Platelet function and thrombin activity in patients with recent cerebral transient ischemic attacks.

Platelet function and thrombin activity were investigated in 12 hospitalized patients (7 men and 5 women, mean age 53 years) who had had transient cerebral ischemic attacks in the previous 2-12 weeks. Each patient was given an extensive clinical and instrumental evaluation, including Doppler sonography of the cervical and lower limb vessels, cerebral angiography, and head computed tomography scan, after which relevant atherosclerotic disease was excluded. The controls consisted of 12 subjects hospitalized for nonvascular neurologic problems and matched for age, sex, and risk factors to the transient ischemic attack patients. Collagen-induced platelet thromboxane B2 production, plasma beta-thromboglobulin, and fibrinopeptide A were significantly higher in the patients than the controls. Platelet aggregability by collagen was the same in the 2 groups. Platelet hyperfunction and enhanced thrombin activity are present in patients some weeks after the acute episode, suggesting that the hemostatic system has a primary pathogenetic role.