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Posts Tagged ‘Coronary circulation’

Curation, HealthCare System in the US, and Calcium Signaling Effects on Cardiac Contraction, Heart Failure, and Atrial Fibrillation, and the Relationship of Calcium Release at the Myoneural Junction to Beta Adrenergic Release


Curation, HealthCare System in the US, and Calcium Signaling Effects on Cardiac Contraction, Heart Failure, and Atrial Fibrillation, and the Relationship of Calcium Release at the Myoneural Junction to Beta Adrenergic Release

Curator and e-book Contributor: Larry H. Bernstein, MD, FCAP
Curator and BioMedicine e-Series Editor-in-Chief: Aviva Lev Ari, PhD, RN

and 

Content Consultant to Six-Volume e-SERIES A: Cardiovascular Diseases: Justin Pearlman, MD, PhD, FACC

This portion summarises what we have covered and is now familiar to the reader.  There are three related topics, and an extension of this embraces other volumes and chapters before and after this reading.  This approach to the document has advantages over the multiple authored textbooks that are and have been pervasive as a result of the traditional publication technology.  It has been stated by the founder of ScoopIt, that amount of time involved is considerably less than required for the original publications used, but the organization and construction is a separate creative process.  In these curations we amassed on average five articles in one curation, to which, two or three curators contributed their views.  There were surprises, and there were unfulfilled answers along the way.  The greatest problem that is being envisioned is the building a vision that bridges and unmasks the hidden “dark matter” between the now declared “OMICS”, to get a more real perspective on what is conjecture and what is actionable.  This is in some respects unavoidable because the genome is an alphabet that is matched to the mino acid sequences of proteins, which themselves are three dimensional drivers of sequences of metabolic reactions that can be altered by the accumulation of substrates in critical placements, and in addition, the proteome has functional proteins whose activity is a regulatory function and not easily identified.  In the end, we have to have a practical conception, recognizing the breadth of evolutionary change, and make sense of what we have, while searching for more.

We introduced the content as follows:

1. We introduce the concept of curation in the digital context, and it’s application to medicine and related scientific discovery.

Topics were chosen were used to illustrate this process in the form of a pattern, which is mostly curation, but is significantly creative, as it emerges in the context of this e-book.

  • Alternative solutions in Treatment of Heart Failure (HF), medical devices, biomarkers and agent efficacy is handled all in one chapter.
  • PCI for valves vs Open heart Valve replacement
  • PDA and Complications of Surgery — only curation could create the picture of this unique combination of debate, as exemplified of Endarterectomy (CEA) vs Stenting the Carotid Artery (CAS), ischemic leg, renal artery stenosis.

2. The etiology, or causes, of cardiovascular diseases consist of mechanistic explanations for dysfunction relating to the heart or vascular system. Every one of a long list of abnormalities has a path that explains the deviation from normal. With the completion of the analysis of the human genome, in principle all of the genetic basis for function and dysfunction are delineated. While all genes are identified, and the genes code for all the gene products that constitute body functions, there remains more unknown than known.

3. Human genome, and in combination with improved imaging methods, genomics offers great promise in changing the course of disease and aging.

4. If we tie together Part 1 and Part 2, there is ample room for considering clinical outcomes based on individual and organizational factors for best performance. This can really only be realized with considerable improvement in information infrastructure, which has miles to go.

Curation

Curation is an active filtering of the web’s  and peer reviewed literature found by such means – immense amount of relevant and irrelevant content. As a result content may be disruptive. However, in doing good curation, one does more than simply assign value by presentation of creative work in any category. Great curators comment and share experience across content, authors and themes.
Great curators may see patterns others don’t, or may challenge or debate complex and apparently conflicting points of view.  Answers to specifically focused questions comes from the hard work of many in laboratory settings creatively establishing answers to definitive questions, each a part of the larger knowledge-base of reference. There are those rare “Einstein’s” who imagine a whole universe, unlike the three blindmen of the Sufi tale.  One held the tail, the other the trunk, the other the ear, and they all said this is an elephant!
In my reading, I learn that the optimal ratio of curation to creation may be as high as 90% curation to 10% creation. Creating content is expensive. Curation, by comparison, is much less expensive.  The same source says “Scoop.it is my content marketing testing “sandbox”. In sharing, he says that comments provide the framework for what and how content is shared.

Healthcare and Affordable Care Act

We enter year 2014 with the Affordable Care Act off to a slow start because of the implementation of the internet signup requiring a major repair, which is, unfortunately, as expected for such as complex job across the US, and with many states unwilling to participate.  But several states – California, Connecticut, and Kentucky – had very effective state designed signups, separate from the federal system.  There has been a very large rush and an extension to sign up. There are many features that we can take note of:

1. The healthcare system needed changes because we have the most costly system, are endowed with advanced technology, and we have inexcusable outcomes in several domains of care, including, infant mortality, and prenatal care – but not in cardiology.

2. These changes that are notable are:

  • The disparities in outcome are magnified by a large disparity in highest to lowest income bracket.
  • This is also reflected in educational status, and which plays out in childhood school lunches, and is also affected by larger class size and cutbacks in school programs.
  • This is not  helped by a large paralysis in the two party political system and the three legs of government unable to deal with work and distraction.
  • Unemployment is high, and the banking and home construction, home buying, and rental are in realignment, but interest rates are problematic.

3.  The  medical care system is affected by the issues above, but the complexity is not to be discounted.

  •  The medical schools are unable at this time to provide the influx of new physicians needed, so we depend on a major influx of physicians from other countries
  • The technology for laboratories, proteomic and genomic as well as applied medical research is rejuvenating the practice in cardiology more rapidly than any other field.
  • In fields that are imaging related the life cycle of instruments is shorter than the actual lifetime use of the instruments, which introduces a shortening of ROI.
  • Hospitals are consolidating into large consortia in order to maintain a more viable system for referral of specialty cases, and also is centralizing all terms of business related to billing.
  • There is reduction in independent physician practices that are being incorporated into the hospital enterprise with Part B billing under the Physician Organization – as in Partners in Greater Boston, with the exception of “concierge” medical practices.
  • There is consolidation of specialty laboratory services within state, with only the most specialized testing going out of state (Quest, LabCorp, etc.)
  • Medicaid is expanded substantially under the new ACA.
  • The federal government as provider of services is reducing the number of contractors for – medical devices, diabetes self-testing, etc.
  • The current rearrangements seeks to provide a balance between capital expenses and fixed labor costs that it can control, reduce variable costs (reagents, pharmaceutical), and to take in more patients with less delay and better performance – defined by outside agencies.

Cardiology, Genomics, and calcium ion signaling and ion-channels in cardiomyocyte function in health and disease – including heart failure, rhythm abnormalities, and the myoneural release of neurotransmitter at the vesicle junction.

This portion is outlined as follows:

2.1 Human Genome: Congenital Etiological Sources of Cardiovascular Disease

2.2 The Role of Calcium in Health and Disease

2.3 Vasculature and Myocardium: Diagnosing the Conditions of Disease

Genomics & Genetics of Cardiovascular Disease Diagnoses

actin cytoskeleton

wall stress, ventricular workload, contractile reserve

Genetic Base of Atherosclerosis and Loss of Arterial Elasticity with Aging

calcium and actin skeleton, signaling, cell motility

hypertension & vascular compliance

Genetics of Conduction Disease

Ca+ stimulated exostosis: calmodulin & PKC (neurotransmitter)

complications & MVR

disruption of Ca2+ homeostasis cardiac & vascular smooth muscle

synaptotagmin as Ca2+ sensor & vesicles

atherosclerosis & ion channels


It is increasingly clear that there are mutations that underlie many human diseases, and this is true of the cardiovascular system.  The mutations are mistakes in the insertion of a purine nucleotide, which may or may not have any consequence.  This is why the associations that are being discovered in research require careful validation, and even require demonstration in “models” before pursuing the design of pharmacological “target therapy”.  The genomics in cardiovascular disease involves very serious congenital disorders that are asserted early in life, but the effects of and development of atherosclerosis involving large and medium size arteries has a slow progression and is not dominated by genomic expression.  This is characterized by loss of arterial elasticity. In addition there is the development of heart failure, which involves the cardiomyocyte specifically.  The emergence of regenerative medical interventions, based on pleuripotent inducible stem cell therapy is developing rapidly as an intervention in this sector.

Finally, it is incumbent on me to call attention to the huge contribution that research on calcium (Ca2+) signaling has made toward the understanding of cardiac contraction and to the maintenance of the heart rhythm.  The heart is a syncytium, different than skeletal and smooth muscle, and the innervation is by the vagus nerve, which has terminal endings at vesicles which discharge at the myocyte junction.  The heart specifically has calmodulin kinase CaMK II, and it has been established that calmodulin is involved in the calcium spark that triggers contraction.  That is only part of the story.  Ion transport occurs into or out of the cell, the latter termed exostosis.  Exostosis involves CaMK II and pyruvate kinase (PKC), and they have independent roles.  This also involves K+-Na+-ATPase.  The cytoskeleton is also discussed, but the role of aquaporin in water transport appears elsewhere, as the transport of water between cells.  When we consider the Gibbs-Donnan equilibrium, which precedes the current work by a century, we recall that there is an essential balance between extracellular Na+ + Ca2+ and the intracellular K+ + Mg2+, and this has been superceded by an incompletely defined relationship between ions that are cytoplasmic and those that are mitochondrial.  The glass is half full!

 

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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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Coronary Circulation Combined Assessment: Optical Coherence Tomography (OCT), Near-Infrared Spectroscopy (NIRS) and Intravascular Ultrasound (IVUS) – Detection of Lipid-Rich Plaque and Prevention of Acute Coronary Syndrome (ACS)

Author, and Content Consultant to e-SERIES A: Cardiovascular Diseases: Justin Pearlman, MD, PhD, FACC

and

Article Curator: Aviva Lev-Ari, PhD, RN

The clinical motivations for coronary artery imaging include identifying and characterizing obstructive lesions, analyzing suitability for various feasible interventions, and assessing comparative risk with and without interventions. With improvements in non-invasive detection of fixed obstructions in the coronary arteries, it should not be surprising that half of the lesions that cause heart attacks (myocardial infarction) among those who had recent imaging consisted of unstable plaques that were less than 50% obstructive. Therefore there is growing interest not only in more reliable detection of lesions that exceed 50% obstruction, but also improved characterization of lesions that are not obstructive but may be unstable.

By way of analogy, think of impaired blood supply to the heart as a traffic jam in a roadway. The best time to check for a traffic jam is during rush hour. The corresponding clinical scenario is stress testing. There are three major roadways in the heart: left anterior, left circumflex, and right, each with branches (forks). The two left major vessels stem from a short but treacherous left main (“widow maker”). A temporary traffic jam results in symptoms of impaired delivery (angina, from hunger due to late delivery of food). Alternatively, a prolonged traffic disruption can result in suicidal tissue destruction (starvation). A fixed obstruction consists of potholes and landslides resulting in a persisting shutdown of half or more of the lanes in the highway. An unstable plaque consists of a less severe abnormality that can cause accidents (plaque rupture, local hemorrhage, sudden occlusion). A road may shutdown not only from progressive road damage, but also a truck can flip over and shutdown a relatively clean roadway.

Among patients who had recent coronary imaging prior to the onset of a heart attack, half do not have occlusive lesions. Instead of slow progressive reduction in vessel diameter leading to a critically severe flow reduction, the mechanism in the cases of no severe narrowing is attributed to unstable plaque, meaning plaque with thin fibrous caps that rupture, causing sudden thrombosis. Stress tests focus on detection of fixed obstructions and do not warn who has unstable plaque. Thus the next great frontier for coronary imaging is not just to identify flow reducing lesions, but also to identify unstable plaque even if it is not currently flow limiting. This article presents candidate imaging methods and their current capabilities.

Coronary imaging methods include:

  • intra-coronary ultrasound (IVUS)
  • optical coherence imaging (fiberoptic)
  • computed tomographic xray angiography (CTA)
  • magnetic resonance angiography (MRA)
  • near infra-red spectroscopic imaging (NIRS)

    NIRS-IVUS Imaging To Characterize the Composition and Structure of Coronary Plaques 

    David Rizik, MD1 and James, A. Goldstein, MD2

    1. Scottsdale Healthcare Hospital, Scottsdale, AZ

    2. Department Cardiovascular Medicine, William Beaumont Hospital, Royal Oak, MI

    This supplement,

    http://www.invasivecardiology.com/files/Infraredx_FINALPDF.pdf

    authored by highly experienced interventional cardiologists expert in the field of coronary plaque characterization, contains a detailed description of the new NIRS-IVUS combination catheter, and the clinical information obtained during its use in over 90 hospitals in over 10 countries. Case vignettes, cohort outcomes, reviews, and plans for future studies are also presented. It is our hope that this information will be useful in the near term to those seeking to improve PCI. For the longer term, we believe that the NIRS-IVUS system is an excellent candidate for evaluation as a detector of vulnerable plaque. Success in the prospective studies that are planned will make it possible to detect vulnerable plaques and thereby enhance efforts to prevent coronary events.

    Imaging Methods for Detection of Intravascular Plaque – Direct, Robust and/or Validated

    Cap Thickness – OCT

    Expansive Remodeling – IVUS & NIRS-IVUS [Combination TVC System & TVC Insight Catheter]

    Plaque Volume – IVUSNIRS-IVUS

    Calcification – Angiography, IVUS & NIRS-IVUS

    Thrombus – Angioscopy & OCT

    Inflammation Macrophages – Indirect by OCT

    Lipid Core – IVUS & NIRS-IVUS

    Requires Blood-Free FOV – Angioscopy & OCT

    based on Table 1 p.5

    http://www.invasivecardiology.com/files/Infraredx_FINALPDF.pdf

    Comparative Intravascular Imaging for Lipid Core Plaque: VH-IVUS vs OCT vs NIRS

    Eric Fuh, MD and Emmanouil S. Brilakis, MD, PhD

    VA North Texas Healthcare System, Dallas, TX and Division of Cardiology, Dept of Medicine, UT Southwestern Medical Center, Dallas, TX

    Conclusions

    VH-IVUS, OCT, and NIRS can assist in the detection and evaluation of lipid core plaque. Comparative studies have shown important differences between modalities, but are all limited from lack of comparison with the gold standard of histology. Given the different strengths and weaknesses of each modality, combination imaging will likely provide the best results.41 Further refinement of the clinical implications of LCP detection and its impact on optimizing treatment strategy selection will stimulate advances in LCP detection imaging.

    OCT and NIRS can image through calcified lesions, whereas IVUS cannot. LCPs are often accompanied by neovascularization, which can only be visualized by OCT. VH-IVUS may classify stents, which usually appear white (misclassified as “calcium”) surrounded by red (misclassified as “necrotic core”), although this does not appear to be a limitation for NIRS and OCT.54

    Reference 41:

    Bourantas CV, Gracia-Gracia HM, Naka KK, et al. Hybrid intravascular imaging: current applications and prospective potential in the study of coronary atherosclerosis, JACC 2013;61:1369-1378

    Abstract

    The miniaturization of medical devices and the progress in image processing have allowed the development of a multitude of intravascular imaging modalities that permit more meticulous examination of coronary pathology. However, these techniques have significant inherent limitations that do not allow a complete and thorough assessment of coronary anatomy. To overcome these drawbacks, fusion of different invasive and noninvasive imaging modalities has been proposed. This integration has provided models that give a more detailed understanding of coronary artery pathology and have proved useful in the study of the atherosclerotic process. In this review, the authors describe the currently available hybrid imaging approaches, discuss the technological innovations and efficient algorithms that have been developed to integrate information provided by different invasive techniques, and stress the advantages of the obtained models and their potential in the study of coronary atherosclerosis.

    http://content.onlinejacc.org/article.aspx?articleid=1671094

    Reference 54

    Kim SW, Mintz GS, Hong YJ, et al. The virtual histology intravascular ultrasound appearance of newly placed drug-eluting stents. Am J Cardiol. 2008;102:1182-1186.

