

  • there was no clinical evidence of gastrointestinal bleeding.

The patients were randomized consecutively into two groups:

  • Group A, 16 patients, was treated with sc EPO and IV Fe to achieve a target Hb of at least 12.5 g%.
  • Group B, 16 patients, did not receive the EPO and IV Fe.

Treatment protocol for correction of anemia.

All patients in Group A received the combination of sc EPO and IV Fe. The EPO was given once a week at a starting dose of 4,000 international units (IU) per week  and
the dose was increased  to two  or  three  times a week or decreased to once every few weeks as  necessary

  • to achieve and maintain a target Hb of 12.5 g%.

The IV Fe (Venofer-Vifor International, Switzerland), a ferric sucrose product, was given in a dose of 200 mg IV in 150 ml saline over 60 min every two weeks

  • until the serum ferritin reached 400 g/l or
  • the %Fe saturation (%Fe Sat is serum iron/total iron binding capacity 100) reached 40% or
  • the Hb reached 12.5g%. 

The IV Fe was then given at longer intervals as needed to maintain these levels.

Investigations. 

Visits to the clinic were at two- to three week intervals depending on the patient’s status. This was the same frequency of visits to the CHF clinic as before then,

  • potassium and ferritin and %Fe Sat were performed on every visit.
  • blood pressure was measured by an electronic device on every visit.
  • LVEF was measured initially and at four- to six-month intervals by MUGA radioisotope ventriculography.

This technique measures

  • the amount of blood in the ventricle at the end of systole and at the end of diastole, thus giving
  • a very accurate assessment of the ejection fraction.

It has been shown to be an accurate and reproducible method of measuring the ejection fraction (14).  Hospital records were reviewed at the end of the intervention period to compare

  • the number of days hospitalized during the study with 
  • the number of days hospitalized during a similar period 
    • when the patients were treated in the CHF clinic before the initial randomization and entry into the study.

Clinic records were reviewed to evaluate the types and doses of CHF medications used before and during the study. The mean follow-up for patients was 8.2 +/-  2.7 months (range 5 to 12 months).  The study was done with the approval of the local ethics committee.Statistical analysis.

An analysis of variance with repeated measures (over time) was performed to compare the two study groups (control vs. treatment) and

  • to assess time trend and the interactions between the two factors.
  • A separate analysis was carried out for each of the outcome parameters.
  • The Mann-Whitney test was used to compare the change in NYHA class between two groups.

All the statistical analysis was performed by SPSS (version 10).

RESULTS

The mean age in Group A (EPO and Fe) was 75.3 +/-  14.6 years and in group B was 72.2 +/-  9.9 years. There were 11 and 12 men in Groups A and B, respectively.
Before the study the two groups were similar in
  1. cardiac function,
  2. comorbidities,
  3. laboratory investigations and
  4. medications
  • (Tables 1, 2 and 3), except for IV furosemide (Table 3),
which was higher in the treatment group. The mean NYHA class of Group A before the study was 3.8  0.4 and was 3.5  0.5 in Group B. The contributing factors to CHF in Groups A and B, respectively, are seen in Table 1 and were similar.
Table 1. Medical Conditions and Contributing Factors to Congestive Heart Failure in the 16 Patients Treated for the Anemia and in the 16 Controls

Table 1 medical conditions heart failure anemia

Table 2. The Effect of Correction of Anemia by Intravenous Iron and Erythropoietin Therapy on Various Parameters in 16 Patients in the Treatment (A) and 16 in the Control (B) Group

Table 2 medications to treat heart failure anemia

p values are given for analysis of variance with repeated measures and for independent t tests for comparison of baseline levels between the two groups.
BP  blood pressure; Fe Sat  iron saturation; Hb  hemoglobin; IV  intravenous; NS  not stated; Std Dev.  standard deviation.

The main contributing factors to CHF were considered to be

  • ischemic heart disease (IHD) in 11 and 10 patients respectively,
  • hypertension in two and two patients,
  • valvular heart disease in twoand two patients, and
  • idiopathic cardiomyopathy in one and two patients, respectively.

A significant change after treatment was observed in the two groups in the following parameters:

  • IV furosemide,
  • days in hospital,
  • Hb,
  • ejection fraction,
  • serum creatinine and
  • serum ferritin.
In addition, the interaction between the study group and time trend was significant in all measurements except for blood pressure and %Fe Sat. This interaction indicates that
  • the change over time was significantly different in the two groups.
Table 3. The Effect of Correction of Anemia by Intravenous Iron and Erythropoietin Therapy on Various Parameters in 16 Patients in the Treatment (A) and 16 in the Control (B) Group

Table 3  CHF aneia EPO

p values are given for analysis of variance with repeated measures and for independent t tests for comparison of baseline levels between the two groups.
BP  blood pressure; Fe Sat  iron saturation; Hb  hemoglobin; IV  intravenous; NS  not stated; Std Dev.  standard deviation.

We find in the comparisons of Tables 2 and 3:

  1. before treatment the level of oral furosemide was higher in the control group (136.2 mg/day) compared with the treatment group (132.2 mg/day).
  2. after treatment, while the dose of oral furosemide of the treated patients was reduced  to 64.4 mg/day
  • the dose of the nontreated patients was increased to 175 mg/day.

The same results of improvement in the treated group and deterioration in the control group are expressed in the following parameters:

  1. IV furosemide, days in hospital,
  2. Hb,
  3. ejection fraction and
  4. serum creatinine.

The NYHA class was

  • 3.8 +/- 0.4 before treatment and 2.2 +/- 0.7 after treatment in Group A  (delta mean = – 1.6) and
  • 3.5 +/-  0.7 before treatment and 3.9 +/- 0.3 after treatment in Group B. (delta mean = 0.4)

The improvement in NYHA class was significantly higher (p < 0.0001) in the treatment group compared with the control group (Table 4).

Table 4. Changes from Baseline to Final New York Heart Association (NYHA) Class
Initial minus final

Table 4  changes from NYHA baseline  CHF anemia

The improvement in NYHA class was statistically higher (p <  0.0001) in the treatment group compared with control.

There were no deaths in Group A and four deaths in Group B.

Case 1: A 71-year-old woman with severe mitral insufficiency and severe pulmonary hypertension  (a pulmonary artery [PA] pressure of 75 mm Hg) had persistent NYHA 4 CHF  and died during mitral valve surgery  seven months after onset of the study. She was hospitalized for 21 days  in the seven months before randomization and for 28 days  during the seven months after randomization.

Case 2:

A 62-year-old man with a longstanding history of hypertension complicated by IHD, coronary artery bypass graft (CABG) and atrial fibrillation had persistent NYHA 4 CHF  and a PA pressure of 35 mm Hg,  and died from pneumonia and septic shock eight months after onset of the study. He was hospitalized for seven days in the eight months before randomization and for 21 days during the eight months  after
randomization.

Case 3:
A 74-year old man with IHD, CABG, chronic obstructive pulmonary disease, a history of heavy smoking and diabetes had persistent NYHA 4 CHF and a PA pressure of  28 mm Hg, and died of pulmonary  edema and cardiogenic shock nine months after onset of the study. He was hospitalized for 14 days in the nine months before  randomization and for 41 days during the nine months after randomization.

Case 4:
A 74-year-old man with a history of IHD, CABG, diabetes, dyslipidemia, hypertension and atrial fibrillation, had persistent NYHA 4 CHF and a PA pressure of 30 mm Hg,  and died of pneumonia and septic shock   six months after onset of the study. He was hospitalized for five days in the six months before randomization and for 16 days during the nine months after randomization.

DISCUSSION

 Main findings.

The main finding of the present study is that the correction of

  • even mild anemia in patients with symptoms of very severe CHF despite being on maximally tolerated drug therapy
  • resulted in a significant improvement in their cardiac function and NYHA functional class.

There  was also a large

  • reduction in the number of days of  hospitalization compared with a similar period before the  intervention.
  • all this was achieved despite a marked reduction in the dose of oral and IV furosemide.

In the group in whom the anemia was not treated, four  patients died during the study. In all four cases

  • the CHF was unremitting and contributed to the deaths. 

In addition,  for the group as a whole, 

  • the LVEF, the NYHA class and  the renal function worsened.

There was also need for

  • increased oral and IV furosemide as well as increased  hospitalization.

Study limitations.

The major limitations of this study are

  1. the smallness of the sample size and
  2. the fact that randomization and treatment were not done in a blinded fashion.

Nevertheless, the two groups were almost identical in

  1. cardiac, renal and anemia status;
  2. in the types and doses of medication they were taking before and during the intervention and
  3. in the number of hospitalization days before the intervention.

Although the results of this study, like those of  our previous uncontrolled study (5), suggest that

  • anemia may play an important role in the mortality and morbidity of  CHF,
  • a far larger double-blinded controlled study should be carried out to verify our findings.

Anemia as a risk factor for hospitalization and death in CHF.

Our results are consistent with a recent analysis of 91,316 patients hospitalized with CHF (15). Anemia was found to be a stronger predictor of

  • the need for early rehospitalization than  was hypertension,  IHD or the presence of a previous CABG.  

A recent analysis of the Studies Of Left Ventricular Dysfunction (SOLVD) (16) showed that

  • the level of hematocrit (Hct) was an independent risk factor for mortality.

During a mean follow-up of 33 months the mortality was

  • 22%, 27% and 34% for those with a Hct of 40, 35 to 40 and 35 respectively.

The striking response of our patients to

  • correction of mild anemia suggests that the failing heart may be very susceptible to anemia.

It has, in fact, been found in both animal (17) and human studies (17–19) that

  • the damaged heart is more vulnerable to anemia and/or ischemia than is the normal heart.

These stimuli may result in a more marked reduction in cardiac function than occurs in the normal heart and may explain why,  in our study,

  • the patients were so resistant to high doses of CHF medications and
  • responded so well when the anemia was treated.

Our findings about the importance of anemia in CHF are not surprising when one considers that, in dialysis patients,

  • anemia has been shown to be associated with an increased prevalence and incidence of CHF (20) and that
  • correction of anemia in these patients is associated with improved
    • cardiac function (21,22),
    • less mortality (23,24) and
    • fewer hospitalizations (23,25).

Effect of improvement of CHF on CRF.

Congestive heart failure can cause progressive renal failure (26,27). Renal ischemia is found very early on

  • in patients with cardiac dysfunction (28,29), and
  • chronic ischemia may cause progression of renal failure (30). Indeed, the development of
  • CHF in patients with essential hypertension has been found to be one of the most powerful predictors of
  • the eventual development of end-stage renal disease (31).

Patients who develop CHF after a myocardial infarction experience a

  • fall in the glomerular filtration rate (GFR) of about 1 ml/min/month if the CHF is not treated (32).

In another recent analysis of the SOLVD study, treating the CHF with

  • both angiotensin-converting enzyme inhibitors and beta-blockers resulted in better preservation of the renal function than did
  • angiotensin-converting enzyme inhibitors alone (26),
suggesting that the more aggressive the treatment of the CHF, the better the renal function is preserved. In the present study, as in our previous one (5), we found that the deterioration of GFR was prevented with
  • successful treatment of the CHF, including correction of the anemia, whereas
  • the renal function worsened when the CHF remained severe

All these findings suggest that early detection and treatment of CHF and systolic and/or diastolic dysfunction from whatever cause could prevent

  • the deterioration not only of the cardiac function
  • but of the renal function as well.

