Abstract 3347: Does Aprotinin Increase the Risk of Renal Failure in Cardiac Surgery Patients?
Background: Aprotinin is frequently used in high-risk cardiac surgery patients to decrease bleeding complications and transfusions of packed red blood cells (tPRBC). tPRBC are known to increase the risk of new onset postoperative renal failure (RF) in cardiac surgery patients. A recent highly publicized report in the New England Journal of Medicine implicated Aprotinin as an independent causal factor for postoperative renal failure, but ignored the potential confounding affect of tPRBC on RF. We sought to investigate that claim with a detailed analysis that included all perioperative risk factors for renal failure, including tPRBC.
Methods: Prospectively collected patient data from 12 centers contributing to the Merged Cardiac Registry (an international multi-center cardiac surgery database) between 2000 and Feb 2006 were retrospectively analyzed. A previously published risk model for RF incorporating 12 variables was used to calculate a baseline RF risk score for each patient in whom those variables were available (n=15174). After adding tPRBC data 11,198 patients remained for risk-adjusted assessment of RF in relation to Aprotinin use. Risk-adjusted multivariable analyses (MVA) were carried out with, and without, consideration of tPRBC.
Findings: Aprotinin was utilized in 24.6%(2,757/11,198). The overall incidence of RF was 1.6% (180/11,198) and was higher in the Aprotinin subset (2.6%,72/2757 vs 1.3%, 108/8441; p<0.001). The incidence of RF directly and significantly increased with increasing tPRBC use (p<0.001). Importantly, tPRBC use was also higher in the Aprotinin group (2.1±3.3 vs 1.7±2.9 units tPRBC / patient; p<0.001) Risk-adjusted MVA without tPRBC in the model suggests that Aprotinin significantly impacts RF (P = 0.005; OR = 1.5). However, further risk adjustment with the addition of the highly significant tPRBC variable (p<0.0001; OR = 1.23/tPRBC used) to the model negates the supposed independent affect of Aprotinin (p=0.274) on RF.
Conclusions: The increase in renal failure seen in patients who were administered Aprotinin was directly related to increased transfusions seen in that high-risk patient population. Aprotinin use does not independently increase the risk of renal failure in cardiac surgery patients.