    American Journal of Cardiology
    Volume 102, Issue 9 , Pages 1182-1186, 1 November 2008

    The Virtual Histology Intravascular Ultrasound Appearance of Newly Placed Drug-Eluting Stents

    Received 17 January 2008; received in revised form 17 March 2008; accepted 17 March 2008. published online 13 June 2008.

    Intravascular ultrasound (IVUS) is used before and after intervention and at follow-up to assess the quality of the acute result as well as the long-term effects of stent implantation. Virtual histology (VH) IVUS classifies tissue into fibrous and fibrofatty plaque, dense calcium, and necrotic core. Although most interventional procedures include stent implantation, VH IVUS classification of stent metal has not been validated. In this study, the VH IVUS appearance of acutely implanted stents was assessed in 27 patients (30 lesions). Most stent struts (80%) appeared white (misclassified as “calcium”) surrounded by red (misclassified as “necrotic core”); 2% appeared just white, and 17% were not detectable (compared with grayscale IVUS because of the software-imposed gray medial stripe). The rate of “white surrounded by red” was similar over the lengths of the stents; however, undetectable struts were mostly at the distal edges (31%). Quantitatively, including the struts within the regions of interest increased the amount of “calcium” from 0.23 ± 0.35 to 1.07 ± 0.66 mm2 (p <0.0001) and the amount of “necrotic core” from 0.59 ± 0.65 to 1.31 ± 0.87 mm2 (p <0.0001). Most important, because this appearance occurs acutely, it is an artifact, and the red appearance should not be interpreted as peristrut inflammation or necrotic core when it is seen at follow-up. In conclusion, acutely implanted stents have an appearance that can be misclassified by VH IVUS as “calcium with or without necrotic core.” It is important not to overinterpret VH IVUS studies of chronically implanted stents when this appearance is observed at follow-up. A separate classification for stent struts is necessary to avoid these misconceptions and misclassifications.

    Table 2. Comparison of three intravascular imaging modalities for the detection of coronary lipid core plaque.

    Intravascular Imaging Modalities for Detecting LCP

    Vol. 25, Supplement A, 2013

    13A

     VH-IVUS (20 MHz)                        OCT                          NIRS-IVUS (40 MHz)

    Hybrid intravascular imaging  No No Yes

    Axial resolution, μm 200 10 100

    Imaging through blood ++ – ++

    Need for blood column clearance during image acquisition No Yes No

    Imaging through stents No Yes Yes

    Imaging through calcium No Yes Yes for NIRS – No for IVUS

    Imaging neovascularization No Yes No

    Detection of non-superficial LCPs Yes No No

    Evaluation of LCP cap thickness + ++ *

    Detection of thrombus – + *

    Expansive remodeling ++ – ++

    Need for manual image processing for LCP detection Yes Yes No

    ++ = excellent; + = good; ± = possible; – = impossible; * = potential under investigation

    VH-IVUS = virtual histology intravascular ultrasound; OCT = optical coherence tomogra-phy; NIRS = near-infrared spectroscopy; LCP = lipid core plaque 

    The Search for Vulnerable Plaque — The Pace Quickens

     

    Ryan D. Madder, MD1, Gregg W. Stone, MD2, David Erlinge, MD3, James E. Muller, MD4

    Affiliations

    1Frederik Meijer Heart & Vascular Institute, Spectrum Health, Grand Rapids, Michigan;

    2New York Presbyterian Hospital, Columbia University and Car-diovascular Research Foundation, New York, New York;

    3Department of Cardiology, Lund University, Lund, Sweden;

    4Infraredx, Inc., Burlington, Massachusetts

    Disclosure: Drs. Madder and Erlinge report no financial relationships or conflicts of interest regarding the content herein.

    Dr. Stone is a consultant for Infraredx, Inc., Volcano Corp., Medtronic, and Boston Scientific, and is a member of the scientific advisory boards for Boston Scientific and Abbott Vascular.

    Dr. Muller is a full-time employee of Infraredx, Inc from which he receives salary and equity.

    Address for Correspondence: Email: ryan.madder@spectrumhealth.org

    The search for the vulnerable plaque has been a lengthy endeavor requiring the work of multiple individuals and institutions over many years. It is disappointing that in more than 2 decades since the “vulnerable plaque” concept was formulated, over 40 million coronary events have occurred. However, it is encouraging that positive answers are now available for most of the questions related to a vulnerable plaque detection and treatment strategy. As shown in Table 1, most of the essential preconditions of a successful vulnerable plaque strategy are present. This positive information has accelerated the pace of work in this area. The pathophysiology of coronary events is well-understood; powerful imaging methods are available; and therapies, both existing and novel, may well be effective (although appropriately powered randomized trials are required to demonstrate their safety and effectiveness). The time is approaching for the conduct of prospective outcome trials to determine the value of a vulnerable plaque strategy for more effective prevention of coronary events.

    Table 1. Essential Components of a Strategy to Prevent Coronary Events by the Detection and Treatment of Vulnerable Plaques

     
    Essential Components Evidencefrom  Published Research
    Pathophysiology of Coronary Events
    Are the causes of coronary events known? Yes Constantinides and others have shown that most coronary events are caused by rupture of a thin-capped LRP with subsequent formation of an occlusive thrombus.1-5
    Are LRPs focal? Yes Cheruvu et al demonstrated that ruptures and TCFA occupy less than 4% of the length of arteries studied at autopsy.8
    Are LRPs stable over time? Yes Kubo et al demonstrated that most fibroatheromas by radiofrequency IVUS remain fibroatheromas over time.39
    Detection of Suspected Vulnerable Plaque by Invasive Imaging (For Secondary Prevention)
    Can invasive imaging safely detect LRP? Yes Waxman et al, Ino et al, and many others have demonstrated the safety of detecting LRP in patients.40
    Do cross-sectional studies show increased LRP concentrated at culprit sites? Yes Madder et al, Erlinge et al, Ino et al have shown LRP concentrated at the culprit site across the spectrum of ACS.14,16,41
    Do prospective studies show that suspected vulnerable plaque can be detected in advance? Yes PROSPECT, VIVA, PREDICTION established the principle by proving that increased plaque burden predicted events but prediction lacked specificity.23-25
    Is more specific detection of vulnerable plaque possible? ? NIRS-IVUS and OCT may provide more specific detection of VP, but have not yet been tested in a prospective study.
    Can Vulnerable Plaques be Treated?
    Is systemic treatment of LRPs possible with current agents? Yes YELLOW study showed a reduction in LRP with rosuvastatin.33
    Is focal treatment of LRPs possible with current methods? Yes Ruptured LRPs are routinely stented in ACS in clinical practice with good outcomes.
    Can systemic treatment be enhanced with new agents? ? PCSK9 inhibitors, Apo A1 Milano, other agents in development may be more effective than statins, but more costly.35,36
    Can focal treatments be enhanced with new methods? ? Bioresorbable vascular scaffolds and/or drug-coated balloons may be useful for VP.
    Primary Prevention
    Can demographic and serum biomarkers be used as a first step in a screening strategy? Yes Framingham Risk Score, improved serum biomarkers, and genetic markers can identify individuals at increased risk.
    Can non-invasive imaging with CTA detect LRP and increased risk? Yes Motoyama et al have identified CTA markers associated with future events.26
    Cost-Effectiveness
    Will a strategy of detection and treatment of vulnerable plaque, if proven to be successful, be cost-effective for secondary prevention? Probably Bosch et al demonstrated that for patients already undergoing invasive imaging, the added costs of detection and treatment of VP are likely to be less than the cost of second events, leading to a cost-saving approach that also improves health.38
    Will a strategy of detection and treatment of vulnerable plaque, if proven to be successful, be cost-effective for primary prevention? ? Bosch et al: For primary prevention the cost of screening would be greater than for secondary prevention. Cost-effectiveness would depend upon cost, the accuracy of detection, and effectiveness of therapy.38
    ACS = acute coronary syndrome; CTA = coronary computed tomographic angiography; LRP = lipid-rich plaque; TCFA = thin-capped fibroatheroma; 

    References

    1. Constantinides P. Plaque fissures in human coronary thrombosis. J Atheroscler Res. 1966;6:1-17.

    2. Friedman M, Van den Bovenkamp GJ. The pathogenesis of a coronary thrombus. Am J Pathol. 1966;48:19-44.

    3. Burke AP, Farb A, Malcom GT, et al. Coronary risk factors and plaque morphology in men with coronary disease who died suddenly. N Engl J Med. 1997;336:1276-1282.

    4. Farb A, Tang AL, Burke AP, et al. Sudden coronary death. Frequency of active coronary lesions, inactive coronary lesions, and myocardial infarction. Circulation. 1995;92:1701-1709.

    5. Virmani R, Kolodgie FD, Burke AP, Farb A, Schwartz SM. Lessons from sudden coronary death: a comprehensive morphological classification scheme for atherosclerotic lesions. Arterioscler Thromb Vasc Biol. 2000;20:1262-1275.

    6. Waksman R, Serruys PW. Handbook of the Vulnerable Plaque. Martin Dunitz: London, England, 2004.

    7. Libby P, Ridker PM, Hansson GK. Progress and challenges in translating the biology of atherosclerosis. Nature. 2011;473:317-325.

    8. Cheruvu P, Finn A, Gardner C, et al. Frequency and distribution of thin-cap fibroatheroma and ruptured plaques in human coronary arteries – a pathologic study. J Am Coll Cardiol. 2007;50:940-949.

    9. Hong M, Mintz GS, Lee CW, et al. Comparison of coronary plaque rupture between stable angina and acute myocardial infarction: a three-vessel intravascular ultrasound study in 235 patients. Circulation. 2004;110:928-933.

    10. Fujii K, Kobayashi Y, Mintz GS, et al. Intravascular ultrasound assessment of ulcerated ruptured plaques. A comparison of culprit and non-culprit lesions of patients with acute coronary syndromes and lesions in patients without acute coronary syndromes. Circulation. 2003;108:2473-2478.

    11. Ehara S, Kobayashi Y, Yoshiyama M, et al. Spotty calcification typifies the culprit plaque in patients with acute myocardial infarction. An intravascular ultrasound study. Circulation. 2004;110:3424-3429.

    12. Lee SY, Mintz GS, Kim SY, et al. Attenuated plaque detected by intravascular ultrasound: clinical, angiographic, and morphologic features and post-percutaneous coronary intervention complications in patients with acute coronary syndromes. J Am Coll Cardiol Intv. 2009;2:65-72.

    13. Asakura M, Ueda Y, Yamaguchi O, et al. Extensive development of vulnerable plaques as a pan-coronary process in patients with myocardial infarction: an angioscopic study. J Am Coll Cardiol. 2001;37:1284-1288.

    14. Ino Y, Kubo T, Tanaka A, et al. Difference of culprit lesion morphologies between ST-segment elevation myocardial infarction and non-ST-segment elevation acute coronary syndrome. J Am Coll Cardiol Intv. 2011;4:76-82.

    15. Madder RD, Smith JL, Dixon SR, Goldstein JA. Composition of target lesions by near-infrared spectroscopy in patients with acute coronary syndrome versus stable angina. Circ Cardiovasc Interv. 2012;5:55-61.

    16. Madder RD, Goldstein JA, Madden SP, et al. Detection by near-infrared spectroscopy of large lipid core plaques at culprit sites in patients with acute ST-segment elevation myocardial infarction. J Am Coll Cardiol Intv. In press, 2013.

    17. Hoffmann U, Moselewski F, Nieman K, et al. Noninvasive assessment of plaque morphology and composition in culprit and stable lesions in acute coronary syndrome and stable lesions in stable angina by mulitdetector computed tomography. J Am Coll Cardiol. 2006;47:1655-1662.

    18. Motoyama S, Kondo T, Sarai M, et al. Multislice computed tomographic characteristics of coronary lesions in acute coronary syndromes. J Am Coll Cardiol. 2007;50:319-326.

    19. Madder RD, Chinnaiyan KM, Marandici AM, Goldstein JA. Features of disrupted plaques by coronary computed tomographic angiography: correlates with invasively proven complex lesions. Circ Cardiovasc Imaging. 2011;4:105-113.

    20. Muller JE, Tofler GH, Stone PH. Circadian variation and triggers of onset of acute cardiovascular disease. Circulation. 1989;79;733-743.

    21. Kolodgie FD, Burke AP, Farb A, et al. The thin-cap fibroatheroma: a type of vulnerable plaque: the major precursor lesion to acute coronary syndromes. Curr Opin Cardiol. 2001;16:285-292.

    22. Yamagishi M, Terashima M, Awano K, et al. Morphology of vulnerable coronary plaque: insights from follow-up of patients examined by intravascular ultrasound before an acute coronary syndrome. J Am Coll Cardiol. 2000;35:106-111.

    23. Stone GW, Maehara A, Lansky A, et al. A prospective natural-history study of coronary atherosclerosis. N Engl J Med. 2011;364:226-235.

    24. Calvert PA, Obaid DR, O’Sullivan M, et al. Association between IVUS findings and adverse outcomes in patients with coronary artery disease: the VIVA (VH-IVUS in Vulnerable Atherosclerosis) study. J Am Coll Cardiol Imaging. 2011;4:894-901.

    25. Stone PH, Saito S, Takahashi S, et al. Prediction of progression of coronary artery disease and clinical outcomes using vascular profiling of endothelial shear stress and arterial plaque characteristics: the PREDICTION study. Circulation. 2012;126:172-181.

    26. Motoyama S, Sarai M, Harigaya H, et al. Computed tomographic angiography characteristics of atherosclerotic plaques subsequently resulting in acute coronary syndrome. J Am Coll Cardiol. 2009;54:49-57.

    27. Stone GW, Maehara A, Mintz GS. The reality of vulnerable plaque detection. J Am Coll Cardiol Imaging. 2011;4:902-904.

    28. Madder RD, Steinberg DH, Anderson RD. Multimodality direct coronary imaging with combined near-infrared spectroscopy and intravascular ultrasound: Initial US experience. Catheter Cardiovasc Interv. 2013;81:551-7.

    29. Kume T, Akasaka T, Kawamoto T, et al. Measurement of the thickness of the fibrous cap by optical coherence tomography. Am Heart J. 2006;152:755.e1-4.

    30. Nissen SE, Tuzcu EM, Schoenhagen P, et al. Effect of intensive compared with moderate lipid-lowering therapy on progression of coronary atherosclerosis: a randomized controlled trial. JAMA. 2004;291:1071-1080.

    31. Nissen SE, Nicholls SJ, Sipahi I, et al. Effect of very high-intensity statin therapy on regression of coronary atherosclerosis: the ASTEROID trial. JAMA. 2006;295:1556-1565.

    32. Nicholls SJ, Ballantyne CM, Barter PJ, et al. Effect of two intensive statin regimens on progression of coronary disease. N Engl J Med. 2011;365:2078-2087.

    33. Kini AS, Baber U, Kovacic JC, et al. Changes in plaque lipid content after short-term, intensive versus standard statin therapy: the YELLOW trial. J Am Coll Cardiol. 2013 (In press).

    34. Takarada S, Imanishi T, Kubo T, et al. Effect of statin therapy on coronary fibrous-cap thickness in patients with acute coronary syndrome: assessment by optical coherence tomography study. Atherosclerosis. 2009;202:491-497.

    35. Stein EA, Gipe D, Bergeron J, et al. Effect of a monoclonal antibody to PCSK9, REGN727/SAR236553, to reduce low-density lipoprotein cholesterol in patients with heterozygous familial hypercholesterolaemia on stable statin dose with or without ezetimibe therapy: a phase 2 randomised controlled trial. Lancet. 2012;380:29-36.

    36. Nissen SE, Tsunoda T, Tuzcu EM, et al. Effect of recombinant ApoA-I Milano on coronary atherosclerosis in patients with acute coronary syndromes: a randomized controlled trial. JAMA. 2003;290:2292-2300.