This finding has very broad implications in the prevention of CRFbecause most patients with advanced CRF have

  • either clinical evidence of CHF or at least some degree of systolic dysfunction (33).

Systolic and/or diastolic dysfunction can occur early on in many  conditions, such as

  • essential hypertension (34),
  • renal disease of any cause (35,36) or
  • IHD, especially after a myocardial infarction (37).

The early detection and adequate treatment of this cardiac dysfunction, including correction of the anemia, could prevent this cardiorenal insufficiency. To detect cardiac dysfunction early on, one would need  at least an echocardiogram and MUGA radio-nucleotide ventriculography. These tests should probably be done not only in patients with signs and symptoms of CHF,   but in all patients where CHF or systolic  and/or diastolic dysfunction are suspected, such as those with a history of heart disease or suggestive changes of ischemia or hypertrophy on the electrocardiogram, or in patients with hypertension or renal disease.

Other positive cardiovascular effects of EPO treatment.

Another possible explanation for the improved cardiac function in this study may be the direct effect that EPO itself has on improving cardiac muscle function (38,39) and myocardial cell growth (39,40) unrelated to its  effect of the anemia. In fact EPO may be  crucial in the formation of the heart muscle in utero (40). It may also improve  endothelial function (41).  Erythropoietin may be superior to blood transfusions  not only  because adverse reactions to EPO are infrequent, but also because

  • EPO causes the production and release of young cells from the bone marrow into the blood.

These cells have an oxygen dissociation curve that is shifted to the right of the normal curve, causing the release of

  • much greater amounts of oxygen into the tissues than occurs normally (42).

On the other hand, transfused blood consists of older red cells with an oxygen dissociation curve that is

  • shifted to the left, causing the release of much less oxygen into the tissues than occurs normally (42).

The combination of IV Fe and EPO. The use of IV Fe along with EPO has been found to have an additive effect, 

  • increasing the Hb even more than would occur with EPO alone while at the same time
  • allowing the dose of EPO to be reduced (10 –13).
  • The lower dose of EPO will be cost-saving and also reduce the chances of hypertension developing (43).
 We used iron sucrose (Venofer) as our IV Fe medication because, in our experience, it is extremely well tolerated (10,11) and  
  • has not been  associated  with any serious side effects in more than 1,200 patients over six years.

Implications of treatment of anemia in CHF. The correction of anemia is not a substitute for the well-documented effective therapy of CHF but seems to be  an important, if not vital,  addition to the therapy. It is surprising, therefore,  that judging from  the  literature  on CHF,

  • such an obvious treatment for improving CHF is so rarely considered.

We believe that correction of the anemia will have an important role to play in

  • the amelioration of cardiorenal insufficiency, and that this improvement will have
  • significant economic  implications as well.

Acknowledgments

The authors thank Rina Issaky, Miriam Epstein, Hava Ehrenfeld and Hava Rapaport for their secretarial assistance.
Reprint requests and correspondence: Dr. D. S. Silverberg, Department of Nephrology, Tel Aviv Medical Center, Weizman 6, Tel Aviv, 64239, Israel.

 THIRD ARTICLE

The use of subcutaneous erythropoietin and intravenous iron for the treatment of the anemia of severe, resistant congestive heart failure improves cardiac and renal function and functional cardiac class, and markedly reduces hospitalizations

Donald S Silverberg, MDa; Dov Wexler, MDa; Miriam Blum, MDa; Gad Keren, MDa; David Sheps, MDa; Eyal Leibovitch, MDa; David Brosh, MDa; Shlomo Laniado, MDa; Doron Schwartz, MDa; Tatyana Yachnin, MDa; Itzhak Shapira, MDa; Dov Gavish, MDa; Ron Baruch, MDa; Bella Koifman, MDa; Carl Kaplan, MDa; Shoshana Steinbruch, RNa; Adrian Iaina, MDa

J Am Coll Cardiol. 2000;35(7):1737-1744. doi:10.1016/S0735-1097(00)00613-6

http://content.onlinejacc.org/article.aspx?articleid=1126474

OBJECTIVES

This study evaluated the prevalence and severity of anemia in patients with congestive heart failure (CHF) and

  • the effect of its correction on cardiac and renal function and hospitalization.

BACKGROUND

The prevalence and significance of mild anemia in patients with CHF is uncertain, and the role of erythropoietin with intravenous iron supplementation in treating this anemia is unknown.

METHODS

In a retrospective study, the records of the 142 patients in our CHF clinic were reviewed to find
  • the prevalence and severity of anemia (hemoglobin [Hb]12 g).
In an intervention study, 26 of these patients, despite maximally tolerated therapy of CHF for at least six months, still had had severe CHF and were also anemic. They were treated with
  • subcutaneous erythropoietin and intravenous iron sufficient to increase the Hb to 12 g%.
The doses of the CHF medications, except for diuretics, were not changed during the intervention period.

RESULTS

The prevalence of anemia in the 142 patients increased with the severity of CHF,
  • reaching 79.1% in those with New York Heart Association class IV.
In the intervention study, the anemia of the 26 patients was treated for a mean of 7.2 5.5 months.
  • The mean Hb level and mean left ventricular ejection fraction increased significantly.
  • The mean number of hospitalizations fell by 91.9% compared with a similar period before the study.
  • The New York Heart Association class fell significantly,
  • as did the doses of oral and intravenous furosemide.
  • The rate of fall of the glomerular filtration rate slowed with the treatment.

CONCLUSIONS

Anemia is very common in CHF and its successful treatment is associated with a significant improvement in
  • cardiac function,
  • functional class,
  • renal function and
  • in a marked fall in the need for diuretics and hospitalization.
Abbreviations and Acronyms
ACE Angiotensin-converting enzyme
CHF congestive heart failure
COPD chronic obstructive pulmonary disease
CRF chronic renal failure
CVA cerebrovascular accident
EPO erythropoietin
Fe iron
g% grams Hb /100 ml blood
GFR glomerular filtration rate
Hb hemoglobin
Hct hematocrit
IV intravenous
LVEF left ventricular ejection fraction
LVH left ventriculr hypertrophy
NYHA New York Heart Association
%Fe Sat percent iron saturation
sc subcutaneous
TNF tumor becrosis factor
ACE Angiotensin-converting enzyme
CHF congestive heart failure
COPD chronic obstructive pulmonary disease
CRF chronic renal failure
CVA cerebrovascular accident
EPO erythropoietin
Fe iron
g% grams Hb /100 ml blood
GFR glomerular filtration rate
Hb hemoglobin
Hct hematocrit
IV intravenous
LVEF left ventricular ejection fraction
LVH left ventriculr hypertrophy
NYHA New York Heart Association
%Fe Sat percent iron saturation
sc subcutaneous
TNF tumor becrosis factor

The mean hemoglobin (Hb) in patients with congestive heart failure (CHF) is about 12 g Hb per 100 ml blood (g%) (1–3), which is considered to be the lower limit of normal in adult men and postmenopausal women (4). Thus, many patients with CHF are anemic, and

  • this anemia has been shown to worsen as the severity of the CHF progresses (5,6).
Severe anemia of any cause can produce CHF, and treatment of the anemia can improve it (7). In patients with chronic renal failure (CRF) who are anemic,
  • treatment of the anemia with erythropoietin (EPO) has improved many of the abnormalities seen in CHF,
  • reducing left ventricular hypertrophy (LVH) (8 –10),
  • preventing left ventricular dilation (11) and,
    • in those with reduced cardiac function, increasing the left ventricular ejection fraction (LVEF)(8 –10),
    • the stroke volume (12) and
    • the cardiac output (12).
In view of the high prevalence of anemia in CHF, it is surprising that we could find no studies in which EPO was used in the treatment of the anemia of CHF, and the use of EPO is not included in U.S. Public Health Service guide-lines of treatment of the anemia of CHF (13). In fact, anemia has been considered
  • only a rare contributing factor to the worsening of CHF, estimated as contributing to
  • no more than 0% to 1.5% of all cases (14 –16).
Perhaps for this reason, recent guidelines for the prevention and treatment of CHF do not mention treatment of anemia at all (17). If successful treatment of anemia could improve cardiac function and patient function in CHF,
  • this would have profound implications, because,
  • despite all the advances made in the treatment of CHF, it is still a major and steadily increasing cause of hospitalizations, morbidity and mortality (18 –20).
The purpose of this study is to examine
  • the prevalence of anemia (Hb 12 g%) in patients with different levels of severity of CHF and
  • to assess the effect of correction of this anemia in severe CHF patients
  • resistant to maximally tolerated doses of CHF medication.
A combination of subcutaneous (SC) EPO and intravenous (IV) iron (Fe) was used. We have found this combination to be additive in improving the anemia of CRF (21,22).

METHODS 

Patients.

The medical records of the 142 CHF patients being treated in our special outpatient clinic devoted to CHF were reviewed to determine the prevalence and severity of anemia and CRF in these patients. These patients were referred to the clinic either from general practice or from the various wards in the hospital.

Intervention study.

Despite at least six months of treatment in the CHF clinic,
  • 26 of the above patients had persistent, severe CHF (New York Heart Association [NYHA] class III),
  • had a Hb level of 12 g% and were on
    • angiotensin-converting enzyme [ACE] inhibitors, the 
    • alpha-beta-blocker carvedilol,
    • long-acting nitrates,
    • digoxin, 
    • aldactone and
    • oral and IV furosemide.

These 26 patients participated in an intervention study. The mean age was 71.76  8.12 years. There were 21 men and 5 women. They  all had a

  • LVEF below 35%,
  • persistent fatigue and
  • shortness

    of breath on mild to moderate exertion and often at rest, and had

  • required hospitalizations at least once during their follow-up in the CHF clinic for pulmonary edema.
In 18 of the 26 patients, the CHF was associated with ischemic heart disease either
  • alone in four patients, or
  • with hypertension in six,
  • diabetes in four,
  • the two together in three, or with
  • valvular heart disease in one.
Of the remaining eight patients,
  • four had valvular heart disease alone and
  • four had essential hypertension alone.
Secondary causes of anemia including
  • gastrointestinal blood loss (as assessed by history and by three negative stool occult blood examinations),
  • folic acid and vitamin B12 deficiency and
  • hypothyroidism were ruled out.
Routine gastrointestinal endoscopy was not carried out. The study passed an ethics committee.
Table 1. Initial Characteristics of the 142 Patients With CHF Seen in the CHF Clinic
Age, yearsMale/female,  %Associated conditionsDiabetesHypertensionDyslipidemiaSmoking

Main cardiac diagnosis
Ischemic heart disease

Dilated CMP

Valvular heart disease

Hypertension

LVEF,  %

Left atrial area (n 15 cm2)

Pulmonary artery pressure  (15 mm Hg)

Previous hospitalizations/year

Serum Na, mEq/liter

Serum creatinine, mg%

Hemoglobin, g%

70.1 +/- 11.1

79/21

28%

64%

72%

40%

74%

15%

6%

5%

32.5 +/- 12.2

31.3  +/- 10.3

43.1  +/-14.9

3.2  +/- 1.5

139.8  +/- 4.0

1.6   +/-  1.1

11.9   +/- 1.5

CMP  cardiomyopathy; LVEF  left ventricular ejection fraction; NYHA  New York Heart Association class.

