Aspirin is best stroke tool, study says

Patients at risk of stroke from narrowed brain arteries should take aspirin rather than the common anti-clotting drug warfarin, a major new study concludes.

The condition, called intracranial stenosis, is caused by the same hardening of the arteries, or buildup of fatty deposits along artery walls, that causes heart attacks. It is responsible for about 10 percent of the more than 900,000 strokes and transient (mini) strokes Americans suffer each year.

Those who suffer a stroke due to such narrowing have a much greater risk of having a second stroke, about 15 percent a year. Studies in the 1950s suggested that anti-clotting drugs, such as warfarin, could reduce the risk in such patients.

But over the past several decades, doubts about warfarin's safety and side effects and smaller studies on aspirin's effectiveness have cast enough doubt on the drug that a recent survey of neurologists found them split 50-50 on which treatment they used on patients with intracranial disease.

"Our goal was to answer this question which has been asked for 20 years: Is warfarin more effective than aspirin?" said Dr. Marc Chimowitz, a professor of neurology at Emory University's School of Medicine and lead author of the study, published Thursday in The New England Journal of Medicine.

The $15 million study was cut off early -- after just 569 patients, rather than the planned 800, were randomly assigned to one of the treatments at 59 U.S. medical centers -- because researchers were concerned about the safety of those getting warfarin. The drug is sold under the brand name Coumadin.

All the patients had a major brain artery that was blocked more than 50 percent, and had suffered a transient stroke or a non- disabling stroke within 90 days of enrolling in the study.

Those taking aspirin got 1,300 milligrams a day, a considerably higher dose than what's usually recommended for treating heart disease or other types of stroke risk. The researchers said other recent studies suggested the higher dose was better, possibly because higher doses of aspirin have more effect against inflamed arteries.

For patients taking warfarin, the dose was adjusted monthly based on blood tests to measure the response.

Regardless of whether they were getting warfarin or aspirin, about 22 percent of the patients had a second stroke caused by a blocked artery or a brain hemorrhage, or died from another cause related to blood vessels, suggesting that better approaches need to be found, Chimowitz said.

But over a follow-up period that averaged 1.8 years, complication rates for aspirin patients were much lower than for those taking warfarin -- 3.2 percent vs. 8.3 percent for major bleeding anywhere in the body; 4.3 percent vs. 9.7 percent for death.

The high-dose-aspirin treatment also carries increased risk of stomach ulcers and bleeding in the stomach or intestines. But Chimowitz said that the bleeding complications from warfarin are greater. And, he added, because the drug is more expensive, switching all patients with narrowed brain arteries to aspirin would save the health-care system more than $20 million a year.

"This trial is good news," said Dr. John Marler, assistant director for clinical trials at the National Institute of Neurological Disorders and Stroke, which paid for the study. "A simple, low-cost drug works just as well as one that requires complicated and expensive monitoring and dose adjustment."

Chimowitz stressed that the study's results only applied to those at risk for strokes from intracranial artery disease. "People who are taking warfarin for other conditions, such as atrial fibrillation (irregular heart rhythm) or clots in the legs or lungs should not stop taking the drug," because other studies have shown them to be the best option for those conditions.

He also cautioned those taking aspirin or warfarin not to change what or how much they're taking without consulting their physician.

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