    37. Braunwald, E. Epilogue: What do clinicians expect from imagers? J Am Coll Cardiol. 2006;47:C101-C103.

    38. Bosch JL, Beinfeld MT, Muller JE, Brady T, Gazelle GS. A cost-effectiveness analysis of a hypothetical catheter-based strategy for the detection and treatment of vulnerable coronary plaques with drug-eluting stents. J Interv Cardiol. 2005;18:339-349.

    39. Kubo T, Maehara A, Mintz GS, et al. The dynamic nature of coronary artery lesion morphology assessed by serial virtual histology intravascular ultrasound tissue characterization. J Am Coll Cardiol. 2010;55:1590-1597.

    40. Waxman S, Dixon SR, L’Allier P, et al. In vivo validation of a catheter-based near-infrared spectroscopy system for detection of lipid core coronary plaques: initial results and exploratory analysis of the SPECTroscopic Assessment of Coronary Lipid (SPECTACL) multicenter study. J Am Coll Cardiol Imaging. 2009;2:858-868.

    41. Erlinge D, Muller JE, Puri R, et al. Validation of a near-infrared spectroscopic signature of lipid located at culprit lesions in ST-segment elevation myocardial infarction. European Atherosclerosis Society. June 2013 (abstract).

    http://www.invasivecardiology.com/files/Infraredx_FINALPDF.pdf

    Proposed Algorithm for Vulnerable Plaque Screening and Treatment 

    SOURCE

    Page 31A in

    http://www.invasivecardiology.com/files/Infraredx_FINALPDF.pdf

    Long-term Consequences of a Lipid Core Plaque

    Christos V. Bourantas, MD, PhD1, Hector M. Garcia, MD, PhD1, Roberto Diletti, MD1, Carlos A.M. Campos, MD1, Yaojun Zhang, MD, PhD1, Scot Garg, MRCP, PhD2, Patrick W. Serruys, MD, PhD1

    1Department of Interventional Cardiology, Erasmus University Medical Centre, Thoraxcenter, Rotterdam, The Netherlands and 2Department of Cardiology, East Lancashire NHS Trust, Haslingden Road, Blackburn, Lancashire, United Kingdom.

    Disclosures: The authors report no financial relationships or conflicts of interest regarding the content herein.

    Address for correspondence:  Email: p.w.j.c.serruys@erasmusmc.nl

    The advent of intravascular imaging in the 1980s allowed us to study in vivo plaque morphology and its prognostic implications.

    • Angioscopy and intravascular ultrasound (IVUS) were the first imaging techniques that provided information about the composition of plaque and allowed detection of its lipid component.7,8

    However, the first applications of these modalities in the clinical setting not only underscored their potential value in the study of atherosclerosis but also highlighted their limitations in characterizing atheroma.9-11 Therefore an effort was made over the last few years to develop advanced techniques that would allow more reliable assessment of a plaque’s composition. Today several modalities are available for this purpose including:

    • the radiofrequency analysis of the IVUS backscatter signal (RF-IVUS),
    • near-infrared spectroscopy (NIRS),
    • optical coherence tomography (OCT),
    • magnetic resonance spectroscopy,
    • intravascular magnetic resonance imaging,
    • Raman spectroscopy,
    • photoacoustic imaging, and
    • time resolved spectroscopic imaging (Figure 1).

    Some of these modalities are still in their infancy, while others have already been used in the clinical setting providing robust evidence about the prognostic implications of the differing compositions of the plaque. The aim of this review article is to present the most recent evidence about the long-term consequences of the atheroma’s phenotype. 

    Current Evidence from NIRS-based Clinical Studies

    NIRS relies on the principle that different organic molecules absorb and scatter NIRS light to different degrees and wavelengths. Recent advances in device technology enabled the development of a catheter suitable for assessing the plaque in human coronaries that is able to emit NIR light and acquire the scattered signal. Spectral analysis of the obtained signal provides a color-coded display, called a chemogram (Figure 1C), which provides the probability that lipid core is present in the superficial plaque (studied depth approximately: 1 mm). Several studies have examined the reliability of this technique using histology as the gold standard and demonstrated a high overall accuracy in detecting lipid-rich plaques while others demonstrated its feasibility in the clinical setting.19-20

    The European Collaborative Project on Inflammation and Vascular Wall Remodeling in Atherosclerosis (NCT01789411) – NIRS sub-study was the first prospective trial designed to evaluate the prognostic implications of an increased lipid component, as detected by NIRS, in coronary plaques. Two hundred three patients that underwent X-ray angiography, and PCI if it was indicated, had NIRS in a non-culprit coronary segment and were followed-up for 1 year. Twenty-eight patients sustained a MACE during the follow-up period; 21 of these events were non-culprit lesion related. Lipid plaque burden index appeared to be an independent predictor of MACE (hazard ratio: 4.04, 95% confidence interval: 1.33-12.29; P=0.01). 

    Currently, the Chemometric Observation of Lipid Rich Plaque of Interest in Native Coronary Arteries (COLOR, NCT00831116) registry is recruiting patients. This study is planning to recruit 2000 patients that will be investigated with NIRS imaging, and aims to examine the association between the presence of a necrotic core in the atheroma and subsequent coronary events. Preliminary results indicate that the absence of lipid-rich plaques is related with better outcomes (www.infraredx.com/the-color-registry). 

    Current Evidence From OCT-based Clinical Studies

    OCT imaging with its high resolution appears able to provide detailed assessment of the superficial plaque and visualize structures that are unseen by other techniques such as the presence of micro calculations of thin-capped fibroatheroma (TCFA). However, a significant limitation of this technique is its poor penetration (1-2 mm), which does not permit through visualization of plaque burden, as well as its low capacity in differentiating lipid from calcific tissue when these are deeply embedded in the vessel wall.21

    In this analysis, 53 patients who underwent PCI had OCT imaging in non-obstructive lesion sat baseline and repeat angiography at 7 months follow-up. They found that plaques with a TCFA phenotype, exhibiting vessel walldiscontinuities, macrophages, neo-vessels, and thrombi were morelikely to progress and cause significant angiographic obstructions.22

    Future Perspective in Plaque Imaging – Conclusions

    Cumulative data derived from intravascular imaging studies have provided robust evidence about the prognostic implications of plaque’s composition and burden, and demonstrated a strong association between the presence of lipid-rich plaques and future cardiovascular events. Plaque pathology and quantification of lipid components is done by hybrid catheters able to acquire different intravascular imaging data.23

    References on page 26A in

     http://www.invasivecardiology.com/files/Infraredx_FINALPDF.pdf

    1.Kragel AH, Reddy SG, Wittes JT, Roberts WC. Morphometric analysis of the composition ofatherosclerotic plaques in the four major epicardial coronary arteries in acute myocardial infarctionand in sudden coronary death. Circulation. 1989;80:1747-1756.

    2.ᆳacteristics of coronary atherosclerotic plaques underlying fatal occlusive thrombi. Br Heart J.1983;50:127-134.

    3.Clark E, Graef I, Chasis H. Thrombosis of the aorta and coronary arteries. Archives of Pathology.1936;22:183-212.

    4.Virmani R, Kolodgie FD, Burke AP, Farb A, Schwartz SM. Lessons from sudden coronary death:a comprehensive morphological classification scheme for atherosclerotic lesions. ArteriosclerThromb Vasc Biol. 2000;20:1262-1275.

    5.Stary HC, Chandler AB, Glagov S, et al. A definition of initial, fatty streak, and intermediatelesions of atherosclerosis. A report from the Committee on Vascular Lesions of the Council onArteriosclerosis, American Heart Association. Circulation. 1994;89:2462-2478.

    6.ᆳrotic lesions and a histological classification of atherosclerosis. A report from the Committee onVascular Lesions of the Council on Arteriosclerosis, American Heart Association. Circulation.1995;92:1355-1374.

    7.Di Mario C, The SH, Madretsma S, et al. Detection and characterization of vascular lesionsby intravascular ultrasound: an in vitro study correlated with histology. J Am Soc Echocardiogr. 1992;5:135-146.

    8.ᆳdation by histomorphologic analysis and association with stable and unstable coronary syndromes.J Am Coll Cardiol. 1996;28:1-6.

    9.Hiro T, Leung CY, Russo RJ, et al. Variability in tissue characterization of atherosclerotic plaqueby intravascular ultrasound: a comparison of four intravascular ultrasound systems. Am J CardImaging. 1996;10:209-218.

    10.ᆳdial infarction: ability of optical coherence tomography compared with intravascular ultrasoundand coronary angioscopy. J Am Coll Cardiol. 2007;50:933-939.

    11.ᆳated with future risk of acute coronary syndrome: detection of vulnerable patients by angioscopy.J Am Coll Cardiol. 2006;47:2194-2200.

    12.ᆳnary syndrome using integrated backscatter intravascular ultrasound. J Am Coll Cardiol.2006;47:734-741.

    13.Amano T, Matsubara T, Uetani T, et al. Lipid-rich plaques predict non-target-lesion ischemicevents in patients undergoing percutaneous coronary intervention. Circ J. 2011;75:157-166.

    14.ᆳsclerosis. N Engl J Med. 2011;364:226-235.

    15.Calvert PA, Obaid DR, O’Sullivan M, et al. Association between IVUS findings and adverseᆳsclerosis) Study. JACC Cardiovasc Imaging. 2011;4:894-901.

    16.Granada JF, Wallace-Bradley D, Win HK, et al. In vivo plaque characterization using intravascularultrasound-virtual histology in a porcine model of complex coronary lesions. Arterioscler ThrombVasc Biol. 2007;27:387-393.

    17.Sales FJ, Falcao BA, Falcao JL, et al. Evaluation of plaque composition by intravascular ultrasound“virtual histology”: the impact of dense calcium on the measurement of necrotic tissue. ᆳvention. 2010;6:394-399.

    18.ᆳtual histology intravascular ultrasound in porcine coronary artery disease. Circ Cardiovasc Imaging. 2010;3:384-391.

    19.ᆳmens with a novel catheter-based near-infrared spectroscopy system. JACC Cardiovasc Imaging. 2008;1:638-648.

    20.Waxman S, Dixon SR, L’Allier P, et al. In vivo validation of a catheter-based near-infrared spectrosᆳcopy system for detection of lipid core coronary plaques: initial results of the SPECTACL study.JACC Cardiovasc Imaging. 2009;2:858-868.

    21.Manfrini O, Mont E, Leone O, et al. Sources of error and interpretation of plaque morphology byoptical coherence tomography. Am J Cardiol. 2006;98:156-159.

    22.Uemura S, Ishigami K, Soeda T, et al. Thin-cap fibroatheroma and microchannel findings inoptical coherence tomography correlate with subsequent progression of coronary atheromatousplaques. Eur Heart J. 2012;33:78-85.

    23.ᆳplications and prospective potential in the study of coronary atherosclerosis. J Am Coll Cardiol.2013;61:1369-378.

    24.ᆳtroscopy and intra-vascular ultrasound catheter to identify composition and structure of coronaryplaque. EuroIntervention. 2010;5:755-756.

    25.ᆳᆳgrated Biomarker and Imaging Study-3 (IBIS-3). EuroIntervention. 2012;8:235-241.

     http://www.invasivecardiology.com/files/Infraredx_FINALPDF.pdf

    NIRS-IVUS Imaging Identifies Lesions at High Risk of Peri-Procedural Myocardial Infarction

    James A. Goldstein, MD, Simon R. Dixon, MBChB*, Gregg W. Stone, MD

    From the Department of Cardiovascular Medicine, William Beaumont Hospital, Royal Oak, MI.

    Address for correspondence: James A. Goldstein, MD, FACC, Department of Cardiovascular Medicine, William Beaumont Hospital, 3601 West 13 Mile Road, Royal Oak, Michigan 48073. Email: jgoldstein@beaumont.edu

    Disclosures: Dr. Goldstein is a consultant for and owns equity in Infraredx, Inc. Dr. Stone is a consultant for Infraredx, Inc., Volcano Corp., Medtronic, and Boston Scientific, and is a member of the scientific advisory boards for Boston Scientific and Abbott Vascular. Dr. Dixon reports no financial relationships or conflicts

    Abstract:

    Percutaneous coronary intervention (PCI) is associated with distal embolization complications, including peri-procedural myocardial infarction (PPMI), including no-reflow, in 3%-15% of cases. These complications are predominantly related to distal embolization of lipid core plaque (LCP) components. Catheter-based near-infrared spectroscopy (NIRS) provides rapid, automated detection of LCPs, the magnitude of which appears associated with a high-risk of PPMI. Employing this technique may facilitate development of preventive measures such as embolic protection devices (EPDs).

    J INVASIVE CARDIOL 2013;25 (Suppl A):14A-16A

    Key words: Distal embolization, lipid core plaque, near-infrared spectroscopy, peri-procedural myocardial infarction

    Figures 1. A 62-year-old man with stable angina underwent coronary angiography, which demonstrated a complex hazy ulcerated culprit lesion in the mid-right coronary artery (Figure 1A, solid arrow). Neither the angiogram nor an intravascular ultrasound image indicated the presence of thrombus. NIRS demonstrated a large yellow signal spanning the circumference of the culprit site (Figure 1B, white rectangle), indicating the presence of a napkin-ring LCP; a smaller LCP was evident distally (Figure 1, open arrow).

    Figure 2. Balloon angioplasty was performed (Figure 2A, arrow), which led to prompt no-reflow (Figure 2B, arrow) associated with severe bradyarrhythmia and profound hypotension (Figure 2C). After brief cardiopulmonary resuscitation and pharmacological support with atropine and dopamine, physiologic rhythm and blood pressure were restored and stenting resulted in excellent angiographic outcome. However, the patient developed a peri-stenting non-transmural infarction (peak creatine kinase of 512 ng/mL) and required an additional day of hospital care in an intensive care unit. (Goldstein JA, et al. JACC Cardiovasc Imaging. 2009;2(12):1420-1424. Reproduced with permission.)

    On Page 14A in

    http://www.invasivecardiology.com/files/Infraredx_FINALPDF.pdf

    Pharmacological Therapy of Lipid Core Plaque

    Jason C. Kovacic, MD, PhD, Annpoorna Kini, MD, MRCP

    From The Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai School of Medicine, New York, New York.

    Address for correspondence: Dr. Annapoorna Kini, Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1030, New York, NY, 10029. Email: annapoorna.kini@mountsinai.org

    Disclosures: Dr. Kovacic is supported by National Institutes of Health Grant K08HL111330 and has received research support from AstraZeneca. Dr. Kini acknowledges honoraria from Medscape and has received research grant support from InfraReDx.

    A new group of terms is slowly creeping in to the atherosclerotic disease lexicon: “Lipid Arc,” “Lipid Core Plaque,” “Lipid-Rich Plaque,” “Lipid Core Burden Index” and other similar phrases. While clinicians and researchers have long been aware of the central importance of lipid in the biology of atherosclerosis, the growing use of these terms is driven by the recent widespread use of novel imaging modalities that provide accurate detection, and even quantification, of the extent of lipid that is contained within the core of an atherosclerotic plaque. Our ability to detect and quantify lipid in plaques is opening up new therapeutic opportunities for modifying the atherosclerotic disease process, which may ultimately be of benefit to patients.

    At the present time there are 3 methods that are commonly used to measure the extent of lipid in atherosclerotic plaques. Perhaps most familiar of these is coronary computer tomographic (CT) scanning. While more commonly used to quantitate calcification or luminal stenosis, CT scanning is readily able to quantitate the extent of lipid associated with an atherosclerotic lesion. However, while several studies have reported various Hounsfield Unit (HU)-based criteria to distinguish lipid-rich from fibrous plaques, the HU cut-off points have so far been inconsistent. The use of CT for detecting lipid-rich plaque is further limited by its relatively low spatial resolution and the fact that the HU values for distinguishing between fibrous and lipid-rich plaques are overlapping.1 In contrast, optical coherence tomography (OCT) offers perhaps the greatest spatial resolution of all clinically available coronary imaging devices. OCT can offer exquisite detail of abluminal coronary artery anatomy, including detection of lipid core plaque. However, while automated systems are being developed, at the present time the quantitation of lipid by OCT is a somewhat specialized process that typically involves detailed off-line analysis.

