To investigate the factors contributing to the «ECMO gap,» the discrepancy between successful weaning from venoarterial extracorporeal membrane oxygenation (VA-ECMO) and survival to hospital discharge, using different definitions of successful weaning.

Single-center retrospective observational study.

A tertiary academic medical center intensive care unit.

Patients aged ≥18 years who underwent VA-ECMO between January 2018 and June 2023. Patients who died while on ECMO were excluded. Successful weaning from ECMO was defined using two criteria: survival for 48 hours (Definition 1) and independence from mechanical circulatory support (MCS) within 30 days (Definition 2).

None.

Multivariate logistic regression analysis was performed to identify factors associated with the ECMO gap for each definition, with Bayesian logistic regression conducted as a sensitivity analysis. Of the 130 ECMO patients, 110 were included in the analysis. Acute myocardial infarction and sepsis-induced cardiogenic shock (SICS) were associated with the ECMO gap under Definition 1. Under Definition 2, age (p = 0.04) was significantly associated with the ECMO gap,” while SICS showed a trend toward significance (p = 0.06). Bayesian analysis supported the association between age (odds ratio [95% confidence interval]: 0.08 [0.01-0.16]) and the ECMO gap. SICS showed a possible association (odds ratio [95% confidence interval]: 3.15 [0.26-6.33]); however, the wide credible interval suggests caution in interpretation.

The factors associated with the ECMO gap vary depending on the definition of successful weaning from ECMO. Specifically, advanced age and sepsis (eg, SICS) may hinder long-term recovery and contribute to the ECMO gap. Standardizing the definition of successful ECMO weaning is essential to improving patient outcomes and refining treatment strategies.