Activation of blood platelets after percutaneous transluminal coronary angioplasty and coronary artery bypass graft surgery

We have evaluated the activation of platelets in blood samples taken from p atients with stable angina undergoing balloon angioplasty (percutaneous tra nsluminal coronary angioplasty [PTCA]) (n = 11) or coronary artery bypass g rafting (CABG) under hypothermic (n = 11) or normothermic conditions (n = 1 1). We have found that surface expression of P-selectin on platelets in who le blood from PTCA patients upon thrombin treatment was significantly reduc ed, as compared with control platelets from healthy subjects. This effect w as partially reversed when platelets washed from the same blood sample were used, but even then P-selectin expression was significantly lower in PTCA patients than it was in control subjects. There was a significant increase in basal expression of P-selectin in blood platelets taken from patients wh o underwent CABG under normothermic conditions (warm blood cardioplegia) as opposed to hypothermic patients (cold crystalloid cardioplegia). These pla telets retain the ability to respond to agonists, although to a much lower extent than do those from healthy control donors. The surface exposure of P -selectin on resting and thrombin-treated platelets isolated from CABG surg ery patients was not different from that of the control platelets. The adhe sion to fibrinogen of resting and thrombin-treated platelets from patients who underwent balloon angioplasty as well as CABG surgery under normothermi c and hypothermic conditions was significantly reduced when compared with t he fibrinogen of the control platelets. These results suggest that the func tion of platelet fibrinogen receptor is impaired in patients with stable an gina pectoris and that PTCA and CABG surgery activates platelets.