Pro: Aprotinin has a good efficacy and safety profile relative to other alternatives for prevention of bleeding in cardiac surgery.

Simon C. Body, MBChB, MPH* C. David Mazer, MD, FRCPC† Two recently published reports have evoked partisan debate and regulatory review on the safety of the widely used protease inhibitor, aprotinin (Bayer Pharma, West Haven, CT) (1,2). These retrospective observational studies claimed significant increases in several adverse postoperative events after cardiac surgery, without important reduction in blood loss or other benefits. However, several earlier studies have documented the efficacy of aprotinin in decreasing blood loss and transfusion exposure, and have found an acceptable safety profile, even a reduction in the incidence of stroke without alteration in renal function or increased risk of adverse thrombotic events (3–6). The dichotomy between two nonrandomized, observational clinical studies published in well-regarded journals, and many well-conducted randomized trials is, as yet, unresolved, and may depend on details of statistical analyses. Because of this controversy, we wish to summarize the large body of prior literature demonstrating the efficacy and safety of aprotinin, review potential weaknesses of the two recent observational studies, point out remaining “holes” that require future study, and summarize the ongoing BART study (Blood conservation using Antifibrinolytics: Randomized Trial in high-risk cardiac surgery), which is the largest randomized trial comparing all the three antifibrinolytic drugs.