Renal function following On-pump versus Off-pump CABG

Introduction- Despite the success of on-pump coronary artery bypass grafting (CABG) in the treatment of coronary artery disease, morbidity and mortality due to renal failure is a wellknown complication of this method. Currently, it is believed that off-pump CABG can be done with the same result and fewer adverse renal effects due to a lack of the use of the cardiopulmonary bypass machine. The aim of this study was to compare postoperative renal function between off-pump CABG and on-pump CABG. Method- Sixty-seven consecutive candidates for elective isolated CABG were enrolled in this study and randomized into two groups. The on-pump group consisted of 34 patients and the off-pump group included 33 patients. All the patients were operated on via the same technique and surgeon. Blood samples were obtained before surgery and 6, 24, and 48 hours after surgery to measure the serum creatinine and assess creatinine clearance. Either 20% increase in the serum creatinine level or 20% decrease in creatinine clearance was considered as renal dysfunction. Results- In the off-pump group, 5, 9, and 4 patients developed renal dysfunction 6, 24, and 48 hours postoperatively, respectively in comparison with 13, 22 ,and 11 patients of the on-pump group at the same time. There was a significant difference between the two groups regarding renal dysfunction 6 and 24 hours postoperatively (p value=0.038 and 0.003, respectively), but no significant difference was observed at 48 hours after surgery. We found no relationship between age and weight and postoperative renal dysfunction in either of the groups. Preoperative hypertension and diabetes had no effect on postoperative renal dysfunction. Conclusions- Renal function was better preserved in the patients undergoing off-pump CABG than on-pump CABG. Old age was not a risk factor for renal function but it could be a matter of debate and must be studied in future experiments.