Off-Pump Coronary Revascularization preserves Renal Function in patients with Preoperative Non-Dialysis dependent renal dysfunction - A Prospective, Randomized Study

Abstract

The off-pump coronary artery bypass operation (OPCAB) is a relatively new surgical procedure, which avoids the use of cardiopulmonary bypass and is intuitively considered renoprotective in patients with preoperative normal renal function. However, no prospective, randomized study has been done so far to show whether these benefits may also apply to patients with preoperative non-dialysis dependent renal dysfunction. This first ever prospective, randomized, controlled trial was performed in 50 patients (45 men, mean age 51.2±4.8 yrs) with preoperative nondialysis dependent renal insufficiency, undergoing first-time elective coronary artery bypass grafting. Patients were randomly assigned to conventional revascularization with cardiopulmonary bypass (on-pump) or beating heart revascularization (off-pump). Glomerular and tubular functions were assessed upto 48 hrs postoperatively. There were no deaths, strokes or myocardial infarctions in either group. Glomerular function as assessed by creatinine clearance and the urinary microalbumin/creatinine ratio was significantly worse in the on-pump group (p=0.0003 and p=0.008, respectively). Renal tubular function was also significantly impaired in the on-pump group as assessed by the increased N- acetyl glucosaminidase activity (p=0.021). Six patients in the on-pump group developed acute renal failure requiring renal support compared with one in the off-pump group although statistically the comparison was not significant (p=0.098). This study suggests that off-pump coronary artery bypass surgery reduces the likelihood of acute renal failure in patients with preoperative non-dialysis dependent renal dysfunction and thus shortens postoperative intensive care and length of hospital stay.