Renal function and outcome from coronary artery bypass grafting: impact on mortality after a 2.3-year follow-up

Abstract

Background - Severe renal dysfunction is associated with a worse outcome after coronary artery bypass graft surgery (CABG). Less is known about the effects of milder degrees of renal impairment, and previous studies have relied on levels of serum creatinine, an insensitive indicator of renal function. Recent studies have suggested that estimated glomerular filtration rate (eGFR) is a more discriminatory measure. However, data on the utility of eGFR in predicting outcome from CABG are limited.Methods and Results - We studied 2067 consecutive patients undergoing CABG. Demographic and clinical data were collected preoperatively, and patients were followed up a median of 2.3 years after surgery. Estimated GFR was calculated from the Modification of Diet in Renal Disease equation. The primary outcome was all-cause mortality. Mean +/- SD eGFR was 57.9 +/- 17.6 mL/min per 1.73 m(2) in the 158 patients who died during follow-up compared with 64.7 +/- 13.8 mL/min per 1.73 m(2) in survivors ( hazard ratio [HR], 0.71 per 10 mL/min per 1.73 m(2); 95% CI, 0.64 to 0.80; P < 0.001). Estimated GFR was an independent predictor of mortality in both models with other individual univariable predictors (HR, 0.80 per 10 mL/min per 1.73 m(2); 95% CI, 0.72 to 0.89; P < 0.001) and the European system for cardiac operative risk evaluation (HR, 0.88 per 10 mL/min per 1.73 m(2); 95% CI, 0.78 to 0.98; P = 0.02).Conclusions - Estimated GFR is a powerful and independent predictor of mortality after CABG.Background - Severe renal dysfunction is associated with a worse outcome after coronary artery bypass graft surgery (CABG). Less is known about the effects of milder degrees of renal impairment, and previous studies have relied on levels of serum creatinine, an insensitive indicator of renal function. Recent studies have suggested that estimated glomerular filtration rate (eGFR) is a more discriminatory measure. However, data on the utility of eGFR in predicting outcome from CABG are limited.Methods and Results - We studied 2067 consecutive patients undergoing CABG. Demographic and clinical data were collected preoperatively, and patients were followed up a median of 2.3 years after surgery. Estimated GFR was calculated from the Modification of Diet in Renal Disease equation. The primary outcome was all-cause mortality. Mean +/- SD eGFR was 57.9 +/- 17.6 mL/min per 1.73 m(2) in the 158 patients who died during follow-up compared with 64.7 +/- 13.8 mL/min per 1.73 m(2) in survivors ( hazard ratio [HR], 0.71 per 10 mL/min per 1.73 m(2); 95% CI, 0.64 to 0.80; P < 0.001). Estimated GFR was an independent predictor of mortality in both models with other individual univariable predictors (HR, 0.80 per 10 mL/min per 1.73 m(2); 95% CI, 0.72 to 0.89; P < 0.001) and the European system for cardiac operative risk evaluation (HR, 0.88 per 10 mL/min per 1.73 m(2); 95% CI, 0.78 to 0.98; P = 0.02).Conclusions - Estimated GFR is a powerful and independent predictor of mortality after CABG.