December 6, 2001. Copyright 2001. Graphic News. All rights reserved.

Embargoed for release: 16:00 Eastern U.S. time, 21:00 GMT, December 6, 2001

Aspirin appears to reduce stroke severity

LONDON, December 6, Graphic News: A new study adds to evidence that stroke victims who had taken aspirin had milder strokes than people who had not taken the humble pill, according to a major study published in the December issue of Stroke: Journal of the American Heart Association.

Only one in ten individuals who had taken at least one aspirin in the week before suffering an ischemic stroke had a severe stroke, compared with one in six non-users. An ischemic stroke is caused by a blood clot blocking an artery supplying oxygen-carrying blood to the brain. 

The study compared stroke severity of aspirin users and non-users with data from ÒTOAST,Ó a five-year clinical trial conducted between 1990 and 1996. Of 1,275 patients in the study, 509 (almost 40 percent) reported aspirin use during the week before their stroke. 

Using the National Institutes of Health Stroke Scale (NIHSS), 50.3 percent of aspirin users had mild strokes, compared with 43.0 percent of non-users; only 9.6 percent of aspirin users had severe strokes, compared with 14.8 percent of non-users. 

On the Supplemental Motor Examination (SME) ranking that measures the severity of muscle weakness in arms and legs, 55.6 percent of aspirin users had mild strokes, compared with 48.7 percent of non-users; 19.8 percent of aspirin users had severe strokes, compared with 24.0 percent of non-users. Several different mechanisms are responsible for aspirinÕs protective effect, say the researchers. 

An ischemic stroke results from atherosclerosis -- hardening and narrowing of the arteries -- and the formation of a blood clot. Deposits of cholesterol and plaques within the artery build up, reducing blood flow and causing the artery to lose its ability to stretch.

Blood platelets which stick to the roughened surface of the plaque are activated, releasing chemicals which stimulate the production of fibrin. Red blood cells are then bound together by filaments of fibrin to form a thrombus, or blood clot. Flakes of the thrombus may break off, becoming an embolus, travel through the bloodstream and block small arteries in the brain. Aspirin reduces the stickiness of the platelets, which in turn reduces blood clotting and the chance of an ischemic stroke.

In addition to aspirinÕs anti-platelet effect, which may improve blood circulation in the brain, other mechanisms are believed to enhance the drugÕs protective effect, say the researchers. These include its antioxidant properties, which may reduce oxidative tissue damage; and some possible anti-inflammatory, neuroprotective effect, which at this time is still under investigation.

The findings may actually give an edge to aspirin over the other commonly used blood-thinning drug, warfarin, because it is much cheaper and demands less medical supervision.

ÒAspirin has a rich pharmacology, some of which is still being elucidated,Ó says primary researcher Janet L. Wilterdink, M.D., of the department of neurology at Brown Medical School in Providence, Rhode Island. ÒI believe that a combination of all these mechanisms has the potential to play a significant role in aspirinÕs beneficial effect.Ó
/ENDS
Source: Stroke: Journal of the American Heart Association