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Archive for the ‘Peripheral Arterial Disease & Peripheral Vascular Surgery’ Category


The Golden Hour of Stroke Intervention

Reporter: Irina Robu, PhD

The removal of thrombus under the image guidance, endovascular thrombectomy is preferred for an arterial embolism which is characteristic for an arterial blockage frequently caused by atrial fibrillation, a heart rhythm disorder. An arterial embolism causes restricted blood supply which leads to pain in the affected area. A thrombectomy can too be used to treat conditions in your organs which is usually associated with less benefit and more risk, a large retrospective study found.

Alejandro Spiotta, MD from Medical University of South Carolina in Charleston stated that functional independence rates were 45% for those treated in less than 30 minutes, 33% with procedures 30 to 60 minutes long, and 27% when procedures took more than 60 minutes. The results indicate that complications double after 50 minutes and the mortality risk is significantly for the over 60-minute group than in those treated in 30 to 60 minutes.

Earlier research has shown that when it comes to mechanical thrombectomy, procedure time has a noteworthy effect on patient outcomes. Based on these findings, it seems reasonable to conclude that at 60 minutes, one should consider the futility of continuing the procedure. However, procedures that last longer were connected with increased cost, worse outcomes, and increased incidence of complications, the investigators noted. Yet, the findings underscore the importance of timely recanalization and suggest there’s a point at which continuing to manipulate the intracranial artery may not be helpful for the patient.

Spiotta’s group evaluated 1,357 participants at seven U.S. medical centers, but only 12% out of the patients showed signs of posterior circulation stroke and 46% of cases received IV tissue-type plasminogen activator. The scientists use a prospectively-maintained database which consists of clinical and technical outcomes and baseline variables and can evaluate patients that underwent endovascular thrombectomy with direct aspiration as first pass technique or a stent retriever.

They collected their experience with the benefit of hindsight and joint it together, so there’s always a chance of case ascertain bias or other bias in the collection of the cases. One limitation is the fact that these are quality, busy centers, and the results might even worse if less experienced centers were included. It’s a little bit like getting the cream of the crop and analyzing their data. Upcoming studies should gather data on the relationship between specific thrombectomy devices and techniques and the success of recanalization procedures for patients with AIS.

SOURCE
https://www.medpagetoday.com/cardiology/strokes/78251

 

 

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Lesson 3 Cell Signaling & Motility: G Proteins, Signal Transduction: Curations and Articles of reference as supplemental information: #TUBiol3373

Curator: Stephen J. Williams, Ph.D.

Lesson 3 Powerpoint (click link below):

cell signaling and motility 3 finalissima sjw

Four papers to choose from for your February 11 group presentation:

Structural studies of G protein Coupled receptor

Shapiro-2009-Annals_of_the_New_York_Academy_of_Sciences

G protein as target in neurodegerative disease

fish technique

 

 

Today’s lesson 3 explains how extracellular signals are transduced (transmitted) into the cell through receptors to produce an agonist-driven event (effect).  This lesson focused on signal transduction from agonist through G proteins (GTPases), and eventually to the effectors of the signal transduction process.  Agonists such as small molecules like neurotransmitters, hormones, nitric oxide were discussed however later lectures will discuss more in detail the large growth factor signalings which occur through receptor tyrosine kinases and the Ras family of G proteins as well as mechanosignaling through Rho and Rac family of G proteins.

Transducers: The Heterotrimeric G Proteins (GTPases)

An excellent review of heterotrimeric G Proteins found in the brain is given by

Heterotrimeric G Proteins by Eric J Nestler and Ronald S Duman.

