Off-pump coronary revascularization attenuates transient renal damage compared with on-pump coronary revascularization.

STUDY OBJECTIVES Cardiopulmonary bypass (CPB) represents a specific risk factor for renal damage during coronary revascularization. The purpose of this study was to compare the perioperative renal damage in patients undergoing on-pump and off-pump coronary surgery. DESIGN AND PATIENTS The progress and extent of renal damage was prospectively studied in two groups of patients undergoing cardiac surgery without concomitant morbidity, undergoing elective coronary revascularization with (n = 12) and without (n = 10) CPB. Markers of glomerular function (creatinine clearance) and damage (microalbuminuria), and markers of tubular function (fractional excretion of sodium [FENa] and free water clearance) and damage (N-acetyl-beta-D glucosaminidase [NAG]) were evaluated. Measuring plasma concentrations of free hemoglobin assessed hemolysis. Plasma and urinary specimens were obtained at the following points: (1) baseline; (2) heparinization; (3) the end of CPB or completing graft for off-pump surgery; (4) skin closure; (5) the sixth hour in the ICU; and (6) the second postoperative day. Free water and creatinine clearances, FENa, and the urinary excretion of microalbumin and NAG were calculated for the corresponding time intervals. SETTING University hospital. RESULTS We found that off-pump coronary revascularization induced significantly less changes in microalbuminuria, FENa, free water clearance, NAG, and free hemoglobin as compared with operations with CPB. Markers returned to baseline within 2 days after the operation, and there was no clinical or laboratory evidence of overt renal dysfunction in both groups. CONCLUSION Off-pump coronary surgery attenuates transient renal injury compared with traditional on-pump coronary artery bypass grafting.