Coronary Artery Bypass Surgery and Acute Kidney Injury: Impact of the Off-Pump Technique

Background: Acute kidney injury (AKI) is a common major complication after coronary artery bypass grafting (CABG) especially when the cardiopulmonary bypass is performed. This study was conducted to evaluate the impact of the off-pump technique on the incidence of AKI, also to determine the major risk factors for AKI. Methods: In this prospective cohort study, 535 consecutive adult patients who underwent CABG between January 2007 and May 2010 in a tertiary Hospital. Some 64 of 535 patients were operated through the off-pump coronary artery bypass (OPCAB) technique and another 471 patients by the on-pump coronary artery bypass graft (CABG) technique. Stratified sampling was used to assign patients to be operated either by the OPCAB or ONCAB technique. The AKI incidence and severity were compared between the two groups. Results: In OPCAB group 9.4% (6 patients) and in ONCAB group 4.1% (19 patients) developed AKI with no significant difference. Furthermore, the AKI severity was alike in the two groups and 10.5% (2 patients) in ONCAB and 33.3% (2 patients) in OPCAB group had mild AKI, 78.9% (15 patients) in ONCAB and 50% (3 patients) in OPCAB group had moderate AKI, and 10.5% (2 patients) in ONCAB and 16.7% (1 patients) in OPCAB group had severe AKI. Conclusion: As the differences of incidence and severity of postoperative AKI between OPCAB and ONCAB groups were not significant, further studies to find other useful protective methods such as free-radical scavengers, anti-inflammatory agents, and other modalities are recommended to prevent AKI.