The impact of acute cerebral blood flow disturbances on platelet aggregation

OBJECTIVE: To determine the changes in platelet function, manifesting as deviations of their aggregation intensity, in persons with acute ischemic stroke and transient ischemic attacks, to evaluate the effect of aspirin on platelet aggregation, dependent upon degree of cerebral blood flow disturbances and patient's gender, and to compare these changes with those in healthy persons. MATERIAL AND METHODS: We examined 50 patients aged 33 to 98 years (mean age, 63.7+/-2.1 years; 20 men and 30 women) with cerebral blood flow disturbances during acute period (18 with transient ischemic attacks and 32 with ischemic stroke). The diagnosis was confirmed by computer tomography and other clinical examinations. Adenosine diphosphate-, epinephrine-, and collagen-induced platelet aggregation was assessed in platelet-rich plasma. Twelve patients used aspirin at prophylactic doses (100-150 mg/d), and 38 patients did not use. The control group consisted of 25 healthy persons aged 31-64 years (mean age, 45.4+/-1.9 years; 17 men and 8 women). RESULTS: Increased platelet aggregation induced by all three inducers was significantly more frequent in stroke group. Platelet reaction to collagen was more expressed. Aspirin suppressed aggregation, but did not protect against development of ischemic stroke. Higher activity of platelet function during ischemic stroke was observed in platelets from men's plasma. CONCLUSIONS: During acute period, platelet aggregation in platelet-rich plasma statistically significantly increases in the stroke group, independently of the severity of the disease. A part of patients, using recommended dose of prophylactic aspirin, developed ischemic stroke. The effect of aspirin on platelets was more pronounced in women than men.