A new study outlines the criteria for identifying hundreds of thousands of Americans who have the most or least to gain from the use of anticoagulants such as warfarin to prevent stroke. The study identifies certain patients with a common type of irregular heartbeat called atrial fibrillation, and a low-risk for stroke who fare well by taking aspirin instead of warfarin to prevent stroke. Previous studies have shown that warfarin can cut by two-thirds the stroke risk in patients with atrial fibrillation who are at high risk for stroke. However, because treatment with aspirin carries a lower risk of bleeding and requires less medical monitoring than warfarin, doctors have been interested in identifying the specific group of patients who would do well on aspirin alone.
People with atrial fibrillation are six times more likely to have a stroke than people without, and account for as many as 80,000 strokes a year.
The findings are from Part III of a decade-long study called Stroke Prevention in Atrial Fibrillation (SPAF), designed to find the best way to reduce strokes in the 2 million Americans who have atrial fibrillation. This series of clinical trials is funded by the National Institute of Neurological Disorders and Stroke (NINDS). All of the SPAF studies look at preventive treatment with aspirin and warfarin, both of which lessen the tendency of blood to clot. The latest research appears in the April 22, 1998, issue of The Journal of the American Medical Association.* SPAF is coordinated by Robert G. Hart, M.D., and David G. Sherman, M.D., from the University of Texas Health Sciences Center at San Antonio.
"Stroke prevention research is absolutely vital. The number of strokes has risen so dramatically in recent years that we must find ways to stop strokes from happening in the first place," said Audrey Penn, M.D., Acting Director of the NINDS.
A group of 892 low-risk atrial fibrillation patients in the study took a daily
Contact: Margo Warren
NIH/National Institute of Neurological Disorders and Stroke