PREOPERATIVE PLATELET DYSFUNCTION INCREASES THE BENEFIT OF APROTININ IN CARDIOPULMONARY BYPASS

Background. This study was designed to determine the benefit of aproti nin therapy in reducing bleeding during and after cardiopulmonary bypa ss in patients with preoperative platelet dysfunction. Platelet functi on involvement in the mechanism by which aprotinin acts was also inves tigated. Methods. In a double-blind, randomized study, patients receiv ed high-dose aprotinin (n = 54) or placebo (n = 52). Whole blood aggre gation was measured preoperatively. Platelet function and activation i n both groups were assessed intraoperatively and postoperatively at fi ve times. Results. Aprotinin significantly reduced perioperative bleed ing and postoperative blood transfusion. Placebo-treated patients with reduced preoperative platelet aggregation bled more postoperatively, but aprotinin reduced the bleeding in patients with normal or reduced platelet function to similar levels. Any cardiopulmonary bypass-induce d changes in platelet aggregation, platelet activation as measured by P-selectin expression, and von Willebrand factor antigen and function were similar in aprotinin-treated and placebo-treated groups. Conclusi ons. The mechanism by which aprotinin reduced bleeding was independent of any effect on platelet function. However, aprotinin produced a gre ater reduction in bleeding among patients whose condition was hemostat ically compromised by preoperative platelet dysfunction.aprotinin, pla telet aggregation, platelet activation, cardiopulmonary bypass, von Wi llebrand factor (C) 1997 by The Society of Thoracic Surgeons