Off-pump versus on-pump coronary artery bypass surgery and postoperative renal dysfunction

Renal dysfunction is a serious complication after coronary bypass surgery w ith cardiopulmonary bypass (CABG). Because duration of cardiopulmonary bypa ss (CPB) is associated with renal outcome, it has been proposed that avoida nce of CPB with off-pump coronary bypass (OPCAB) may reduce perioperative r enal insult. We therefore tested the hypothesis that OPCAB is associated wi th less postoperative renal dysfunction compared with CABG surgery. With IR B approval, we gathered data for 690 primary elective coronary bypass patie nts (OPCAB, 55; CABG, 635). Perioperative change in creatinine clearance (D CrCl) was calculated by using preoperative (CrPre) and peak postoperative ( CrPost) serum creatinine values, and the Cockroft-Gault equation (DCrCl = C rPreCl - CrPostCl). Univariate and linear multivariate tests were used in t his retrospective analysis; P < 0.05 was considered significant. Multivaria te analysis did not identify OPCAB surgery as an independent predictor of D CrCl. However, previously reported associations of PreCrCl, age, and diabet es with DCrCl were confirmed. Power analysis demonstrated an 80% power to d etect a 7.0 mL/min DCrCl difference between study groups. In this retrospec tive study, we could not confirm that OPCAB significantly reduces periopera tive renal dysfunction compared with CABG surgery. Our findings suggest tha t reduction of renal risk alone should not be an indication for OPCAB over CABG surgery.