Methods: Between August 2007 and March 2011, a total of 1,359 consecutive patients (975 females, 384 males; mean age 58.6±10.1 years; range 23 to 87 years) who underwent isolated coronary artery bypass grafting (CABG) surgery in Shariati Hospital, Tehran, Iran were retrospectively analyzed. Patients were classified based on the preoperative creatinine clearance values to group renal (group R; n=21) (<30 mL/min) and group control (group C; n=1338) (≥30 mL/min). Two groups were compared for preoperative characteristics. Effects of preoperative renal insufficiency on post-CABG mortality and morbidity rates were measured using stepwise multivariate logistic regression analyses.

Results: Post-coronary artery bypass grafting surgery renal failure (9.5% vs. 0.4%) and mortality rates (19.0% vs. 3.3%) were higher in group R compared to group C (p<0.001). Renal impairment was an independent predictor for post- CABG surgery renal insufficiency and dialysis (OR=1.05, 95% CI: 1.02-1.07; p=0.001) and early mortality (OR=1.16, 95% CI: 1.07-1.25; p=0.001).

Conclusion: Preoperative non-dialysis-dependent renal insufficiency is the most important risk factor for post-CABG surgery renal failure and mortality. A specific attention is warranted to patients with pre-existing risk factors especially renal impairments.