DETECTION AT PLATELETS ACTIVATED DURING ACETYLCHOLINE-INDUCED CORONARY VASOSPASM

Although platelet activation may play a role in coronary artery spasm, platelets activated following coronary vasospasm have not been clinic ally detected. We performed flow cytometric analysis of activation-dep endent granular proteins, CD62P (P-selectin), CD63, PAC-I (activated g lycoprotein [GP] IIb/IIIa) and thrombospondin on the platelet plasma m embrane in patients who exhibited acetylcholine-induced coronary vasos pasm and compared findings with those in control patients without vaso spasm. We simultaneously investigated the plasma levels of thrombin an ti-thrombin III complex (TAT), plasmin alpha(2)-plasmin inhibitor comp lex (PIC), and thrombomodulin. In patients with vasospasm, the express ion of CD62P, CD63 and PAC-I on the platelet membrane surface increase d in coronary sinus blood samples following coronary vasospasm, althou gh the expression in aortic samples did not change. The TAT level also increased in the coronary sinus after vasospasm. Platelets might be a ctivated by coronary vasospasm within the coronary circulation. The pl atelet activation process may be modulated by thrombin generation.