A study appearing in the November 15, 2001, issue of The New England Journal of Medicine* shows that aspirin works as well as warfarin in helping to prevent recurrent strokes in most patients.
The Warfarin versus Aspirin Recurrent Stroke Study (WARSS) was a 7-year double-blind, randomized clinical trial involving 2,206 patients at 48 participating centers the largest trial to date comparing aspirin to warfarin for recurrent stroke prevention. The study was sponsored by the National Institute of Neurological Disorders and Stroke (NINDS).
Treatment is far superior to no treatment and treatment with either aspirin or warfarin is safe under carefully monitored conditions, says J. P. Mohr, M.D., director of the Stroke Unit at New Yorks Columbia University and lead investigator of the trial.
Both drugs slow clotting of the blood, and blood clots are involved in the final stages of the most common type of stroke due to blockage of the vessels that supply oxygen-rich blood to the brain.
Aspirin affects the blood platelets, while warfarin inhibits circulating clotting proteins in the blood. Aspirin has been used for over 100 years, but its beneficial effects to prevent stroke and heart attack only started to be recognized in the 1970s.
Whether warfarin was superior to aspirin for stroke prevention was unclear prior to WARSS. Numerous previous studies have proven that use of aspirin reduces recurrent stroke by about 25 percent.
Part of the controversy about aspirin versus warfarin for stroke prevention has been the thinking among clinicians that warfarin may be a better blood thinner than aspirin to prevent almost all forms of stroke, but that it has greater side effects, increased risk of hemorrhage, and higher costs due to the need for blood tests to monitor the treatment effect for patients.
An earlier NINDS trial, Stroke Prevention in Atrial Fibrillation Study (SPAF), cleared up some of the confusion by showing a
Contact: Margo Warren
NIH/National Institute of Neurological Disorders and Stroke