Impella Versus Intra-Aortic Balloon Pump in Patients With Cardiogenic Shock Treated With Venoarterial Extracorporeal Membrane Oxygenation: An Observational Study

BACKGROUND: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly used for patients with cardiogenic shock. Although Impella or intra-aortic balloon pump (IABP) is frequently used for left ventricular unloading (LVU) during VA-ECMO treatment, there are limited data on comparative outcomes. We compared outcomes of Impella and IABP for LVU during VA-ECMO. METHODS AND RESULTS: Using the Nationwide Readmissions Database between 2016 and 2020, we analyzed outcomes in 3 groups of patients with cardiogenic shock requiring VA-ECMO based on LVU strategies: extracorporeal membrane oxygenation (ECMO) only, ECMO with IABP, and ECMO with Impella. Of 15 980 patients on VA-ECMO, IABP and Impella were used in 19.4% and 16.4%, respectively. The proportion of patients receiving Impella significantly increased from 2016 to 2020 (6.5% versus 25.8%; P-trend<0.001). In-hospital mortality was higher with ECMO with Impella (54.8%) compared with ECMO only (50.4%) and ECMO with IABP (48.4%). After adjustment, ECMO with IABP versus ECMO only was associated with lower in-hospital mortality (adjusted odds ratio [aOR], 0.83; P=0.02). ECMO with Impella versus ECMO only had similar in-hospital mortality (aOR, 1.09; P=0.695) but was associated with more bleeding (aOR, 1.21; P=0.007) and more acute kidney injury requiring hemodialysis (aOR, 1.42; P<0.001). ECMO with Impella versus ECMO with IABP was associated with greater risk of acute kidney injury requiring hemodialysis (aOR, 1.49; P=0.002), higher in-hospital mortality (aOR, 1.32; P=0.001), and higher 40-day mortality (hazard ratio, 1.25; P<0.001). CONCLUSIONS: In patients with cardiogenic shock on VA-ECMO, LVU with Impella, particularly with 2.5/CP, was not associated with improved survival at 40 days but was associated with increased adverse events compared with IABP. More data are needed to assess Impella platform-specific comparative outcomes of LVU.