Beyond the STEMI paradigm: Expanding the scope of microAxial flow pump in cardiogenic shock

Microaxial flow pumps (mAFP) are increasingly used to treat cardiogenic shock (CS), but most evidence comes from acute myocardial infarction-related CS (AMI-CS). It remains unclear whether patients with non-ischemic CS (Non-AMI-CS) derive comparable benefits from mAFP support. This study aimed to compare clinical profiles, management strategies, and outcomes between AMI-CS and Non-AMI-CS patients treated with mAFP.

We retrospectively analyzed CS patients managed with mAFP (Impella CP and 5 + [5.0 and 5.5]) across 11 high-volume centers between 2010 and 2023. Propensity score matching was performed to account for baseline differences. The primary outcome was all-cause mortality at 180 days. Independent predictors of mortality were identified using multivariable logistic regression analysis.

A total of 976 patients were included (64.0% AMI-CS; 36.0% Non-AMI-CS). From 2010 to 2023, 180-day mortality significantly declined in both groups (Ptrend = 0.01 for AMI-CS and 0.03 for Non-AMI-CS). After propensity score matching (n = 444), 180-day mortality was comparable between AMI-CS and Non-AMI-CS patients (32.9% vs 33.3%; HR 0.89 [95% CI, 0.65-1.21]; p = 0.46). Rates of heart transplantation (5.0% vs 9.0%; p = 0.08) and durable LVAD implantation (10.8% vs 9.0%; p = 0.77) were also similar. These findings were consistent across all prespecified subgroups and at 10-year follow-up. Independent predictors of mortality in both groups included age (per 5-year increase), SCAI stage E, lactate ≥6 mmol/L), norepinephrine use, and renal replacement therapy. Despite similar survival, Non-AMI-CS patients demonstrated greater myocardial recovery, with larger LVEF improvement (+17.8 ± 17.0% vs +11.2 ± 14.5%; p < 0.001).

In this large, real-world cohort, ischemic and non-ischemic CS showed equivalent long-term outcomes under mAFP support. These findings suggest that patient selection should be guided by shock severity and hemodynamic phenotype rather than etiology alone, supporting broader evaluation of mAFP use.