    A specific intra-coronary imaging catheter for the quantitation of coronary artery lipid content is now available and FDA approved: diffuse reflectance near-infrared spectroscopy (NIRS). The application of NIRS to identify lipid deposition within coronary arteries has been validated ex vivo2-5 and in vivo.6,7 Although NIRS itself is essentially only able to detect and quantitate lipid, design changes and technological advances to this catheter have now made it possible to combine intravascular ultrasound (IVUS) and NIRS technology on a single instrument. In one of the few clinical studies published to date using this device, NIRS has already shown that a high lipid burden in a target lesion undergoing percutaneous coronary intervention (PCI) is associated with an increased likelihood of peri-procedural myocardial infarction.7

    It is well known that the reduction of cholesterol levels by statin therapy is associated with significant decreases in plaque burden. REVERSAL,8 ASTEROID,9 and more recently the SATURN II10 trial showed that in patients with coronary artery disease (CAD), lipid lowering with high-dose statin therapy reduced progression of plaque atheroma burden, even causing plaque regression of some lesions. However, while reduction in atheroma burden and plaque size are important anatomical endpoints, a major unresolved question had been the mechanism of action of statins and the unanswered question of whether they reduce plaque lipid content. Indeed, a high burden of plaque lipid is one of the cardinal features of a rupture-prone vulnerable lesion.11 Therefore, the ability to reduce plaque lipid content may have important effects on lesion stability and therefore, might impact clinical endpoints.

    The advent of sensitive imaging tools for the evaluation of plaque lipid content has paved the way for the investigation of potential pharmacological therapies for lipid core plaque. In particular, the ability of NIRS to provide an automated quantitation of plaque lipid provides a ready-made platform for this task. We recently completed the YELLOW study of high-dose statin therapy for the potential reduction of coronary artery lipid content as assessed by NIRS. We randomized 87 patients with multivessel CAD undergoing elective PCI to rosuvastatin 40 mg daily vs conventional statin therapy. Following PCI of the culprit lesion, non-culprit lesions with a fractional flow reserve (FFR) <0.8 were interrogated using IVUS and NIRS. Changes in plaque composition were assessed after 6-12 weeks during follow-up angiography. The core finding of this study was that high-dose statin therapy was associated with significant reductions in the lipid content of coronary atherosclerotic plaques. Interestingly, despite reduced plaque lipid content, in this relatively short time period concordant changes in gross lesion characteristics such as total atheroma volume or % plaque burden were not observed.12 In short, the YELLOW study identified that even before gross atheroma regression occurs, lipid removal from plaques is an early event upon initiation of high-dose statin therapy. Furthermore, the results of the YELLOW study are concordant with the known acute benefits of statin therapy in patients presenting with acute coronary syndromes, where the early introduction of these agents is known to be of clinical benefit.13 While the YELLOW study was the first of this nature and the results remain to be replicated in a larger trial, these findings have revived interest in the concept of the “vulnerable plaque” because it appears possible that by causing lipid core reduction over a just few weeks, high-dose statin therapy may have rapid plaque stabilizing effects. We are now embarking on the YELLOW II study, where we will further explore the utility of high-dose rosuvastatin for the early reduction of plaque lipid content and potential mechanistic pathways.

    What other agents might have therapeutic efficacy for lipid core reduction? This question is perhaps more complex than it might first appear, because at the present time we do not know the specific mechanism whereby high-dose rosuvastatin causes lipid reduction in plaques. Theoretically it may be due to reduced LDL, increased HDL, other mechanisms or a combination of these effects. Potentially, other agents that are already available such as bile acid sequestrants, ezetimibe, and fibrates may have a weak lipid core reducing effect. However, we would underscore the fact that at the present time the utility of these agents is speculative, and no other agent (apart from high-dose rosuvastatin in the YELLOW study) has been shown to reduce lipid content in vivo in human plaques. Furthermore, given the fact that these other agents are far less potent in their overall effect than rosuvastatin 40 mg/day, it may be clinically challenging to determine if they have efficacy for lipid core reduction beyond that of statins.

    In addition to pharmacotherapy, it must be remembered that we have several non-pharmacological treatments in our armamentarium that may impact lipid core reduction. For example, exercise is known to be associated with reduced plaque lipid content,14 and proper adherence to current guidelines with respect to lifestyle and diet are of paramount importance in any patient in whom it is considered desirable to reduce plaque lipid content.

    Looking ahead, there are several emerging and investigational agents that may hold promise for lipid core reduction. Microsomal triglyceride transfer protein (MTP) is expressed in the liver, intestine, and the heart and is required for the proper assembly of VLDL and chylomicrons. In animals, treatment with an MTP inhibitor leads to a rapid reduction in plasma lipid levels, with a significant decrease in lipid content and monocyte-derived (CD68+) cells in atherosclerotic plaques.15 On December 21, 2012, the first of the MTP inhibitors was approved for clinical use. Lomitapide (marketed as Juxtapid) was approved by the FDA as an adjunct to a low fat diet and other lipid-lowering treatments for patients with homozygous familial hypercholesterolemia. However, concerns have been raised due to hepatic side effects and liver toxicity. As a result, lomitapide will carry a boxed warning and will only be available through a restricted program.16 Another new drug that was recently given restricted approval in the US for homozygous familial hypercholesterolemia is mipomersen. This agent is an antisense therapeutic that targets messenger RNA for apolipoprotein B, leading to reduced apoB protein and LDL levels. While showing efficacy for lowering LDL,17 safety concerns have thus far prohibited this agent from gaining approval for use in Europe. PCSK9 inhibitors are yet another novel class of agents that may hold promise for reducing lipid core plaque. PCSK9 is involved in the degradation of the LDL receptor (LDLR), and by inhibiting PCSK9 it is believed that this permits more LDL receptors to remain active and participate in LDL removal from the blood, thereby reducing plasma LDL and cholesterol levels. Denis et al18 recently demonstrated that gene inactivation of PCSK9 in mice reduced aortic cholesterol accumulation and atherosclerotic lesion development in atherosclerosis-prone mice. Based on their powerful LDL lowering effect, intense efforts are currently underway to develop clinically efficacious PCSK9 inhibitors with several agents already moving to phase II/III human studies.19 While all of these new and emerging therapies are cause for optimism, the recent experience with CETP-inhibitors and the overall failure of this class so far to stand up to rigorous testing as HDL raising agents in phase III studies20,21 serves to remind us that not all “promising future therapies” survive through the arduous clinical testing pipeline.

    In conclusion, there is renewed interest in the concept of “plaque regression” and pharmacological therapy for “lipid core reduction.” This has been driven by our increasing ability to image and quantify these phenomena, and more recently by the provocative findings that high-dose statin therapy may achieve both of these clinical endpoints. Further studies are now required to evaluate novel agents, define mechanisms of action and, most importantly, to confirm that atherosclerotic lipid core reduction is associated with plaque stabilization and fewer clinical endpoints.

    References, pp. 27A-28A in the Supplement

    1. Kristanto W, van Ooijen PM, Greuter MJ, et al. Non-calcified coronary atherosclerotic plaque visualization on CT: effects of contrast-enhancement and lipid-content fractions. Int J Cardiovasc Imaging. 2013; online ahead of print.

    2. Cassis LA, Lodder RA. Near-IR imaging of atheromas in living arterial tissue. Anal Chem. 1993;65:1247-1256.

    3. Jaross W, Neumeister V, Lattke P, et al. Determination of cholesterol in atherosclerotic plaques using near infrared diffuse reflection spectroscopy. Atherosclerosis. 1999;147:327-337.

    4. Moreno PR, Lodder RA, Purushothaman KR, et al. Detection of lipid pool, thin fibrous cap, and inflammatory cells in human aortic atherosclerotic plaques by near-infrared spectroscopy. Circulation. 2002;105:923-927.

    5. Wang J, Geng YJ, Guo B, et al. Near-infrared spectroscopic characterization of human advanced atherosclerotic plaques. J Am Coll Cardiol. 2002;39:1305-1313.

    6. Waxman S, Dixon SR, L’Allier P, et al. In vivo validation of a catheter-based near-infrared spectroscopy system for detection of lipid core coronary plaques: initial results of the SPECTACL study. JACC Cardiovasc Imaging. 2009;2:858-868.

    7. Goldstein JA, Maini B, Dixon SR, et al. Detection of lipid-core plaques by intracoronary near-infrared spectroscopy identifies high risk of periprocedural myocardial infarction. Circ Cardiovasc Interv. 2011;4:429-437.

    8. Nissen SE, Tuzcu EM, Schoenhagen P, et al. Statin therapy, LDL cholesterol, C-reactive protein, and coronary artery disease. N Engl J Med. 2005;352:29-38.

    9. Nissen SE, Nicholls SJ, Sipahi I, et al. Effect of very high-intensity statin therapy on regression of coronary atherosclerosis: the ASTEROID trial. JAMA. 2006;295:1556-1565.

    10. Nicholls SJ, Ballantyne CM, Barter PJ, et al. Effect of two intensive statin regimens on progression of coronary disease. N Engl J Med. 2011;365:2078-2087.

    11. Varnava AM, Mills PG, Davies MJ. Relationship between coronary artery remodeling and plaque vulnerability. Circulation. 2002;105:939-943.

    12. Kini AS, Baber U, Kovacic JC, et al. Changes in plaque lipid content after short-term, intensive versus standard statin therapy: The YELLOW Trial. J Am Coll Cardiol. 2013;62:21-29.

    13. Hulten E, Jackson JL, Douglas K, et al. The effect of early, intensive statin therapy on acute coronary syndrome: a meta-analysis of randomized controlled trials. Arch Intern Med. 2006;166:1814-1821.

    14. Yoshikawa D, Ishii H, Kurebayashi N, et al. Association of cardiorespiratory fitness with characteristics of coronary plaque: assessment using integrated backscatter intravascular ultrasound and optical coherence tomography. Int J Cardiol. 2013;162:123-128.

    15. Hewing B, Parathath S, Mai CK, et al. Rapid regression of atherosclerosis with MTP inhibitor treatment. Atherosclerosis. 2013;227:125-129.

    16. Cuchel M, Bloedon LT, Szapary PO, et al. Inhibition of microsomal triglyceride transfer protein in familial hypercholesterolemia. N Engl J Med. 2007;356:148-156.

    17. Raal FJ, Santos RD, Blom DJ, et al. Mipomersen, an apolipoprotein B synthesis inhibitor, for lowering of LDL cholesterol concentrations in patients with homozygous familial hypercholesterolaemia: a randomised, double-blind, placebo-controlled trial. Lancet. 2010;375:998-1006.

    18. Denis M, Marcinkiewicz J, Zaid A, et al. Gene inactivation of proprotein convertase subtilisin/kexin type 9 reduces atherosclerosis in mice. Circulation. 2012;125:894-901.

    19. Roth EM, McKenney JM, Hanotin C, et al. Atorvastatin with or without an antibody to PCSK9 in primary hypercholesterolemia. N Engl J Med. 2012;367:1891-1900.

    20. Schwartz GG, Olsson AG, Abt M, et al. Effects of dalcetrapib in patients with a recent acute coronary syndrome. N Engl J Med. 2012;367:2089-2099.

    21. Kovacic JC, Fuster V. From Treating Complex Coronary Artery Disease to Promoting Cardiovascular Health: Therapeutic Transitions and Challenges, 2010-2020. Clin Pharmacol Ther. 2011;90:509-518.

    KOVACIC and KINI

    28A

    The Journal of Invasive Cardiology®

    KEY SOURCE for this Article

    Journal of Invasive Cardiology, August 2013, Vol 25/Supplement A

    Print ISSN 1042-3931 / Electronic ISSN 1557-2501

    Introduction 

    NIRS-IVUS Imaging To Characterize the Composition and Structure of Coronary Plaques

    D. RIZIK AND J.A. GOLDSTEIN……………………………………..2A

    Background 

    Imaging of Plaque Composition and Structure with the TVC Imaging System™ and TVC Insight™ Catheter

    B. SHYDO, ET AL…………………………………………………………5A

    Comparative Intravascular Imaging for Lipid Core Plaque: NIRS vs VH-IVUS vs OCT

    E. FUH AND E.S. BRILAKIS……………………………………………9A

    Plaque Characterization and PCI Procedural Outcomes

    NIRS-IVUS Imaging Identifies Lesions at High Risk of

    Peri-Procedural Myocardial Infarction

    J.A. GOLDSTEIN, ET AL……………………………………………..14A

    Case Vignettes:

    Multiple Plaque Ruptures in a Patient with ST-Segment Elevation Myocardial Infarction: Does Infrared Spectroscopy Evidence Explain a Significant Change in the Angiogram?

    M.J. LIM AND J.M. STOLKER……………………………………….16A

    Missing the Culprit Yellow Plaque

    D. ERLINGE…………………………………………………………….18A

    The Use of Near-Infrared Spectroscopy to Optimize Stent Length

    G.A. STOUFFER ………………………………………………………19A

    Employing NIRS-IVUS to Guide Optimal Lesion Coverage—Avoidance of Geographic Miss

    I. HANSON, ET AL……………………………………………………..20A

    Peri-Procedural Myocardial Injury Unraveled: Combined

    Assessment by Optical Coherence Tomography, Near-Infrared

    Spectroscopy, and IVUS

    A. KARANASOS, ET AL………………………………………………..22A

    Plaque Characterization and Long-Term 

    Clinical Outcomes

    Long-term Consequences of a Lipid Core Plaque

    C.V. BOURANTAS, ET AL…………………………………………….24A

    Pharmacological Therapy of Lipid Core Plaque

    J.C. KOVACIC AND A. KINI………………………………………….27A

    The Search for Vulnerable Plaque — The Pace Quickens

    R.D. MADDER, ET AL…………………………………………………29A

    Case Vignettes:

    Observations from Intracoronary Near-Infrared Spectroscopy in Patients with ST-Segment Elevation Myocardial Infarction

    R.D. MADDER…………………………………………………………34A

    NIRS Imaging of Cardiac Allograft Vasculopathy

    G. WEISZ ……………………………………………………………….35A

Read Full Post »


Comment by Cardiologists posted on LinkedIn’s

European Cardiovascular Medical Devices Group, a subgroup of Cardiovascular Medical Devices Group

on Stenting for Proximal LAD Lesions: In Reference to the Invasive Procedure performed on former President George W. Bush

UPDATED on 8/7/2018

Long-Term Outcomes of Stenting the Proximal LAD

Study Questions:

What are the outcomes of patients undergoing drug-eluting stent (DES) implantation according to lesion location within or outside the proximal left anterior descending (LAD) artery?

Methods:

Among the 8,709 patients enrolled in PROTECT (Patient Related Outcomes With Endeavor Versus Cypher Stenting Trial), a multicenter percutaneous coronary intervention (PCI) trial, the investigators compared the outcomes of 2,534 patients (29.1%; 3,871 lesions [31.5%]) with stents implanted in the proximal LAD with 6,172 patients (70.9%; 8,419 lesions [68.5%]) with stents implanted outside the proximal LAD. For each event, a multivariate model was constructed that examined the effect of several individual baseline clinical and angiographic characteristics, including proximal LAD target lesion, on outcomes (i.e., MACE [major adverse cardiac events], target vessel failure [TVF], and myocardial infarction [MI]).

Results:

At 4-year follow-up, death rates were the same (5.8% vs. 5.8%; p > 0.999), but more MIs occurred in the proximal LAD group (6.2% vs. 4.9%; p = 0.015). The rates of clinically driven TVF (14.8% vs. 13.5%; p = 0.109), MACE (15.0% vs. 13.7%; hazard ratio, 1.1; 95% CI, 0.97-1.31; p = 0.139), and stent thrombosis (2.1% vs. 2.0%; p = 0.800) were similar. DES type had no interaction with MACE or TVF. In multivariate analysis, the proximal LAD was a predictor for MI (p = 0.038), but not for TVF (p = 0.149) or MACE (p = 0.069).

Conclusions:

The authors concluded that proximal LAD location was associated with higher rates of MI during the long-term follow-up, but there were no differences in stent thrombosis, death, TVF, or overall MACE.

