Clinical outcomes in acute myocardial infarction cardiogenic shock patients supported with a high-flow, surgically...

Impella micro-axial pumps are increasingly used in cardiogenic shock. Recent randomized controlled data showed a survival benefit with use of the Impella CP in ST-elevation myocardial infarction-related cardiogenic shock. Use of the Impella 5.5, a high-flow surgically implanted micro-axial pump, in patients with acute myocardial infarction cardiogenic shock remains largely unexplored. We analyzed data from the Surgical Unloading Renal Protection and Sustainable Support study, a prospective, multicenter, observational registry evaluating real-world outcomes in patients with acute myocardial infarction cardiogenic shock supported with the Impella 5.5.

Patients with cardiogenic shock enrolled in Surgical Unloading Renal Protection and Sustainable Support study at 15 sites between August 2020 and December 2023 were included and stratified into those receiving the Impella 5.5 only versus other non-extracorporeal membrane oxygenation forms of temporary mechanical devices before or during Impella 5.5 (Impella 5.5 + other temporary mechanical circulatory support devices). In this analysis, patients receiving venoarterial and venovenous extracorporeal membrane oxygenation were excluded. In-hospital outcomes and longitudinal survival were studied, specifically adverse events while on support and survival at hospital discharge, 30 days, and 1 year.

Among 177 patients with acute myocardial infarction cardiogenic shock, 31% (n = 55) received only an Impella 5.5 and 69% (n = 122) received an Impella 5.5 + other tMCS. Their mean age was 61 ± 12 years, and 80% of subjects were male. Comorbidities included diabetes (49%), hypertension (67%), heart failure (34%), peripheral vascular disease (17%), and previous stroke (8%). Overall in-hospital survival was 65%, with higher survival among patients with only an Impella 5.5 (75% vs 61%, P = .089). Among all survivors, 78% had native heart survival, 4% underwent heart transplant, and 11% underwent durable left ventricular assist device placement. Adverse events while on support included stroke (4%), hemolysis (9%), all-cause bleeding (16%), and acute kidney injury (23%). Hemolysis was lower among patients with only an Impella 5.5 (1.8% vs 12.3%, P < .05). The 30-day survival was 81.7% for the Impella 5.5 alone group and 66.0% for the Impella 5.5 + temporary mechanical circulatory support devices group (P = .044): 6-month survival of 64.8% versus 51.8% (P = .081) and 12-month survival of 58.0% versus 46% (P = .090).

There is considerable variation in how the Impella 5.5 is used to treat patients with acute myocardial infarction cardiogenic shock, with the majority of patients being exposed to other forms of temporary mechanical circulatory support devices. The majority of patients were discharged on their native heart, and patients supported with only the Impella 5.5 had a trend toward higher survival and significantly lower all-cause bleeding, hemolysis, and stroke rates.