Correction of the anemia.

All patients received the combination of SC EPO and IV Fe. The EPO was given once a week at a starting dose of 2,000 IU per week subcutaneously, and the dose was increased or decreased as necessary to achieve and maintain a target Hb of 12 g%. The IV Fe (Venofer-Vifor International, St. Gallen, Switzerland), a ferric sucrose product, was given in a dose of 200 mg IV in 150 ml saline over 60 min every week until the serum ferritin reached 400  g/liter or the percent Fe saturation (%Fe Sat: serum iron/total iron binding capacity   100) reached 40% or until the Hb reached 12 g%. The IV Fe was then given at longer intervals as needed to maintain these levels.

Medication dose.

Except for oral and IV furosemide therapy, the doses of all the other CHF medications, which were used in the maximum tolerated doses before the intervention, were kept unchanged during the intervention period.

Duration of the study.

The study lasted for a mean of 7.2  5.5 months (range four to 15 months).

Investigations.

Visits were at weekly intervals initially and then at two- to three-week intervals depending on the patient’s status. This was the same frequency of visits to the CHF clinic as before the intervention study.
  • A complete blood count, serum creatinine, serum ferritin and % Fe Sat were performed on every visit.
  •  An electronic device measured the blood pressure on every visit.
  • The LVEF was measured by a multiple gated ventricular angiography heart scan initially and at four- to six-month intervals.
Hospital records were reviewed to compare the number of hospitalizations during the time the patients were treated for the anemia with the number of hospitalizations
  • during a similar period of time that they were treated in the CHF clinic 
    before the anemia was treated.
Clinic records were reviewed to evaluate the types and doses of CHF medications used 
before and during the study.

Period of time that they were treated in the CHF clinic before the anemia was treated.

Clinic records were reviewed to evaluate the types and doses of CHF medications used before and during the study.  The glomerular filtration rate (GFR) was calculated from the serum creatinine by the formula: 1/serum creatinine in mg% x 100 GFR in ml/min. The rate of change of the GFR before and during the intervention period was calculated by comparing the change in GFR per month in the year before the intervention with that during the intervention.

Statistical analysis.

Mean standard deviation was calculated. One-way analysis of variance (ANOVA) was performed to compare parameter levels between the four NYHA groups. Hochberg’s method of multiple comparisons (23) was used for pair-wise comparison between two groups. A p value of less than 0.05 was considered statistically significant. In the intervention study, the significance of the difference between the initial values and those at the end of the study for the individual parameters in the 26 treated patients was assessed by paired student’s t test; p < 0.05 was considered statistically significant. All the statistical analysis was performed by the SPSS program (Version 9, Chicago, Illinois).

 RESULTS

CHF: the whole study group.

The clinical, biochemical and hematological characteristics of the 142 patients seen in the clinic are shown in Tables 1 and 2.

  • Sixty-seven patients (47%) had severe CHF as judged by a NYHA class of IV (Table 2).
  • Seventy- nine of the 142 patients (55.6%) were anemic (Hb  12 g%).

The mean Hb level fell progressively from 13.73 +/- 0.83 g% in class I NYHA to 10.90 +/- 1.70 g% in class IV NYHA (p  0.01). The percentage of patients with Hb  12 g% increased from 9.1% in class I to 79.1% in class IV.
Fifty eight patients (40.8%) had CRF as defined as a serum creatinine  1.5 mg%. The mean serum creatinine increased from 1.18 +/_  0.38 mg% in class I NYHA, to 2.0 +/-    1.89 mg% in class IV NYHA, p  0.001. The percentage of patients with an elevated serum creatinine ( 1.5 mg%)      increased from 18.2% in class I to 58.2% in class IV.

The mean ejection fraction fell from 37.67 +/-  15.74% in class I to 27.72 +/-  9.68% (p  0.005) in class IV.

Table 2. LVEF and Biochemical and Hematological Parameters by NYHA Class in 142 Patients With CHF 
NYHA Class I II III IV  Significantly Different Pairs*

 *p  0.05 at least between the two groups by pair-wise comparison between groups.

†p  0.05 at least between the groups by ANOVA.

No. of patients

11

26  

38

67

(total 142) (%)

    (7.7)    (18.3)    (26.8)    (47.2)

Hb, g%†

13.73 (0.83)

13.38 (1.26)

11.95 (1.48)

10.90 (1.70) 

1–3, 1–4, 2–3, 2–4

Serum creatinine,

1.18

1.22

1.32

2.00

1–2, 1–3, 1–4

mg%†

    (0.38)     (0.29)      (0.38)     (1.89)

LVEF, %†

37.67 (15.74)

32.88 (12.41)

32.02 (10.99)

27.72 (9.68)

1–4, 2–4

Hb 12 g%,  (%)

1
(9.1)

5 (19.2) 

20 (52.6) 

53 (79.1)

Serum creatinine

    2      5     12     39

1.5 mg%,  (%) 

 (18.2)

(19.2)

(31.6)

 (58.2)

The intervention study: medications.

The percentage of patients receiving each CHF medication before and after the intervention period and the reasons for not receiving  them are seen in Table 3.

Table 3. Number (%) of the 26 Patients Taking Each Type of Medication Before and During the Intervention Period and the Reason Why the Medication Was Not Used

Medication    No. of Patients  (%)         Reason for Not Receiving the Medications (No. of Patients)
BP  blood pressure; CRF  chronic renal failure; IV  intravenous.

The main reason for not receiving:

  • 1) ACE inhibitors was the presence of reduced renal function;
  • 2) carvedilol was the presence of chronic obstructive pulmonary disease (COPD);
  • 3) nitrates was low blood pressure and aortic stenosis and
  • 4) aldactone was hyperkalemia.
Table 4. Mean Dose of Each Medication Initially and at the End of the Intervention Period in the 26 Patients

                                       No. of Patients                                 Initial Dose ^                 Final Dose^
Carvedilol (mg/day)                      20                                                        26.9 15.5                                   28.8 14.5
Captopril (mg/day)                          7                                                        69.6 40.0                                 70.7 40.4
Enalapril (mg/day)                        13                                                        25.7 12.5                                   26.9 12.6
Digoxin (mg/day)                          25                                                       0.10 0.07                                    0.10 0.07
Aldactone (mg/day)                       19                                                        61.2 49.2                                   59.9 47.1
Long-acting nitrates                      23                                                        53.2 13.2                                   54.1 14.4
Oral furosemide (mg/day)           26                                                      200.9 120.4                                78.3 41.3*
IV furosemide (mg/month)         26                                                      164.7 178.9                                  19.8 47.0*
*p  0.05 at least vs. before by paired Student’s t test.
^  +/-

The mean doses of the medications are shown in Table 4. 

The mean dose of oral furosemide was 200.9 +/-  120.4 mg/day before and 78.3 +/-  41.3 mg/day after the intervention (p   0.05). The dose of IV furosemide was 164.7 +/-  19.8,  178.9 mg/month before and  7.0 mg/month after the intervention (p  0.05).  

The doses of the other CHF medications were almost identical in the two periods.

Clinical results.

DEATHS.
There were three deaths during the intervention period. An 83-year-old man died after eight months of respiratory failure after many years of COPD, a 65-year-old man at eight months of a CVA with subsequent pneumonia and septic shock and a 70-year-old man at four months of septicemia related to an empyema that developed after aortic valve replacement.
HEMODIALYSIS.
Three patients, a 76-year-old man, an 85-year-old woman and a 72-year-old man, required chronic hemodialysis after six, 16 and 18 months, respectively. The serum creatinines of these three patients at onset of the anemia treatment were 4.2, 3.5 and 3.6 mg%, respectively. All three had improvement in their NYHA status but
  • their uremia worsened as the renal function deteriorated, demanding the initiation of dialysis.

In no cases, however, was pulmonary congestion an indication for starting dialysis.

Functional results (Table 5).

During the treatment period, the NYHA class fell from a mean of 3.66 +/- 0.47 to 2.66 +/- 0.70 (p 0.05), and
  • 24 had some improvement in their functional class.
The mean LVEF increased from 27.7 +/- 4.8 to 35.4  +/- 7.6% (p 0.001), an increase of 27.8%.
Compared with a similar period of time before the onset of the anemia treatment, the mean number of hospitalizations fell from 2.72 +/-  1.21 to 0.22 +/-  0.65 per patient (p   0.05)a decrease of 91.9%.
No significant changes were found in the mean systolic/diastolic blood pressure.

Hematological results (Table 5).

  • The mean hematocrit (Hct) increased from 30.14 +/- 3.12%) to 35.9  +/- 4.22% (p < 0.001).
  • The mean Hb increased from 10.16 +/- 0.95 g%) to 12.10 +/-  1.21 g% (p <  0.001).
  • The mean serum ferritin increased from 177.07 +/-  113.80  g/liter to 346.73 +/- 207.40 g/liter (p  0.005).
  • The mean serum Fe increased from 60.4 +/- 19.0 g% to 74 +/- .80  20.7 g% (p  0.005). 
  • The mean %Fe Sat increased from 20.05   6.04% to 26.14 =/- 5.23% (p  0.005).
  • The mean dose of EPO used throughout the treatment period was 5,227  +/- 455 IU per week, and
  • the mean dose of IV Fe used was 185.1 +/- 57.1 mg per month.
In four of the patients, the target Hb of 12 g% was maintained despite stopping the EPO for at least four months.

Renal results (Table 5).

The changes in serum creatinine were not significant. The estimated creatinine clearance fell at a rate of 0.95 + 1.31 ml/min/month before the onset of treatment of the anemia and increased at a rate of 0.85 + 2.77 ml/min/month during the treatment period.
Table 5. The Hematological and Clinical Data of the 26 CHF Patients at Onset and at the End of the Intervention Period

————–                                         Initial ^                                    Final^
Hematocrit, vol%                              30.14 3.12                            35.90 4.22*
Hemoglobin, g%                                10.16 0.95                              2.10 1.21*
Serum ferritin, g/liter                    177.07 113.80                       346.73  207.40*
Serum iron, g%                                  60.4 19.0                               74.8  20.7*
% iron saturation                              20.5 6.04                               26.14 5.23*
Serum creatinine, mg%                   2.59 0.77                                 2.73 1.55
LVEF, %                                              27.7 4.8                                   35.4  7.6*
No. hospitalizations/patient          2.72 1.21                                 0.22   0.65*
Systolic BP, mm Hg                       127.1 19.4                                128.9  26.4
Diastolic BP, mm Hg                       73.9 9.9                                   74.0   12.7
NYHA (0–4)                                     3.66 0.47                                2.66 0.70*
*p  0.05 at least vs before by paired Student’s t test.     ^ +/-
BP  blood pressure; LVEF  left ventricular ejection fraction; NYHA  New York Heart Association.

DISCUSSION

The main findings in the present study are that anemia is common in CHF patients and becomes progressively more prevalent and severe as CHF progresses. In addition, for patients with resistant CHF, the treatment of the associated anemia causes a marked improvement in their

  1. functional status,
  2. ejection fraction and
  3. GFR.
        • All these changes were associated with a markedly
            • reduced need for hospitalization and
            • for oral and IV furosemide.