 

 

from Seven-Transmembrane receptors – Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/Examples-of-heterotrimeric-G-protein-effectors_tbl1_11180073 [accessed 4 Feb, 2019] and see references within

 

 

See below for the G Protein Cycle

 

 

 

 

 

 

 

 

<a href=”https://www.researchgate.net/figure/32-The-G-protein-cycle-In-the-absence-of-agonist-A-GPCRs-are-mainly-in-the-low_fig2_47933733″><img src=”https://www.researchgate.net/profile/Veli_Pekka_Jaakola/publication/47933733/figure/fig2/AS:669499451781133@1536632516635/32-The-G-protein-cycle-In-the-absence-of-agonist-A-GPCRs-are-mainly-in-the-low.ppm&#8221; alt=”.3.2: The G protein cycle. In the absence of agonist (A), GPCRs are mainly in the low affinity state (R). After agonist binding, the receptor is activated in the high affinity state (R*), and the agonist-GPCR-G protein complex is formed. GTP replaces GDP in Gα. After that the G protein dissociates into the Gα subunit and the Gβγ heterodimer, which then activate several effector proteins. The built-in GTPase activity of the Gα subunit cleaves the terminal phosphate group of GTP, and the GDP bound Gα subunit reassociates with Gβγ heterodimer. This results in the deactivation of both Gα and Gβγ. The G protein cycle returns to the basal state. RGS, regulator of G protein signalling.”/></a>

 

From Citation: Review: A. M. Preininger, H. E. Hamm, G protein signaling: Insights from new structures. Sci. STKE2004, re3 (2004)

 

For a tutorial on G Protein coupled receptors (GPCR) see

https://www.khanacademy.org/test-prep/mcat/organ-systems/biosignaling/v/g-protein-coupled-receptors

 

 

 

cyclic AMP (cAMP) signaling to the effector Protein Kinase A (PKA)

from https://courses.washington.edu/conj/gprotein/cyclicamp.htm

Cyclic AMP is an important second messenger. It forms, as shown, when the membrane enzyme adenylyl cyclase is activated (as indicated, by the alpha subunit of a G protein).

 

The cyclic AMP then goes on the activate specific proteins. Some ion channels, for example, are gated by cyclic AMP. But an especially important protein activated by cyclic AMP is protein kinase A, which goes on the phosphorylate certain cellular proteins. The scheme below shows how cyclic AMP activates protein kinase A.

Additional information on Nitric Oxide as a Cellular Signal

Nitric oxide is actually a free radical and can react with other free radicals, resulting in a very short half life (only a few seconds) and so in the body is produced locally to its site of action (i.e. in endothelial cells surrounding the vascular smooth muscle, in nerve cells). In the late 1970s, Dr. Robert Furchgott observed that acetylcholine released a substance that produced vascular relaxation, but only when the endothelium was intact. This observation opened this field of research and eventually led to his receiving a Nobel prize. Initially, Furchgott called this substance endothelium-derived relaxing factor (EDRF), but by the mid-1980s he and others identified this substance as being NO.

Nitric oxide is produced from metabolism of endogenous substances like L-arginine, catalyzed by one of three isoforms of nitric oxide synthase (for link to a good article see here) or release from exogenous compounds like drugs used to treat angina pectoris like amyl nitrate or drugs used for hypertension such as sodium nitroprusside.

The following articles are a great reference to the chemistry, and physiological and pathological Roles of Nitric Oxide:

46. The Molecular Biology of Renal Disorders: Nitric Oxide – Part III

Curator and Author: Larry H Bernstein, MD, FACP

https://pharmaceuticalintelligence.com/2012/11/26/the-molecular-biology-of-renal-disorders/

47. Nitric Oxide Function in Coagulation – Part II

Curator and Author: Larry H. Bernstein, MD, FCAP

https://pharmaceuticalintelligence.com/2012/11/26/nitric-oxide-function-in-coagulation/

48. Nitric Oxide, Platelets, Endothelium and Hemostasis

Curator and Author: Larry H Bernstein, MD, FACP

https://pharmaceuticalintelligence.com/2012/11/08/nitric-oxide-platelets-endothelium-and-hemostasis/

49. Interaction of Nitric Oxide and Prostacyclin in Vascular Endothelium

Curator and Author: Larry H Bernstein, MD, FACP

https://pharmaceuticalintelligence.com/2012/09/14/interaction-of-nitric-oxide-and-prostacyclin-in-vascular-endothelium/

