Role of platelets and antiplatelet agents in cerebrovascular disease. Clues from trials.

Abstract

Significant reductions in mortality and in the incidence of nonfatal strokes have been shown in many trials of antiplatelet drugs, such as aspirin, in cerebrovascular disease. The limitations of these trials must be considered; however, if the trials are to provide useful information on the role of platelets in thrombotic processes. Difficulties arise because of the variable composition of emboli and the many possible causes of strokes. Some emboli are composed mainly of platelets while others consist of atheromatous material. Strokes may result from hemorrhage, hemodynamic disturbances, or lacunar infarction rather than thromboembolism. Nonetheless, the results of clinical trials suggest that at least some strokes can be prevented by antiplatelet drugs, thus implying that platelets are involved in the underlying disease process.