Predictors of Survival in Postcardiotomy VA-ECMO: A Single-Center Retrospective Cohort Study

Abstract

Background: Postcardiotomy cardiogenic shock remains one of the most severe complications following cardiac surgery, often requiring veno-arterial extracorporeal membrane oxygenation (VA-ECMO) for hemodynamic stabilization. Despite advances in surgical technique and critical care, mortality in this population remains high. Identifying early predictors of survival could guide clinical decision-making and optimize patient selection for ECMO support.
Objective: This study aimed to determine whether variables obtained before and within the first 24–48 hours after VA-ECMO implantation are associated with in-hospital survival in patients experiencing postcardiotomy shock.
Methods: In this retrospective, single-center cohort study, 59 adult patients undergoing VA-ECMO for postcardiotomy shock between 2016 and 2019 were included. Patients were stratified into survivor and non-survivor groups based on discharge status. Clinical and laboratory parameters were collected before ECMO initiation and at 24 and 48 hours post-implantation. Primary outcome was survival to hospital discharge. Statistical comparisons were performed using the Mann–Whitney U test for continuous variables and the chi-square or Fisher’s exact test for categorical variables. Logistic regression was used to identify independent predictors of survival.
Results: Overall hospital survival was 32.2% (19 out of 59 patients). Survivors had significantly lower serum lactate concentrations before ECMO initiation (3.60 ± 2.6 mmol/L vs 7.21 ± 4.0 mmol/L; p = 0.015) and required lower doses of noradrenalin (0.30 ± 0.2 vs 0.55 ± 0.3 μg/kg/min; p = 0.022). Pulmonary systolic blood pressure was markedly higher in survivors (40.1 ± 7.2 mmHg vs 12.2 ± 5.9 mmHg; p < 0.001). Lactate and noradrenalin levels remained significantly different between groups at 24 hours post-ECMO. Chronic lung disease was more prevalent in non-survivors (43.8% vs 15.2%; p = 0.031), while insulin-dependent diabetes showed a trend toward association with improved survival (p = 0.059). Multivariate logistic regression identified pre-ECMO lactate (OR 1.28 per mmol/L, 95% CI 1.05–1.70; p = 0.011) and pulmonary systolic pressure (OR 0.82 per mmHg, 95% CI 0.71–0.94; p = 0.004) as independent predictors of in-hospital mortality.
Conclusion: This study demonstrates that both pre-ECMO and early post-implantation variables can provide valuable prognostic information. Elevated lactate and vasopressor demand prior to and after ECMO initiation are associated with poor outcomes, while preserved pulmonary systolic pressure may indicate favorable right ventricular reserve and improved survival. These findings support the integration of dynamic hemodynamic and biochemical data into early risk stratification protocols for postcardiotomy ECMO patients.