Is preoperative serum creatinine a reliable indicator of outcome in patients undergoing coronary artery bypass surgery?

Objective: Evaluating renal function by calculating creatinine clearance as an alternative measure to serum creatinine may give a better estimation of postoperative renal function in patients undergoing coronary artery bypass grafting.

Methods: Using our database, we conducted a retrospective review of the records of all 11,884 patients aged 21 years or older undergoing pure bypass grafting who required cardiopulmonary bypass. Preoperative renal function was categorized as normal renal function (serum creatinine 60 mL/min), occult renal insufficiency (serum creatinine 1.5 mg/dL and creatinine clearance
Results: Out of 11,884 patients in the sample, 7856 (66.1%) had normal renal function, and 706 (5.9%) had occult renal insufficiency. The rate of postoperative mortality, renal failure, atrial fibrillation, prolonged ventilation, intra-aortic balloon pump usage, and prolonged hospital stay (>7 days) was higher in patients with occult renal insufficiency than in the normal group in univariable analysis. Multivariable logistic regression analysis demonstrated that patients with occult renal insufficiency compared with the group with normal renal function were at higher risk for mortality (odds ratio = 2.59, 95% confidence interval 1.15-5.86; P = .022) and prolonged hospital stay (>7 d) (odds ratio = 1.30, 95% confidence interval 1.08-1.57; P = .005).

Conclusions: To identify higher-risk patients requiring special intensive care, and in whom new interventions can be performed to improve outcome, we recommend the preoperative calculation of creatinine clearance, especially in older women with a lower body mass index.