The effect of anemia on the ischemic myocardium.

We used the IV Fe together with EPO to avoid the Fe deficiency caused by the use of EPO alone (38,39).
The Fe deficiency will cause

  • a resistance to EPO therapy and
  • increase the need for higher and higher doses to maintain the Hb level (39,40).

These high doses will not only be expensive but may increase the blood pressure excessively (41). The IV Fe reduces the dose of EPO needed to correct the anemia, because

  • the combination of SC EPO and IV Fe has been shown to have an additive effect on correction of the anemia of CRF (21,22,39,42).

Oral Fe, however, has no such additive effect (39,42). The relatively low dose of EPO needed to control the anemia in our study may explain why

  • the blood pressure did not increase significantly in any patient.

We used Venofer, an Fe sucrose product, as our IV Fe supplement because, in our experience (21,22,43), it has very few side effects and, indeed, no side effects with its use were encountered in this study.

The Effect of Anemia Correction on Renal Function.

Congestive heart failure is often associated with some degree of CRF (1–3,27–29), and

  • this is most likely due to renal vasoconstriction and ischemia (28,29).

When the anemia is treated and the cardiac function improves,

  • an increase in renal blood flow and glomerular filtration is seen (7,28).

In the present study, renal function decreased as the CHF functional class worsened (Table 2). The rate of deterioration of renal function was slower during the intervention period. Treatment of anemia in CRF has been associated with

  • a rate of progression of the CRF that is either unchanged (30) or is slowed (31–33).

It is possible, therefore, that adequate treatment of the anemia in CHF may, in the long term, help slow down the progression of CRF.

Possible Adverse Effects of Correction of the Anemia.

There has been concern, in view of the recent Amgen study (34), that correction of the Hct to a mean 42% in hemodialysis patients might increase cardiovascular events in those receiving EPO compared with those maintained at a Hct of 30%. Although there is much uncertainty about how to interpret this study (35), there is a substantial body of evidence that shows

  • correction of the anemia up to a Hb of 12 g% (Hct 36%) in CRF on dialysis is safe and desirable (35–38), and
  • results in a reduction in mortality, morbidity and in the number and length of hospitalizations.

The same likely holds true for the anemia of CHF with or without associated CRF. Certainly, our patients’ symptoms were strikingly improved, as was their cardiac function (LVEF) and need for hospitalization and diuretics. It remains to be established

  • if correction of the anemia up to a normal Hb level of 14 g% might be necessary in order to further improve the patient’s clinical state.

The Role of Fe Deficiency and its Treatment in the Anemia of CHF.

We used the IV Fe together with EPO to avoid the Fe deficiency caused by the use of EPO alone (38,39). The Fe deficiency will cause

  • a resistance to EPO therapy and increase the need for higher and higher doses to maintain the Hb level (39,40).

These high doses will not only be expensive but may

  • increase the blood pressure excessively (41).

The IV Fe reduces the dose of EPO needed to correct the anemia, because the combination of SC EPO and IV Fe has been shown to have an additive effect on correction of the anemia of CRF (21,22,39,42). Oral Fe,  however, has no such additive effect (39,42). The relatively low dose of EPO needed to control the anemia in our study may explain

  • why the blood pressure did not increase significantly in any patient.

We used Venofer, an Fe sucrose product, as our IV Fe supplement because, in our experience (21,22,43), it has very few side effects and, indeed, no side effects with its use were encountered in this study.

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Ischemic Stable CAD: Medical Therapy and PCI no difference in End Point: Meta-Analysis of Contemporary Randomized Clinical Trials

Reporter: Aviva Lev-Ari, PhD, RN

 

SOURCE

Stergiopoulos K, Boden WE, Hartigan P, et al. Percutaneous coronary intervention outcomes in patients with stable obstructive coronary artery disease and myocardial ischemia: A collaborative meta-analysis of contemporary randomized clinical trialsJAMA Intern Med 2013; DOI:10.1001/jamainternmed.2013.12855. Available at:http://www.jamainternalmedicine.com.

 

PCI No Benefit Over Medical Therapy in Ischemic Stable CAD

December 02, 2013

NEW YORK, NY — A new analysis is calling into question the de facto rationale for many of the revascularization procedures taking place today, at least in patients with stable coronary artery disease[1]. In a meta-analysis of more than 5000 patients, PCI was no better than medical therapy in patients with documented ischemia by stress testing or fractional flow reserve (FFR).

“Cardiology has a long history of finding a marker of a bad outcome and treating that marker of that bad outcome as if it were the cause of the bad outcome,” senior author on the study, Dr David Brown (State University of New York [SUNY]–Stony Brook School of Medicine), told heartwire . In the case of proceeding to PCI on the basis of documented ischemia, that stems from evidence that patients with ischemia have a worse prognosis than patients who don’t.”It has gotten to the point that a positive stress test [is the gateway] to doing an intervention, even if the ischemia is not in the same ischemic territory as the vessel being treated,” he said. “The medical/industrial complex in cardiology is now focused on finding and treating ischemia, and I think that’s not justified, and these data suggest that that’s not justified.”

Brown and colleagues, with first author Dr Kathleen Stergiopoulus (SUNY–Stony Brook School of Medicine), reviewed the literature for randomized clinical trials of PCI and medical therapy for stable CAD conducted over the past 40 years, ultimately including five trials of 5286 patients. These were a small German trial published in 2004, plus MASS II COURAGE , BARI 2D , and FAME 2 . In all, 4064 patients had myocardial ischemia documented by exercise, nuclear or echo stress imaging, or FFR.

Over a median follow-up of five years, mortality, nonfatal MI, unplanned revascularization, and angina were no different between patients treated medically vs those treated with PCI.

Odds Ratio, PCI vs Medical Therapy

Outcome Odds ratio 95% CI
Death 0.90 0.71–1.16
Nonfatal MI 1.24 0.99–1.56
Unplanned revascularization 0.64 0.35–1.17
Angina 0.91 0.57–1.44

“These findings are unique in that this is the first meta-analysis to our knowledge limited to patients with documented, objective findings of myocardial ischemia, almost all of whom underwent treatment with intracoronary stents and disease-modifying secondary-prevention therapy,” Stergiopoulus et al write.

The findings, they continue, “strongly suggest that the relationship between ischemia and mortality is not altered or ameliorated by catheter-based revascularization of obstructive, flow-limiting coronary stenosis.”

To heartwire , Brown pointed out that their analysis could not separate out patients who had small amounts of ischemia from those with larger ischemic territories. “Maybe that’s where the differentiating factor will be,” he acknowledged, adding that the 8000-patient ISCHEMIA trial, still ongoing, will hopefully yield some insights.

Current practice, however, is to check for ischemia and to proceed with catheterization and, usually, revascularization when ischemia is confirmed by stress testing or during FFR. “But if that doesn’t improve outcomes, why are we doing it?” Brown asked. “We think that needs to be rethought.”

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Commenting on the study for heartwire Dr Peter Berger(Geisinger Health System, Danville, PA) pointed out: “There is no question that PCI is more effective than medical therapy for relief of symptoms: the more severe the angina and the more active the patient, the greater the superiority of PCI.” And, as Berger noted, most of the studies included in this analysis documented ischemia but did not report on the frequency or severity of angina at baseline.

That said, “Patients with minimal angina—and certainly those with silent ischemia but no angina—are unlikely to have a significantly greater reduction of symptoms with PCI, and PCI is rarely beneficial in such patients.”

Moreover, Berger continued, it has been clearly established that PCI does not reduce the risk of death or MI in most such patients.

“I very much agree with the authors, however, that just because more severe ischemia has been shown to be associated with a worse long-term prognosis, reducing the ischemic burden ought not be assumed to reduce the likelihood of death or MI. In most such patients, it does not.”

Stergiopoulos and Brown had no disclosures. Disclosures for the coauthors are listed in the paper.

SOURCE 

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Acute Chest Pain/ER Admission: Three Emerging Alternatives to Angiography and PCI – Corus CAD, hs cTn, CCTA

Curator: Aviva Lev-Ari, PhD, RN

We examine the emergence of Alternatives to Angiography and PCI as most common strategy for ER admission with listed cause of Acute Chest Pain. The Goal is to use methods that will improve the process to identify for an Interventional procedure only the patients that a PCI is a must to have.

Alternative #1: Corus®  CAD

Alternative #2: High-Sensitivity Cardiac Troponins in Acute Cardiac Care

Alternative #3: Coronary CT Angiography for Acute Chest Pain

 

After presenting the Three alternatives, the Editorial by R.F. Redberg, Division of Cardiology, UCSF, will be analyzed.
  • Alternative #1:  First-Line Test to Help Clinicians Exclude Obstructive CAD as a Cause of the Patient’s Symptoms

Corus®  CAD, a blood-based  gene expression test, demonstrated high accuracy with both a high negative predictive value (96 percent) and high sensitivity (89 percent) for assessing  obstructive coronary artery disease  (CAD) in a population of patients referred for stress testing with myocardial perfusion imaging (MPI).

COMPASS enrolled stable patients with symptoms suggestive of CAD who had been referred for MPI at 19 U.S. sites.  A blood sample was obtained in all 431 patients prior to MPI and Corus CAD gene expression testing was performed with study investigators blinded to Corus CAD test results.Following MPI, patients underwent either invasive coronary angiography orcoronary CT angiography, gold-standard anatomical tests for the diagnosis of coronary artery disease.

A Blood Based Gene Expression Test for Obstructive Coronary Artery Disease Tested in Symptomatic Non-Diabetic Patients Referred for Myocardial Perfusion Imaging: The COMPASS Study

https://pharmaceuticalintelligence.com/2012/08/14/obstructive-coronary-artery-disease-diagnosed-by-rna-levels-of-23-genes-cardiodx-heart-disease-test-wins-medicare-coverage/

  • Alternative #2: High-Sensitivity Cardiac Troponins in Acute Cardiac Care

Recommendations for the use of cardiac troponin (cTn) measurement in acute cardiac care have recently been published.[1] Subsequently, a high-sensitivity (hs) cTn T assay was introduced into routine clinical practice.[2] This assay, as others, called highly sensitive, permits measurement of cTn concentrations in significant numbers of apparently illness-free individuals. These assays can measure cTn in the single digit range of nanograms per litre (=picograms per millilitre) and some research assays even allow detection of concentrations <1 ng/L.[2–4] Thus, they provide a more precise calculation of the 99th percentile of cTn concentration in reference subjects (the recommended upper reference limit [URL]). These assays measure the URL with a coefficient of variation (CV) <10%.[2–4]The high precision of hs-cTn assays increases their ability to determine small differences in cTn over time. Many assays currently in use have a CV >10% at the 99th percentile URL limiting that ability.[5–7] However, the less precise cTn assays do not cause clinically relevant false-positive diagnosis of acute myocardial infarction (AMI) and a CV <20% at the 99th percentile URL is still considered acceptable.[8]

We believe that hs-cTn assays, if used appropriately, will improve clinical care. We propose criteria for the clinical interpretation of test results based on the limited evidence available at this time.

