1 avril, 2005 02:20
Aspirin safer than warfarin after some strokes
Thomas H. Maugh II, Los Angeles Times
Thursday, March 31, 2005
Thomas H. Maugh II, Los Angeles Times
Thursday, March 31, 2005
Common aspirin is just as good as the anticoagulant drug warfarin at preventing strokes caused by partial blockage of arteries in the brain and is much safer, according to the first clinical trial comparing the two treatments.
The trial was halted prematurely, in fact, because of the excess bleeding and deaths associated with using warfarin, researchers reported today in the New England Journal of Medicine.
The partial blockage, called intracranial arterial stenosis, causes about 90,000 strokes among Americans every year -- about 10 percent of all strokes.
Currently, physicians are divided between the two drugs in treating such patients, but the new findings should tip the balance strongly in favor of aspirin, said Dr. Marc Chimowitz of Emory University, who led the study.
Physicians emphasized that the findings do not relate to other uses of warfarin. For example, warfarin is more effective at treating strokes caused by atrial fibrillation, a fluttering of the atrial valve of the heart that can produce blood clots that enter the brain and cause a stroke.
That efficacy is one reason why neurologists use warfarin to treat strokes caused by stenosis, said Dr. Michael R. Frankel of Emory, one of the study's co-authors. Doctors assumed that if it was good for the heart, it was good for the brain. Early studies seemed to back that conclusion.
Researchers were surprised to find that their assumption was incorrect.
In a study sponsored by the National Institute of Neurological Diseases and Stroke, the team enrolled 569 patients who had suffered either a transient ischemic attack -- a so-called mini-stroke that is often a precursor of a more serious stroke -- or a non-disabling stroke. All of the patients had at least a 50 percent blockage in a major intracranial artery.
Half the patients received 1,300 milligrams of aspirin per day (a normal tablet is 325 milligrams) and half received a conventional dosage of warfarin. After an average of about 1.8 years of follow up, 20.7 percent of those receiving aspirin had a stroke, compared to 17.6 percent of those receiving warfarin. But 8.3 percent of those receiving warfarin had a major bleeding incident and 9.7 percent died, compared to 3.2 percent and 4.3 percent of the aspirin users, respectively. When the increased risks of warfarin became clear, Chimowitz and his colleagues stopped the trial.
