Outcomes of patients supported on Impella 5.5 for more than 14 days: A Cardiogenic Shock Working Group registry analysis

Abstract

Background: The Impella 5.5 (ABIOMED, Danvers, MA) is a micro-axial pump that is currently approved for up to 14 days of support in the United States. However, in clinical practice it is being used for longer durations of time, especially as a bridge to heart replacement therapies (HRT). We aimed to define patient characteristics and outcomes (mortality and serious adverse events/SAE) in patients supported on Impella 5.5 for >14 days in a large, multi-center registry.

Methods: The Cardiogenic Shock Working Group (CSWG) registry enrolling consecutive patients in heart failure (HF) or myocardial infarction related CS (MI-CS) from 34 international sites between 2022 and 2024 was analyzed. Patients supported with Impella 5.5 >14 days were compared to those supported for ≤14 days for baseline characteristics. In-hospital outcomes were further classified as ''favorable'' (heart recovery, successful bridge to HRT and discharged alive) or ''unfavorable'' (death, need for escalation to veno-arterial extracorporeal membrane oxygenation [VA-ECMO]). Predictors of favorable outcomes were assessed using uni- and multi-variable analysis.

Results: A total of 927 patients were supported on Impella 5.5 of whom 381 had the device for >14 days. Median time of support in the 2 groups (> or ≤14 days) was 23.9 [21.2] and 7.1 [IQR 5.7] days, respectively. Patients with Impella 5.5 >14 days were younger (mean age 57 vs 61 years, p < 0.001), more likely to have HF-CS vs MI-CS (78% vs 61%; p < 0.001) and have a dilated left ventricle (left ventricular end diastolic dimension [LVEDD] 6.4 vs 5.9 cm, p = 0.002) and chronic kidney disease (38% vs 30%, p = 0.03) as compared to those supported ≤14 days. Baseline Society for Cardiovascular Angiography and Interventions (SCAI) stage, lactate, and vital signs were not significantly different. Unadjusted survival was higher (80% vs 68%, p < 0.001) in those supported for >14 days, with a significantly higher HRT for those supported for >14 days, compared to the ≤14 days cohort (58% vs 38%, p < 0.001). Less than a fourth (19.1%) had an SAE, with highest rates seen in MI-CS supported for ≤14 days. The majority (75%) of patients on support for >14 days had favorable outcomes with no linear increments in rates of SAE with prolonged duration of support.

Conclusion: Patients supported with Impella 5.5 beyond the Food and Drug Administration (FDA) approved duration of 14 days had high rates of favorable outcomes, especially as bridge to HRT. Use of Impella 5.5 for longer durations needs to be further investigated in prospective studies.

Keywords: Impella 5.5; cardiogenic shock; duration; outcomes; safety.