Blood-Thinner Warfarin Underused in Heart Attack Patients

Review says teaming it with aspirin halves the risk of a second attack

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By Ed Edelson
HealthDay Reporter

MONDAY, Aug. 15, 2005 (HealthDay News) -- Cardiologists aren't using the combination of aspirin and the blood-thinner warfarin often enough when they treat patients who have had heart attacks, according to a review of studies about a controversial issue in cardiology.

An analysis of 10 trials that included nearly 6,000 patients shows the combined treatment halved the risk of a second heart attack and stroke, said the report in Aug. 16 issue of the Annals of Internal Medicine.

"A lot more people can benefit from it [the dual therapy] than we realize," said study author Dr. Michael B. Rothberg, an associate professor of medicine at Tufts University School of Medicine in Boston.

There are several reasons why warfarin is underused, Rothberg said. "It hasn't been included in any of the guidelines," he said. "It's not on the radar screen for myocardial infarction [heart attack]. And warfarin is an inconvenient drug to manage, so physicians are reluctant to prescribe it in general."

The purpose of the paper "is to try to push warfarin back into the conversation," Rothberg said.

But that assumption was challenged by Dr. Jonathan L. Halperin, a professor of medicine at Mount Sinai School of Medicine in New York City, and a spokesman for the American Heart Association.

The use of warfarin after a heart attack is "a widely debated issue," Halperin said. And while the new study is "very well done," he added, "there is a lot of uncertainty about the conclusion."

One reason is that the report includes only studies that have been published in medical journals, "and if a trial is not showing positive results, it is less likely to be submitted for publication. There is an intrinsic bias in favor of showing a favorable outcome," Halperin said.

Rothberg acknowledged that the risk of excess bleeding with warfarin makes him limit the combined therapy to "patients who are at medium-to-high risk of recurrent myocardial infarction," such as those with diabetes and congestive heart failure.

And even then, he limits its use to no more than three months, in large part because of the risk of excess bleeding. "The longer you stay on it, the less benefit you have in terms of a second heart attack," Rothberg said.

Halperin said he limits the use of warfarin to cases in which it is specifically needed, such as when a blood clot forms in the heart.

"Recent guidelines are moving away from dual use [of aspirin and warfarin] because the benefits are difficult to prove," he said.

Halperin said an alternative therapy has more proven benefits. The combination of aspirin and the blood thinner clopidogrel (Plavix) has been shown in trials to reduce the incidence of second heart attacks without the complications presented by warfarin, he said.

More information

For more on warfarin, visit the National Library of Medicine.

SOURCES: Michael B. Rothberg, associate professor, medicine, Tufts University School of Medicine, Boston; Jonathan L. Halperin, M.D., professor, medicine, Mount Sinai School of Medicine, New York City; Aug. 16, 2005, Annals of Internal Medicine

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