Christian Camacho-Mondragon, MD: No financial relationships to disclose
Background: Cardiogenic shock occurs in 5–7% of myocardial infarctions and carries high mortality despite modern reperfusion and intensive care. Although mechanical circulatory support (MCS) is widely used to stabilize hemodynamics, randomized trials have not shown a clear survival benefit over conventional therapy, and the comparative effectiveness of available devices remains uncertain.
Methods: We conducted a systematic review and network meta-analysis of randomized controlled trials enrolling adult patients with myocardial infarction complicated by cardiogenic shock (MI-CS). The study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) statement and the PRISMA extension for network meta-analyses (PRISMA-NMA), and the protocol was prospectively registered in PROSPERO (CRD420251144408). Eligible trials compared Impella devices (2.5, CP, or 5.0), veno-arterial extracorporeal membrane oxygenation (VA-ECMO), or TandemHeart with conventional therapy, as well as direct head-to-head comparisons between MCS devices in patients with MI-CS. The primary outcome was all-cause mortality at 30 days, and secondary outcomes included all-cause mortality at 180 days and major safety events. Random-effects pairwise and network meta-analyses were performed, consistency between direct and indirect evidence was assessed, and treatment ranking was estimated using the surface under the cumulative ranking curve (SUCRA). Statistical analyses were performed using Stata/SE version 17, R version 4.5.1, and Python version 3.13.
Outcome: Ten randomized trials comprising 1,084 patients were included. In pairwise analyses, the use of MCS was not associated with a reduction in 30-day all-cause mortality compared with CT (risk ratio [RR] 0.94; 95% confidence interval [CI] 0.85–1.05), with no evidence of statistical heterogeneity. Network meta-analysis showed no significant short-term mortality benefit for any individual device compared with CT at 30 days. However, Impella CP demonstrated the lowest relative risk among the evaluated strategies. At 180 days, pairwise analysis did not demonstrate a significant reduction in mortality with MCS compared with CT (RR 0.92; 95% CI 0.81–1.04). However, in the network meta-analysis, Impella CP was associated with a statistically significant reduction in all-cause mortality compared with CT (RR 0.80; 95% CI 0.67–0.97) and ranked highest for efficacy (SUCRA 85.5%). VA-ECMO and TandemHeart did not demonstrate significant mortality benefits at either time point. Reporting of adverse events was inconsistent across trials, with variable definitions and incomplete reporting of bleeding, cerebrovascular events, and acute kidney injury. This heterogeneity precluded robust pooled safety comparisons and limited conclusions regarding the relative safety profiles of individual devices.
Conclusion: In MI-CS, MCS does not reduce short-term mortality compared with conventional therapy. However, Impella CP is associated with improved 180-day survival, suggesting a potential mid-term benefit and highlighting the need for appropriate patient selection, optimal timing, device choice, and phenotype-focused randomized trials.
