Acute kidney injury and 1-year mortality after left ventricular assist device implantation

Background: Data on the consequences of acute kidney injury (AKI) after continuous-flow left ventricle assist device (LVAD) implantation are scarce and inconsistent. In this study, we evaluated the incidence, predictors and the impact of AKI on mortality and renal function in the first year after LVAD implantation. Methods: A retrospective, multicenter cohort study was conducted, including all patients (age ≥18 years) undergoing LVAD implantation (91% with a HeartMate II device and 9% with a HeartWare device). The definition proposed by the Kidney Disease Improving Global Outcome (KDIGO) criteria was used to define AKI. Results: Overall, 241 patients (mean age 52.4 ± 12.9 years, 76% males) were included in the study. AKI criteria were met in 169 (70%) patients, of whom 109 (45%) were in AKI Stage I, 22 (9%) in Stage II and 38 (16%) in Stage III. Two factors, the need for pre-operative inotropic support and pre-existent chronic kidney disease Stage ≤II (estimated glomerular filtration rate [eGFR] <30 ml/min/1.73 m2), were independently associated with the development of AKI and the severity of AKI stages. One-year mortality rates in patients without AKI and AKI Stages I, II and III were 18.7%, 26.4%, 23%, and 51%, respectively (log rank, p = 0.001). In the multivariable analysis, AKI Stage ≥II was independently associated with mortality (hazard ratio 2.2 [95% confidence interval 1.1 to 4.5], p = 0.027) and worse renal function (β = -7.4 [95% confidence interval -12.6 to -2.1], p < 0.01) at 1 year. Conclusion: AKI is highly frequent after LVAD implantation. More severe AKI stages are associated with higher mortality rates and impaired renal function at 1 year after LVAD implantation.