Objective

Redo-surgery and acute kidney injury (AKI) are two independent risk factors for adverse outcomes in patients undergoing coronary surgery. The aim of this study was to investigate the relationship between redo coronary surgery and in-hospital AKI and their combined impact on early and long term survival.

Methods

We undertook an observational cohort comparative study of prospectively collected data from 15,436 patients undergoing isolated CABG between 1998- 2014, of whom 398 underwent redo-CABG. AKI was defined according to the Risk, Injury, Failure, Loss, and End-stage (RIFLE) criteria. Outcome measures included the rate of in-hospital AKI, all-cause 30-days and long-term mortality via UK Office of National Statistics.

Results

Cox multivariate analysis showed that AKI [OR 3.74, CI95%- 1.3-10.5, p<0.01] is independent predictor of in-hospital mortality. In-hospital AKI had a significant impact on late survival. Overall survival at 1, 5, 10, and 15 years post surgery was significantly different between patients favouring those patients who did not experience post-operative AKI (80% vs 93%, 64% vs 85%; 51% vs 68%; and 15% vs 54%, AKI vs non-AKI respectively).

Conclusion

Our study suggests that in patients undergoing redo-CABG the occurrence of in-hospital AKI is associated with increased in-hospital and long-term mortality. These findings might help improving the decision-making process and patient consenting.