BACKGROUND: Patients having cardiac operations often require blood transfusions. Aprotinin reduces the need for blood transfusions during coronary artery bypass graft operations. To determine the safety and effectiveness of aprotinin in reducing the use of allogeneic blood and postoperative mediastinal chest tube drainage, we studied 212 patients undergoing primary sternotomy for valve replacement or repair. METHODS: This study was multicenter, randomized, prospective, double-blind, and placebo-controlled. Patients received high-dose aprotinin (n = 71), low-dose aprotinin (n = 70), or placebo (n = 71). The study medication was given as a loading dose followed by a continuous infusion and pump prime dose. Heparin administration was standardized. Transfusions, postoperative mediastinal shed blood, and adverse events were tracked. RESULTS: Demographic profiles were similar among the treatment groups. Aprotinin did not decrease the percentage of patients receiving transfusions when compared with placebo (high-dose aprotinin, 63%, p = 0.092; low-dose aprotinin, 52%, p = 0.592; placebo, 48%). Aprotinin was associated with a reduction in the volume of mediastinal shed blood (high-dose aprotinin vs placebo, p = 0.002; low-dose aprotinin vs placebo, p = 0.017). Adverse events were equally distributed among the treatment groups except for postoperative renal dysfunction (high-dose aprotinin, 11%; low-dose aprotinin, 7%; placebo, 0%; p = 0.01). A disproportionate number of patients in the high-dose aprotinin group with postoperative renal dysfunction also had diabetes mellitus. CONCLUSIONS: Aprotinin treatment in this population did not reduce allogeneic blood use, although there were significant reductions in the volume of mediastinal shed blood.