Introduction: The Impella has emerged as a viable percutaneous ventricular assist device for cardiogenic shock. However, previous comparisons with the intra-aortic balloon pump (IABP) have shown conflicting evidence on safety and effectiveness, although these studies have their limitations. The aim of this project is to develop a comparative effectiveness study with more recent robust data to further elucidate the differences between Impella and IABP. We hypothesize that Impella use is associated with higher in-patient mortality and hospital resource utilization compared to IABP in a nationally representative population.
Methods: We performed a retrospective cohort study using the National Inpatient Sample (NIS) from 2016 to 2022, extracting adult patients with cardiogenic shock (International Classification of Diseases, Tenth Revision code R57.0). Treatment groups were assigned based on the intervention – either Impella or IABP. Patients who received both devices were excluded from analysis. Primary outcome was in-hospital mortality with secondary outcomes including acute kidney injury (AKI), dialysis requirement, stroke, and major bleeding requiring transfusion. Analysis controlled for confounding variables including demographics, hospital characteristics, and the Charlson and Elixhauser comorbidity indices.
Results: A total of 19,266 patients (9,633 Impella and 9,633 IABP) were included after matching. Compared to IABP, overall Impella was associated with significantly higher in-hospital mortality (45.0% vs 38.0%, OR 1.33, p< 0.0001), AKI (35.0% vs 28.0%, OR 1.38, p< 0.0001), and bleeding events (15.0% vs 13.0%, OR 1.18, p=0.0001). There was a small but statistically significant increase in dialysis use (12.0% vs 11.0%, OR 1.10, p=0.032). Stroke rates were equivalent between groups (5.0% each, OR 1.00, p=1.000). These results persisted across subgroups and sensitivity analyses.
Conclusions: In this recently updated nationally representative sample of cardiogenic shock patients, Impella was shown to have higher odds of in-hospital mortality and complications including AKI and bleeding. These findings emphasize the necessity for added caution when using percutaneous assist devices, and provide evidence for Impella performance in real-world critical care settings.
