Reducing allogeneic transfusion in cardiac surgery: a randomized double-blind placebo-controlled trial of antifibrinolytic therapies used in addition to intra-operative cell salvage

Background. The transfusion of allogeneic red blood cells and allogeneic coagulation products is associated with risk to the patient and the depletion of an increasingly scarce resource. This prospective, randomized, double-blind, placebo-controlled trial investigated practices to avoid transfusion in patients undergoing first-time cardiac surgery. Methods. Patients were randomized to one of three treatment groups: an aprotinin group, a tranexamic acid group, and a control group receiving normal saline. Intra-operative cell salvage was used for all patients. The primary outcomes were the number of patients exposed to allogeneic red blood cells, allogeneic coagulation products or any allogeneic transfusion (allogeneic red blood cells and/or allogeneic coagulation products). Results. Patients were 2.5 times more likely to receive any allogeneic transfusion in the tranexamic group than in the aprotinin group (21 patients out of 60 compared with nine out of 60, respectively). The relative risk of any allogeneic transfusion comparing aprotinin with tranexamic acid was 0.43 (95% confidence interval 0.21-0.86; P=0.019). Patients in the control group were four times more likely to receive any allogeneic transfusion when compared with the aprotinin group (37 patients out of 60 compared with nine out of 60, respectively). The relative risk of any allogeneic transfusion comparing aprotinin with control was 0.24 (95% confidence interval 0.13-0.46; P<0.001). Conclusions. When used in addition to intra-operative cell salvage, aprotinin is the most efficacious pharmacological therapy for reducing patient exposure to any allogeneic transfusion during first-time cardiac surgery.