EARLY DETECTION OF PLATELET ACTIVATION AFTER CORONARY ANGIOPLASTY

Background Although platelet activation has been considered an importa nt reaction after percutaneous transluminal coronary angioplasty (PTCA ), it is still difficult to detect the activated platelets in vivo dir ectly. Methods To detect platelets activated at an early stage after P TCA, blood samples were taken from the coronary sinus and the aorta in 22 patients with coronary artery disease, who underwent PTCA for a le sion of the left anterior descending artery. Ten patients with coronar y artery disease, who underwent diagnostic coronary angiography only, were compared with them. The expression of activation-dependent granul ar protein, CD62P (P-selectin) and CD63, on the platelet membrane surf ace was analysed using flow cytometry, The plasma thrombomodulin level was also measured. Results The percentage of platelets positive for C D62P (0.53+/-0.04 to 0.80+/-0.11%, P <0.01) and CD63 (16.0+/-1.4 to 19 .8+/-2.0%, P <0.05) increased after PTCA in the coronary sinus, althou gh it did not change in the aorta. The plasma thrombomodulin level als o increased after PTCA in the coronary sinus (16.7+/-1.0 to 20.4+/-2.0 u/ml, P <0.05). However, these parameters did not change after corona ry angiography only, After PTCA, the plasma thrombomodulin level was c orrelated with the percentage of platelets positive for CD62P (r=0.88, P <0.001) and with that for CD63 (r=0.69, P <0.001) in the coronary s inus. Conclusions PTCA produced activation of circulatory platelets, w hich might have been caused by balloon-induced vascular endothelial in jury. One should take care to avoid needless vascular injury during th e PTCA procedure to inhibit the platelet activation.