Using the “Blood Thinner” Low-Molecular-Weight-Heparin Improves Outcomes after Heart Attacks
Boston, MA and Dallas, TX – In the largest angiographic study to date assessing low-molecular-weight-heparin (LMWH) versus standard unfractionated heparin (UFH) as a “blood thinner” for patients who have experienced a heart attack, researchers from Brigham and Women’s Hospital (BWH) found more evidence that LMWH improves blood flow and patient outcomes after a heart attack. In addition, this new data offers evidence that combining LMWH and clopidogrel, along with a standard fibrinolytic “clot-buster” and aspirin is the best option for patients who have a heart attack. These data will be published in the American Heart Association’s (AHA) journal Circulation simultaneous with a presentation at the AHA Scientific Sessions on November 15, 2005.
Low-molecular-weight-heparin is a special form of heparin that is designed to be more reliable and easier to administer than traditional unfractionated heparin. According to lead author Marc S. Sabatine, MD, MPH, an associate physician in the Cardiovascular Division at BWH and an instructor in Medicine at Harvard Medical School, patients who experience heart attack now have available to them a comprehensive drug therapy regimen that treats every aspect of the blood clot responsible for a patient’s restricted coronary artery. “For patients who experience a large heart attack, we found that low-molecular-weight-heparin is better than the standard unfractionated heparin. We recommend the combination of a fibrinolytic, aspirin, clopidogrel and LMWH as the most efficacious and safest regimen for patients presenting with a heart attack.”
The CLARITY-TIMI 28 trial included 3,491 men and women, 75 years or younger, at 319 sites in 23 countries. All patients in the trial experienced the onset of their heart attack within the 12 hours preceding treatment and received standard clot-busting treatment and aspirin to open the clogged artery. They then received either clopidogrel (300 mg loading dose, then 75 mg once daily) or placebo up to the time of coronary angiography.
For this particular sub-study, 1,431 patients were treated by their physician with UFH and 1,429 were treated with LMWH. Sabatine and colleagues analyzed angiographic and clinical outcomes among these patients and found that after adjustment for baseline characteristics, the odds of having a blocked artery or dying or having a second heart attack before angiogram were 24 percent lower in the patients administered LMWH. In addition, by 30 days, patients treated with LMWH had 32 percent lower odds of dying or a second heart attack. Patients who received both clopidogrel and LMWH had particularly low rates of cardiovascular death (3.2 percent) and a recurrent heart attack (3.0 percent). Importantly, despite the increased efficacy, bleeding was no more common with LMWH than with UFH (1.6 percent versus 2.2 percent, respectively).
“Physicians should feel confident in substituting low-molecular weight heparin for unfractionated heparin for patients who present with severe heart attack,” Sabatine stated. “LMWH is a safe and effective medication that does not cause an excess in bleeding.”
In addition, according to Sabatine’s colleague and co-author Elliott Antman, MD a professor of Medicine in the Cardiovascular Division at BWH and Principal Investigator of the ExTRACT-TIMI 25 trial, “These are extremely encouraging observations about LMWH and allow us to further refine our understanding of this important medication.” Antman has just completed enrollment of 20,506 heart attack patients in a very large trial called ExTRACT-TIMI 25, a worldwide study designed to determine if a specific LMWH, enoxaparin, is better than standard unfractionated heparin in reducing the risk of dying or having a second heart attack in the first month. The results of ExTRACT-TIMI 25 will be reported in 2006.
The trial was sponsored by the pharmaceutical partnership of Sanofi-Aventis and Bristol-Myers Squibb.
Please contact BWH Media Relations for more information at (617) 534-1600 or BWHMediaRelations@partners.org.
BWH is a 747-bed nonprofit teaching affiliate of Harvard Medical School and a founding member of Partners HealthCare System, an integrated health care delivery network. BWH is committed to excellence in patient care with expertise in virtually every specialty of medicine and surgery. The BWH medical preeminence dates back to 1832 and today that rich history in clinical care is coupled with its national leadership in quality improvement and patient safety initiatives, dedication to educating and training health care professionals, and strength in biomedical research. With $370M in funding and more than 500 research scientists, BWH is an acclaimed leader in clinical, basic and epidemiological investigation - including the landmark Nurses Health Study, Physicians Health Studies, and the Women's Health Initiative. For more information visit www.brighamandwomens.org.
Send Feedback to: 
