[The relationship among hematocrit, platelet aggregation and the time of onset in patients with acute stage-cerebral infarction].
We evaluated time relation among hematocrit (Ht), platelet aggregation (PA) and the onset of acute stage-cerebral infarction in 221 patients. Lacunar infarctions were likely to occur in the evening or at midnight. The elevated Ht value was frequently found in patients with infarctions occurring at midnight, suggesting that the elevation of blood viscosity has an intimate etiology to the onset. The decrease of PA was often found in those who suffered from their stroke while awake in the morning or at midnight, and frequently had been associated with elevated Ht in the latter patients. Decrease of PA is often reported during acute stage-cerebral infarction. Our results indicate that increased platelet aggregation may play an important role in developing cerebral infarction, especially in those who had onset of illness in the morning.