References

1. Thygesen K, Mair J, Katus H, Plebani M, Venge P, Collinson P, Lindahl B,

Giannitsis E, Hasin Y, Galvani M, Tubaro M, Alpert JS, Biasucci LM, Koenig W,

Mueller C, Huber K, Hamm C, Jaffe AS; Study Group on Biomarkers in Cardiology

of the ESC Working Group on Acute Cardiac Care. Recommendations

for the use of cardiac troponin measurement in acute cardiac care. Eur Heart J

2010;31:2197–2204.

2. Saenger AK, Beyrau R, Braun S, Cooray R, Dolci A, Freidank H, Giannitsis E,

Gustafson S, Handy B, Katus H, Melanson SE, Panteghini M, Venge P, Zorn M,

Jarolim P, Bruton D, Jarausch J, Jaffe AS. Multicenter analytical evaluation of a highsensitivity

troponin T assay. Clin Chim Acta 2011;412:748–754.

3. Zaninotto M, Mion MM, Novello E, Moretti M, Delprete E, Rocchi MB, Sisti D,

Plebani M. Precision performance at low levels and 99th percentile concentration

of the Access AccuTnI assay on two different platforms. Clin Chem Lab Med 2009;

47:367–371.

4. Todd J, Freese B, Lu A, Held D, Morey J, Livingston R, Goix P. Ultrasensitive flowbased

immunoassays using single-molecule counting. Clin Chem 2007;53:

1990–1995.

5. van de Kerkhof D, Peters B, Scharnhorst V. Performance of Advia Centaur

second-generation troponin assay TnI-Ultra compared with the first-generation

cTnI assay. Ann Clin Biochem 2008;45:316–317.

6. Lam Q, Black M, Youdell O, Spilsbury H, Schneider HG. Performance evaluation

and subsequent clinical experience with the Abbott automated Architect STAT

Troponin-I assay. Clin Chem 2006;52:298–300.

7. Tate JR, Ferguson W, Bais R, Kostner K, Marwick T, Carter A. The determination

of the 99th percentile level for troponin assays in an Australian reference population.

Ann Clin Biochem 2008;45:275–288.

8. Jaffe AS, Apple FS, Morrow DA, Lindahl B, Katus HA. Being rational about (im)-

precision: a statement from the Biochemistry Subcommittee of the Joint European

Society of Cardiology/American College of Cardiology Foundation/

American Heart Association/World Heart Federation Task Force for the definition of myocardial infarction. Clin Chem 2010;56:921–943.

To the Editor:

Hoffmann et al. (July 26 issue)1 conclude that, among patients with low-to-intermediate-risk acute coronary syndromes, the incorporation of coronary computed tomographic angiography (CCTA) improves the standard evaluation strategy.2 However, it may be difficult to generalize their results, owing to different situations on the two sides of the Atlantic and the availability of high-sensitivity troponin T assays in Europe. In the United States, the Food and Drug Administration has still not approved a high-sensitivity troponin test, and patients in the Rule Out Myocardial Infarction/Ischemia Using Computer Assisted Tomography (ROMICAT-II) trial only underwent testing with the conventional troponin T test. As we found in the biomarker substudy in the ROMICAT-I trial, a single high-sensitivity troponin T test at the time of CCTA accurately ruled out acute myocardial infarction (negative predictive value, 100%) (Table 1TABLE 1Results of High-Sensitivity Troponin T Testing for the Diagnosis of Acute Coronary Syndromes in ROMICAT-I.).3 In addition, patients with acute myocardial infarction can be reliably identified, with up to 100% sensitivity, with the use of two high-sensitivity measurements of troponin T within 3 hours after admission.4,5

It seems plausible to assume that the incorporation of high-sensitivity troponin T assays in this trial would have outperformed CCTA. Therefore, it is important to assess the performance of such testing and compare it with routine CCTA testing in terms of length of stay in the hospital and secondary end points, especially cumulative costs and major adverse coronary events at 28 days.

Mahir Karakas, M.D.
Wolfgang Koenig, M.D.
University of Ulm Medical Center, Ulm, Germany
wolfgang.koenig@uniklinik-ulm.de

References

  1. Hoffmann U, Truong QA, Schoenfeld DA, et al. Coronary CT angiography versus standard evaluation in acute chest pain. N Engl J Med 2012;367:299-308

  2. Redberg RF. Coronary CT angiography for acute chest pain. N Engl J Med 2012;367:375-376

  3. Januzzi JL Jr, Bamberg F, Lee H, et al. High-sensitivity troponin T concentrations in acute chest pain patients evaluated with cardiac computed tomography. Circulation2010;121:1227-1234

  4. Keller T, Zeller T, Ojeda F, et al. Serial changes in highly sensitive troponin I assay and early diagnosis of myocardial infarction. JAMA 2011;306:2684-2693

  5. Thygesen K, Mair J, Giannitsis E, et al. How to use high-sensitivity cardiac troponins in acute cardiac care. Eur Heart J 2012;33:2252-2257

Author/Editor Response

In response to Karakas and Koenig: we agree that high-sensitivity troponin T assays may permit more efficient care of low-risk patients presenting to the emergency department with acute chest pain1 and may also have the potential to identify patients with unstable angina because cardiac troponin T levels are associated with the degree and severity of coronary artery disease.2 Hence, high-sensitivity troponin T assays performed early may constitute an efficient and safe gatekeeper for imaging. CCTA, however, may be useful for ruling out coronary artery disease in patients who have cardiac troponin T levels above the 99th percentile but below levels that are diagnostic for myocardial infarction. The hypothesis that high-sensitivity troponin T testing followed by CCTA, as compared with other strategies, may enable safe and more efficient treatment of patients in the emergency department who are at low-to-moderate risk warrants further assessment. The generalizability of our data to clinical settings outside the United States may also be limited because of differences in the risk profile of emergency-department populations and the use of nuclear stress imaging.3

Udo Hoffmann, M.D., M.P.H.
Massachusetts General Hospital, Boston, MA
uhoffmann@partners.org

W. Frank Peacock, M.D.
Baylor College of Medicine, Houston, TX

James E. Udelson, M.D.
Tufts Medical Center, Boston, MA

Since publication of their article, the authors report no further potential conflict of interest.

References

  1. Than M, Cullen L, Reid CM, et al. A 2-h diagnostic protocol to assess patients with chest pain symptoms in the Asia-Pacific region (ASPECT): a prospective observational validation study. Lancet 2011;377:1077-1084

  2. Januzzi JL Jr, Bamberg F, Lee H, et al. High-sensitivity troponin T concentrations in acute chest pain patients evaluated with cardiac computed tomography. Circulation2010;121:1227-1234

  3. Peacock WF. The value of nothing: the consequence of a negative troponin test. J Am Coll Cardiol 2011;58:1340-1342

  • Alternative #3: Coronary CT Angiography for Acute Chest Pain

The Study concluded:

There was increased diagnostic testing and higher radiation exposure in the CCTA group, with no overall reduction in the cost of care. 

Coronary CT Angiography versus Standard Evaluation in Acute Chest Pain

Udo Hoffmann, M.D., M.P.H., Quynh A. Truong, M.D., M.P.H., David A. Schoenfeld, Ph.D., Eric T. Chou, M.D., Pamela K. Woodard, M.D., John T. Nagurney, M.D., M.P.H., J. Hector Pope, M.D., Thomas H. Hauser, M.D., M.P.H., Charles S. White, M.D., Scott G. Weiner, M.D., M.P.H., Shant Kalanjian, M.D., Michael E. Mullins, M.D., Issam Mikati, M.D., W. Frank Peacock, M.D., Pearl Zakroysky, B.A., Douglas Hayden, Ph.D., Alexander Goehler, M.D., Ph.D., Hang Lee, Ph.D., G. Scott Gazelle, M.D., M.P.H., Ph.D., Stephen D. Wiviott, M.D., Jerome L. Fleg, M.D., and James E. Udelson, M.D. for the ROMICAT-II Investigators

N Engl J Med 2012; 367:299-308 July 26, 2012DOI: 10.1056/NEJMoa1201161

BACKGROUND

It is unclear whether an evaluation incorporating coronary computed tomographic angiography (CCTA) is more effective than standard evaluation in the emergency department in patients with symptoms suggestive of acute coronary syndromes.

METHODS

In this multicenter trial, we randomly assigned patients 40 to 74 years of age with symptoms suggestive of acute coronary syndromes but without ischemic electrocardiographic changes or an initial positive troponin test to early CCTA or to standard evaluation in the emergency department on weekdays during daylight hours between April 2010 and January 2012. The primary end point was length of stay in the hospital. Secondary end points included rates of discharge from the emergency department, major adverse cardiovascular events at 28 days, and cumulative costs. Safety end points were undetected acute coronary syndromes.

RESULTS

The rate of acute coronary syndromes among 1000 patients with a mean (±SD) age of 54±8 years (47% women) was 8%. After early CCTA, as compared with standard evaluation, the mean length of stay in the hospital was reduced by 7.6 hours (P<0.001) and more patients were discharged directly from the emergency department (47% vs. 12%, P<0.001). There were no undetected acute coronary syndromes and no significant differences in major adverse cardiovascular events at 28 days. After CCTA, there was more downstream testing and higher radiation exposure. The cumulative mean cost of care was similar in the CCTA group and the standard-evaluation group ($4,289 and $4,060, respectively; P=0.65).

CONCLUSIONS

In patients in the emergency department with symptoms suggestive of acute coronary syndromes, incorporating CCTA into a triage strategy improved the efficiency of clinical decision making, as compared with a standard evaluation in the emergency department, but it resulted in an increase in downstream testing and radiation exposure with no decrease in the overall costs of care. (Funded by the National Heart, Lung, and Blood Institute; ROMICAT-II ClinicalTrials.gov number, NCT01084239.)

http://www.nejm.org/doi/full/10.1056/NEJMoa1201161#t=abstract

REFERENCES

  1. Roe MT, Harrington RA, Prosper DM, et al. Clinical and therapeutic profile of patients presenting with acute coronary syndromes who do not have significant coronary artery disease. Circulation 2000;102:1101-1106

  2. Miller JM, Rochitte CE, Dewey M, et al. Diagnostic performance of coronary angiography by 64-row CT. N Engl J Med 2008;359:2324-2336

  3. Budoff MJ, Dowe D, Jollis JG, et al. Diagnostic performance of 64-multidetector row coronary computed tomographic angiography for evaluation of coronary artery stenosis in individuals without known coronary artery disease: results from the prospective multicenter ACCURACY (Assessment by Coronary Computed Tomographic Angiography of Individuals Undergoing Invasive Coronary Angiography) trial. J Am Coll Cardiol 2008;52:1724-1732

  4. Marano R, De Cobelli F, Floriani I, et al. Italian multicenter, prospective study to evaluate the negative predictive value of 16- and 64-slice MDCT imaging in patients scheduled for coronary angiography (NIMISCAD-Non Invasive Multicenter Italian Study for Coronary Artery Disease). Eur Radiol 2009;19:1114-1123
  5. Meijboom WB, Meijs MF, Schuijf JD, et al. Diagnostic accuracy of 64-slice computed tomography coronary angiography: a prospective, multicenter, multivendor study. J Am Coll Cardiol 2008;52:2135-2144
  6. Hoffmann U, Bamberg F, Chae CU, et al. Coronary computed tomography angiography for early triage of patients with acute chest pain: the ROMICAT (Rule Out Myocardial Infarction using Computer Assisted Tomography) trial. J Am Coll Cardiol 2009;53:1642-1650

