Off-Pump Coronary Artery Bypass Surgery and Acute Kidney Injury

Abstract

Off-pump coronary artery bypass grafting (CABG) has been advocated to cause less inflammation, morbidity, and mortality than the more traditional on-pump technique. This meta-analysis compares these two surgical techniques with respect to causing acute kidney injury (AKI). This study searched for randomized controlled trials in MEDLINE and abstracts from the proceedings of scientific meetings through February 2010. Included were trials comparing off-pump to on-pump CABG that reported the incidence of AKI, as defined by a mixture of criteria including biochemical parameter/urine output/dialysis requirement. Mortality was evaluated among the studies that reported kidney-related outcomes. For primary and subgroup analyses, fixed-effect meta-analyses of odds ratios (OR) were performed. In 22 identified trials (4819 patients), the weighted incidence of AKI in the on-pump CABG group was 4.0% (95% confidence interval [CI] 1.8%, 8.5%), dialysis requirement 2.4% (95% CI 1.6%, 3.7%), and mortality 2.6% (95% CI 1.6%, 4.0%). By meta-analysis, off-pump CABG was associated with a 40% lower odds of postoperative AKI (OR 0.60; 95% CI 0.43, 0.84; P = 0.003) and a nonsignificant 33% lower odds for dialysis requirement (OR 0.67; 95% CI 0.40, 1.12; P = 0.12). Within the selected trials, off-pump CABG was not associated with a significant decrease in mortality. Off-pump CABG may be associated with a lower incidence of postoperative AKI but may not affect dialysis requirement, a serious complication of cardiac surgery. However, the different definitions of AKI used in individual trials and methodological concerns preclude definitive conclusions.