Formation of platelet aggregates after attacks of coronary spastic angina pectoris.

Using a novel laser-light scattering method, we examined platelet aggregability, especially small-sized platelet aggregates, at baseline and after spontaneous coronary spastic attacks in 14 patients with coronary spastic angina, and before and after anginal attacks during an exercise test in 11 patients with stable exertional angina. The number of small-sized platelet aggregates after coronary spastic anginal attacks increased significantly, but not in patients with stable exertional angina. These results imply that an increase in the number of small-sized platelet aggregates from coronary spasm may be a trigger for coronary thrombosis via medium- and large-sized platelet aggregates.