Perspective:

This post hoc analysis of a prospective, multicenter study reports no difference in the rates of death, MACE, or TVF at 4 years according to intervention at a proximal LAD or nonproximal LAD lesion. The occurrence of the predefined primary endpoint of stent thrombosis was also not dependent on whether a proximal LAD or nonproximal LAD site was treated. However, of note, stenting of proximal LAD lesions was associated with significantly higher rates of MI compared with stenting of nonproximal LAD lesions. Overall, these findings appear to suggest that proximal LAD lesions may not have additional risk in the contemporary DES era, but the higher risk of MI needs to be studied further. Future studies should compare longer-term clinical outcomes between proximal LAD PCI with DES and minimally invasive left internal mammary artery to LAD.

SOURCE

https://www.acc.org/latest-in-cardiology/journal-scans/2017/03/22/15/11/long-term-outcomes-of-stenting-the-proximal-lad

 

Stenting for Proximal LAD Lesions

Curator: Aviva Lev-Ari, PhD, RN

Michael Reinhardt • First, the media really should not be calling this “stent surgery” its a stent procedure just ask any post-CABG patient… Anyway it really is not possible to determine whether or not is was “unnecessary” without all the relevant patient data; which coronary vessel(s) involved, percent stenosis, etc. Actually I find it interesting that they apparently decided to stent the former president on the basis of a CT Angiogram which is not the standard of care for coronary imaging. I have to assume they performed an additional testing like a CT perfusion analysis and saw a clinically relevant defect and this support the decision to stent. Regarding the post-stent drugs cloplidigrel is not a benign drug but benefits far outweigh the downside of a sub-acute thrombosis which might result in a more serious future event = acute MI.

Rafael Beyar • This was absolutely an indicated procedure and almost all rational physician will treat a young patient with proximal LAD lesions with either a stent or bypass surgery

Dov V Shimon MD • No doubt! Proximal (‘close to origin’) LAD lesions are the leading “Widow makers”. Reestablishing of flow in the artery is saving from cardiac damage and death. Drug eluting stent have 2nd and 3rd generations with very low and acceptable reclosure rates and almost no abrupt closure (thrombosis). True, CTA is a screening test, but it astablishes the need for diagnostic and therapeutic angiogram. We, heart surgeons can provide long-term patency to the LAD using LIMA arterial bypass. The current advantage of stent is the incovenience and pain of surgery. Any responsible physician would opt the procedure even for himself, his relatives , his patients and for definitely for GW Bush.

http://www.linkedin.com/groupItem?view=&gid=3358310&type=member&item=265974376&commentID=157366758&goback=%2Egmr_3358310&report%2Esuccess=8ULbKyXO6NDvmoK7o030UNOYGZKrvdhBhypZ_w8EpQrrQI-BBjkmxwkEOwBjLE28YyDIxcyEO7_TA_giuRN#commentID_157366758

Coronary anatomy and anomalies

On the left an overview of the coronary arteries in the anterior projection.

Coronary anatomy and anomalies

RCA, LAD and Cx in the anterior projection

On the left an overview of the coronary arteries in the lateral projection.

  • Left Main or left coronary artery (LCA)
    • Left anterior descending (LAD)
      • diagonal branches (D1, D2)
      • septal branches
    • Circumflex (Cx)
      • Marginal branches (M1,M2)
  • Right coronary artery
    • Acute marginal branch (AM)
    • AV node branch
    • Posterior descending artery (PDA)

Eur J Cardiothorac Surg. 2004 Apr;25(4):567-71.

Isolated high-grade lesion of the proximal LAD: a stent or off-pump LIMA?

Source

Thoraxcentre, Groningen University Hospital, Groningen, The Netherlands.

Abstract

OBJECTIVES:

The objective of this study was to compare the long-term outcome of patients with an isolated high-grade stenosis of the left anterior descending (LAD) coronary artery randomized to percutaneous transluminal coronary angioplasty with stenting (PCI, stenting) or to off-pump coronary artery bypass grafting (surgery).

METHODS:

Patients with an isolated high-grade stenosis (American College of Cardiology/American Heart Association classification type B2/C) of the proximal LAD were randomly assigned to stenting (n=51) or to surgery (n=51) and were followed for 3-5 years (mean 4 years). Primary composite endpoint was freedom from major adverse cardiac and cerebrovascular events (MACCEs), including cardiac death, myocardial infarction, stroke and repeat target vessel revascularization. Secondary endpoints were angina pectoris status and need for anti-anginal medication at follow-up. Analysis was by intention to treat.

RESULTS:

MACCEs occurred in 27.5% after stenting and 9.8% after surgery (P=0.02; absolute risk reduction 17.7%). Freedom from angina pectoris was 67% after stenting and 85% after surgery (P=0.036). Need for anti-anginal medication was significantly lower after surgery compared to stenting (P=0.002).

CONCLUSION:

Patients with an isolated high-grade lesion of the proximal LAD have a significantly better 4-year clinical outcome after off-pump coronary bypass grafting than after PCI.

Daily Dose

08/12/2013 | 5:48 PM

Was George Bush’s stent surgery really unnecessary?

By Deborah Kotz / Globe Staff

VIEW VIDEO

Ever since President George W. Bush had stent surgery last Tuesday to open a blocked artery, leading physicians who weren’t involved in his care have wondered publically why he had this “unnecessary” procedure. Large clinical trials have demonstrated that stent placement doesn’t extend lives or prevent a future heart attack or stroke in those with stable heart disease.

What’s more, Bush could wind up with complications like a reblockage where the stent was placed or excessive bruising or internal bleeding from the blood thinners that he must take likely for the next year.

Dr Richard Besser, the chief medical correspondent for ABC News, questioned why Bush had an exercise stress test as part of his routine physical exam given that he had no symptoms like chest pain or shortness of breath. The stress test indicated signs of an artery blockage.

“In people who are not having symptoms, the American Heart Association says you should not do a stress test,” Besser said, “since the value of opening that artery is to relieve the symptoms.”

Cleveland Clinic cardiologist Dr. Steve Nissen agreed in his interview with USA Today. Bush, he said, likely “got the classical thing that happens to VIP patients, when they get so-called executive physicals and they get a lot of tests that aren’t indicated. This is American medicine at its worst.”

Two physicians wrote in an Washington Post op-ed column titled “President Bush’s unnecessary surgery” that they worry that the media coverage of Bush’s stent will lead “patients to pressure their own doctors for unwarranted and excessive care.”

But none of these doctors actually treated Bush or examined his medical records, so I’m a little surprised they’re making such firm calls.

Bush, an avid biker who recently completed a 100-kilometer ride, probably shouldn’t have had the exercise stress test if he wasn’t having any heart symptoms. “Routine stress testing used to be done 20 years ago, but isn’t recommended any longer since it doesn’t have any benefit,” said Brigham and Women’s cardiologist Dr. Christopher Cannon.

But Bush’s spokesman insisted the stent was necessary after followup heart imaging via a CT angiogram “confirmed a blockage that required opening.”

Cannon said Bush’s doctors may have seen signs that blood flow wasn’t getting to a significant part of the heart muscle, a condition known as ischemia. Researchers have found that those with moderate to severe ischemia appear to experience a reduction in fatal heart attacks when they have a stent placement along with medical therapy, rather than just taking medications alone. (Larger studies, though, are needed to confirm this finding.)

“If a blockage occurs at the very start of the artery and it’s extensive—95 percent blocked—then chances are it will cause significant ischemia,” Cannon said. While severe ischemia usually causes light-headedness or dizziness during exercise, Bush may have had more moderate ischemia that didn’t cause such symptoms.

It’s impossible to know for certain, he added, without seeing his medical records firsthand.

http://www.boston.com/lifestyle/health/blogs/daily-dose/2013/08/12/was-george-bush-stent-surgery-really-unnecessary/DzklhNCGVlgriNxgpKZtuO/blog.html

President Bush’s unnecessary heart surgery

  • By Vinay Prasad and Adam Cifu, Published: August 9

Vinay Prasad is chief fellow of medical oncology at the National Cancer Institute and the National Institutes of Health. Adam Cifu is a professor of medicine at the University of Chicago.

Former president George W. Bush, widely regarded as a model of physical fitness, received a coronary artery stent on Tuesday. Few facts are known about the case, but what is known suggests the procedure was unnecessary.

Before he underwent his annual physical, Mr. Bush reportedly had no symptoms. Quite the opposite: His exercise tolerance was astonishing for his age, 67. He rode more than 30 miles in the heat on a bike ride for veterans injured in the wars in Iraq and Afghanistan.

If Mr. Bush had visited a general internist practicing sound, evidence-based care, he would not have had cardiac testing. Instead, the doctor would have had conducted age-appropriate cancer screening. For the former president, this would include only colon cancer screening. It no longer would include even prostate-specific antigen testing for cancer. The doctor would have screened for cholesterol, checked for hypertension and made sure the patient was up to date on age-appropriate vaccinations, including those for pneumococcal pneumonia and shingles. Presumably Mr. Bush got these things, and he got the cardiac test as well.What value does a stress test add for an otherwise healthy 67-year-old?No study has shown that this examination improves outcomes. The trials that have been done for so-called routine stress testing examined higher-risk patients. They found that performing stress tests on people at high risk of cardiovascular disease may detect blockages but does not improve symptoms or survival. Routine stress testing does, however, increase the use of procedures such as coronary stenting.Unfortunately, Mr. Bush, like many VIPs, may be paying the price of these in-depth investigations. His stress test revealed an abnormality, prompting another test: a CT angiogram. This study showed a blockage, which was stented open during an invasive procedure. It is worth noting that at least two large randomized trials show that stenting these sorts of lesions does not improve survival. Because Mr. Bush had no symptoms, it is impossible that he felt better after these procedures.

Instead, George W. Bush will have to take two blood thinners, aspirin and Plavix, for at least a month and probably a year. (The amount of time a blood thinner is needed depends on the type of stent placed). While he takes these medications, he will have a higher risk of bleeding complications with no real benefit.

Although this may seem like an issue important only to the former president, consider the following: Although the price of excessive screening of so-called VIPs is usually paid for privately, follow-up tests, only “necessary” because of the initial unnecessary screening test, are usually paid for by Medicare, further stressing our health-care system. The media coverage of interventions like Mr. Bush’s also leads patients to pressure their own doctors for unwarranted and excessive care.

http://www.washingtonpost.com/opinions/president-bushs-unnecessary-heart-surgery/2013/08/09/c91c439c-0041-11e3-9a3e-916de805f65d_story.html

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Normal and Anomalous Coronary Arteries: Dual Source CT in Cardiothoracic Imaging

Reporters: Justin D Pearlman, MD, PhD, FACC and Aviva Lev-Ari, PhD, RN

Coronary anatomy and anomalies

“Coronary” describes the crown-like position of arteries on the heart that provide its nutrient blood supply. The heart does not live off of the blood in its chambers, but rather receives its nutrient perfusion from branches of the aorta, like all other organs. The most relied on method to exam coronary artery anatomy is angiography – xray image movies obtained while the blood is opacified by injection of iodine (high atomic number to block xrays) to provide a contrast between arterial flow channel (the lumen) and the surrounding tissues. Computed tomography is providing a second-best alternative with 3D reconstructions that can be obtained less invasively (no catheters), but it often fails to see the posterior descending artery (PDA) well, and is lower in resolution (point-discrimination detail) than xray angiography (XRA). Magnetic resonance angiography (MRA) comes in as a distant third place method for examining coronary anatomy (lower quality, lower reliability), but non-invasive with no ionizing radiation. A major goal of defining coronary anatomy in individual patients is to identify coronary artery disease (CAD) and to clarify best options for management – to relieve angina and to avoid adverse consequences, e.g., heart attacks (myocardial infarction), heart failure (CHF) and death. The COURAGE trial showed that for many, aggressive medical management with statins and blood pressure control may obviate need for percutaneous or surgical interventions to control angina and minimize the risk of adverse outcomes. Patients with blockage of the left main coronary artery, or two vessel blockage including proximal left anterior descending (LAD) especially with below normal ejection fraction may be better off in the long run with bypass surgery. Therefore less invasive imaging sufficient to rule out left main disease and proximal LAD disease may suffice for decision making (except that the BARI trial results have not been overturned in favoring bypass surgery for diabetics).

On the left an overview of the coronary arteries in the anterior projection.

Coronary anatomy and anomalies

  • Left Main or left coronary artery (LCA)
    • Left anterior descending (LAD)
      • diagonal branches (D1, D2)
      • septal branches
    • Circumflex (Cx)
      • Marginal branches (M1,M2)
  • Right coronary artery
    • Acute marginal branch (AM)
    • AV node branch
    • Posterior descending artery (PDA)
RCA, LAD and Cx in the anterior projection

On the left an overview of the coronary arteries in the lateral projection.

  • Left Main or left coronary artery (LCA)
    • Left anterior descending (LAD)
      • diagonal branches (D1, D2)
      • septal branches
    • Circumflex (Cx)
      • Marginal branches (M1,M2)
  • Right coronary artery
    • Acute marginal branch (AM)
    • AV node branch
    • Posterior descending artery (PDA)

RCA, LAD and Cx in the right anterior oblique projection
On the left an overview of the coronary arteries in the lateral projection.

  • Left Main or left coronary artery (LCA)
    • Left anterior descending (LAD)
      • diagonal branches (D1, D2)
      • septal branches
    • Circumflex (Cx)
      • Marginal branches (M1,M2)
  • Right coronary artery
    • Acute marginal branch (AM)
    • AV node branch
    • Posterior descending artery (PDA)

RCA, LAD and Cx in the lateral projection

Left Coronary Artery (LCA)

The left coronary artery (LCA) is also known as the left main.
The LCA arises from the left coronary cusp.

The aortic valve has three leaflets, each having a cusp or cup-like configuration.
These are known as the left coronary cusp (L), the right coronary cusp (R) and the posterior non-coronary cusp (N).
Just above the aortic valves there are anatomic dilations of the ascending aorta, also known as the sinus of Valsalva. The left aortic sinus gives rise to the left coronary artery.
The right aortic sinus which lies anteriorly, gives rise to the right coronary artery.
The non-coronary sinus is postioned on the right side.

Left coronary (LC), right coronary (RC) and posterior non-coronary (NC) cusp
The LCA divides almost immediately into the circumflex artery (Cx) and left anterior descending artery (LAD).
On the left an axial CT-image.
The LCA travels between the right ventricle outflow tract anteriorly and the left atrium posteriorly and divides into LAD and Cx.

On the image on the left we see the left main artery dividing into

  • Cx with obtuse marginal branch (OM)
  • LAD with diagonal branches (DB)

On volume rendered images the left atrial appendage needs to be removed to get a good look on the LCA.
In 15% of cases a third branch arises in between the LAD and the Cx, known as the ramus intermedius or intermediate branch.
This intermediate branche behaves as a diagonal branch of the Cx.
Left Anterior Descending (LAD)
The LAD travels in the anterior interventricular groove and continues up to the apex of the heart.
The LAD supplies the anterior part of the septum with septal branches and the anterior wall of the left ventricle with diagonal branches.
The LAD supplies most of the left ventricle and also the AV-bundle.Mnemonic: Diagonal branches arise from the LAD.

CT image of the LAD in RAO projection
The diagonal branches come off the LAD and run laterally to supply the antero-lateral wall of the left ventricle.
The first diagonal branch serves as the boundary between the proximal and mid portion of the LAD (2).
There can be one or more diagonal branches: D1, D2 , etc.
Circumflex (Cx)
The Cx lies in the left AV groove between the left atrium and left ventricle and supplies the vessels of the lateral wall of the left ventricle.
These vessels are known as obtuse marginals (M1, M2…), because they supply the lateral margin of the left ventricle and branch off with an obtuse angle.
In most cases the Cx ends as an obtuse marginal branch, but 10% of patients have a left dominant circulation in which the Cx also supplies the posterior descending artery (PDA).Mnemonic: Marginal branches arise from the Cx and supply the lateral Margin of the left ventricle.

