Acute Kidney Injury in Patients With Veno-venous Extracorporeal Membrane Oxygenation: An Observational Retrospective Analysis of Risk-factors and Outcome.

Abstract

Background: AKI is a frequent concomitant organ failure during veno-venous extracorporeal membrane oxygenation (VV-ECMO). This study investigated the prevalence and the impact of AKI on survival to hospital discharge and up to 365 days after discharge, and risk-factors for developing AKI during VV-ECMO.

Methods: This is an observational retrospective study of 500 consecutive patients receiving VV-ECMO between November 2014 and December 2021. Patients were divided into three groups: 1)AKI onset before ECMO 2)AKI onset during ECMO 3)AKI onset before and new onset during ECMO. Kidney Disease: Improving Global Outcomes (KDIGO) definition was used to define AKI. Follow-up was 365 days after hospital discharge. Propensity-score-matching was performed for patients without AKI and patients with AKI onset during ECMO to analyse risk-factors for AKI onset during VV-ECMO.

Results: 320 patients (64.0%) had AKI, 182 (36.4%) with onset before ECMO and 158 (31.6%) with onset during ECMO. At ECMO-initiation, patients with AKI onset before VV-ECMO presented significantly higher inflammatory markers and higher norepinephrine dosage, while patients developing AKI during VV-ECMO did not differ from those without AKI. Survival to hospital discharge was 67.0% (AKI: 60.9%, No-AKI: 77.8%, p<0.001). Cox-regression-analysis revealed AKI KDIGO-stage 3, independent from onset, as independent risk-factor for reduced survival to hospital discharge (HR 2.15, 95% CI: 1.37-3.37, p=0.001). During follow-up, survival was 92.5%; age was shown as the sole risk-factor for reduced survival in hospital survivors in the multivariate-logistic-regression-model. In the propensity-score-matched cohort (41 patients in each group), the AKI-group had lower MAP and significantly higher CRP levels the days before AKI. Factors associated with VV-ECMO support (blood-flow, cell-free haemoglobin) did not differ.

Conclusions: Severe AKI is associated with reduced hospital survival, regardless of whether it occurs before or during ECMO. AKI onset during VV-ECMO is less due to ECMO-related factors than to recurrent septic episodes.