Microaxial Flow Pump Use and Renal Outcomes in Infarct-Related Cardiogenic Shock – a Secondary Analysis of the DanGer Shock Trial

Background: In the Danish–German Cardiogenic Shock (DanGer Shock) trial, use of a microaxial flow pump (mAFP) in patients with ST-segment elevation myocardial infarction (STEMI)-related CS led to lower all-cause mortality but higher rates of renal replacement therapy (RRT). In this prespecified analysis, rates and predictors of acute kidney injury (AKI) and RRT were assessed. Methods: In this international, randomized, open label, multicenter trial, 355 adult patients with STEMI-CS were randomized to mAFP (N=179) or standard care alone (N=176). AKI was defined according to Risk, Injury, and Failure, sustained Loss and End-stage kidney disease (RIFLE) criteria and assessed using logistic regression models. Use of RRT was assessed accounting for the competing risk of death using Fine-Gray subdistribution hazard models. Results: AKI (RIFLE≥1) was recorded in 110 patients (61%) in mAFP group and 79 (45%) in control group (p<0.01); RRT was used in 75 (42%) and 47 (27%) patients, respectively (p<0.01). About 2/3 of the RRTs were initiated within the first 24h from admission (n=48 (64%) in mAFP group, n=31 (66%) in control group). Occurrence of AKI and RRT were associated with higher 180-day mortality in both study arms. At 180 days, all patients alive were free of RRT. mAFP use was associated with higher rates of RRT, even when accounting for competing risk of death (subdistribution hazard: 1.67 [1.18-2.35]). This association was largely consistent among prespecified subgroups. Allocation to mAFP was associated with lower 180-day mortality irrespective of AKI or RRT (p=0.8 for interaction). Relevant predictors of AKI in both groups comprised reduced left ventricular ejection fraction, baseline kidney function, shock severity, bleeding events, and positive fluid balance. In addition, predictors of AKI specific to mAFP were suction events, higher pump speed, and longer duration of support. Conclusions: Shock severity, allocation to mAFP, and device-related complications were associated with an increased risk of AKI. AKI was generally associated with higher mortality, but the allocation to mAFP consistently led to lower mortality rates at 180 days irrespective of the occurrence of AKI with or without RRT initiation.