Low- Versus High-capacity Impella for CS After AMI: A Systematic Review and Pooled Data Analysis.

BACKGROUND

Acute myocardial infarction with cardiogenic shock (AMI-CS) remains highly fatal despite advances in revascularization and intensive care. The Impella, a micro-axial pump, offers a potential balance of hemodynamic support and minimal invasiveness.

AIMS: This study examined its optimal configuration of low- versus high-capacity for effectiveness and safety.

METHODS

We conducted a systematic review and pooled analysis of 20 studies, including three randomized controlled trials (RCTs) and 3896 AMI-CS patients, comparing high-capacity (Impella 5.0/5.5) versus low-capacity (Impella 2.5/CP) devices. The primary outcome was in-hospital or 30-day mortality, with secondary endpoints including mortality on support, ischemic and bleeding complications, acute kidney injury requiring renal replacement therapy (RRT), and hemolysis.

RESULTS

Among the included patients, 2022 received low-capacity Impella, while 771 received high-capacity Impella. The high-capacity Impella group demonstrated lower in-hospital or 30-day mortality (41.4% vs. 45.4%; p = 0.045) and significantly reduced mortality on support (17.9% vs. 46.1%; p < 0.001). Major bleeding events (1.4% vs. 6.0%; p < 0.001) and ischemic complications (3.9% vs. 5.9%; p = 0.05) were also lower in the high-capacity group. However, transfusion requirements were higher in the high-capacity Impella cohort (52.1% vs. 23.1%; p < 0.001). There were no significant differences in stroke rates (4.3% vs. 4.3%; p = 1.0) or AKI requiring RRT (36.5% vs. 34.9%; p = 0.69).

CONCLUSION

High-capacity Impella, when compared to low-capacity devices, may provide superior survival benefits and lower complication rates, particularly in reducing ischemic and major bleeding events, in AMI-CS patients. These findings support the early consideration of high-capacity Impella in treatment algorithms.