Impella Versus Intra-aortic Balloon Pump in Cardiogenic Shock: Arrhythmias, Bleeding Complications, and In-Hospital Outcomes in a Propensity-Matched Analysis of the National Inpatient Sample

Background: With no robust data indicating a mortality benefit of Impella over the intra-aortic balloon pump (IABP), we conducted a retrospective analysis to assess the frequency of morbidity outcomes, including arrhythmias, associated with the two devices. Materials and methods: We performed a retrospective observational study using the National Inpatient Sample (NIS) database (2009-2014). Hospitalizations involving acute myocardial infarction or cardiogenic shock, valve surgery, cardiac bypass, or percutaneous coronary intervention, which received Impella or IABP on the day of admission, were identified. Propensity score matching was conducted to account for baseline demographic characteristics and admitting diagnoses. The difference-in-differences statistic was used to assess the difference in arrhythmia outcomes between the two groups. Analyses were performed using RStudio (Posit Software, PBC, Boston, MA, USA). Primary outcomes included arrhythmia rates and in-hospital mortality. Results: The unmatched data included 5,053 hospitalizations receiving Impella and 133,042 receiving IABP on the day of admission. A 1:1 propensity score matching yielded 10,106 matched hospitalizations. We observed significantly higher odds of ventricular tachycardia (VT) in the Impella group and of supraventricular tachycardia (SVT) in the IABP group. Bleeding, hematoma, and extracorporeal membrane oxygenation (ECMO) use were higher with Impella, whereas iatrogenic cardiac complications and heart transplant were higher with IABP. Subgroup analysis showed higher in-hospital mortality among patients with VF, AF, stroke, and ECMO use in the Impella group. Conclusions: Our study showed a greater association between VT and Impella, whereas iatrogenic complications and SVT were more commonly associated with IABP use. Impella was associated with significantly higher rates of VT, VF, and in-hospital cardiac arrest and with higher in-hospital mortality, while AF was significantly more common with IABP. These findings suggest a potential benefit of increased post-procedural surveillance in patients receiving Impella, pending confirmation in prospective studies.