Effects of renin-angiotensin system inhibitors on the occurrence of acute kidney injury following off-pump coronary artery bypass grafting

Background: Despite several studies that evaluated the effects of renin-angiotensin system (RAS) inhibitors on postoperative renal function in cardiac surgery patients, no final conclusions are available. The aim of the present study was to determine the effect of RAS inhibitors on renal function following off-pump coronary artery bypass grafting (OPCAB). Methods and Results: Among patients who underwent OPCAB, perioperative characteristics, postoperative renal function and incidence of acute kidney injury (AKI) were compared between those who received RAS inhibitors for at least 2 weeks (RASI group, n=296) and those not treated with RAS inhibitors (Control group, n=176). AKI was defined as an increase in serum creatinine >0.3 mg/dl or >50% from baseline. Preoperative comorbidities were more frequent in the RASI group. Operative data were similar. Incidence of postoperative AKI (19.9% vs 20.9%, P=0.815) and of postoperative renal function was comparable between groups. In the adjusted multivariate logistic regression model for propensity scores between groups, diabetes mellitus, preoperative creatinine level and perioperative transfusion were significant risk factors for postoperative AKI, whereas preoperative treatment with RAS inhibitors did not increase the risk. Conclusions: Chronic preoperative use of RAS inhibitors did not affect postoperative renal function or increase the risk of postoperative AKI in patients undergoing OPCAB.