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Tuesday, 30 July 2013

High platelet reactivity on clopidogrel predicts stent thrombosis, heart attack, and bleeding

Main Category: Cardiovascular / Cardiology
Also Included In: Medical Devices / Diagnostics; Blood / Hematology
Article Date: 30 Jul 2013 - 0:00 PDT Current ratings for:
High platelet reactivity on clopidogrel predicts stent thrombosis, heart attack, and bleeding
5 stars

Patients who receive a drug-eluting stent (DES) and demonstrate high platelet reactivity on clopidogrel are more likely to have blood clots form on the stent and to suffer a heart attack; however, these patients are less likely to develop bleeding complications. One-year results of the ADAPT-DES trial was published online in The Lancet. The findings were first presented at last year's Transcatheter Cardiovascular Therapeutics (TCT) annual scientific symposium.

ADAPT-DES is the largest study ever to explore the overall treatment implications of platelet reactivity on patient outcomes after successful coronary drug-eluting stent implantation. Researchers investigated the relationship between platelet reactivity during dual therapy with aspirin and clopidogrel and clinical outcomes such as stent thrombosis, major bleeding, and other adverse events.

The study enrolled 8,583 patients at 11 sites in the US and Germany who underwent a percutaneous coronary intervention (PCI) with at least one drug-eluting stent between January 7, 2008, and September 16, 2010. Researchers assessed platelet reactivity with the VerifyNow Aspirin, P2Y12, and IIb/IIIa tests. Patients were followed for one year to determine the relationship between platelet reactivity and subsequent events. At one year, stent thrombosis had occurred in 70 patients (0.8 percent), heart attack in 269 (3.1 percent), major bleeding in 531 (6.2 percent), and death in 161 (1.9 percent).

Platelet reactivity units (PRU), an index of platelet inhibition to clopidogrel, were measured by the VerifyNow P2Y12 test. High platelet reactivity, defined as a PRU of greater than 208, was present in 42.7 percent of patients. At one year, researchers found that high platelet reactivity was significantly associated with stent thrombosis (1.3 percent vs. 0.5 percent) and heart attack (3.9 percent vs. 2.7 percent), but was also found to be protective against major bleeding (5.6 percent vs. 6.7 percent). High platelet reactivity was also associated with one-year mortality (2.4 percent vs. 1.5 percent). However, because high platelet reactivity is also associated with other patient risk factors and baseline characteristics, multivariable modeling was also performed; it showed no independent association between high platelet reactivity and mortality.

"Results from the ADAPT-DES registry definitely demonstrate that high platelet reactivity after implantation of drug-eluting stents is an independent predictor of one-year stent thrombosis and heart attack, but it is also protective against major bleeding, both of which impact mortality," said lead investigator Gregg W. Stone, MD. Dr Stone is professor of medicine at Columbia University College of Physicians and Surgeons and Director of Cardiovascular Research and Education at the Center for Interventional Vascular Therapy at NewYork-Presbyterian Hospital/Columbia University Medical Center. Dr. Stone is also co-director of the Medical Research and Education Division at the Cardiovascular Research Foundation (CRF).

"Because of the counteracting effects of ischemia and bleeding, platelet reactivity was not an independent predictor of one-year mortality. Therefore, overcoming high platelet reactivity with more potent antiplatelet agents is unlikely to improve survival unless the beneficial effect of reducing stent thrombosis and heart attack can be separated from the likely increase in bleeding that results from greater platelet inhibition," said Dr. Stone.

Dr. Stone added: "Platelet reactivity on aspirin was unrelated to stent thrombosis, heart attack, or death, but may be related to bleeding. This raises questions as to the utility of aspirin in patients treated with drug-eluting stents."

Article adapted by Medical News Today from original press release. Click 'references' tab above for source.
Visit our cardiovascular / cardiology section for the latest news on this subject.

The ADAPT-DES trial was sponsored by CRF with research support from Boston Scientific, Abbott Vascular, Medtronic, Cordis, Biosensors, The Medicines Company, Daiichi Sankyo, Eli Lilly, Volcano, and Accumetrics.

