A new tool to stop heart attacks
In what scientists said was the first new treatment in a decade for heart attacks, researchers reported last week that the drug clopidogrel, when used in combination with other standard treatments, could prevent repeat heart attacks and reduce death rates by as much as 36%.
Taken together, the findings of three studies presented at the American College of Cardiology meeting last week in Orlando, Fla., indicate that more common use of clopidogrel, a blood thinning treatment that works differently from widely used aspirin, could save thousands of lives every year.
“There is no doubt now that a combination of aspirin and clopidogrel should become standard practice straightaway in the emergency treatment of myocardial infarctions,” said Dr. Michael Gent of McMaster University in Hamilton, Ontario, Canada.
Clopidogrel, sold by Sanofi-Aventis and Bristol-Myers Squibb Co. under the brand name Plavix, is cheap enough that it could be widely used, reducing the death toll even in the absence of more effective, but more expensive, treatments. Its use could be particularly significant in poorer nations, where physicians often do not have access to expensive clot-busting drugs to treat heart attacks.
In one study, Dr. Marc S. Sabatine of Brigham and Women’s Hospital in Boston and his colleagues studied 3,491 men and women, at 319 hospitals, who suffered a heart attack and received standard clot-busting therapy -- in which tPA or other drugs are used to dissolve the clot. Patients also received aspirin, which by itself had previously been shown to reduce deaths by 25%.
Half the patients also received clopidogrel during the treatment and for a month afterward. The rest received a placebo.
Sabatine reported that, by the time the patients went on to receive a coronary angiogram after their clot-busting treatment, 22% of those receiving standard therapy had had a second heart attack or had died, compared with 15% of those who received Plavix. He noted that about a third of the 1 million Americans who have a heart attack each year require such therapy.
Patients receiving the anticoagulant did not have an increase in overall bleeding or in the incidence of bleeding strokes, he said. Some critics have feared that the drug might produce such problems if used widely.
The team’s report was published online last week in the New England Journal of Medicine and will appear in print in the March 24 issue.
In an editorial to be published in the same issue of the journal, Dr. Richard A. Lange of the Johns Hopkins Medical Institutions in Baltimore and Dr. L. David Hillis of the University of Texas Southwestern Medical Center in Dallas endorsed the therapy, noting that the combination therapy “appears, in fact, to be effective and safe.”
A second study enrolled nearly 46,000 heart attack patients who were treated at 1,250 hospitals in China. Only about half of the patients received clot-busting therapy because it was not available in many of the smaller hospitals, according to Dr. Zhengming Chen of Oxford University, who led the study. The rest received only aspirin and supportive therapy.
Half the patients -- including half of those who received clot-busters and half of those who did not -- received clopidogrel and half a placebo.
Chen told the meeting that clopidogrel reduced the risk of death in the hospital by 7% and the risk of death, repeat heart attack or stroke by 10%.
“That means that, on average, adding clopidogrel to current therapies benefits one out of every 100 patients. So, for every 1 million patients having a heart attack, giving this simple additional treatment for about two weeks would save 5,000 lives and prevent another 5,000 repeat heart attacks and strokes.” There are about 10 million heart attacks in the world every year, he said.
Noting the results from the Chinese study and his own, Sabatine said: “This is the first time in a decade that we have had a new treatment for heart attack.”
A third study presented at the meeting found that doubling the dose of clopidogrel given to patients before they undergo a balloon angioplasty to open clogged arteries can reduce the number of adverse events suffered during the procedure by as much as two-thirds.
The study involved 255 patients undergoing elective angioplasty. Dr. Germano Di Sciascio and his colleagues at Campus Bio-Medico University of Rome gave half the patients the usual dose of 300 milligrams of clopidogrel four to eight hours before the procedure and half double that dose.
He reported that in the 30 days after the procedure, 12% of the patients receiving standard care had required another artery-opening procedure, had suffered a heart attack, or died. Among those receiving the double dose of clopidogrel, only 4% suffered the events. In both groups, all of the events occurred during the original procedure.
“We can improve the outcome by doubling the dose of clopidogrel,” Di Sciascio said. “Thus, our traditional therapy associated with angioplasty will probably need to be changed.”
The team’s report was published last week in Circulation: Journal of the American Heart Assn.
