Abstract
It is already well known that aspirin is one of the representative antiplatelet drug. To confirm the clinical usefulness of aspirin as an antiplatelet drug, its influences on platelet functions in various arteriosclerotic patients were examined. The patients with arteriosclerosis were consisted of those with myocardial infarction (10), angina pectoris (5) and cerebral infarction (10) with the ages of 67.2±7.3. Normal controls were consisted of healthy young adults with the ages of 28.4±3.8 years and middle aged persons with the ages of 61.6±4.0 years. As indices of platelet functions, platelet aggregation test and the determination of prostanoids and platelet releasing substances were performed. Those parameters were determined after the first administration and during the consecutive administration of the drug of 300 mg once everyday for 4 weeks. The results thus obtained could be summarized as below : 1. The enhanced platelet aggregation of the patients with arteriosclerosis before the administration normalized throughout the whole periods of aspirin adminisration. 2. The serum levels of TXB_2 and 6-Keto-PGF_<1α> simultaneously decreased, but significant decrease was observed in the latter. The ratio of TXB_2 to 6-Keto-PGF_<1α> also decreased throughout the study. 3. In cases of arteriosclerosis serum levels of β-TG and PF4 significantly decreased which were similar to that of platelet releasing reaction. 4. The inhibitory effects of aspirin on platelet functions tapered, although those were still present even after 4 weeks. It was concluded that aspirin almost normalized the platelet aggregation even at the low dosis of 300mg per day. The administration of aspirin in this dosis could prevent the formation of thrombosis and improve hemodynamics in patients with arteriosclerosis.