Cardiovascular Research Foundation

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Sunday, 21 July 2013

Predicting STEMI, the most severe heart attack: JACC study

Main Category: Cardiovascular / Cardiology
Also Included In: Medical Devices / Diagnostics
Article Date: 19 Jul 2013 - 2:00 PDT Current ratings for:
Predicting STEMI, the most severe heart attack: JACC study
5 stars

Infraredx, Inc., a medical device company committed to advancing the diagnosis and management of coronary artery disease, has announced the publication of key data supporting the ability of its TVC Imaging System to detect lipid core plaque in patients with ST-Segment Elevation Myocardial Infarction (STEMI). The study, published in JACC: Cardiovascular Interventions, details the identification of a specific cholesterol signature by Near Infrared Spectroscopy (NIRS) at the site of the culprit lesions causing STEMI, a dangerous type of heart attack. While the TVC Imaging System has been used in more than 3,000 patients worldwide, the present study is the first report of its use in a consecutive series of STEMI patients.

The research was led by Ryan D. Madder, M.D., a practicing interventional cardiologist at Spectrum Health, in Grand Rapids, Mich. The study utilized the TVC Imaging System, which is a first-in-class intravascular imaging system that integrates near-infrared spectroscopy (NIRS) lipid core plaque detection and enhanced intravascular ultrasound (IVUS) imaging technology to assess vessel composition and structure.

"We have discovered a near-infrared spectroscopic signature of the plaques which cause myocardial infarction, a leading cause of morbidity and mortality worldwide," said Dr. Madder. "This signature is detectable at the time of cardiac catheterization using a novel intracoronary imaging device. It is our hope that this signature may be capable of predicting a myocardial infarction before it happens. Through an international collaboration with several other centers, further studies are currently underway and others are being planned to validate this signature and to determine if near-infrared spectroscopy can accurately predict future myocardial infarction."

In this study, researchers utilized the TVC imaging system to image the culprit vessel, as identified by angiography, in 20 STEMI patients referred acutely for primary percutaneous coronary intervention. In 19 of the 20 patients, a distinct signature of lipid core plaque (LCP) was identified with NIRS specifically at the location of the culprit lesion. To confirm plaque composition, the researchers compared the NIRS imaging results from the sites causing the blockage and subsequent heart attack to results from non-culprit segments of the patients' vessels as well as to 46 autopsy specimens serving as the gold-standard of histology. The study's novel in vivo findings of lipid core plaque at STEMI culprit sites correspond with multiple autopsy studies that have demonstrated that rupture of a large lipid core plaque is the most frequent cause of a fatal myocardial infarction. Most importantly for predictive and preventive purposes, it is likely that the large lipid core plaques observed at STEMI culprit sites were present and detectable before plaque rupture and thrombus formation and the acute coronary event.

"There are many possible treatments already available for coronary plaques at increased risk for rupture and thrombosis," said James E. Muller, M.D., founder and chief medical officer of Infraredx. "The primary challenge cardiologists have faced has been the identification of plaques likely to cause major adverse events, including heart attacks. The identification of a clear signal so closely associated with culprit plaques in patients suffering STEMI is a major step forward in the effort to identify and treat vulnerable coronary plaques before they cause a catastrophic event."

Myocardial infarctions (heart attack) occur when a plaque ruptures and its contents are exposed to blood, creating a thrombus (blood clot) that, in turn, leads to a rapid, complete blockage of an artery. ST-Segment Elevation Myocardial Infarction (STEMI) is the more severe type of heart attack. In the United States alone, more than 1 million individuals experience a myocardial infarction or sudden cardiac death each year.[1]

The TVC Imaging System™ is a first-in-class intravascular imaging system that holds the potential to revolutionize the management of coronary artery disease by providing information that is critical for evaluating vessel structure and composition, also known as true vessel characterization. The TVC Imaging System helps interventional cardiologists identify which patients are prone to complications during stenting. The device enables cardiologists to predict peri-procedural heart attacks by assessing not only the degree of stenosis, but also the presence and extent of lipid-rich plaques (LRP).

The device is the only multimodality imaging system to combine both intravascular ultrasound (IVUS) and near-infrared spectroscopy (NIRS). Through IVUS technology, the TVC Imaging System provides clear and relevant information about vessel structure, in real time. The TVC Imaging System is the only device available in both the U.S. and Europe for the detection of LCPs. NIRS measurements have been made in over 5,000 patients in over 90 hospitals worldwide.

Article adapted by Medical News Today from original press release. Click 'references' tab above for source.
Visit our cardiovascular / cardiology section for the latest news on this subject.

[1] Heart disease and stroke statistics – 2012 update: a report from the American Heart Association. Circulation 2012; 125;e2-e220.

The paper: "Detection of Near-infrared Spectroscopy of Large Lipid Core Plaques at Culprit Sites in Patients with Acute ST-Segment Elevation Myocardial Infarction," is available online.

Infraredx