A STUDY OF PLATELET ACTIVATION AFTER CORO NARY ANGIOPLASTY - INFLUENCE ON ACUTE OCCLUSION AND RESTENOSIS

The development of monoclonal anti-platelet antibodies to activation-d ependant epitopes has made possible the study of the appearance of act ivated platelets in the blood by cytometry. This was undertaken in 35 patients undergoing coronary angioplasty. Blood was sampled through th e femoral venous catheter introducer before the procedure, at 3 minute s and 3, 24 and 48 hours after angioplasty. Systematic coronary angiog raphy was performed at about 6 months and vessel diameters were quanti fied by a digitised technique. In general, platelet activation was not observed before angioplasty or in the first hours following the proce dure. On the other hand, a significant number of activated platelets w as observed secondarily : 7 +/- 7.3 % at the 24th hour and 6.8 +/- 5.9 % at the 48 th hour. There was a significant correlation between the level of platelet activation before angioplasty and that at the 24th h our (r = 0.52, p = 0.01). There was a tendency to more activated circu lating platelets before and 24 hours after angioplasty in patients wit h acute occlusion. The correlation coefficient between the level of ac tivated platelets 24 hours after angioplasty and progression of stenos is at 6 months was not statistically significant (r = 0.29). Therefore , the authors demonstrated platelet activation, which was sometimes co nsiderable, inconstantly in circulating venous blood of patients with angina 24 hours after coronary angioplasty despide treatment with aspi rin. Activated platelets may play a role in constituting acute occlusi on by thrombosis but their detection was not predictive of restenosis.