50. Nitric Oxide and Immune Responses: Part 1

Curator and Author:  Aviral Vatsa PhD, MBBS

https://pharmaceuticalintelligence.com/2012/10/18/nitric-oxide-and-immune-responses-part-1/

51. Nitric Oxide and Immune Responses: Part 2

Curator and Author:  Aviral Vatsa PhD, MBBS

https://pharmaceuticalintelligence.com/2012/10/28/nitric-oxide-and-immune-responses-part-2/

56. Nitric Oxide and iNOS have Key Roles in Kidney Diseases – Part II

Curator and Author: Larry H Bernstein, MD, FACP

https://pharmaceuticalintelligence.com/2012/11/26/nitric-oxide-and-inos-have-key-roles-in-kidney-diseases/

57. New Insights on Nitric Oxide donors – Part IV

Curator and Author: Larry H Bernstein, MD, FACP

https://pharmaceuticalintelligence.com/2012/11/26/new-insights-on-no-donors/

59. Nitric Oxide has a ubiquitous role in the regulation of glycolysis -with a concomitant influence on mitochondrial function

Curator and Author: Larry H Bernstein, MD, FACP

https://pharmaceuticalintelligence.com/2012/09/16/nitric-oxide-has-a-ubiquitous-role-in-the-regulation-of-glycolysis-with-         a-concomitant-influence-on-mitochondrial-function/

Biochemistry of the Coagulation Cascade and Platelet Aggregation: Nitric Oxide: Platelets, Circulatory Disorders, and Coagulation Effects

Nitric Oxide Function in Coagulation – Part II

Nitric oxide is implicated in many pathologic processes as well.  Nitric oxide post translational modifications have been attributed to nitric oxide’s role in pathology however, although the general mechanism by which nitric oxide exerts its physiological effects is by stimulation of soluble guanylate cyclase to produce cGMP, these post translational modifications can act as a cellular signal as well.  For more information of NO pathologic effects and how NO induced post translational modifications can act as a cellular signal see the following:

Nitric Oxide Covalent Modifications: A Putative Therapeutic Target?

58. Crucial role of Nitric Oxide in Cancer

Curator and Author: Ritu Saxena, Ph.D.

https://pharmaceuticalintelligence.com/2012/10/16/crucial-role-of-nitric-oxide-in-cancer/

Note:  A more comprehensive ebook on Nitric Oxide and Disease Perspectives is found at

Cardiovascular Diseases, Volume One: Perspectives on Nitric Oxide in Disease Mechanisms

available on Kindle Store @ Amazon.com

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

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FDA Approval marks first presentation of bivalirudin in frozen, premixed, ready-to-use formulation

Reporter: Aviva Lev-Ari, PhD, RN

 

Baxter Announces FDA Approval of Ready-to-Use Cardiovascular Medication Bivalirudin

Approval marks first presentation of bivalirudin in frozen, premixed, ready-to-use formulation

https://www.dicardiology.com/product/baxter-announces-fda-approval-ready-use-cardiovascular-medication-bivalirudin?eid=333021707&bid=1983307

Dosing and Uses

https://reference.medscape.com/drug/angiomax-angiox-bivalirudin-342137

 

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Spectranetics, a Technology Leader in Medical Devices for Coronary Intervention, Peripheral Intervention, Lead Management to be acquired by Philips for 1.9 Billion Euros

Reporter and Curator: Aviva Lev-Ari, PhD, RN

 

 

Philips to buy medical device maker Spectranetics for 1.9 billion euros

By Toby Sterling | AMSTERDAM

Dutch healthcare company Philips (PHG.AS) has agreed to buy U.S.-based Spectranetics Corp (SPNC.O), a maker of devices to treat heart disease, for 1.9 billion euros (£1.68 billion) including debt, as it expands its image-guided therapy business.

Spectranetics uses techniques including lasers and tiny drug-covered balloons to clean the insides of veins and arteries that have become clogged due to heart disease.

Philips will pay Spectranetics shareholders $38.50 per share, a 27 percent premium to their closing price on June 27.

