Preoperative 24-hour urine amount as an independent predictor of renal outcome in poor cardiac function patients after coronary artery bypass grafting

PURPOSE: To investigate the incidence and the main pre-operative risk factors for the development of acute renal failure (ARF) in triple vessels coronary artery bypass grafting (CABG) with special reference to a subset of patients with poor cardiac function (ejection fraction <50%). PATIENTS: The study included the patients (n = 66) requiring CABG from January 1, 1995 to January 1, 2002 in a medical center. RESULTS: A high percentage (84.8%) of patients developed ARF and 57.6% of patients received hemodialysis (HD). Preoperative variables significantly associated with the development of ARF included increased age, increased preoperative serum creatinine, decreased preoperative 24-hour urine output and accepted emergent CABG. By the logistic multivariate regression model, increased age (OR = 1.16), preoperative serum creatinine (OR = 3.58,), decreased preoperative 24-hour urine amount (OR = 0.99,) and emergent CABG (OR = 2.01) were independently associated with ARF. As for the need for HD, those factors including, preoperative serum creatinine (2.11 +/- 1.13 v 3.08 +/- 1.67 mg/dL) and preoperative 24-hour urine output (1358.6 +/- 745.9 v 755.2 +/- 572.1 mL/day) were significantly associated with requirement of dialysis. Using multivariate logistic regression, the significant risk factors independently associated with dialysis were preoperative serum creatinine (OR = 1.34) and preoperative 24-hour urine output (OR = 0.99). Patients with non- oliguric renal failure had significantly greater chance of recovering their renal function after cardiac surgery compared to those with oliguria (36.9% v 10.0%, P <.05). CONCLUSION: Preoperative 24-hour urine amount and pre-operative serum creatinine can provide valuable information for predicting the likelihood of developing acute renal failure and requiring dialysis in this subgroup of patients.