Clinical outcomes among cardiogenic shock patients supported with high-capacity Impella axial flow pumps: A report from the Cardiogenic Shock Working Group

Background: The Impella 5.0 and 5.5 pumps (Abiomed, Danvers, MA) are large-bore transvalvular micro-axial assist devices used in cardiogenic shock (CS) for patients requiring high-capacity flow. Despite their increasing use, real-world data regarding indications, rates of utilization and clinical outcomes with this therapy are limited. The objective of our study was to examine clinical profiles and outcomes of patients in a contemporary, real-world CS registry of patients who received an Impella 5.0/5.5 alone or in combination with other temporary mechanical circulatory support (tMCS) devices.

Methods: The CS Working Group (CSWG) Registry includes patients from 34 US hospitals. For this analysis, data from patients who received an Impella 5.0/5.5 between 2020-2023 were analyzed. Use of Impella 5.0/5.5 with or without additional tMCS therapies, duration of support, adverse events and outcomes at hospital discharge were studied. Adverse events including stroke, limb ischemia, bleeding and hemolysis were not standardized by the registry but reported per individual CSWG Primary Investigator discretion. For those who survived, rates of native heart recovery (NHR) or heart replacement therapy (HRT) including heart transplant (HT), or durable ventricular assist device (VAD) were recorded. We also assessed outcomes based on shock etiology (acute myocardial infarction or MI-CS vs. heart failure-related CS or HF-CS).

Results: Among 6,205 patients, 754 received an Impella 5.0/5.5 (12.1%), including 210 MI-CS (27.8%) and 484 HF-CS (64.1%) patients. Impella 5.0/5.5 was used as the sole tMCS device in 32% of patients, while 68% of patients received a combination of tMCS devices. Impella cannulation sites were available for 524/754 (69.4%) of patients, with 93.5% axillary configuration. Survival to hospital discharge for those supported with an Impella 5.0/5.5 was 67%, with 20.4% NHR and 45.5% HRT. Compared to HF-CS, patients with MI-CS supported on Impella 5.0/5.5 had higher in-hospital mortality (45.2% vs 26.2%, p < 0.001) and were less likely to receive HRT (22.4% vs 56.6%, p < 0.001. For patients receiving a combination of tMCS during hospitalization, this was associated with higher rates of limb ischemia (9% vs. 3%, p < 0.01), bleeding (52% vs 33%, p < 0.01), and mortality (38% vs 25%; p < 0.001) compared to Impella 5.0/5.5 alone. Among Impella 5.0/5.5 recipients, the median duration of pump support was 12.9 days (IQR: 6.8-22.9) and longer in patients bridged to HRT (14 days; IQR: 7.7-28.4).

Conclusions: In this multi-center cohort of patients with CS, use of Impella 5.0/5.5 was associated with an overall survival of 67.1% and high rates of HRT. Lower adverse event rates were observed when Impella 5.0/5.5 was the sole support device used. Further study is required to determine whether a strategy of early Impella 5.0/5.5 use for CS improves survival.

Condensed abstract: High capacity Impella heart pumps are capable of provide up to 5.5 liter/min of flow while upper body surgical placement allows for ambulation. Patients with advanced cardiogenic shock from acute myocardial infarction or heart failure requiring temporary mechanical circulatory support may benefit from upfront use of Impella 5.5 to improve overall survival, including native heart recovery or successful bridge to durable left ventricular assist device surgery or heart transplantation.