On-pump versus off-pump coronary revascularization: Evaluation of renal function

Background. Coronary revascularization with cardiopulmonary bypass has the potential risk of renal dysfunction related to the nonphysiologic nature of cardiopulmonary bypass. Recently, there has been a revival of interest in performing myocardial revascularization on the beating heart and we investi gated whether this prevents renal compromise. Methods. A prospective, randomized, controlled trial was performed in 50 pa tients (45 males, mean age 61 +/- 3.7 years) undergoing elective coronary a rtery bypass grafting. Patients were randomly assigned to conventional reva scularization with cardiopulmonary bypass (on pump) or beating heart revasc ularization (off pump). Glomerular and tubular function were assessed up to 48 hours postoperatively. Results. There were no deaths, myocardial infarctions or acute renal failur e in either group. Glomerular filtration as assessed by creatinine clearanc e and the urinary microalbumin/creatinine ratio was significantly worse in the on pump group (p < 0.0004 and 0.0083, respectively). Renal tubular func tion was also impaired in the on pump group as assessed by increased N-acet yl glucosaminidase activity (p < 0.0272). Conclusions. These results suggest that oft: pump coronary revascularizatio n offers a superior renal protection when compared with conventional corona ry revascularization with cardiopulmonary bypass and cardioplegic arrest in first time coronary bypass patients. (C) 1999 by The Society of Thoracic S urgeons.