Philips Chief Executive Frans van Houten has transformed the former conglomerate into a focused maker of healthcare equipment over the past five years, spinning off its lighting division (LIGHT.AS) and selling most of its remaining consumer products business.

Philips said Spectranetics, which expects sales of around $300 million this year, will continue to grow revenues at double-digit rates and will begin adding to Philips’ earnings in 2018.

SOURCE

http://uk.reuters.com/article/uk-spectranetics-m-a-philips-idUKKBN19J0MZ?em_pos=small&ref=headline&nl_art=1

Home / About Spectranetics / Overview

http://www.spectranetics.com/about/overview/

Spectranetics’ History – 30 years of Innovations and M&A

http://www.spectranetics.com/about/history/

Products

Coronary Intervention

Coronary Artery Disease (CAD) is the leading cause of death among men and women. Each year, one in four deaths are attributed to CAD in the United States, accounting for over a half million lives lost. From scoring balloon technology to laser atherectomy to thrombus aspiration and removal, Spectranetics offers a comprehensive portfolio of solutions to cross, prep and treat compromised vessels. Learn more about CAD by navigating through the tile grid below and exploring the products that are saving lives.

SOURCE

http://www.spectranetics.com/solutions/coronary-intervention/

 

 Peripheral Intervention

Spectranetics is dedicated to helping physicians cross, prep and treat complex clinical challenges of Peripheral Artery Disease, such as Critical Limb Ischemia, Chronic Total Occlusions and In-Stent Restenosis. We provide expert tools, training, ongoing support and patient education so that you can help eradicate restenosis, and amputation and modify all plaque. Explore the tile grid below to learn more about Peripheral Artery Disease and Spectranetics’ comprehensive portfolio of products to successfully treat this challenging cardiovascular condition at every stage.

Products

 SOURCE

Lead Management

Managing cardiac implantable electronic device (CIED) leads has never been more important. Patients with CIEDs are on a lifelong journey, and Spectranetics is there to make sure it’s a healthy one. Making the right decision at the right time, for every patient, is critical. Lives depend on it. Explore the tile grid below to learn more about Lead Management and the products that ensure lead extraction is done safely, responsibly and predictably.

Other related articles published in this Open Access Online Scientific Journal include the following:

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Right Internal Carotid Artery Clot Aspiration: 4.5 Minute Thrombectomy Using the ADAPT-FAST Technique and the ACE68 Catheter

Reporter: Aviva Lev-Ari, PhD, RN

 

WATCH VIDEO

http://mus.2.broadcastmed.net/videos/4-5-minute-thrombectomy-using-the-adapt-fast-technique-and-the-ace68-catheter?utm_source=social&utm_medium=facebook&utm_content=Thrombectomy&utm_campaign=mus_7952

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Advanced Peripheral Artery Disease (PAD): Axillary Artery PCI for Insertion and Removal of Impella Device

Reporter: Aviva Lev-Ari, PhD, RN

 

 

July 15, 2016
Authors:

Rajiv Tayal, MD, MPH1,2;  Mihir Barvalia, MD, MHA1;  Zeshan Rana, MD2;  Benjamin LeSar, MD1;  Humayun Iftikhar, MD1;  Spas Kotev, MD1;  Marc Cohen, MD1;  Najam Wasty, MD1

Abstract: Traditionally, brachial and common femoral arteries have served as access sites of choice, with many operators recently converting to radial artery access for coronary angiography and percutaneous intervention due to literature suggesting reduced bleeding risk, better patient outcomes, and lower hospital-associated costs. However, radial access has limitations when percutaneous procedures requiring larger sheath sizes are performed. Six Fr sheaths are considered the limit for safe use with the radial artery given that the typical luminal diameter of the vessel is approximately 2 mm, while peripheral artery disease (PAD) may often limit use of the common femoral artery, particularly in patients with multiple co-morbid risk factors. Similarly, the brachial artery has fallen out of favor due to both thrombotic and bleeding risks, while also not safely and reliably accommodating sheaths larger than 7 Fr. Here we describe 3 cases of a new entirely percutaneous technique utilizing the axillary artery for delivery of Impella 2.5 (13.5 Fr) and CP (14 Fr) cardiac-assist devices for protected percutaneous coronary intervention in the setting of prohibitive PAD.

