Cardiologists should give more than the recommended dosage of the clot preventing drug Plavix before performing angioplasty.

The Study

The analysis of 10 previous studies found that giving angioplasty patients double the current recommended dose of Plavix-600 milligrams rather than 300-cuts the combined risk of heart attack and cardiac death by half, according to Dr. Anthony Abbate, an assistant professor of medicine at Virginia Commonwealth University.

The 10 studies analyzed by Abbate and Dr. Giuseppe G. Biondi Zoccai, assistant professor of cardiology at the University of Turin in Italy, included 1,500 patients who had angioplasty Most had either 300 milligrams or 600 milligrams of Plavix before the procedure.

The incidence of cardiac death or nonfatal heart attack was 50% lower in the following 30 days in those getting the higher dose of Plavix. Only 3.1% of those getting the 600-milligram dose had in-hospital heart attacks, compared with 6.4% of those getting the 300-milligram dose. The overall 30-day incidence of death or heart attack was 3.8% for the higher dose and 7.3% for the lower dose.


"The evidence shown by this meta-analysis is very strong," said Dr. Gregory Dehmer, past president of the Society for Cardiovascular Angiography and Interventions and a professor of medicine at Texas A&M College of Medicine. "Although Plavix is powerful stuff, the metaanalysis did not find an excessive amount of bleeding. So we have a lower risk of myocardial infarction [heart attack] with no significant increase in adverse side effects."

This research has important clinical and cost implications," Biondi-Zoccai added.

AHA Guidelines

Current guidelines by the American Heart Association, the American College of Cardiology and the Society for Cardiovascular Angiography and Interventions say that physicians should strongly consider giving 300 milligrams of Plavix before angioplasty, a medical procedure to open narrowed or blocked blood vessels of the heart.

"Those guidelines are in the process of being updated," Dehmer said, adding that new guidelines are expected in the next few months.

"In practical terms, many practitioners are concerned about the current recommendations," Dehmer said. "One concern is that should the patient require elective bypass surgery, does a higher dose of clopidogrel (the generic name of Plavix) increase the risk of excessive bleeding?

"This bleeding risk is addressed in this metaanalysis, which shows very minimal potential downside," he added.

Future Plans

But the final word is not in yet, according to Dr. Marc S. Sabatine, associate professor in the cardiovascular division of Brigham and Women's Hospital in Boston. That will come from a major international study, to include up to 14,000 angioplasty patients, which is still enrolling participants.

Timing also plays a role in treatment, he noted. Plavix must be activated in the liver, which takes about six hours, so giving it earlier makes it more effective.

"But even with those side considerations, many laboratories are considering switching to 600 milligrams," Sabatine said.

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