Off-pump versus on-pump coronary artery bypass surgery: an updated meta-analysis of randomized controlled trials on acute kidney injury and mortality outcomes

Background: The risk of acute kidney injury (AKI) in patients undergoing coronary artery bypass surgery (CABG) with on-pump and off-pump techniques for ischemic heart disease is controversial. The objective of this meta-analysis was to compare these two techniques with respect to causing AKI.

Methods: Comprehensive literature searches for randomized controlled trials (RCTs) of CABG with on-pump and off-pump was performed using MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials Systematic Reviews and clinicaltrials.gov from inception through August 2014. Primary outcome was the incidence of AKI.

Results: Thirty one prospective RCTs (11,851 patients) were included in our analysis. By meta-analysis, patients in off-pump CABG group had overall lower incidence of AKI (19.1%) compared to on-pump CABG group (22.2%). There was a significant protective effect of off-pump CABG on the incidence of AKI compared to on-pump CABG group [risk ratios (RR): 0.87; 95% CI: 0.77-0.98, I2 of 5%]. The post hoc analysis assessing the mortality outcome demonstrated pooled RR of 0.97 (95% CI, 0.77-1.23) in off-pump vs on-pump CABGs.

Conclusion: Our study demonstrates significantly beneficial effect of off-pump CABG on the incidence of AKI compared to conventional on-pump CABG. However, our meta-analysis does not show survival benefit among patients undergoing CABG.