SUNDAY, Sept. 4, 2005 (HealthDay News) -- Heart attack patients who start receiving the anticlotting drug clopidogrel before -- rather than during -- artery-opening angioplasty experienced almost half the incidence of death, a second heart attack or stroke, according to a new study.
Clopidogrel, sold as Plavix, works by preventing cells called platelets from banding together to form the blood clots that can block arteries. It's commonly used as part of drug therapy accompanying angioplasty, a procedure where surgeons inflate a tiny balloon to widen a clogged vessel.
"We [already] had data showing that giving dual antiplatelet therapy with aspirin and clopidogrel is beneficial," said Dr. Marc S. Sabatine, who was to present the trial results Sunday at the European Society of Cardiology Congress, in Stockholm. "And we know that at the time of angioplasty, blowing up the balloon can do damage to the lining of the artery. So we thought it made sense to test pretreatment" use of the drug, he said.
Evidence of the benefit of clopidogrel during angioplasty came from a study done earlier this year at Brigham and Women's Hospital in Boston, where Sabatine is an associate physician in the cardiovascular division. That study showed that clopidogrel reduced the risk of a second heart attack by 31 percent.
The new study enrolled 1,863 people treated for a recent heart attack. Half of them were given an immediate dose of clopidogrel, plus a smaller daily dose, in addition to standard drug therapy when they arrived at the hospital. The other half received an inactive placebo on top of standard therapy.
The incidence of death, subsequent heart attack or a stroke was 46 percent lower for the patients who got clopidogrel before their angioplasty versus those for whom clopidogrel treatment was initiated during surgery, Sabatine said. Providing the earlier dose of the drug also reduced the odds of a patient having a heart attack or stroke while waiting for angioplasty by 38 percent, he added.
"That is an amazingly big benefit that results from one to three extra doses of clopidogrel," Sabatine said.
Some of the people in the study had angioplasty as soon as they arrived at the hospital, while others waited as long as several days. Nevertheless, the benefit derived from clopidogrel pretreatment was the same, no matter when angioplasty was done, Sabatine said.
"The consistent message is to start early, as soon as someone comes in," he said.
While the study did not speak to the issue of people who have angioplasty to prevent a heart attack, other studies have shown the same kind of benefit from clopidogrel pretreatment, Sabatine said.
"We have looked at three different studies on elective angioplasty," he said. "The results are consistent across the board. Pretreatment reduced the risk of a heart attack before angioplasty by about a third, and also after angioplasty."
But the issue is not entirely resolved, said Dr. Sidney Smith, professor of medicine at the University of North Carolina, a past president of the American Heart Association.
Giving clopidogrel early to someone who is scheduled for angioplasty as a preventive measure also means delaying bypass surgery due to the risk of excess bleeding linked to the drug.
There is "an ongoing discussion" about whether it is best to give an early 300-milligram dose of clopidogrel, the dose used in the new study, or to wait and give a 600-milligram dose just before angioplasty, Smith said.
"We need a study to show whether a larger dose given closer to the procedure has the same benefit," he said.
The results of the Brigham and Women's study will be published in the Sept. 14 issue of the Journal of the American Medical Association.
The whys and hows of angioplasty are described by the American Heart Association.