Aspirin dose, bleeding time, platelet adhesion and aggregation in cerebral thrombosis

Bleeding time, platelet aggregation and platelet adhesiveness were measured before and after each of 11 consecutive therapeutic sequences in 17 patients who had recently suffered a cerebro-vascular accident of atheromatous ischemic origin. The first 10 sequences were each of 15 days duration and during the first 8 of these, aspirin was increased with each sequence from 300 mg/2 days to 3 g/day. During the 10th sequence a placebo was given. The final sequence (11th) lasted 3 months and during this time the dose of aspirin was fixed at 1 g/day. Significant modification of platelet aggregation was obtained with 300 mg/2 days, platelet adhesiveness was significantly modified with 500 mg/2 days while significant bleeding time modification required a minimum 500 mg/day. The results did not vary significantly with higher doses of acetylsalicylic acid (ASA). Only the results for the platelet aggregation were individually reproducible. There was no statistical correlation between the results of the tests. As far as the 3 tests are considered, the best efficiency is obtained with the therapeutic range of 500 mg to 1 g/day.