  7. Hollander JE, Chang AM, Shofer FS, et al. One-year outcomes following coronary computerized tomographic angiography for evaluation of emergency department patients with potential acute coronary syndrome. Acad Emerg Med 2009;16:693-698

  8. Rubinshtein R, Halon DA, Gaspar T, et al. Usefulness of 64-slice cardiac computed tomographic angiography for diagnosing acute coronary syndromes and predicting clinical outcome in emergency department patients with chest pain of uncertain origin. Circulation2007;115:1762-1768

  9. Schlett CL, Banerji D, Siegel E, et al. Prognostic value of CT angiography for major adverse cardiac events in patients with acute chest pain from the emergency department: 2-year outcomes of the ROMICAT trial. JACC Cardiovasc Imaging 2011;4:481-491

  10. Goldstein JA, Chinnaiyan KM, Abidov A, et al. The CT-STAT (Coronary Computed Tomographic Angiography for Systematic Triage of Acute Chest Pain Patients to Treatment) trial. J Am Coll Cardiol 2011;58:1414-1422

  11. Litt HI, Gatsonis C, Snyder B, et al. CT angiography for safe discharge of patients with possible acute coronary syndromes. N Engl J Med 2012;366:1393-1403

  12. Shreibati JB, Baker LC, Hlatky MA. Association of coronary CT angiography or stress testing with subsequent utilization and spending among Medicare beneficiaries. JAMA2011;306:2128-2136

  13. Hoffmann U, Truong QA, Fleg JL, et al. Design of the Rule Out Myocardial Ischemia/Infarction Using Computer Assisted Tomography: a multicenter randomized comparative effectiveness trial of cardiac computed tomography versus alternative triage strategies in patients with acute chest pain in the emergency department. Am Heart J2012;163:330-338

  14. Abbara S, Arbab-Zadeh A, Callister TQ, et al. SCCT guidelines for performance of coronary computed tomographic angiography: a report of the Society of Cardiovascular Computed Tomography Guidelines Committee. J Cardiovasc Comput Tomogr 2009;3:190-204

  15. Gerber TC, Carr JJ, Arai AE, et al. Ionizing radiation in cardiac imaging: a science advisory from the American Heart Association Committee on Cardiac Imaging of the Council on Clinical Cardiology and Committee on Cardiovascular Imaging and Intervention of the Council on Cardiovascular Radiology and Intervention. Circulation 2009;119:1056-1065

  16. von Ballmoos MW, Haring B, Juillerat P, Alkadhi H. Meta-analysis: diagnostic performance of low-radiation-dose coronary computed tomography angiography. Ann Intern Med2011;154:413-420[Erratum, Ann Intern Med 2011;154:848.]

  17. Achenbach S, Marwan M, Ropers D, et al. Coronary computed tomography angiography with a consistent dose below 1 mSv using prospectively electrocardiogram-triggered high-pitch spiral acquisition. Eur Heart J 2010;31:340-346

  18. Than M, Cullen L, Reid CM, et al. A 2-h diagnostic protocol to assess patients with chest pain symptoms in the Asia-Pacific region (ASPECT): a prospective observational validation study. Lancet 2011;377:1077-1084

In the EDITORIAL by Redberg RF. Dr. Redberg, Cardiology Division, UCSF made the following points in:

Coronary CT angiography for acute chest pain. N Engl J Med 2012;367:375-376

  • Six million people present to ER annually with Acute Chest Pain, most have other diseases that Heart.
  • Current diagnostic methods lead to admission to the hospital, unnecessary stays and over-treatment – improvement of outcomes is needed.
  • Rule Out Myocardial Infarction Using Computer Assisted Tomography II (ROMICAT-II) 100 patients were randomly assigned to CCTA group or Standard Diagnosis Procedures Group in the ER which involved Stress Test in 74%.

CRITIQUE and Study FLAWS in MGH Study:

  • ROMICAT-II enrolled patients only during “weekday daytime hours, no weekend or nights when the costs are higher.
  • Assumption that a diagnostic test must be done before discharge for low-to-intermediate-risk patients is unproven and probably unwarranted.. No evidence that the tests performed let to improved outcomes.
  • Events rate for patient underwent CCTA, Stress test or no testing at al were less that 1% to have an MI, no one died. Thus, it is impossible to assign a benefit to the CCTA Group. So very low rates were observed in other studies
  • CCTA patients were exposed to substantial dose of Radiation, , contrast die,
  • Patients underwent ECG and Negative Troponin, no evidence that additional testing further reduced the risk.
  • Average age of patients: 54, 47% women.Demographic Characteristics with low incidence of CAD, NEJM, 1979; 300:1350-8
  • Risk of Cancer from radiation in younger population is higher, same in women.
  • Hoffmann’s Study: Radiation burden was clinically significant: Standard Evaluation Group: (4.7+-8.4 mSv), CCTA: (13.9+-10.4 mSv), exposure of 10 mSv have been projected to lead to 1 death from Cancer per 2000 persons, Arch Intern Med 2009; 169:2071-7
  • Middle Age women, increased risk of Breast Cancer from radiation, Arch Intern Med 2012 June 11 (ePub ahead of Print)
  • ROMICAT-II study: discharge diagnosis Acute Coronary Syndrome – less than 10%
  • CCTA Group: more tests, more radiation, more interventions tht the standard-evaluation group.
  • Choose Wisely Campaign – order test only when the benefit will exceed the risks

Dr. Redberd advocates ECG and Troponin, if NORMAL, no further testing.

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Coronary artery disease in symptomatic patients referred for coronary angiography: Predicted by Serum Protein Profiles

Reporter: Aviva Lev-Ari, PhD, RN
BMC Med. 2012 Dec 5;10(1):157. [Epub ahead of print]

Serum protein profiles predict coronary artery disease in symptomatic patients referred for coronary angiography.

Laframboise WADhir RKelly LAPetrosko PKrill-Burger JMSciulli CMLyons-Weiler MAChandran URLomakin AMasterson RVMarroquin OC,Mulukutla SRMcNamara DM.

ABSTRACT:

BACKGROUND: More than a million diagnostic cardiac catheterizations are performed annually in the US for evaluation of coronary artery anatomy and the presence of atherosclerosis. Nearly half of these patients have no significant coronary lesions or do not require mechanical or surgical revascularization. Consequently, the ability to rule out clinically significant coronary artery disease (CAD) using low cost, low risk tests of serum biomarkers in even a small percentage of patients with normal coronary arteries could be highly beneficial.

METHODS:

Serum from 359 symptomatic subjects referred for catheterization was interrogated for proteins involved in atherogenesis, atherosclerosis, and plaque vulnerability. Coronary angiography classified 150 patients without flow-limiting CAD who did not require percutaneous intervention (PCI) while 209 required coronary revascularization (stents, angioplasty, or coronary artery bypass graft surgery). Continuous variables were compared across the two patient groups for each analyte including calculation of false discovery rate (FDR [less than or equal to]1%) and Q value (P value for statistical significance adjusted to [less than or equal to]0.01).

RESULTS:

Significant differences were detected in circulating proteins from patients requiring revascularization including increased apolipoprotein B100 (APO-B100), C-reactive protein (CRP), fibrinogen, vascular cell adhesion molecule 1 (VCAM-1), myeloperoxidase (MPO), resistin, osteopontin, interleukin (IL)-1beta, IL-6, IL-10 and N-terminal fragment protein precursor brain natriuretic peptide (NT-pBNP) and decreased apolipoprotein A1 (APO-A1). Biomarker classification signatures comprising up to 5 analytes were identified using a tunable scoring function trained against 239 samples and validated with 120 additional samples. A total of 14 overlapping signatures classified patients without significant coronary disease (38% to 59% specificity) while maintaining 95% sensitivity for patients requiring revascularization. Osteopontin (14 times) and resistin (10 times) were most frequently represented among these diagnostic signatures. The most efficacious protein signature in validation studies comprised osteopontin (OPN), resistin, matrix metalloproteinase 7 (MMP7) and interferon gamma (IFNgamma) as a four-marker panel while the addition of either CRP or adiponectin (ACRP-30) yielded comparable results in five protein signatures.

CONCLUSIONS:

Proteins in the serum of CAD patients predominantly reflected (1) a positive acute phase, inflammatory response and (2) alterations in lipid metabolism, transport, peroxidation and accumulation. There were surprisingly few indicators of growth factor activation or extracellular matrix remodeling in the serum of CAD patients except for elevated OPN. These data suggest that many symptomatic patients without significant CAD could be identified by a targeted multiplex serum protein test without cardiac catheterization thereby eliminating exposure to ionizing radiation and decreasing the economic burden of angiographic testing for these patients.

 
 SOURCE:

Other related articles on this Open Access Online Scientific Journal:

 

Assessing Cardiovascular Disease with Biomarkers

https://pharmaceuticalintelligence.com/2012/12/25/assessing-cardiovascular-disease-with-biomarkers/#comment-6990

 

To Stent or Not? A Critical Decision

https://pharmaceuticalintelligence.com/2012/10/23/to-stent-or-not-a-critical-decision/

Obstructive coronary artery disease diagnosed by RNA levels of 23 genes – CardioDx heart disease test wins Medicare coverage

https://pharmaceuticalintelligence.com/2012/08/14/obstructive-coronary-artery-disease-diagnosed-by-rna-levels-of-23-genes-cardiodx-heart-disease-test-wins-medicare-coverage/

 

https://pharmaceuticalintelligence.com/?s=PCI

 

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Coronary Artery Disease – Medical Devices Solutions: From First-In-Man Stent Implantation, via Medical Ethical Dilemmas to Drug Eluting Stents

Author: Aviva Lev-Ari, PhD, RN

Real medical ethical dilemmas involved in physician assignment of patients to participate in Clinical Trials

Randomized controlled clinical trials have become the method of choice or the standard technique for obtaining scientific information to be used in changing diagnostic or therapeutic methods. The use of this technique creates an ethical dilemma (Hellman and Hellman, 1991).

Physicians using a randomized clinical trial are cast in two opposing roles at the same time: clinicians and researchers. As clinicians, they have an ethical commitment to individual patients: to practice professionally in an empathetic profession that is concerned with each patient as an individual. By entering into a relationship with an individual patient, the physician assumes obligations and commitments to act always in the patient’s best interest, derived from values of loyalty and the virtue of fidelity to his/her patients. Modifications of these relationships, otherwise dyadic relationship, occurs when a physician assumes legal obligations to report wounds of a suspicious nature and certain infectious diseases. Such obligations do not conflict with the physician’s ethical obligation to act in the best medical interests of his/her patient. Social concerns have pre-empted physician reporting of disease manifestations which are suspected to have public health bearing (Hellman and Hellman, 1991).