J INVASIVE CARDIOL 2016;28(9):374-380. 2016 July 15 (Epub ahead of print)

Key words: axillary artery, percutaneous access, high-risk PCI

 

SOURCE

http://amptheclimeeting.com/ampcentral/articles/totally-percutaneous-insertion-and-removal-impella-device-using-axillary-artery-setting

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New method for performing Aortic Valve Replacement: Transmural catheter procedure developed at NIH, Minimally-invasive tissue-crossing – Transcaval access, abdominal aorta and the inferior vena cava

 

Reporter: Aviva Lev-Ari, PhD, RN

 

VIEW VIDEO

 

The new method was developed by researchers at the National, Heart, Lung and Blood Institute (NHLBI) and tested in a trial on 100 patients at 20 hospitals across the United States. Researchers said it proved successful in 99 of the patients.

“This is a seminal study,” said the lead author, cardiologist Adam B. Greenbaum, M.D., co-director of the Henry Ford Hospital Center for Structural Heart Disease, Detroit. “It challenged conventional wisdom, which objected to the idea of safe passage between the vena cava and the aorta. More important, it is the first of many non-surgical minimally-invasive tissue-crossing, or so-called transmural catheter procedures developed at NIH that can be applied to diverse fields of medicine.”

Robert J. Lederman, M.D., a senior investigator in NHLBI’s Division of Intramural Research who led the study, said researchers developed the method to address a specific clinical need, even though they knew it would be a challenging proposition for most surgeons and physicians to accept. The proposed and counterintuitive mechanism of action is that bleeding from the aorta spontaneously decompresses into a corresponding hole the physician makes in the vein, because the surrounding area behind the peritoneum has higher pressure than the vein.

The results of the research, which were independently confirmed by a committee of outside cardiologists, show the procedure not only has a high success rate, but also an acceptable rate of bleeding and vascular complications, particularly in the high risk patients studied. The study builds on the access technique that Lederman’s NHLBI team developed and first tested in animals in 2012 and first applied with Henry Ford physicians to help patients in 2013. NHLBI and its collaborators are now working to find ways to train more specialists to perform the procedure.

The study will also be presented on Monday, October 31 at the Transcatheter Cardiovascular Therapeutics conference in Washington, D.C. Co-authors include researchers from

  • Henry Ford Hospital;
  • Emory University, Atlanta;
  • Oklahoma Heart Institute, Tulsa;
  • Lexington Medical Center, West Columbia, South Carolina; and
  • Oschner Medical Center, New Orleans.

Researchers at the National Institutes of Health have developed a new, less invasive way to perform transcatheter aortic valve replacement (TAVR), a procedure widely used to treat aortic valve stenosis, a lethal heart condition. The new approach, called transcaval access, will make TAVR more available to high risk patients, especially women, whose femoral arteries are too small or diseased to withstand the standard procedure. The Journal of the American College of Cardiology published the findings.

Aortic valve stenosis involves the narrowing of the heart’s aortic valve which reduces blood flow through the heart. For about 85 percent of patients with this condition, doctors typically perform TAVR through the femoral artery in the leg. But for the other 15 percent, doctors must find a different access route. The most common alternative routes are through the chest, which requires surgery and are associated with significantly more complications.

Transcaval access, which can be performed in awake patients, involves electrifying a small wire so that it crosses between neighboring blood vessels in the abdomen. The technique calls for making large holes in both the abdominal aorta and the inferior vena cava, which physicians previously considered dangerous because of the risk of fatal bleeding.

SOURCE

https://www.nih.gov/news-events/news-releases/new-method-performing-aortic-valve-replacement-proves-successful-high-risk-patients

http://www.medscape.com/viewarticle/871196?nlid=110314_3866&src=WNL_mdplsfeat_161101_mscpedit_card&uac=93761AJ&spon=2&impID=1226378&faf=1

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