Creatinine clearance and risk of early mortality in patients undergoing coronary artery bypass grafting

Abstract

We sought to evaluate renal function assessed on the basis of calculated creatinine clearance as a predictor of early mortality and postoperative complications in patients undergoing coronary artery bypass grafting and to assess whether calculated creatinine clearance is superior to serum creatinine concentration in predicting early death postoperatively. Six thousand seven hundred eleven consecutive patients without dialysis-dependent renal insufficiency undergoing a first isolated coronary artery bypass grafting were included. Preoperative serum creatinine concentrations and creatinine clearance calculated by using the Cockroft-Gault formula were related to mortality within 30 days postoperatively. There were 136 early deaths. After adjustment for age and other confounders in multivariate analyses, moderate (calculated creatinine clearance 30-60 mL/min) and severe (calculated creatinine clearance < 30 mL/min) renal insufficiency predicted early mortality (odds ratio of 2.4 [95% confidence interval, 1.2-4.8] and odds ratio of 4.8 [95% confidence interval], 1.6-13.9, respectively) compared with normal (calculated creatinine clearance > or = 90 mL/min) renal function. The area under the receiver operating characteristic curve for calculated creatinine clearance and serum creatinine concentration was 0.71 and 0.62, respectively, yielding a difference of 0.08 (P = .0004). No increased risk of mediastinitis or bleeding was observed in patients with renal insufficiency. Moderate and severe renal insufficiency independently increase the risk of early death after coronary artery bypass grafting. Our results indicate that calculated creatinine clearance is a better predictor of early mortality postoperatively than serum creatinine concentration.