A systematic review and meta-analysis of the efficacy and safety of combined mechanical circulatory support in cardiogenic shock complicating acute myocardial infarction
Authors: Soh B W T , Gracias C S , Dean A , Kumar J , Asgedom S , Matiullah S , Owens P 
Published: October 2024

Abstract

Background
Cardiogenic shock complicating acute myocardial infarction (CSAMI) is a severe complication associated with unacceptably high mortality rates. Since early revascularisation was introduced more than 20 years ago, no subsequent innovation has demonstrated conclusive efficacy in reducing mortality in CSAMI. While mechanical circulatory support (MCS) has emerged as a potential intervention, randomised controlled trials evaluating independent use of veno-arterial extracorporeal membrane oxygenation (VA-ECMO), and intra-aortic balloon pump (IABP) have not shown benefit in CSAMI. In contrast, systematic reviews of observational studies have revealed significant mortality reduction when CSAMI was treated with combined use of MCS, specifically VA-ECMO in conjunction with a left ventricular (LV) unloading device (Impella or IABP). Combination MCS (VA-ECMO + LV unloading) may therefore present a promising approach to CSAMI, but an unresolved dilemma concerning the optimal selection between two LV unloading devices (VA-ECMO + Impella vs VA-ECMO + IABP) warrants further investigation and clarification.

Purpose
We perform the first systematic review and meta-analysis assessing the short-term efficacy and safety of VA-ECMO + Impella versus VA-ECMO + IABP in treatment of CSAMI.

Methods
A systematic search was performed on the EMBASE and MEDLINE databases. Studies reporting the short-term (30-day/inpatient) mortality and complications of adult patients with CSAMI treated with VA-ECMO + Impella and VA-ECMO + IABP were included. Fixed effect meta-analyses using Mantel-Haenszel model was used to analyse the pooled odds ratio for short-term mortality and major complications. Subgroup analysis was performed including studies with ACS predominant CS (Cause of CS 100% by AMI).

Results
Four observational studies with 14,247 patients were included. These studies showed high heterogeneity for the total CSAMI cohort and low heterogeneity for the ACS predominant cohort. There was no significant difference in mortality between VA-ECMO + Impella and VA-ECMO + IABP 56.5% vs 66.5%; OR, 0.90; 95% CI, 0.79–1.02; P=0.09. However, VA-ECMO + Impella was associated with significantly lower mortality in patients with ACS predominant CS 53.2% vs 67.7%; OR, 0.72; 95% CI, 0.62–0.85; P&lt;0.0001. VA-ECMO + Impella was associated with significantly higher risk of major bleeding 15.1% vs 8.6%; OR, 1.87; 95% CI, 1.50–2.32; P&lt;0.00001 and vascular complications 15.0% vs 6.7%; OR, 1.75; 95% CI, 1.41–2.18; P&lt;0.00001.

Conclusions
When comparing LV unloading devices in patients with CSAMI requiring combination MCS, VA-ECMO + Impella was superior in mortality reduction only in the cohort where 100% of CS was caused by AMI. Concomitantly, VA-ECMO + Impella was associated with greater risk of major bleeding and vascular complications. Additional randomised studies are needed to validate and strengthen the findings presented in these observational data.Forrest plot on short-term mortalityForrest plot on major complications