Temporary Mechanical Circulatory Support in Acute Myocardial Infarction-Related Cardiogenic Shock: Lessons from Contemporary Randomized Trials

Background: Acute myocardial infarction-related cardiogenic shock (AMI-CS) remains associated with high mortality despite advances in revascularization, critical care, and temporary mechanical circulatory support (MCS). Recent randomized trials have challenged the concept of routine device-based therapy and highlighted the importance of matching MCS strategy to shock phenotype, timing, and patient risk profile. Methods: We reviewed contemporary randomized clinical trials and prespecified or post hoc analyses evaluating temporary MCS strategies in adult patients with AMI-CS. PubMed was searched for English-language studies published from January 2021 through June 2026, focusing on intra-aortic balloon pump (IABP), microaxial flow pumps, and venoarterial extracorporeal membrane oxygenation (VA-ECMO/ECLS). Outcomes of interest included mortality, hemodynamic recovery, end-organ outcomes, and device-related complications. Results: Recent randomized evidence demonstrates that no temporary MCS device provides universal benefit across the heterogeneous AMI-CS population. Routine IABP use has not been associated with improved survival and is now reserved for selected patients requiring modest circulatory support, bridge-to-decision strategies, or specific mechanical complications. The DanGer Shock trial provided the strongest contemporary randomized evidence supporting temporary MCS, demonstrating reduced 180-day mortality with routine Impella CP support in carefully selected patients with STEMI-related cardiogenic shock. However, this benefit was accompanied by increased major bleeding, limb ischemia, acute kidney injury, and renal replacement therapy. Prespecified secondary and exploratory post hoc analyses have generated hypotheses that treatment response may vary according to age, baseline hemodynamics, timing of support, and shock phenotype; however, these findings require prospective validation and should not be interpreted as established treatment-selection criteria. In contrast, ECLS-SHOCK, ECMO-CS, EURO SHOCK, and randomized meta-analytic data did not demonstrate a survival benefit for routine early VA-ECMO in broad AMI-CS populations and consistently identified higher rates of bleeding and vascular complications. Strategies for routine early left ventricular unloading during VA-ECMO have improved physiologic parameters but have not demonstrated a mortality benefit. Conclusions: Contemporary randomized trials have shifted the role of temporary MCS in AMI-CS from routine device deployment toward individualized, phenotype-guided therapy. Impella CP, as evaluated in the DanGer Shock trial, currently provides the strongest randomized survival signal but should be applied selectively in patients with predominantly left ventricular failure treated within experienced shock systems. VA-ECMO remains an important rescue option in carefully selected patients with refractory circulatory collapse, severe hypoxemia, cardiac arrest, or biventricular failure, although routine early use is not supported. Future research should focus on earlier shock phenotyping, physiology-guided device selection, complication reduction, and strategies that integrate mechanical support with recovery-focused care.