The other role assumed by a physician participating in randomized clinical trials, is that of a scientific researcher, committed to determine the validity of formally constructed hypotheses and their testing. Results of scientifically formulated studies using the methods developed in experimental design, derived from the disciplines of Statistics and Operations Research, are presumed to benefit humanity in general, and not only the individual patient participating in such a formally designed clinical trial. The goals of randomized clinical trials were stated by the Director of the National Institute of Allergy and Infectious Diseases, in these words: “It’s not to deliver therapy. It’s to answer a scientific question so that the drug can be available for everybody once you’ve established safety and efficacy” (as cited in Hellman and Hellman, 1991).

How do randomized clinical trials conflict with a physician’s duty towards his/her individual patients? It is a conflict between rights-based Moral Theories on one hand and Utilitarian Theory on the other.  Moral theories by Immanuel Kant and John Rowls assert that human beings, by virtue of their unique capacity for rational thinking, are bearers of dignity and ought to be treated as ends in themselves not as means to an end. In contrast, Utilitarianism by Stuart Mills defines what is right as the greatest good for the greatest number, known as social utility (Hellman and Hellman, 1991). Pleasures among them, health and well-being, need be counterbalanced by pain. The morally correct act is the act that produces the most pleasure and the least pain overall. Respectively, believers in Moral theory oppose conduct and self participation in randomized clinical trials, while believers in Utilitarianism support them in earnest.

However, since the distribution of pleasure and pain does have moral consequences, physicians must care about that distribution, since they enter into relationships with many patients. They can’t be indifferent to whether it is these patients or others that suffer for the general benefit of society, even though society might gain from the suffering of a few, even if the physician believes that the suffering by a few is worth the benefit to society. The doctor-patient relationship requires doctors to see their patients as bearers of rights who cannot be merely used for the greater good of humanity.

Consider a new agent that promises more effectiveness of treatment. The control group must be given either an unsatisfactory treatment or a placebo. Even though the therapeutic value of the new agent is unproven, if physicians think it has promise, are they acting in the best interest of their patients in allowing them to be randomly assigned to the control group?

Ethical validity of the assignment of patients to randomized clinical trials involves the following three matters in medical ethics (Hellman and Hellman, 1991, Markman, 1992):

  • If the physician has no opinion about whether the new treatment is acceptable, then random assignment is ethically acceptable. Lack of enthusiasm does not lore patients to participate or support the merit of conducting the study anyway. Treatment may show promise of beneficial results but also present undesirable complications (Markman paraphrased)
  • Physician believes that the severity and likelihood of harm and good are evenly balanced, randomization may be ethically acceptable. If the physician has no preference for either treatment, he or she are in a state of equipoise (Freedman, 1992), then randomization is acceptable.
  • If the physician believes that the new treatment may be either more or less successful or more or less toxic, the use of randomization is NOT consistent with fidelity to the patient.

After patient assignment to a Clinical Trial — What are the risks involved in participation in First-In-Man Stent Implantation as a treatment for cardiovascular diseases?

Dr. R. Stack, professor emeritus of medicine at Duke University, Durham, NC, and president of Synecor, a company developing Bioabsorbable stent, traced the evolution of interventional cardiology from inflation of the first angioplasty balloon to implantation of the first Bioabsorbable stent, in a Founders’ Lecture entitled, “How Can You Get Out of a Full-Metal Jacket?” at the Society for Cardiovascular Angiography and Interventions (SCAI), 29th Annual Scientific Sessions in Chicago, May, 2006, and said:

“In the early days of percutaneous transluminal coronary angioplasty (PTCA), each procedure took three to four hours to complete, and fully one in 20 patients suffered a heart attack in the catheterization laboratory. There was little an interventional cardiologist could do, other than rush the patient to surgery. Introduction of the steerable guidewire made PTCA easier to do and shortened procedure times. Development of the perfusion catheter meant that interventional cardiologists could re-establish blood flow to the heart and stabilize patients in case of a sudden arterial blockage. “(cited in David, 2006).

Risks of Participation in Randomized and Non-randomized Clinical Trials: Technology and Procedural Considerations

  • Assignment to a “control group” means implantation of a stent that is gold standard, rather than having the chance of benefiting from an innovative technology such as bioabsorabable stents (Guidant Corporation, 2006) or bioengineered stents (Chadwick, 2006).
  • During the clinical trials manufacturing defects in the device are identified after the device has been implanted in the participants but not in the control group. Wood (2006) reports that: Guidant Corporation has voluntarily stopped enrolling patients in several arms of the nonrandomized portion of its SPIRIT III clinical trial, because one out of every 100 Xience V everolimus-eluting stents may have been manufactured in substandard conditions. The Xience V everolimus-eluting stent received CE Mark approval in 1/2006. Earlier in March 2006, the company announced that it has completed enrollment of 1002 patients in the randomized US portion of the SPIRIT III trial, comparing the Xience V with the TAXUS paclitaxel-eluting stent. Company intents to restock investigators’ supplies and relaunch the trial.
  • Shortcomings of an entire generation of stent technology which is the Gold Standard in major hospitals in US – Drug Eluting Stents (DES)

Drug-eluting stents, introduced just a few years ago, markedly reduce the risk of restenosis. These stents have quickly become a mainstay of interventional therapy, but their use to treat large segments of the coronary circulation has created new challenges. (ABSORB, 2006, Menichelli, 2006, Pfisterer, 2006, Simonton, 2006, Turco, 2006)

Pfisterer, P.E. (2006) at American College of Cardiology 55th Annual ScientificSession, March 11 – 14, 2006, Atlanta, Georgia in his presentation on Basel Stent Cost-Effectiveness Trial-Late Thrombotic Events (BASKET LATE) Trialcompared Drug-eluting stents (DES) with Bare metal stents (BMS) and told the largest audience of interventional cardiologists in the US that

“The results of this small study and the conclusions reached by the authors are certainly a cause for concern. As has been demonstrated by previous studies, the rate of late stent thrombosis after DES implantation was not significantly higher than the rate associated with BMS, but, nevertheless, the consequences are dire. What I find especially troublesome is the fact that we cannot predict with certainty which patients are prone to develop late stent thrombosis and when stent thrombosis is likely to occur — the latter of which is extremely variable in relation to clopidogrel discontinuation. I am not completely convinced that we should advise all patients treated with a DES to continue dual antiplatelet therapy indefinitely, especially when considering high costs and the potential for bleeding complications. This issue generated plenty of debate at the ACC meeting and is far from being resolved” (Pfisterer, 2006).

Does his message have any impact on Cath Labs in US where thousand of drug-eluting stents are stocked and implanted everyday in thousands of cardiovascular patients, and patients with peripheral vascular diseases?

Risk Sources for Complication during Cardiac Catheterization: Patient participation in a randomized or non-randomized Clinical Trial for a new generation of stent devices

  • Clinical – iatrogenic, induced inadvertently by the medical treatment or procedures or activity of a physician
  • Procedural – no change in practice induced, though scientific evidence is available
  • Idiopathic,of the nature of an idiopathy, self originated, of unknown causation.

The first two risk types are addressed, below.

Clinical – iatrogenic, induced inadvertently by the medical treatment or procedures or activity of a physician

  • Access site complications

The most frequently observed complications are related to access site. Such complications, albeit rarely life-threatening, may require additional treatment, including further compression or thrombin injection (for pseudoaneurysms), blood transfusions or vascular surgery. Access site complications may also expose patients to further discomfort, a longer hospital stay and higher hospital costs. For local vascular complications, established predictors are older age, female gender, body surface area, peripheral vascular disease, some antithrombotic regimens and access site (Agostoni, et al. 2006).

  • Expertise level of the physician operator

A recent paper from a non-university hospital showed that expert operators (> 500 procedures performed) had an overall complication rate lower than cardiologists-in-training (despite the fact that it is not clear if they were cardiology fellows or interventional cardiologists-in-training), with a relative risk reduction of approximately 40%, Ammann, et al.(2003). This result is not confirmed by our report. Indeed, fellows, whose maximum caseload is around 300 procedures during the training period, can safely perform cardiac catheterizations, with a complication rate very similar to that of attending physicians. We focused, in particular, on local vascular complications, as arterial puncture is the first procedure step in the training of fellows and usually the only part of the examination they perform alone. An attending physician, who is directly responsible for the whole procedure, supervises the rest. In a recent registry on postcatheterization complications, it was stated: “the involvement of fellows-in-training may have contributed to some complications, especially local” according to Chandrasekar, B., et al.(2001). A study may well complement that report, suggesting the opposite conclusions (Agostoni, et al. 2006).

We report that for Procedural and during Procedure – no change in practice introduced though scientific evidence is available.

  • Extensive use of antithrombotic therapy

The majority of the patients reported in Agostoni, et al.(2006), underwent left heart catheterization because of suspected or known CAD. Thus, they were taking at least one antiplatelet drug despite the fact that it is common practice at our institution to administer a double antiplatelet regimen (aspirin associated with either ticlopidine or clopidogrel) at least 2 days prior to coronary angiography. And for patients with unstable symptoms, they routinely administer subcutaneous unfractionated or low-molecular-weight heparin, which has been shown to significantly increase the risk of local complications. Moreover, in these unstable patients, intravenous heparin was always administered during the procedure, irrespective of the concomitant administration of subcutaneous heparin. Nevertheless, the complication rate in catheterizations performed for reasons other than CAD remained particularly high (3.1%) (Agostoni, et al., 2006).

  • Selection of Access Site

In terms of arterial access site, the radial approach clearly reduced the rate of local complications, with an overall incidence of 0.8% compared to 3.4% after transfemoral catheterizations. A recently published meta-analysis comparing the radial versus the femoral approach for percutaneous coronary diagnostic and interventional procedures, including patients with similar overall characteristics, yielded results comparable to those of the present study. The radial artery approach was electively performed by one senior cardiologist and only occasionally by the others, while cardiology fellows did not perform any transradial procedures (Agostoni, et.al. 2006) [italics added].

If radial artery is implicated with less site access-related complications, why is radial artery used in 30% of the cases, and femoral artery in 70% of percutaneous coronary interventions (PCI)?

  • Additional Risk Factors for Complication during Cardiac Catheterization that are not routinely Checked or Used Peri-procedure.

Percutaneous left heart catheterization, including pressure measurements, left ventriculography, coronary angiography and percutaneous coronary interventions (PCI), is nowadays considered the gold standard for the diagnosis, evaluation and treatment of several cardiac diseases (coronary artery disease [CAD], valvular and congenital heart diseases, cardiomyopathies, status post-heart transplant) (Agostoni, et al. 2006).

Other variables may increase the probability of complication during Cardiac Catheterization.

These intermediate variables are not routinely checked or used.  Thus, they compromise the patient’s chance of achieving the optimal medical results and the best of care. That is after playing the odds of obtaining an assignment in the clinical trial to the “Treatment Group” if a patient was not assigned to either the “Control Group” to be implanted a traditional device or to the “Placebo Group” calling for no device implantation on this round.

Among these variable one finds:

  • antithrombotic regimens other than GP IIb/IIIa inhibitors
  • body surface area calculation
  • identification and consideration of presence of peripheral vascular disease
  • absence of testing for  systematic screening of serum CK-MB levels needed for detection of postprocedural myocardial infarction.
  • absence of cardiac enzymes measurement: before, after, follow up: 2 weeks, 1 month, 6 month, 12 month

Discussion

The first part of the paper deals with the physician’s medical dilemma of assigning patients to randomized clinical trials. The Moral Theory was contrasted with the Utilitarian one. My chosen side/stand on this matter is to identify my values with the Utilitarian group that will participate in randomized clinical trials if medical conditions so require.

