Clopidogrel-aspirin combo can help save MI patients
A cocktail of the antiplatelet drug clopidogrel and aspirin can save victims of massive heart attacks by keeping their arteries open, ACCording to international studies presented at the American College of Cardiology meeting in March.
About 3,500 men and women were studied in North America and Europe on the effects of clopidogrel (Plavix), while a second study was conducted in China on nearly 46,000 people who had suffered major heart attacks.
"The new trials were meant to show Plavix can also keep the artery open and cut risk of another heart attack in people with large heart attacks, and they did so convincingly," said Dr. Marc Sabatine, who supervised the North American-European study.
Plavix is marketed by the French pharmaceutical company Sanofi-Aventis and the US group Bristol-Myers Squibb, which financed a large part of the studies.
CLARITY's CLARITY
Dubbed CLARITY (Clopidogrel as Adjunctive Reperfusion Therapy), the North American-European study enrolled 3,491 patients who had been reported to have an ST-elevation myocardial infarction in the past 12 hours and randomized them into receiving either the clopidogrel-aspirin combination or placebo. When necessary, heparin was added to the treatment.
After two to eight days of treatment, the study participants underwent angiography. The primary efficacy end point was a composite of the following: the presence of occlusion in the infarct-related artery, death prior to scheduled angiography, or recurrent MI before angiography.
As for safety, the study participants were assessed for the rate of major bleeding, using the Thrombolysis in Myocardial Infarction (TIMI) criteria, at the end of the day angiography was performed, or if angiography was not performed, at day eight or upon discharge.
Sabatine, who is from the Brigham and Women's Hospital in Boston, Massachusetts, together with his coinvestigators, reported in the March 9 issue of the New England Journal of Medicine that 22 percent of those on placebo still had clogged arteries, suffered a second heart attack, or died. In the clopidogrel-aspirin group, meanwhile, 15 percent suffered the same fates. This represents a 36-percent decrease (p = 0.001) in the odds of suffering any of those conditions detailed in the end points, in favor of the clopidogrel-aspirin combination.
Among the individual end points, the combination showed the greatest impact on the occluded infarct-related artery (11.7 percent, or a 41-percent odds reduction), and in the rate of recurrent MI (2.5 percent, or an odds reduction of 30 percent). Also, after 30 days, the combination led to a 20-percent (from 14.1 percent to 11.6 percent; p = 0.03) decrease in the odds of the composite end points (cardiovascular death, recurrent MI, or recurrent ischemia requiring revascularization).
As for safety, no significant increases in the risk of major bleeding and intracranial hemorrhage were found in the clopidogrel group.
The "megatrial"
Meanwhile, Oxford University doctor Zhengming Chen discussed the Chinese study at the ACC meeting. Dubbed as a "megatrial," the Clopidogrel and Metoprolol in Myocardial Infarction Trial (COMMIT) was conducted over five years on 45,852 massive-heart-attack victims. It randomized the participants who were reported to have had an MI (ST change or left-bundle-branch block) within the past 24 hours into receiving clopidogrel (75 mg daily) or placebo; all of them received aspirin (162 mg daily). They stayed in the hospital for a mean of 16 days.
The primary end point for the study was a composite of death, reinfarction, or stroke at discharge.
He said the study showed clopidogrel to offer a seven-percent reduction (p = 0.03) in the risk of death and a nine-percent drop (p = 0.002) in the risk of a new heart attack.
The investigators added that the risk reduction in the composite end points for efficacy was evident roughly 24 hours after initiating treatment. Chen added that clopidogrel was able to prevent one major vascular event out of every 100 patients, without giving any significant rise to the risk of bleeding.
Dr. Chris Cannon, also of the Brigham and Women's University, was the designated discussant of COMMIT at the ACC meeting. He remarked that COMMIT's results complemented those of CLARITY.
Cardiologists Richard Lange and David Hillis defended the use of clopidogrel with aspirin in an editorial published in the New England Journal of Medicine.
"For patients receiving clot-busting therapy a combination of Plavix and aspirin appears, in fact, to be effective and safe," they wrote. "Plavix being easier to administer and less expensive than other common treatments adds further to its attractiveness."
with a report from AFP
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