Head to head comparison of ECPELLA versus venoarterial-ECMO in Myocardial Infarction associated cardiogenic shock: a meta-analysis

Background Recent research increasingly highlights the importance of extracorporeal veno-arterial membrane oxygenation (VA-ECMO) with (ECpella) or without Impella for the management of refractory cardiogenic shock (CS) resulting from acute myocardial infarction (AMI). However, there is a notable lack of large-scale, randomized trials that aim to head-to-head comparison of VA-ECMO versus ECpella for treating AMI-related CS. Purpose In order to assess this gap in the literature, we conducted a meta-analysis restricted to studies providing direct, head-to-head comparisons of these two mechanical circulatory support modalities to evaluate differences in 30-day mortality and device-related complications such as critical limb ischemia and major bleeding. Methods This meta-analysis included exclusively studies examining patients undergoing treatment with VA-ECMO with or without Impella for managing AMI-related CS. The primary outcome was the 30-day mortality rate, while secondary outcomes were major bleeding events and ischemic vascular complications. To estimate incidence rates, a random-effects model that used generic inverse-variance weighting for statistical aggregation was employed. The random effects Mantel-Haenszel method was utilized to calculate relative risks (RRs) and pooled mean differences (MDs), along with their respective 95% confidence intervals (CIs) for both categorical and continuous data. Results A total of 13 studies involving 8,288 patients were incorporated into this meta-analysis (Figure 1). The mean age of participants ranged from 56.31 ± 13.9 years in the ECMO cohort to 59.23 ± 10.77 years in the ECpella cohort without any statistically significant differences between the two groups. The results indicated that the ECpella strategy (2,652 patients) was associated with a significantly reduced 30-day mortality rate when compared to VA-ECMO alone (5,636 patients) (RR 0.88, CI 0.78 to 0.99, p=0.04), although the use of ECpella led to statistically significant higher bleeding (RR 1.44, C.I. 1.09 to 1.8, p=0.01) and ischemia complications (RR 1.63, C.I. 1.01 to 2.19, p=0.045). Lactate levels, available in 9 of the included studies, ranged from 4.5 to 12.7 mmol/l in the ECpella cohort and from 3.3 to 13.5 mmol/l in the VA-ECMO cohort, highlighting a serious state of shock. The comparison revealed no statistically significant differences in lactate levels between the two groups (SMD 0.07, CI -0.15 to 0.29). Accordingly age, pH were similar in both groups. Conclusions This meta-analysis indicates that the use of ECpella may be linked to a reduced mortality rate compared to VA-ECMO alone in ischemia-induced CS, despite the higher ischemic and bleeding complications associated with the combined use of these devices. Our findings may imply that Impella should serve as an early escalation therapy option for patients experiencing AMI-related CS treated with a VA-ECMO.