Platelet Activation During Coronary Angioplast in Humans

Background. Previous studies have indicated that balloon angioplasty is associated with local platelet activation. In addition, different contrast media have different effects on thrombus formation during angioplasty in humans. We hypothesized that coronary angioplasty in humans is associated with activation of platelets to specific platelet agonists and that this activation may be differently modified by different angiographic contrast agents. Methods and Results. We studied 25 patients referred for angioplasty of the left anterior descending or circumflex coronary arteries. All patients were pretreated with aspirin and received heparin. Blood samples for assessment of platelet aggregation to serotonin, ADP, epinephrine, and collagen were obtained from the coronary sinus before any contrast injection, after initial diagnostic contrast injections, and after three balloon inflations. Patients were randomized to receive iopamidol, diatrizoate, or ioxaglate. Contrast alone was not associated with altered platelet aggregation. However, balloon angioplasty was consistently associated with increased platelet aggregation to serotonin but not to ADP, epinephrine, or collagen. These effects were similar with the three contrast agents studied except that the use of iopamidol was associated with increased platelet responsiveness to all concentrations ofADP after balloon dilation. Conclsions. Coronary angioplasty in humans was associated with increased platelet aggregation in blood drawn from the coronary sinus. This effect was primarily seen when serotonin was used as an agonist. (Circulation. 1993;88:2728-2734.)