Circumflex and LAD seen in Lateral projection
Right Coronary Artery (RCA)
The right coronary artery arises from the anterior sinus of Valsalva and courses through the right atrioventricular (AV) groove between the right artium and right ventricle to the inferior part of the septum.
In 50-60% the first branch of the RCA is the small conus branch, that supplies the right ventricle outflow tract.
In 20-30% the conus branch arises directly from the aorta.
In 60% a sinus node artery arises as second branch of the RCA, that runs posteriorly to the SA-node (in 40% it originates from the Cx).
The next branches are some diagonals that run anteriorly to supply the anterior wall of the right ventricle.
The large acute marginal branch (AM) comes off with anacute angle and runs along the margin of the right ventricle above the diaphragm.
The RCA continues in the AV groove posteriorly and gives off a branch to the AV node.
In 65% of cases the posterior descending artery (PDA) is a branch of the RCA (right dominant circulation).
The PDA supplies the inferior wall of the left ventricle and inferior part of the septum.
RCA, LAD and LCx in Anterior projection
On the image on the far left we see the most common situation, in which the RCA comes off the right cusp and will provide the conus branch at a lower level (not shown).
On the image next to it, we see a conus branch, that comes off directly from the aorta.
LEFT: RCA comes off the right sinus of Valsalva
RIGHT: Conus artery comes off directly from the aorta
The large acute marginal branch (AM) supplies the lateral wall of the right ventricle.
In this case there is a right dominant circulation, because the posterior descending artery (PDA) comes off the RCA.
Coronary Anomalies

Coronary anomalies are uncommon with a prevalence of 1%.
Early detection and evaluation of coronary artery anomalies is essential because of their potential association with myocardial ischemia and sudden death (3).
With the increased use of cardiac-CT, we will see these anomalies more frequently.

Coronary anomalies can be differentiated into anomalies of the origin, the course and termination (Table).

The illustration in the left upper corner is the most common and clinically significant anomaly.
There is an anomalous origin of the LCA from the right sinus of Valsalva and the LCA courses between the aorta and pulmonary artery.
This interarterial course can lead to compression of the LCA (yellow arrows) resulting in myocardial ischemia.

The other anomalies in the figure on the left are not hemodynamically significant.

Interarterial LCA

On the left images of a patient with an anomalous origin of the LCA from the right sinus of Valsalva and coursing between the aorta and pulmonary artery.
Sudden death is frequently observed in these patients.

ALCAPA

On the left images of a patient with an anomalous origin of the LCA from the pulmonary artery, also known as ALCAPA.
ALCAPA results in the left ventricular myocardium being perfused by relatively desaturated blood under low pressure, leading to myocardial ischemia.
ALCAPA is a rare, congenital cardiac anomaly accounting for approximately 0.25-0.5% of all congenital heart diseases.
Approximately 85% of patients present with clinical symptoms of CHF within the first 1-2 months of life.

Myocardial bridging

Myocardial bridging is most commonly observed of the LAD (figure).
The depth of the vessel under the myocardium is more important that the lenght of the myocardial bridging.
There is debate, whether some of these myocardial bridges are hemodynamically significant.

Fistula

On the image on the left we see a large LAD giving rise to a large septal branch that terminates in the right ventricle (blue arrow).

Left to right shunt: septal branch of LAD teminates in right ventricle
REFERENCES
  1. Introduction to cardiothoracic imaging
    by Carl Jaffe and Patrick J. Lynch
  2. Cardiology Site
    by M. Abdulla
    This site includes instructional movies, 3-D animation, panoramic views, online quiz, interactive video-clips, interactive heart sounds & murmurs and interactive echocardiograms.
  3. Visualization of Anomalous Coronary Arteries on Dual Source Computed Tomography
    by G.J. de Jonge et al
    European Radiology, Volume 18, Number 11 / November, 2008, 2425-2432

SOURCE

Robin Smithuis and Tineke Wilems
Radiology department of the Rijnland Hospital Leiderdorp and the University Medical Centre Groningen, the Netherlands.
http://rad.desk.nl/en/48275120e2ed5 

 

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Revascularization: PCI, Prior History of PCI vs CABG

Curator: Aviva Lev-Ari, PhD, RN

 

UPDATED 9/25/2013

Table. Comparison of Surgical Therapy and Coronary Angioplasty (Open Table in a new window)

Endpoint Pocock et al* Pocock et al BARI Study
CABG(N=358) PTCA(N=374) CABG(N=1303) PTCA(N=1336) CABG(N=914) PTCA(N=915)
Death (%) 0.3 1.9 2.8 3.1 10.7 13.7
Death or MI 4.5 7.2 8.5 8.1 11.7 10.9
Repeat CABG 1.4 16.0§ 0.8 18.3§ 0.7 20.5§
Repeat CABG or PTCA 3.6 30.5§ 3.2 34.5§ 8.0 54.0§
More than mild angina 6.5 14.6§ 12.1 17.8§
*Meta-analysis of results of 3 trials at 1 year. Patients with single-vessel disease were studied.[22] †Meta-analysis of results of 3 trials at 1 year. Patients with multivessel disease were studied.[22] 

‡Reported results are for 5-year follow-up. Patients with multivessel disease were studied.[21] 

§ P < .05.

BARI = Bypass Angioplasty Revascularization Investigation; CABG = coronary artery bypass grafting; MI = myocardial infarction; PTCA = percutaneous transluminal coronary angioplasty.

SOURCE

http://emedicine.medscape.com/article/161446-overview#aw2aab6b2b5

Percutaneous coronary intervention (PCI), also known as coronary angioplasty, is a nonsurgical technique for treating multiple conditions, including unstable angina, acute myocardial infarction (MI), and multivessel coronary artery disease (CAD).

Essential update: Cangrelor decreases periprocedural complications of PCI

According to a pooled analysis of 3 CHAMPION trials—CHAMPION-PCI , CHAMPION-PLATFORM , and CHAMPION-PHOENIX—cangrelor can reduce the risk of periprocedural thrombotic complications of PCI.[1, 2, 3] The 3 trials included patients with ST-elevation MI (STEMI), non-STEMI, and stable CAD who were randomly assigned to receive either cangrelor or control therapy consisting of either clopidogrel or placebo.

The primary outcome in this analysis was a composite of death, MI, ischemia-driven revascularization, or stent thrombosis at 48 hours.[2] The frequency of this outcome was significantly lower in cangrelor-treated patients than in control subjects (absolute difference, 1.9%; relative risk reduction [RRR], 19%). Stent thrombosis was also reduced in the cangrelor-treated group (absolute difference, 0.3%; RRR, 41%). Primary safety outcomes were comparable in the 2 groups, but cangrelor-treated patients had a higher rate of mild bleeding.

Indications and contraindications

Clinical indications for PCI include the following:

In an asymptomatic or mildly symptomatic patient, objective evidence of a moderate-sized to large area of viable myocardium or moderate to severe ischemia on noninvasive testing is an indication for PCI. Angiographic indications include hemodynamically significant lesions in vessels serving viable myocardium (vessel diameter >1.5 mm).

Clinical contraindications for PCI include the presence of any significant comorbid conditions (this is a relative contraindication). Angiographic contraindications include the following:

  • Left main stenosis in a patient who is a surgical candidate (except in carefully selected patients[4] )
  • Diffusely diseased small-caliber artery or vein graft
  • Other coronary anatomy not amenable to PCI

In patients with stable angina, medical therapy is recommended as first-line therapy unless one or more of the following indications for cardiac catheterization and PCI or CABG are present:

  • A change in symptom severity
  • Failed medical therapy
  • High-risk coronary anatomy
  • Worsening left ventricular (LV) dysfunction

American College of Cardiology Foundation/American Heart Association (ACCF/AHA) guidelines on the management of unstable angina/non-STEMI recommend that an early invasive approach (angiography and revascularization within 24 hours) should be used to treat patients presenting with the following high-risk features[5] :

  • Recurrent angina at rest or low level of activity
  • Elevated cardiac biomarkers
  • PCI in the past 6 months or prior CABG
  • New ST-segment depression
  • Elevated cardiac biomarkers
  • High-risk findings on noninvasive testing
  • Signs or symptoms of heart failure or new or worsening mitral regurgitation
  • Hemodynamic instability
  • Sustained ventricular tachycardia
  • LV systolic function < 40%
  • High risk score (eg, Thrombolysis in Myocardial Infarction [TIMI] score >2) (see the TIMI Score for Unstable Angina Non ST Elevation Myocardial Infarction calculator)

See Overview for more detail.

Equipment

Balloon catheters for PCI have the following features:

  • A steerable guide wire precedes the balloon into the artery and permits navigation through the coronary tree
  • Inflation of the balloon compresses and axially redistributes atheromatous plaque and stretches the vessel wall
  • The balloon catheter also serves as an adjunctive device for many other interventional therapies

Atherectomy devices have the following features:

  • These devices are designed to physically remove coronary atheroma, calcium, and excess cellular material
  • Rotational atherectomy, which relies on plaque abrasion and pulverization, is used mostly for fibrotic or heavily calcified lesions that can be wired but not crossed or dilated by a balloon catheter
  • Atherectomy devices may be used to facilitate stent delivery in complex lesions
  • Directional coronary atherectomy (DCA) has been used to debulk coronary plaques
  • Laser atherectomy is not widely used at present
  • Atherectomy is typically followed by balloon dilation and stenting

Intracoronary stents have the following features:

  • Stents differ with respect to composition (eg, stainless steel, cobalt chromium, or nickel chromium), architectural design, and delivery system
  • Drug-eluting stents have demonstrated significant reductions in restenosis and target-lesion revascularization rates
  • In the United States, stents are available that elute the following drugs: sirolimus (Cypher), paclitaxel (Taxus), zotarolimus (Endeavor), and everolimus (Xience V)
  • Stents are conventionally placed after balloon predilation, but in selected coronary lesions, direct stenting may lead to better outcomes

Other devices used for PCI include the following:

  • Thrombus aspiration limits the adverse effects that prolonged time to treatment has on myocardial reperfusion[6]
  • Distal embolic protection during saphenous vein graft intervention has become the standard of care

See Periprocedural Care and Devices for more detail.

Technique

Intravascular ultrasonography (IVUS) is used in PCI as follows:

  • Provide information about the plaque, the vessel wall, and the degree of luminal narrowing
  • Assessment of indeterminate lesions
  • Evaluation of adequate stent deployment

Intracoronary Doppler pressure wires are used in PCI as follows:

  • To characterize coronary lesion physiology and estimate lesion severity
  • Comparison of pressure distal to a lesion with aortic pressure enables determination of fractional flow reserve (FFR)
  • An FFR measurement below 0.75-0.80 during maximal hyperemia (induced via administration of adenosine) is consistent with a hemodynamically significant lesion

Antithrombotic therapy

  • Aspirin and heparin have been the traditional adjunctive medical therapies
  • Direct thrombin inhibitors (ie, hirudin, bivalirudin) are slightly better than heparin in preventing ischemic complications during balloon angioplasty but do not affect restenosis rates
  • Low-molecular-weight heparins (LMWHs) are substituted for standard heparin at some centers

Antiplatelet therapy

Patients receiving stents are treated with a combination of aspirin and clopidogrel. Duration of therapy is as follows:

  • Bare-metal stents: A minimum of 4 weeks
  • Drug-eluting stents: A minimum of 12 months

Use of proton pump inhibitors is appropriate in patients with multiple risk factors for GI bleeding who require antiplatelet therapy.

Glycoprotein inhibitor therapy

  • Abciximab, tirofiban, and eptifibatide have all been shown to reduce ischemic complications in patients undergoing balloon angioplasty and coronary stenting
  • In primary PCI, GPIIb/IIIa receptor inhibitors have also been shown to improve flow and perfusion and to reduce adverse events
  • Abciximab may improve outcomes in patients when given before arrival in the catheterization lab for primary PCI[7]

See Technique and Medication for more detail.

SOURCE & References for the UPDATE, in

http://emedicine.medscape.com/article/161446-overview#aw2aab6b2b5

Outcomes comparison between PCI and CABG was explored in the past by authors on this Open Access Online Scientific Journal, in the following articles:

CABG or PCI: Patients with Diabetes – CABG Rein Supreme

https://pharmaceuticalintelligence.com/2012/11/05/cabg-or-pci-patients-with-diabetes-cabg-rein-supreme/

To Stent or Not? A Critical Decision

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

PCI Outcomes, Increased Ischemic Risk associated with Elevated Plasma Fibrinogen not Platelet Reactivity

https://pharmaceuticalintelligence.com/2013/01/10/pci-outcomes-increased-ischemic-risk-associated-with-elevated-plasma-fibrinogen-not-platelet-reactivity/

New Definition of MI Unveiled, Fractional Flow Reserve (FFR)CT for Tagging Ischemia

https://pharmaceuticalintelligence.com/2012/08/27/new-definition-of-mi-unveiled-fractional-flow-reserve-ffrct-for-tagging-ischemia/

Age-Dependent Depression in Circulating Endothelial Progenitor Cells in Coronary Artery Bypass Grafting Patients

https://pharmaceuticalintelligence.com/2012/08/17/age-dependent-depression-in-circulating-endothelial-progenitor-cells-in-coronary-artery-bypass-grafting-patients/

Now we are reporting  an Original Contribution on this subject which includes also Prior History of PCI, a factor NOT included in the other studies. The major conclusions are the following three:

  1. In a contemporary cohort of STEMI patients undergoing primary PCI, a history of prior CABG was found to be an independent predictor of in-hospital mortality.
  2. In contrast, despite more comorbidities at the time of STEMI, patients with prior PCI had no significant difference in the rates of death, stroke, or periprocedural MI when compared to a STEMI population without prior coronary revascularization.
  3. Thus, only prior surgical — and not percutaneousrevascularization should be considered a significant risk factor in the setting of primary PCI.

Number 1, above is related to patient medical history of cardiovascular disease SEVERITY prior to CABG

Number 2, above indicates that patients can tolerate and benefit several cycles of PCI and stent implantation rather than PCI being a determinant predictor of future prognosis

Number 3, above is as well related to patient medical history of cardiovascular disease SEVERITY prior to CABG

The Original Contribution on this subject is present, below.

The Impact of Previous Revascularization on Clinical Outcomes in Patients Undergoing Primary Percutaneous Coronary Intervention

Travis J. Bench, MD1, Puja B. Parikh, MD1, Allen Jeremias, MD1, Sorin J. Brener, MD2, Srihari S. Naidu, MD3,

Richard A. Shlofmitz, MD4, Thomas Pappas, MD4, Kevin P. Marzo, MD3, Luis Gruberg, MD1

Authors Affiliations:

1Division of Cardiovascular Medicine, Stony Brook University Medical Center, Stony Brook, New York,

2Department of Cardiology, Methodist Hospital, Brooklyn, New York,

3Division of Cardiology, Winthrop University Hospital, Mineola,

New York, and

4The Heart Center, St Francis Hospital, Roslyn, New York.

The authors report no conflicts of interest regarding the content herein.

Manuscript submitted October 10, 2012, provisional acceptance given October 20, 2012, final version accepted November 28, 2012.

Address for correspondence: 

Luis Gruberg, MD, FACC, Department of Medicine, Division of Cardiology, Health Sciences Center, T16-080, Stony Brook, NY 11794- 8160. Email: luis.gruberg@stonybrook.edu

 

Abstract : While the impact of prior coronary artery bypass graft surgery (CABG) on in-hospital outcomes in patients with STelevation myocardial infarction (STEMI) has been described, data are limited on patients with prior percutaneous coronary intervention (PCI) undergoing primary PCI in the setting of an STEMI. The aim of the present study was to assess the effect of previous revascularization on in-hospital outcomes in STEMI patients undergoing primary PCI. Between January 2004 and December 2007, a total of 1649 patients underwent primary PCI for STEMI at four New York State hospitals. Baseline clinical and angiographic characteristics and in-hospital outcomes were prospectively collected as part of the New York State PCI Reporting System (PCIRS). Patients with prior surgical or percutaneous coronary revascularization were compared to those without prior coronary revascularization. Of the 1649 patients presenting with STEMI, a total of 93 (5.6%) had prior CABG, 258 (15.7%) had prior PCI, and 1298 (78.7%) had no history of prior coronary revascularization. Patients with prior CABG were significantly older and had higher rates of peripheral vascular disease, diabetes mellitus, congestive heart failure, and prior stroke. Additionally, compared with those patients with a history of prior PCI as well as those without prior coronary revascularization, patients with previous CABG had more left main interventions (24% vs 2% and 2%; P<.001), but were less often treated with drug-eluting stents (47% vs 61% and 72%; P<.001).

