Postoperative Acute Kidney Injury and Long-Term Outcomes After Lung Transplantation

BACKGROUND We sought to characterize peri-operative risk factors of acute kidney injury and report outcomes associated with its development in the immediate postoperative setting following lung transplantation. METHODS We performed a retrospective analysis of all adult patients undergoing primary lung transplant at our institution (1/1/2011-12/31/2021). AKI was defined using KDIGO criteria following lung transplantation and stratified based on whether they required renal replacement therapy (AKI no-RRT vs AKI-RRT). RESULTS Of the 754 patients included, 369 (48.9%) developed any AKI in the postoperative period (252 AKI no-RRT versus 117 AKI-RRT). Risk factors for postoperative AKI included higher preoperative creatinine levels (OR 5.15, p<0.001), lower preoperative eGFR (OR 0.99, p<0.018), delayed chest closure (OR 2.72, p<0.001) and higher volumes of postoperative blood products (OR 1.09, p<0.001) in the multivariable analysis. On univariate analysis, both AKI groups were also associated with higher rates of pneumonia (p<0.001), reintubation (p<0.001), mortality on index admission (p<0.001), longer ventilator duration (p<0.001), ICU length of stay (p<0.001), and hospital length of stay (p<0.001), with highest rates in the AKI-RRT group. In a multivariable survival analysis, postoperative AKI no-RRT (HR=1.50, p=0.006) and AKI-RRT (HR=2.70, p<0.001) were associated with significantly worse survival independently of severe grade 3 PGD at 72 hours (HR=1.45, p=0.038). CONCLUSIONS The development of postoperative AKI was associated with numerous pre- and intraoperative factors. Postoperative AKI remained significantly associated with poorer post-transplant survival. Severe cases of AKI necessitating renal replacement therapy portended the worst survival following lung transplantation.