Aspirin improves the enhanced erythrocyte aggregability in patients with cerebral infarction.

We examined the effect of aspirin on the enhanced erythrocyte aggregability in 19 patients with cerebral infarction during the chronic phase. Aspirin (81 mg/day) was administered for 8 weeks. The rate of erythrocyte aggregation (aggregability) was measured using the whole-blood erythrocyte aggregometer developed by us (Am. J. Physiol. 251, H1205-H1210, 1986) before, and at 4 and 8 weeks after initiation of the aspirin administration. Concomitant measurements were made of certain blood factors such as the hematocrit, albumin-globulin (A/G) ratio and fibrinogen concentration. The erythrocyte aggregation rates before, and at 4 and 8 weeks were 0.154 +/- 0.019/s, 0.144 +/- 0.020/s, and 0.143 +/- 0.020/s, respectively. The erythrocyte aggregation rates at 4 and 8 weeks were significantly (P < 0.05, Bonferroni's modified t-test) lower than that before aspirin administration. Although the hematocrit value and A/G ratio were not changed at 4 and 8 weeks after the initiation of aspirin, the concentration of fibrinogen were significantly (P < 0.05) reduced at 4 weeks. The above results suggest that aspirin can improve the enhanced erythrocyte aggregability in patients with cerebral infarction during the chronic phase.