Impella in infarction-related cardiogenic shock: evidence, complications, and implementation of microaxial LV unloading

Acute myocardial infarction complicated by cardiogenic shock (AMI-CS) remains highly lethal despite early revascularization. Although left ventricular (LV) failure predominates, AMI-CS may also be triggered or dominated by right ventricular (RV) failure, which carries distinct implications for the choice of mechanical support. Escalating catecholamines may increase afterload, provoke arrhythmias, and raise myocardial oxygen demand. Microaxial left ventricular (LV) support (Impella) provides forward flow while unloading the LV, potentially improving the subendocardial perfusion gradient, reducing pulmonary congestion, and limiting catecholamine exposure. Net clinical benefit is conditional and must be balanced against a substantial and predictable complication burden (major bleeding, vascular/limb complications, hemolysis with acute kidney injury, and infection). In the DanGer Shock trial, a protocolized Impella CP strategy in selected patients with ST-elevation myocardial infarction (STEMI)-CS lowered 180-day mortality (45.8% vs. 58.5%; hazard ratio [HR]: 0.74) but increased major complications and renal replacement therapy. Conversely, early venoarterial extracorporeal membrane oxygenation (VA-ECMO [extracorporal membrane oxygenation]) in the ECLS (extra corporal life support)-SHOCK trial did not improve 30-day survival and increased bleeding and vascular complications. Clinically, Impella should be used as part of phenotype-driven shock pathways-early for LV-dominant, congested low-output shock with a reversible trajectory-combined with standardized access/anticoagulation bundles, close complication surveillance, and early reassessment with deliberate escalation or de-escalation.