Despite a low incidence of adverse in-hospital events, prior CABG was associated with higher all-cause in-hospital mortality (6.5% vs 2.2%; P=.012), and as a result, higher overall MACE (6.5% vs 2.7%; P=.039). By multivariate analysis, prior CABG (odds ratio, 3.40; 95% confidence interval, 1.15-10.00) was independently associated with in-hospital mortality. In contrast, patients with prior PCI had similar rates of MACE (4.3% vs 2.7%; P=.18) and inhospital mortality (3.1% vs 2.2%; P=.4) when compared to the de novo population. Patients with a prior history of CABG, but not prior PCI, undergoing primary PCI in the setting of STEMI have significantly worse in-hospital outcomes when compared with patients who had no prior history of coronary artery revascularization. Thus, only prior surgical — and not percutaneous — revascularization should be considered a significant risk factor in the setting of primary PCI.

J INVASIVE CARDIOL 2013;25(4):166-169

Key words: PCI risk factor, CABG

Demographics and Angiographic Characteristics

Between 2004 and 2007, a total of 25,025 patients underwent PCI at these medical institutions, and their data were prospectively collected and submitted as required by the New York State Department of Health. Of these patients, a total of 1649 underwent primary PCI in the setting of an STEMI and constituted our study population. In this group, a total

No Prior Revascularization (n = 1298)

Prior PCI (n = 258)

Prior CABG (n = 93)

Demographics

Age (years) 61 ± 13 62 ± 12 67 ± 12 <.001

Male gender 956 (73.6%) 194 (75.2%) 76 (81.7%) .21

White 1165 (89.8%) 231 (89.5%) 87 (93.5%) .51

African-American 78 (6%) 18 (7%) 1 (1.1%) .51

Hispanic 91 (7%) 11 (4.3%) 4 (4.3%) .51

Medical history

Ejection fraction (%) 43 ± 12 44 ± 13 45 ± 11 .079

Diabetes mellitus 196 (15.1%) 69 (26.7%) 27 (29%) <.001

Peripheral vascular disease 53 (4.1%) 25 (9.7%) 12 (12.9%) <.001

Chronic lung disease 47 (3.6%) 17 (6.6%) 4 (4.3%) .09

Congestive heart failure 74 (5.7%) 25 (9.7%) 10 (10.8%) .02

Prior myocardial infarction 3 (0.2%) 1 (0.4%) 1 (1.1%) .35

Prior cerebrovascular event 56 (4.3%) 9 (3.5%) 10 (11%) .01

Chronic dialysis 6 (0.5%) 6 (2.3%) 0 (0%) .004

Creatinine (mg/dL) 1.1 ± 0.8 1.3 ± 1.4 1.3 ± 1.1 .002

Glomerular filtration rate (mL/min/1.73 m2) 79 ± 26 75 ± 28 71 ± 27 .002

Angiographic characteristics

Left main 19 (1.5%) 5 (1.9%) 22 (23.7%) <.001

Left anterior descending 942 (72.6%) 178 (69%) 69 (74.2%) .45

Left circumflex 579 (44.6%) 122 (47.3%) 70 (75.3%) <.001

Right coronary 806 (62.1%) 187 (72.5%) 67 (72%) .002

Graft (arterial or venous) n/a n/a 20 (21.5%)

Stent type

Bare-metal stent 241 (18.6%) 52 (20.2%) 23 (24.7%) .31

Drug-eluting stent 928 (71.5%) 158 (61.2%) 44 (47.3%) <.001

of 1298 patients (78.7%) had no prior history of revascularization,

while 93 patients (5.6%) had a history of previous

CABG and 258 (15.7%) had a history of previous PCI. Considerable

differences in baseline clinical and procedural characteristics were noted among these groups (Table 1).

Discussion

While STEMI patients with prior CABG are well known to have worse clinical outcomes than those without prior revascularization, a direct comparison between patients who underwent primary PCI in the setting of prior CABG or prior PCI has not yet been reported. The principal findings from the present analysis suggest that in a contemporary, unrestricted patient population presenting with STEMI and undergoing primary PCI, patients with a prior history of CABG are:

(1) usually older and have multiple comorbidities, including peripheral vascular disease, diabetes, and chronic obstructive lung disease;

(2) are more likely to undergo intervention on a native vessel and not a bypass graft;

(3) are more likely to be treated with bare-metal stents; and (4) have higher rates of in-hospital mortality without a significant increase in stroke or MI rates, when compared with patients with a prior history of PCI or patients with no previous history of coronary artery revascularization. Interestingly, these outcomes did not apply to patients with a history of prior PCI in this analysis. Instead, this cohort of patients had no significant difference in the rate of death, stroke, or periprocedural infarction when compared to a STEMI population without prior coronary revascularization, despite a significantly higher burden of comorbidities than those with no prior revascularization.

Our findings concur with previous studies that have shown higher mortality rates among patients with prior surgical bypass presenting with acute MI.7,9,14 Despite changes in revascularization strategies over the past 30 years, invasive therapies to treat acute coronary syndromes in patients with prior bypass surgery appear to have yielded less robust results than in other populations. In fact, Stone and colleagues already described in the Primary Angioplasty in Myocardial Infarction (PAMI-2) study that patients with a previous CABG undergoing primary PCI in the setting of an acute MI had significantly greater in-hospital mortality than patients without previous CABG, especially if the infarct-related vessel was a bypass conduit. However, by logistic regression analysis, only advanced age (P=.004), triple-vessel disease (P=.004), and Killip class ≥2 (P=.02) were independent predictors of in-hospital mortality in that study.13 In a more contemporary study of 128 STEMI patients with prior CABG, who were enrolled in the Assessment of PEXelizumab in Acute

Figure 1. In-hospital major adverse cardiac and cerebrovascular events (MACCE), mortality, and stroke rates for patients without prior history of coronary revascularization (light grey bars), prior percutaneous coronary revascularization (PCI) (dark grey bars), and prior coronary artery bypass graft (CABG) (black bars). Vol. 25, No. 4, April 2013 169

STEMI and Prior Revascularization Myocardial Infarction (APEX-AMI) trial, Welsh and colleagues reported that post-CABG patients are less likely to undergo acute reperfusion (only 79% underwent primary PCI), have worse angiographic outcomes following primary PCI, and have higher 90-day mortality rates (19.0% vs 5.7%; P=.05). This difference was even more apparent when the infarct-related artery was a bypass graft that was not successfully reperfused (23.1% vs 8.5%; P=.03).3 These results are similar to our current analysis, where in-hospital mortality rates for patients who underwent primary PCI of a graft were numerically roughly 4 times as high as those undergoing PCI of a native vessel. Likewise, Gurfinkel et al reported a significant reduction in hard endpoints, such as all-cause death and MI at 6 months in patients treated with an invasive approach in the Global Registry of Acute Coronary Events (GRACE).15 In this large, multinational, observational study of 3853 patients with prior bypass surgery presenting with an acute coronary syndrome, only 497 (12.9%) were managed invasively and the rest were treated medically.

Despite significant differences in baseline characteristics, including a higher rate of STEMI in patients treated invasively (14% vs 27%; P<.001), in-hospital mortality was similar in both groups (3.4% vs 3.2%; P=.86). However, at 6-month follow-up, mortality was significantly higher in those patients treated medically (6.5% vs 3.4%; P<.02) as was the combined endpoint of death or MI (11% vs 5.8%; P<.01).

Whether these results apply to patients with a prior history of PCI has not been well defined. By the nature of vascular disease, patients with prior PCI are more likely to have more comorbidities than those without prior revascularization, a finding confirmed in our study. Despite considerable differences in baseline characteristics, however, these differences did not translate into a differential risk after STEMI. In fact, the cohort of patients presenting with STEMI who had a history of prior PCI had no statistically significant difference in in-hospital mortality or overall MACCE when compared to a population of patients presenting with STEMI in the absence of any prior revascularization.

Study limitations. The database utilized was derived from four New York State teaching hospitals and was designed to track quality of care and clinical outcomes. As all studies involving multicenter databases and registries, there is potential error in data entry and availability. Potential confounding comorbidities, including smoking status and family history of coronary artery disease, were not collected in this database, and information regarding long-term follow-up is not available, all of which are important limitations of this analysis. As such, deficiencies such as these limit the conclusions that can be drawn from our multivariate analysis. Additionally, there is no audit of data quality, and the low overall event rates limit effective statistical comparison.

Conclusions

In a contemporary cohort of STEMI patients undergoing primary PCI, a history of prior CABG was found to be an independent predictor of in-hospital mortality. In contrast, despite more comorbidities at the time of STEMI, patients with prior PCI had no significant difference in the rates of death, stroke, or periprocedural MI when compared to a STEMI population without prior coronary revascularization. Thus, only prior surgical — and not percutaneous — revascularization should be considered a significant risk factor in the setting of primary PCI.

REFERENCES

1. Kushner FG, Hand M, Smith SC Jr, et al. 2009 focused updates: ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction (updating the 2004 guideline and 2007 focused update) and ACC/AHA/SCAI guidelines on percutaneous coronary intervention (updating the 2005 guideline and 2007 focused update): a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Catheter Cardiovasc Interv. 2009;74(7):E25-E68.

2. Keeley EC, Boura JA, Grines CL. Primary angioplasty versus intravenous thrombolytic therapy for acute myocardial infarction: a quantitative review of 23 randomised trials. Lancet. 2003;361(9351):13-20.

3. Welsh RC, Granger CB, Westerhout CM, et al. Prior coronary artery bypass graft patients with ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention. JACC Cardiovasc Interv. 2010;3(3):343-351.

4. Mathew V, Gersh B, Barron H, et al. In-hospital outcome of acute myocardial infarction in patients with prior coronary artery bypass surgery. Am Heart J. 2002;144(3):463-469.

5. Lee KL, Woodlief LH, Topol EJ, et al. Predictors of 30-day mortality in the era of reperfusion for acute myocardial infarction. Results from an international trial of 41,021 patients. GUSTO-I Investigators. Circulation. 1995;91(6):1659-1668.

6. Dittrich HC, Gilpin E, Nicod P, et al. Outcome after acute myocardial infarction in patients with prior coronary artery bypass surgery. Am J Cardiol. 1993;72(7):507-513.

7. Berry C, Pieper KS, White HD, et al. Patients with prior coronary artery bypass grafting have a poor outcome after myocardial infarction: an analysis of the VALsartan in acute myocardial iNfarcTion trial (VALIANT). Eur Heart J. 2009;30(12):1450-1456.

8. Grines CL, Booth DC, Nissen SE, et al. Mechanism of acute myocardial infarction in patients with prior coronary artery bypass grafting and therapeutic implications. Am J Cardiol. 1990;65(20):1292-1296.

9. Labinaz M, Sketch MH Jr, Ellis SG, et al. Outcome of acute ST-segment elevation myocardial infarction in patients with prior coronary artery bypass surgery receiving thrombolytic therapy. Am Heart J. 2001;141(3):469-477.

10. Peterson LR, Chandra NC, French WJ, Rogers WJ, Weaver WD, Tiefenbrunn AJ. Reperfusion therapy in patients with acute myocardial infarction and prior coronary artery bypass graft surgery (National Registry of Myocardial Infarction-2). Am J Cardiol. 1999;84(11):1287-1291.

11. Nguyen TT, O’Neill WW, Grines CL, et al. One-year survival in patients with acute myocardial infarction and a saphenous vein graft culprit treated with primary angioplasty. Am J Cardiol. 2003;91(10):1250-1254.

12. Al Suwaidi J, Velianou JL, Berger PB, et al. Primary percutaneous coronary interventions in patients with acute myocardial infarction and prior coronary artery bypass grafting, Am Heart J. 2001;142(3):452-459.

13. Stone GW, Brodie BR, Griffin JJ, et al. Clinical and angiographic outcomes in patients with previous coronary artery bypass graft surgery treated with primary balloon angioplasty for acute myocardial infarction. Second Primary Angioplasty in Myocardial Infarction Trial (PAMI-2) Investigators. J Am Coll Cardiol. 2000;35(3):605-611.

14. Labinaz M, Kilaru R, Pieper K, et al. Outcomes of patients with acute coronary syndromes and prior coronary artery bypass grafting: results from the platelet glycoprotein IIb/IIIa in unstable angina: receptor suppression using integrilin therapy (PURSUIT) trial. Circulation. 2002;105(3):322-327.

15. Gurfinkel EP, Perez de la Hoz R, Brito VM, et al. Invasive vs non-invasive treatment in acute coronary syndromes and prior bypass surgery. Int J Cardiol. 2007;119(1):65-72.

 

Other related studies on this subject published on this Open Access Online Scientific Journal include the following:

Lev-Ari, A. 2/12/2013 Clinical Trials on transcatheter aortic valve replacement (TAVR) to be conducted by American College of Cardiology and the Society of Thoracic Surgeons

https://pharmaceuticalintelligence.com/2013/02/12/american-college-of-cardiologys-and-the-society-of-thoracic-surgeons-entrance-into-clinical-trials-is-noteworthy-read-more-two-medical-societies-jump-into-clinical-trial-effort-for-tavr-tech-f/

 

Lev-Ari, A. 12/31/2012 Renal Sympathetic Denervation: Updates on the State of Medicine

https://pharmaceuticalintelligence.com/2012/12/31/renal-sympathetic-denervation-updates-on-the-state-of-medicine/

 

Lev-Ari, A. 9/2/2012 Imbalance of Autonomic Tone: The Promise of Intravascular Stimulation of Autonomics

https://pharmaceuticalintelligence.com/2012/09/02/imbalance-of-autonomic-tone-the-promise-of-intravascular-stimulation-of-autonomics/

Lev-Ari, A. 8/13/2012 Coronary Artery Disease – Medical Devices Solutions: From First-In-Man Stent Implantation, via Medical Ethical Dilemmas to Drug Eluting Stents https://pharmaceuticalintelligence.com/2012/08/13/coronary-artery-disease-medical-devices-solutions-from-first-in-man-stent-implantation-via-medical-ethical-dilemmas-to-drug-eluting-stents/

 

Lev-Ari, A. 7/18/2012 Percutaneous Endocardial Ablation of Scar-Related Ventricular Tachycardia

https://pharmaceuticalintelligence.com/2012/07/18/percutaneous-endocardial-ablation-of-scar-related-ventricular-tachycardia/

 

Lev-Ari, A. 6/13/2012 Treatment of Refractory Hypertension via Percutaneous Renal Denervation

https://pharmaceuticalintelligence.com/2012/06/13/treatment-of-refractory-hypertension-via-percutaneous-renal-denervation/

Lev-Ari, A. 6/22/2012 Competition in the Ecosystem of Medical Devices in Cardiac and Vascular Repair: Heart Valves, Stents, Catheterization Tools and Kits for Open Heart and Minimally Invasive Surgery (MIS)

https://pharmaceuticalintelligence.com/2012/06/22/competition-in-the-ecosystem-of-medical-devices-in-cardiac-and-vascular-repair-heart-valves-stents-catheterization-tools-and-kits-for-open-heart-and-minimally-invasive-surgery-mis/

Lev-Ari, A. 6/19/2012 Executive Compensation and Comparator Group Definition in the Cardiac and Vascular Medical Devices Sector: A Bright Future for Edwards Lifesciences Corporation in the Transcatheter Heart Valve Replacement Market

https://pharmaceuticalintelligence.com/2012/06/19/executive-compensation-and-comparator-group-definition-in-the-cardiac-and-vascular-medical-devices-sector-a-bright-future-for-edwards-lifesciences-corporation-in-the-transcatheter-heart-valve-replace/

 

Lev-Ari, A. 6/22/2012 Global Supplier Strategy for Market Penetration & Partnership Options (Niche Suppliers vs. National Leaders) in the Massachusetts Cardiology & Vascular Surgery Tools and Devices Market for Cardiac Operating Rooms and Angioplasty Suites

https://pharmaceuticalintelligence.com/2012/06/22/global-supplier-strategy-for-market-penetration-partnership-options-niche-suppliers-vs-national-leaders-in-the-massachusetts-cardiology-vascular-surgery-tools-and-devices-market-for-car/

 

Lev-Ari, A. 7/23/2012 Heart Remodeling by Design: Implantable Synchronized Cardiac Assist Device: Abiomed’s Symphony

https://pharmaceuticalintelligence.com/2012/07/23/heart-remodeling-by-design-implantable-synchronized-cardiac-assist-device-abiomeds-symphony/

 

Lev-Ari, A. (2006b). First-In-Man Stent Implantation Clinical Trials & Medical Ethical Dilemmas. Bouve College of Health Sciences, Northeastern University, Boston, MA 02115

 

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Reporter: Aviva Lev-Ari, PhD, RN

Can Coronary Artery Anomalies Be Detected on CT Calcium Scoring Studies?

