Acute Kidney Injury in Post-Lung Transplant Patients a Single Center Retrospective Review

Abstract

Purpose Acute kidney injury (AKI) has been increasingly recognized as a common post-operative complication of lung transplantation (LT). AKI incidence and severity in LT recipients has been associated with higher cost and decreased post-operative survival. To date, no study has evaluated early post-operative AKI and post-operative outcomes. We sought to evaluate the incidence of AKI in our LT program and to identify associated factors for possible intervention. Methods This study is a single center retrospective review conducted from January 2015 to March 2019 under institutional review board approval at our institution. Patients with multi-organ transplants, re-transplants, and patients who expired within 30 days of transplant were excluded. 171 patients were identified and 153 qualified for review. Our protocol adapted RIFLE criteria to identify post-operative AKI. Statistical analysis was completed analyzing incidence of AKI from post-operative days 1 to 14, with subgroup analyses of days 1 to 7 and 8 to 14. AKI status was compared with pre-specified individual covariates using Fisher's exact tests and logistic regression models with AKI status as the outcome and each covariate as the predictor. All calculations were performed using SAS 9.4 (SAS Institute, Cary, NC). Results Post-operative AKI incidence was 36.6%, and ESRD incidence was 9.8% between the years of 2015 and 2019. Survival at one year (p=0.024) and 5 years (p=0.038) following LT was significantly lower in patients with early post-operative AKI. African American recipients (p=0.014), bilateral transplant recipients (p=0.005), and those transplanted on cardiopulmonary bypass (p=0.018) were all more likely to have post-op AKI. Use of vasopressors, longer operative times, and the need for blood products within the first 24 hours of LT were also associated with AKI. The majority of renal injury occurred within the first 7 post-operative days. Conclusion Early post-operative AKI is associated with decreased 1 year and long term survival. Additionally, we identified the first 7 post-operative days to be the most likely time for patients to develop renal injury. We identified variables associated with renal hypoperfusion to be major risk factors for post-op AKI. We also identified susceptible patient populations and operative interventions associated with AKI.