Anti-clotting drugs beat heparin for heart attack
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Heart attack patients treated with anti-thrombosis drugs instead of the blood-thinner heparin are less likely to die or have another heart attack, researchers told a meeting of cardiologists on Tuesday.
“This is a better blood-thinning strategy for patients who have a heart attack,” said Harvard Medical School professor Dr. Elliott Antman, lead investigator of the trial comparing the drug Lovenox to heparin.
Lovenox, sold by France’s Sanofi Aventis , is designed to block thrombin, a blood protein that plays a key role in the formation of new blood clots. It is given by injection.
Heparin, a widely used anticoagulant, is administered by intravenous infusion.
The Lovenox study, along with a study comparing GlaxoSmithKline Plc’s anti-thrombosis drug Arixtra to heparin in heart attack patients, was presented at a meeting of the American College of Cardiology.
The Lovenox study involved 20,000 patients who had a type of severe heart attack. They were first treated with a clot-busting drug and were then randomly assigned to either Lovenox or heparin.
Heparin treatment averaged two days, compared with seven days for Lovenox.
After 30 days, 4.5 percent of patients given heparin had a nonfatal heart attack, compared with 3 percent receiving Lovenox. Lovenox was also shown to reduce the combined risk of a repeat heart attack and death by 17 percent.
All of the findings were statistically significant.
Patients treated with Lovenox were more likely to experience major bleeding, but researchers said the risk was offset by better clinical outcomes.
For every 1,000 patients treated with Lovenox instead of heparin, there would be 15 fewer heart attacks, seven fewer urgent revascularizations, six fewer deaths and four more nonfatal serious bleeding episodes, Antman said.
The rates of serious bleeding reported in the trial were below those previously seen with Lovenox due to the lower dose given to elderly patients, in whom the drug is likely to be cleared more slowly through the kidneys.
Arixtra was tested in more than 12,000 patients. This study, led by Dr. Salim Yusuf from McMaster University in Ontario, found that the death or repeat heart attack rate after 30 days was 11.2 percent in the control group and 9.7 percent in the Arixtra group - a relative reduction of 14 percent.
The researchers said there was a tendency toward fewer severe bleeding events in the Arixtra group.
Procedures such as opening a blocked artery with a balloon-tipped catheter have proven to be best for heart attack patients, but access to the procedures, particularly in developing countries, is limited.
Worldwide, most patients are still treated with clot-busting drugs, Antman said.
The trial results “are directly applicable to clinical practice,” said Duke University Medical Center cardiologist Dr. Robert Harrington, who was not associated with the study.
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