Acute Kidney Injury and In-Hospital Mortality after Coronary Artery Bypass Graft versus Percutaneous Coronary Intervention: A Nationwide Study.

Background: Post-procedural acute kidney injury (AKI) is associated with significantly increased short- and long-term mortalities, and renal loss. Few studies have compared the incidence of post-procedural AKI and in-hospital mortality between 2 major modalities of revascularization - coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) - and results have been inconsistent.

Methods: We generated a propensity score-matched cohort that includes a total of 286,670 hospitalizations with multi-vessel coronary disease undergoing CABG or PCI (2004-2012) from the National Inpatient Sample database. We compared incidence of AKI, AKI requiring renal replacement therapy (RRT), in-hospital mortality, hospital stay, and charges between CABG and PCI groups.

Results: The incidence of AKI after CABG was higher than PCI (8.9 vs. 4.5%, OR 2.05, 95% CI 1.99-2.12, p < 0.001). The incidence of AKI requiring RRT was also higher after CABG (1.1 vs. 0.5%, OR 2.14, 95% CI 1.96-2.34, p < 0.001). Likewise, in-hospital mortality was higher after CABG than PCI (2.0 vs. 1.4%, OR 1.44, 95% CI 1.35-1.52, p < 0.001). Among patients with pre-existing chronic kidney disease (stages I-IV), those undergoing CABG was associated with 2.0-2.3-fold higher odds of developing AKI than those undergoing PCI. The patients treated with CABG had a significantly longer hospital stay and higher hospital charges.

Conclusions: Patients undergoing CABG are associated with (1) increased risk of developing post-procedural AKI, (2) higher likelihood of receiving RRT, and (3) worse short-term survival. Long-term renal outcome remains to be studied.