[Platelet aggregation in patients with migraine during the pain attack and in the pain-free period].

In 31 women with a history of migraine platelet aggregation was studied between migrainous attacks, and in 14 of them during an attack of migraine. The method of Born and Cross was used. The rates of the first and second phases of aggregation were calculated and the quantitative index of aggregation curve according to Cavallero was calculated. Adrenaline in concentrations of 2 and 4 micron M was used as the aggregating factor. No differences were found in the mean rates of the first phase of aggregation between the patients and the controls. The rate of the second phase in the time between migraine attacks was significantly higher in patients with migraine (p less than 0.001) than in healthy subjects. During migraine attack the mean rate of the second phase decreased significantly (p less than 0.02 and p less than 0.001). These changes of the rate of the second phase may be explained as due to disturbances in the release of the aggregating substances from platelets and accumulation of platelet-activating substances.