Platelets in vascular disease.

Platelets play a key role in primary hemostasis and in the pathogenesis of atherosclerosis and atherothrombotic events such as stroke and myocardial infarction. When a plaque ruptures, platelets adhere to the underlying collagen matrix, become activated and aggregate, which may lead to vascular occlusions. Hemorheological aspects are intimately involved in this process. The assessment of this platelet function in vitro is difficult and has not reached the stage of routine use. Inhibition of platelet aggregation is the corner stone of any treatment of vascular disease. It is achieved mainly by to mechanisms, inhibition of thromboxane formation by acetylsalicylic acid, and with ADP receptor antagonists such as clopidogrel. Newer agents are being developed with the difficult mission to inhibit platelet aggregation more efficiently, and simultaneously reduce the risk of bleeding.