In the second part of the paper, I dealt with a realm of risk factors the patient is exposed to after he/she has signed an informed consent and has no longer control. Noteworthy, the risk factors discussed in the paper are not included on any informed consent form. These risks call for modifications to current practices involved in stent implantation technology requiring an immediate consideration.

Two sources of risks were addressed: Clinical and Procedural. These sets of risks are identical for any patient in the Cath Lab, regardless of being assigned to the Treatment Group or to the Control Group. One may not assume that the implantation procedure for a traditional device vs. a new generation device, carries similar risk.  Though the risk of complication during the procedure is very low, when it occurs to someone you care for or to yourself, it is very dire.

Major adverse cardiovascular and cerebrovascular events (MACCE: death, myocardial infarction, cerebrovascular event) were also assessed. The overall access site complication rate was 2.6%. On multivariate regression analysis, the only two predictors of local complications were female gender (odds ratio [OR] 3.2, 95% confidence interval [CI] 1.6–6.5) and femoral approach (OR 3.9, 95% CI 1.2–12.1). The rate of MACCE  (major cardiovascular and cerebrovascular events was 1.2%, mainly after percutaneous coronary interventions, with only 1 death overall (0.07%)(Agostoni, et.al. 2006).

Like most medical ethics issues, there is no single right answer. I would recommend every Cath Lab to revisit every risk factor listed above, discuss them with the Ethics Committee in the Hospital and initiate new procedures to address the clinical and procedural risk factors identified in the context of First-In-Man Stent Implantation.

As other interventional cardiologists, we are looking forward to Generation Five of Stenting Technology that will include the following innovations:

(a) Stents eluding Nitric Oxide (Verma and Marsden, 2005);

(b) stents with coating of an antibody specific (anti-CD34) to the antigen cells that are in the blood, therefore capturing the patient’s circulating endothelial progenitor cells (cEPCs) in order to accelerate the natural healing process (Chadwick, 2006),(Aoki et al., 2005), (Ben-Shoshan & George, 2007), and

(c) EPC-covered intravascular stents deployed for prevention of stent thrombosis and restenosis as well as for rapid formation of normal tissue architecture (Shirota et al., 2003).

Patient safety will be improved if the risk factors identified will raise awareness and will be addressed — preferably, before the next procedure starts in Angiography/Angioplasty Suite #14, ten minutes from now!

According to Rogers & Edelman (2006), “the spectacular success of drug-eluting stents is still plagued by an aura of unease and an insistent drumbeat demanding evidence of success and safety…dramatic reduction in restenosis attended by enhanced rates of thrombosis.” The performance of the two FDA-approved drug-eluting stents (Taxus and Cypher) varies. Cypher is associated with lower restenosis risk. Both devices are pushed into very complex settings to include patients diagnosed with diabetes (different diabetic states may affect restenosis after stenting in different ways). Percutaneous interventions routinely performed in small-vessels, multilesions, diffuse disease, acute coronary syndrome settings and stent-inside-stent as followed up therapy to restenosis. Other failure modes are stent thrombosis, post-procedural myonecrosis, plaque rupture, enhanced disease at a distance and excitation of patients’ already heightened immune state. Other predictors of device failure include lesion type, patient demographics, prior history of coronary bypass surgery, calcification, degree of pre-stent and post-stent stenosis. The variation in performance is critical for patient care decisions and physician’s discrimination between alternative therapies. In most cases the device is selected by the interventional cardiologist with little or no input from the patient.

Research of Clinical/Ethical issues, to emerge in the context of development of clinical trials for First-In-Man Stents, as well as medical ethical issues, to arise during the implantation procedure of the device, and during the period of follow up of the installed base of the device in humans, requires formalization of the data collection and standardization of the statistical analysis procedures. The two leading conferences, where research findings are reported, in the US in 2006 [American College of Cardiology, Annual Scientific Session] and in Europe in 2006 [The European Paris Course on Revascularization (EuroPCR)] are currently presenting challenges for comparative analysis of safety and efficacy.

Development of a schematic rubric, a conceptual proposal for a future study on the “Ethical Medical Issues involved in Clinical Trials for Next Generation Stent Technology.” Implementation of such a study will be most beneficial to all parties involved: physicians, patients, FDA, device manufacturers and medical ethicists. It will involve the following comparative criteria:

  • Medical Ethical Issue
  • Clinical Trial Name
  • Stent Type
  • Number of Patients
  • Major adverse cardiac events
  • Treatment Efficacy
  • Follow up  Studies
  • Clinical Trial Sites
  • Safety of Risk Factors
  • Study Discontinued

REFERENCES

ABSORB (2006). Everolimus Eluting Coronary Stent System First in Man Clinical Investigation. ClinicalTrials.gov Identifier: NCT00300131

Study start: March 2006; Expected completion: June 2011

Last follow-up: March 2011; Data entry closure: May 2011

http://www.clinicaltrials.gov/ct/gui/show/NCT00300131?order=1

Agostoni, P., Anselmi, M., Gasparini, G., Morando, G., Tosi, P., De Benedictis, M.L., Quintarelli, S., Molinari, G., Zardini, P., Turri, M. (2006). Safety of percutaneous left heart catheterization directly performed by cardiology fellows: A cohort analysis. The Journal of Invasive Cardiology, 18 (6), 248-252.

Ammann, P., Brunner-La Rocca H.P., et al. (2003). Procedural complications following diagnostic coronary angiography are related to the operator’s experience and the catheter size. Catheter Cardiovasc Interv , 59, 13–18. 

Aoki, J., Serruys, P.W., van Beusekom, H., Ong, A.T., McFadden, E.P., Sianos, G., et al. (2005). Endothelial progenitor cell capture by stents coated with antibody against CD34: the HEALING-FIM (Healthy Endothelial Accelerated Lining Inhibits Neointimal Growth-First In Man) Registry. J Am Coll Cardiol 45 (10), 1574–1579.

Ben-Shoshan, J. George, J. (2007). Endothelial progenitor cells as therapeutic vectors in cardiovascular disorders: From experimental models to human trials. Pharmacology & Therapeutics, 115, 25-36.

Chadwick , D.(2006) OrbusNeich’s Genous Bioengineered R-stent . Cath Lab Digest, 14 (1), 20-26

Chandrasekar, B., Doucet, S., Bilodeau, L., et al. (2001). Complications of cardiac catheterization in the current era: A single-center experience. Catheter Cardiovasc Interv , 52, 289–295.

David, K.B. (2006). Impressive Progress In Interventional Cardiology – From 1st Balloon Inflation To First Bioabsorbable Stent, Society for Cardiovascular Angiography and Interventions, http://www.scai.org, http://www.medicalnewstoday.com/medicalnews.php?newsid=43313

Freedman, B. (1992). A response to a purported ethical difficulty with randomized clinical trials involving cancer patients.Journal of Clinical Ethics, 3 (3), 231-234.

Guidant Corporation, (2006). Guidant Announces Enrollment of First Patient in Clinical Trial of the World’s First Fully Bioabsorbable Drug Eluting Coronary Stent, 3/9/2006, Source: Guidant Corporation, Indianapolis, IN, www.guidant.com

Hellman, S. and D.S. Hellman (1991). Of mice but not men: Problems of the randomized clinical trial. New England Journal of Medicine, 324 (22), 1589-1592.

Markman, M. (1992). Ethical difficulties with randomized clinical trials involving cancer patients: Examples from the field of gynecologic oncology. Journal of Clinical Ethics, 3 (3), 193-193.

Menichelli, M. (2006). Sirolimus Stent vs. Bare Stent in Acute Myocardial Infarction Trial. Presented at The European Paris Course on Revascularization (EuroPCR), May 16-19, 2006, Paris, France Paris, France. http://www.medscape.com/viewprogram/5505?rss

Pfisterer, P.E. (2006). Basel Stent Cost-effectiveness Trial-Late Thrombotic events (BASKET LATE) Trial. Presented at American College of Cardiology 55th Annual Scientific Session, March 11 – 14, 2006, Atlanta, Georgia. http://www.medscape.com/viewprogram/5185 

Rogers, C. Edelman E.R. (2006). Pushing drug-eluting stents into uncharted territory, Simpler then you think – more complex than you imagine. Circulation, 113, 2262-2265.

Shirota, T., Yasui, H., Shimokawa, H. & Matsuda, T. (2003). Fabrication of endothelial progenitor cell (EPC)-seeded intravascular stent devices and in vitro endothelialization on hybrid vascular tissue. Biomaterials 24(13), 2295–2302.

Simonton, C. (2006). The STENT Registry: A real-world look at Sirolimus- and Pacitaxel-Eluting Stents. Cath Lab Digest, 14 (1), 1-10.

Turco, M. (2006). TAXUS ATLAS Trial – 9-Month results: Evaluation of TAXUS Liberte vs. TAXUS Express. Presented at The European Paris Course on Revascularization (EuroPCR), May 16-19, 2006, Paris, France Paris, France. http://www.medscape.com/viewprogram/5505?rss

Verma, S. and Marsden, P.A. (2005). Nitric Oxide-Eluting Polyurethanes – Vascular Grafts of the Future? New England Journal Medicine, 353 (7), 730-731.

Wood, S. (2006). Guidant suspends release of Xience V everolimus-eluting stent due to manufacturing standards http://www.theheart.org/article/679851.do 

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Reported by: Dr. Venkat S. Karra, Ph.D.

“Comprehensive computer models of entire cells have the potential to advance our understanding of cellular function and, ultimately, to inform new approaches for the diagnosis and treatment of disease.” Not only does the model allow researchers to address questions that aren’t practical to examine otherwise, it represents a stepping-stone towards its use  in bioengineering and medicine.

A team led by Stanford bioengineering Professor Markus Covert used data from more than 900 scientific papers to account for every molecular interaction that takes place in the life cycle of Mycoplasma genitalium. Mycoplasma genitalium is a humble parasitic bacterium, known mainly for showing up uninvited in human urogenital and respiratory tracts. But the pathogen also has the distinction of containing the smallest genome of any free-living organism – only 525 genes, as opposed to the 4,288 of E. coli, a more traditional laboratory bacterium.

“This is potentially the new Human Genome Project,” Karr said who is a co-first author and Stanford biophysics graduate student. “It’s to understand biology generally.”

“It’s going to take a really large community effort to get close to a human model.”

This is a breakthrough effort for computational biology, the world’s first complete computer model of an organism. “This achievement demonstrates a transforming approach to answering questions about fundamental biological processes,” said James M. Anderson, director of the National Institutes of Health Division of Program Coordination, Planning, and Strategic Initiatives.

Study results were published by Stanford researchers in the journal Cell.

The research was partially funded by an NIH Director’s Pioneer Award from the National Institute of Health Common Fund.

Source:

http://www.dddmag.com/news/2012/07/first-complete-computer-model-bacteria?et_cid=2783229&et_rid=45527476&linkid=http%3a%2f%2fwww.dddmag.com%2fnews%2f2012%2f07%2ffirst-complete-computer-model-bacteria

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