The Incidence of Acute Kidney Injury Following Lung Transplantation Performed on Cardiopulmonary Bypass; Risk Factors, Effect on Short and Long-Term Mortality

Abstract

Purpose Acute Kidney Injury (AKI) occurs in approximately 30% after cardiac surgery with cardiopulmonary bypass (CPB) and has negative effect on outcome. The incidence and outcome of AKI after lung transplantation (Ltx) with or without CPB is unclear. Definitions of AKI include RIFLE, AKIN and the most recent 2012 KDIGO criteria. The incidence and effects of AKI after Ltx has been reported inconsistently, using various definitions and often not including use of CPB. Therefore, we aimed to find the incidence, predictors and long-term effects of AKI early after Ltx with CPB. Methods We performed a retrospective cohort study of 186 consecutive Ltx patients at our institution from 2010 through 2015. CPB was used in all cases. The primary outcome was occurrence of AKI in the first 7 postoperative days, defined and staged according to creatinine criteria of the 2012 KDIGO system. Secondary outcomes included risk factors, use of CRRT and mortality. Results Of 177 Ltx recipients included, AKI occurred in 57 (32%), stratified into AKI 1 in 20% (n=36), and AKI 2&3 in 12% (n=21). CRRT was used in 8.5% during hospital stay. In multivariate analysis PAH as underlying diagnosis [OR 12.9 (1.4-123), p=0.026], and CPB time [per minute increase; OR 1.013 (1.003-1.023), p=0.008] were predictive for AKI. Mortality at 3 months was significantly higher in the AKI group compared to the No AKI group (11% vs 2%; p=0.02). At 1-year post transplant there was no significant difference in mortality between groups (18% vs 11%; p=0.22). Kaplan-Meier analysis showed no significant difference between No AKI vs Any AKI in long-term survival (fig.1). Conclusion By the KDIGO definition, AKI occurred in 32% of Ltx recipients with the routine use of CPB. This is similar to the incidence in cardiac surgery, and low compared to previous reports in Ltx recipients. Although short term survival was lower, the occurrence of AKI was not associated with impaired long-term overall survival.