APROTININ AND DIPYRIDAMOLE FOR THE SAFE REDUCTION OF POSTOPERATIVE BLOOD-LOSS

Background. Aprotinin (APR) reduces postoperative blood loss but may i nduce thrombosis. Dipyridamole (DIP) limits platelet aggregation and m ay reduce the thrombotic complications associated with APR. Methods. T o evaluate the safety and effectiveness of combined APR and DIP, we un dertook a prospective randomized trial in patients undergoing cardiac operations. Patients were stratified according to risk for bleeding (l ow or high), and received either DIP with placebo (DIP group; n = 59) or DIP with APR (DIP + APR group; n = 56). Blood samples were obtained for the measurement of hematologic and biochemical parameters. Blood loss and transfusion requirements were documented postoperatively. Res ults. Postoperative blood lass and transfusion requirements were signi ficantly lower in the DIP + APR group at 6, 12, and 24 hours after byp ass (p < 0.01). No significant differences were found between groups i n the incidence of perioperative mortality (DIP, 0%; DIP + APR, 3%), m yocardial infarction (DIP, 0%; DIP + APR, 3%), stroke (DIP, 1%; DIP APR, 1%), or potential thrombotic events (death, myocardial infarction , and stroke: DIP, 2%; DIP + AFR, 5%). In addition, these rates did no t differ from those of nonparticipating matched control patients. Conc lusions. Administration of both drugs simultaneously was more effectiv e than DIP alone in reducing postoperative blood loss. A platelet inhi bitor may be required to reduce the thrombotic complications associate d with APR. Further studies evaluating graft patency and perioperative ischemia are necessary to confirm the potential benefits of the combi nation of a platelet inhibitor and APR. (C) 1998 by The Society of Tho racic Surgeons.