Off-Pump Coronary Revascularization Attenuates Transient Renal Damage Compared With On-Pump Coronary Revascularization* Berthus G. Loef, MD; Anne H. Epema, PhD; Gerjan Navis, PhD; Tjark Ebels, PhD; Wim van Oeveren, PhD; and Robbert H. Henning, PhD 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 glomer- ular function (creatinine clearance) and damage (microalbuminuria), and markers of tubular function (fractional excretion of sodium [FENa] and free water clearance) and damage (N-acetyl- -D glucosaminidase [NAG]) were evaluated. Measuring plasma concentrations of free hemo- globin 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 tradi- tional on-pump coronary artery bypass grafting. (CHEST 2002; 121:1190 –1194) Key words: coronary artery bypass grafting; coronary revascularization; off-pump; renal damage; renal markers Abbreviations: CPB = cardiopulmonary bypass; FENa = fractional excretion of sodium; MAP = mean arterial pressure; NAG = N-acetyl--D-glucosaminidase R enal dysfunction is a serious complication of coronary revascularization with cardiopulmonary bypass (CPB) and results in increased morbidity, mortality, and prolonged hospital stay. 1 The patho- genesis of this complication is usually multifactorial. General risk factors associated with postoperative renal dysfunction are preexisting renal disease, ad- vanced age, and postoperative low cardiac output state. 1,2 In addition, CPB represents a specific risk factor during cardiac surgery. The injurious action of CPB on renal function is caused by several mecha- nisms, including nonpulsatile perfusion and in- creased levels of circulating catecholamines, cyto- kines, and free hemoglobin. 3 These effects result in damage to glomerular as well as tubular structures that, in turn, can produce renal dysfunction espe- cially in the presence of additional risk factors. 4 The renal risk associated with CPB may be avoided by a new surgical technique, off-pump coronary revascu- larization, which is performed on the beating heart and hence does not use CPB. 5 This study assessed the contribution of CPB to perioperative renal dam- *From the Cardiothoracic ICU (Dr. Loef), the Department of Anesthesiology (Dr. Epema), the Department of Nephrology (Dr. Navis), the Department of Cardiopulmonary Surgery (Drs. Ebels and van Oeveren), and the Department of Clinical Phar- macology (Dr. Henning), University Hospital Groningen, Gro- ningen, the Netherlands. Manuscript received May 16, 2001; revision accepted November 19, 2001. Correspondence to: Berthus G. Loef, MD, Cardiothoracic ICU, Department of Cardiopulmonary Surgery, University Hospital Groningen, Hanzeplein 1, PO Box 30.001, 9700 RB Groningen, The Netherlands; e-mail: B.G.Loef@thorax.azg.nl 1190 Clinical Investigations Downloaded From: http://journal.publications.chestnet.org/pdfaccess.ashx?url=/data/journals/chest/21976/ on 04/01/2017