Comparative Outcomes of Transferred vs Nontransferred Cardiogenic Shock Patients Receiving Impella Support

BACKGROUND: Cardiogenic shock (CS) is associated with high in-hospital mortality despite advances in temporary mechanical circulatory support (tMCS) devices, such as Impella. However, access to Impella is not uniform across health care settings, often necessitating interhospital transfers. The impact of transfer status on Impella use, and outcomes in CS remains unclear. OBJECTIVES: The aim of the study was to compare in-hospital mortality, complications, tMCS utilization patterns, and resource utilization between transferred and nontransferred CS patients receiving Impella support. METHODS: Using National Inpatient Sample 2016 to 2021, all CS patients receiving Impella were identified. Patients were grouped by transfer status: those transferred from acute care hospitals vs those managed in-house. Primary outcomes included in-hospital mortality, while secondary outcomes included rates of complications (acute limb ischemia, acute renal failure, and renal replacement therapy), tMCS utilization patterns, and hospital resource utilization. Outcomes were compared using Pearson chi-square test and multivariate regression analysis. RESULTS: A total of 11,264 patients received Impella for CS, and 28.3% were transferred from other hospitals. Sixteen percent had acute myocardial infarction at presentation. Mortality rates were similar between groups (41.6% vs 41.0%; P = 0.589). Transfer status was associated with higher rates of complications, including acute renal failure (71.5% vs 60.3%; P < 0.001) and renal replacement therapy (16.0% vs 11.6%; P < 0.001), as well as higher utilization of intra-aortic balloon pump and extracorporeal membrane oxygenation. Transfer status was also associated with longer hospital stays and higher hospitalization costs. These associations persisted with propensity score-based analysis. CONCLUSIONS: In this study, transfer status was associated with similar in-hospital mortality but higher complication rates, greater use of additional tMCS, and increased resource utilization.