Incidence, Risk Factors and Outcomes of Early Acute Kidney Injury After Heart Transplantation: An 18-year Experience

Little is known about the incidence of acute kidney injury (AKI), as defined using the Kidney Disease Improving Global Outcome classification, after heart transplantation (HT). Our objective was to evaluate the impact of AKI in a cohort of HT recipients. (Setting: University Hospital.) METHODS: We studied 310 consecutive HT recipients from 1999 to 2017, with AKI being defined according to the Kidney Disease Improving Global Outcome criteria. Risk factors were analyzed by multivariable analyses, and survival by Kaplan-Meier curves and a risk-adjusted Cox proportional hazards regression model.

One hundred twenty-five (40.3%) patients developed AKI, with 73 (23.5%), 18 (5.8%), and 34 (11%) patients having AKI stages 1, 2, and 3, respectively. Cardiac tamponade (odds ratio [OR], 16.82; 95% confidence interval [CI], 1.06-138), acute right ventricular failure (OR, 3.54; 95% CI, 1.82-6.88), and major bleeding (OR, 2.46; 95% CI, 1.18-5.1) were the principal risk factors for AKI. Patients with AKI had a greater hospital mortality (3.8% vs 16%, P < 0.05), especially those requiring renal replacement therapy (46.9% vs 5.4%, P = 0.006). Acute kidney injury requiring renal replacement therapy was independently associated with hospital mortality (OR, 11.03; 95% CI, 4.08-29.8). With a median follow-up after hospital discharge of 6.7 years (interquartile range, 2.4-11.6), overall survival at 1, 5, and 10 years was 95.4%, 85.1%, and 75.4% versus 85.2%, 69.8% and 63.5% among patients without AKI and with AKI stages 2 to 3, respectively (P = 0.08).

The onset of AKI after HT is mainly associated with postoperative complications. Only severe AKI stage predicts worse short-term outcome, with this impact appearing to be lost at long-term follow-up.