Academic Radiology, 04/11/2013  Review Article

Maddux PT et al. – The purpose of this study is to determine whether coronary artery anomalies can be detected on noncontrast computed tomography (CT) coronary artery calcium scoring (CCS) studies. Benign and malignant coronary artery anomalies can be detected with relatively high accuracy on noncontrast–enhanced CCS studies. CCS studies should be reviewed for signs of coronary artery anomalies in order to identify malignant variants with possible impact on patient management.

Methods

  • A total of 126 patients (mean age 62 years; 35 women) underwent noncontrast CCS and contrast enhanced coronary CT angiography (cCTA).
  • Thirty–three patients were diagnosed with a coronary anomaly on cCTA, whereas coronary anomalies were excluded in 93.
  • Two observers (reader 1 [R1] and reader 2 [R2]), blinded to patient information independently evaluated each CCS study for: 1) visibility of coronary artery origins, 2) detection of coronary anomalies, and 3) benign or malignant (ie, interarterial) course.
  • Using cCTA as the reference standard, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CCS studies for detecting coronary anomalies were calculated.

Results

  • Of the 33 coronary anomalies, 16 were benign and 17 malignant.
  • Based on noncontrast CCS studies, R1 and R2 correctly identified the left main origin in 123/126 (97.6%) and 121/126 (96%) patients; the left anterior descending origin in 125/126 (99.2%) and 122/126 (96.8%); the circumflex origin in 120/126 (95.2%) and 105/126 (83.3%); and the right coronary artery origin in 117/126 (92.9%) and 103/126 (81.7%), respectively.
  • R1 and R2 identified 34 and 27 coronary anomalies and classified 19 and 15 as malignant, respectively.
  • Interobserver reproducibility for detection of coronary anomalies was good (k = 0.76).
  • Interobserver agreement for detection of malignant variants was even stronger (k = 0.80).
  • On average, coronary artery anomalies were diagnosed with 85.2% sensitivity, 96.4% specificity, 90.5% PPV, and 94.1% NPV on noncontrast CCS studies.

http://www.mdlinx.com/radiology/news-article.cfm/4559774/?xml

http://www.mdlinx.com/radiology/news-article.cfm/4559774/cardiac-ct-coronary-anomaly-coronary-anatomy#ixzz2QrCXwP2q

Advanced CT reconstruction improves cardiac plaque assessment

By Eric Barnes, AuntMinnie.com staff writer

April 12, 2013 — Automated plaque assessment in coronary CT angiography (CCTA) is a promising new way to evaluate a patient’s plaque burden quickly and noninvasively — but it won’t be quick or accurate without the use of advanced iterative reconstruction, according to researchers from Massachusetts General Hospital in Boston.

Automated techniques are still in their infancy, but once they become more reliable they promise to greatly improve risk assessment and management compared with, for example, calcium scoring, by precisely quantifying the amount of coronary artery plaque — fibrotic, lipid core, and calcium — that is present.

“We know the plaque volume and characteristics … are at least as important as the presence of calcium,” said Dr. Stefan Puchner in an interview with AuntMinnie.com. “If we could make plaque assessment more accurate, we could implement all this stuff in our daily practice.”

The process isn’t accurate today. Automated plaque quantification requires significant time for radiologists to fix the incorrectly drawn vessel wall boundaries, making it impractical for routine use. Manually drawing the boundaries would actually take about a day’s work for each patient, so automation is the only way forward, Puchner said. The group wanted to determine if an advanced reconstruction algorithm might produce fewer errors and make semiautomated plaque estimation practical.

In a study that reconstructed ex vivo coronary vessel segments using three different reconstruction methods, the study team found that, indeed, accuracy in plaque quantification depended on the reconstruction algorithm, as well as vessel size and the extent of calcifications. Using advanced reconstruction, fewer corrections were needed to the vessel wall segmentation, Puchner reported at the 2013 European Congress of Radiology (ECR) in Vienna. Specifically, they compared the use of automated vessel assessment using model-based iterative reconstruction (MBIR, GE Healthcare) compared with an earlier IR algorithm, advanced statistical iterative reconstruction (ASIR, GE), or conventional filtered back projection (FBP) reconstruction.

Cross section of a noncalcified plaque reconstructed with the three different algorithms

Cross section of a noncalcified plaque reconstructed with the three different algorithms (left to right: FBP, ASIR, MBIR). No significant differences can be seen between the three algorithms in terms of correct delineation of the plaque borders. All images courtesy of Dr. Stephan Puchner.

For subjects, the group examined three ex vivo human hearts imaged with CCTA and reconstructed with FBP, ASIR, and MBIR. An automated plaque quantification tool (Vitrea Cardiac Solutions, Vital) was applied to each of the three reconstruction algorithms to fit the outer and inner vessel wall boundaries in nine “triplets” constituting 27 vessels. Only the first 40 mm of the contrast-filled vessels was used for analysis.

Each coronary cross section for which the software assigned incorrect boundaries was tallied and corrected in a blinded manner. The group then compared the number of vessel wall corrections between the different reconstruction algorithms using a Chi-square test.

Cross sections reconstructed with ASIR (middle) and MBIR (right) are correctly delineated by the software

Cross ection of a calcified plaque reconstructed with the three different algorithms (left to right: FBP, ASIR, MBIR). In this case, FBP shows an incorrect delineation of the inner vessel wall boundary, including parts of the calcified plaque. In contrast, the vessel wall boundaries in the cross sections reconstructed with ASIR and MBIR are correctly delineated by the software.

“Our analysis included the percentage of corrections between the three algorithms, and a per-vessel comparison of the percentage of corrections between the three algorithms,” Puchner said in his presentation.

In all, the study comprised 2,295 cross sections in 0.5-mm increments from nine coronary vessels, combined into 765 coregistered triplets evaluated with the three algorithms. Overall, 31% of the cross sections needed boundary corrections, he said. Outer vessel wall boundary corrections were needed in 400 cross sections, and inner vessel boundaries were needed in 381 cross sections.

Only in the cross section reconstructed with MBIR (right) are the boundaries correctly delineated

Cross section of a calcified plaque reconstructed with the three different algorithms (left to right: FBPR, ASIR, MBIR). In this case, FBP and ASIR show an incorrect delineation of the inner vessel wall boundary, including the whole or parts of the calcified plaque. Only in the cross section reconstructed with MBIR are the boundaries correctly delineated by the software.

The percentage of corrected cross sections was lower for MBIR (24.1%) versus ASIR (32.4%, p = 0.0003) and FBP (36.6%, p < 0.0001) — but the differences were only marginal between ASIR and FBP, he said.

“We found that MBIR works much better than the conventional algorithms … significantly reducing the number of corrections needed compared to FBP and ASIR, whereas the difference between the two other algorithms was not significant,” Puchner said.

The use of MBIR significantly reduced the need for vessel wall boundary corrections compared with other reconstruction algorithms, particularly at the site of calcifications.

Automated segmentation is certainly faster than manual processing, Puchner said. Just on the three cases used in the study and in the analysis of the proximal 40 mm of each vessel, use of the software saved about three hours compared with what manual segmentation would have required. There is significant processing time required to create MBIR reconstructions, he acknowledged, but in those cases, it’s the technologists, not the physicians, who are spending the additional time, he said.

“The next step will be to look at it in an in vivo environment, to see this application in a beating heart,” Puchner told AuntMinnie.com. And to test other applications and other iterative reconstruction schemes, of course.

“I’m pretty sure that the other newer algorithms will have similar effects, because overall some studies have shown that the use of newer algorithms reduces blooming effects and other stuff that makes it difficult for the software to delineate it correctly,” he said. With manual segmentation, radiologists tend to overcorrect for older reconstruction algorithms and undercorrect for newer techniques, “but if the software does it, the software is much more dependent on image quality, and it makes a difference if it was reconstructed with the newer algorithms or the older algorithms.”

Automated plaque measurements will also have to be compared with assessments in other modalities such as intravascular ultrasound, and even to histology using the donor hearts, he said.

Related Reading

MBIR finds same nodules as ASIR, at fraction of dose, December 13, 2012

MBIR tops ASIR for ultralow-dose CT enterography, November 6, 2012

Study pinpoints optimal ASIR blend for stomach cancer, November 6, 2012

MBIR takes on ASIR in low-dose chest CT, November 6, 2012

Iterative reconstruction cuts CT dose for urinary stone disease, August 20, 2012
Copyright © 2013 AuntMinnie.com

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Coronary CT Angiography in the ED

For an analysis of the finding of ROMICAT II Trial:
Hoffmann U, et al; ROMICAT-II Investigators. Coronary CT angiography versus standard evaluation in acute chest pain. N Engl J Med. 2012 Jul 26;367(4):299-308.
go to:

Acute Chest Pain/ER Admission: Three Emerging Alternatives to Angiography and PCI – Corus CAD, hs cTn, CCTA, Curator: Aviva Lev-Ari, PhD, RN, 3/10/2013

It is well known that taking a good history and physical, getting a non-ischemic EKG, and serial cardiac biomarkers, results in a risk of death/AMI of <5% in 30 days. Patients, in whom you still suspect have CAD, should undergo provocative testing within the next 72 hours based on the AHA/ACC guidelines. Their guidelines deem provocative testing as including:

  • Exercise treadmill stress test,
  • Myocardial perfusion scan,
  • Stress echocardiography, and/or
  • Coronary CT angiography (CCTA).

Myocardial perfusion scans and stress echos have a sensitivity of 85–90% and specificity of 75–80%. In contrast, CCTA’s have been shown to have a sensitivity of 93-97% and specificity of 80-90%.

Recently two landmark trials were published in NEJM discussing the use of CCTA in the emergency department.
ACRIN-PA Trial: Litt HI, et al. CT angiography for safe discharge of patients with possible acute coronary syndromes. N Engl J Med. 2012 Apr 12;366(15):1393-403. PMID: 22449295
What they did: 
  •  Non-inferiority study
  • 5 Pennsylvania EDs
  • 1,370 patients, Age > 30 years
  • Inclusion criteria: TIMI score of 0–2, EKG without ischemic changes, and negative first set of Cardiac Biomarkers
  • Randomized 2 patients to CCTA arm (908 patients) for every 1 patient to Standard Stress arm (462 patients)

Primary Outcome:

  • MI or Death from CAD at 30 days

Secondary Outcomes:

  • Rate of discharge from ED
  • Length of stay (LOS) in ED
  • Rate of detection of CAD
  • Resource utilization

What they found:

  • 640/908 pts (70.5%) who underwent CCTA had coronary stenosis of <50% and none had MI or death due to CAD at 30 days
  • Discharge from ED 49.6% with CCTA vs 22.7% with standard stress arm
  • ED LOS 18 hr in CCTA arm vs 24.8 hr in standard stress arm

Conclusion: CCTA allows early discharge of low to intermediate risk patients presenting to the ED with possible ACS.

ROMICAT II Trial:  Hoffmann U, et al; ROMICAT-II Investigators. Coronary CT angiography versus standard evaluation in acute chest pain. N Engl J Med. 2012 Jul 26;367(4):299-308.PMID: 22830462
What they did:
  • Randomized controlled trial
  • 9 EDs in the US
  • 1,000 patients with acute chest pain with ages 40–74 years
  • CCTA (501 patients) versus Standard Evaluation (499 patients)

Primary Outcome:

  • Hospital length of stay

Secondary Outcomes:

  • Cardiovascular events at 28 days
  • Rate of discharge from ED
  • Time to diagnosis
  • Cost
  • Utilization of resources

What they found:

  • Hospital LOS decreased by 7.6 hr in CCTA group
  • Rate of discharge from ED 47% in CCTA arm vs 12% in Standard Evaluation Arm
  • No difference in cardiovascular events at 28 days
  • Cost was similar between two groups $4,289 CCTA vs $4,060 in Standard arm

Conclusion: CCTA decreases length of stay without an increase in rate of cardiovascular events.

Some discussion points worth mentioning:
  • CCTA with 0 lesions is NEGATIVE: These patients can certainly be discharged home with primary care follow up with a nearly 100% NPV for ACS/AMI.
  • CCTA with <50% lesion is NOT NEGATIVE: This patient has CAD. It may not be clinically significant, but we can see plaques. 2/3 of AMIs occur from plaques that have <50% stenosis. Certainly we can start risk factor modification with beta blockers, ASA, and statins, but there are no studies looking at how this group of patients will do long term.
  • CCTAs are anatomic studies and not functional studies. Identified lesions will lead to more diagnostic tests, which is one of the big arguments against CCTA. CCTA identifies CAD more often than standard stress modalities, which leads to more heart catheterizations and PCIs.
  • As the number of CT slice increases, radiation dose decreases:
    1. A 64 slice CT = 10 – 15 mSv of radiation
    2. A 128 slice CT = 5 – 10 mSv of radiation
    3. A 256 slice CT = 1 – 5 mSv of radiation
    4. In contrast, a single-view CXR = 0.02 mSV of radiation
  • There is currently an ongoing National Heart, Lung, and Blood Institute-funded trial called the PROMISE (Prospective Multi-center Imaging Study for Evaluation of Chest Pain) Study with 10,000 patients. Patients with symptoms suggestive of CAD will be randomized to a CCTA vs usual care with a functional test.  What’s interesting about this study is it is being performed in the offices of primary care physicians and cardiologists rather than EDs. The study authors hypothesize that medically optimizing patients identified, as having non-obstructive CAD will yield improved long-term outcomes.
It is well known that in low risk patients, doing a good H&P, having a negative EKG (no ischemic changes), and negative serial cardiac biomarkers gives us about 99% NPV & 99% sensitivity for ACS/AMI. This is even without additional testing, such as CCTAs.So are CCTAs worth the cost and potential harms in this low-risk group to add another 1% to the 99% NPV and 99% sensitivity rates? In my opinion, that answer is NO.
Additional References:
  1. Jancin B. Comparing Technologies for Imaging Chest Pain in the ED.  ACEP News 2013 Mar; 32(3): 1 – 11.
  2. Goldstein JA. A Randomized Controlled Trial of Multi-Slice Coronary Computed Tomography for Evaluation of Acute Chest Pain.  JACC 2007;49: 863 – 71.  PMID: 17320744
  3. Goldstein JA. The CT-STAT (Coronary Computed Tomographic Angiography for Systematic Triage of Acute Chest Pain Patients to Treatment) Trial.  JACC 2011 Sept; 58: 1414 – 22. PMID: 21939822
  4. Hulten E. Outcomes After Coronary Computed Tomography Angiography in the Emergency Department:  A Systematic Review and Meta-Analysis of Randomized, Controlled Trials.  JACC 2013 Feb; 61: 880 – 92.  PMID: 23395069 
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