Surviving venoarterial extracorporeal membrane oxygenation (VA-ECMO): The roles of severity scores and post-operative lactate clearance.

Background: This study investigated the association of the Survival After VA-ECMO (SAVE) score, Sequential Organ Failure Assessment (SOFA) score, and post-cannulation lactate levels with mortality among patients treated with veno-arterial extra-corporeal membrane oxygenation (VA-ECMO) for refractory cardiogenic shock (CS).

Methods: We performed a retrospective review of adult patients who underwent peripheral VA-ECMO cannulation from January 2018 to September 2022 at a quaternary care center. All-cause in-hospital mortality was assessed and compared to predicted mortality by SAVE and SOFA scores prior to cannulation, with adjusted odds ratio of risk factors for mortality identified by multivariate logistic regression analysis. Additionally, the prognostic value of 8-h post-cannulation serum lactate levels was analyzed by receiver operating characteristic (ROC) curve and Kaplan Meier analysis of 30-day survival.

Results: 244 patients were included in final analysis. All-cause in-hospital mortality was 70 %, and 54 % of patients died while on ECMO or within 24 h of decannulation. Pre-cannulation SAVE score (OR 0.93 per unit increase, 95 % CI 0.86-0.99, p = 0.008), SOFA score (OR 1.54 per unit increase, 95 % CI 1.32-1.75), and 8-h post-cannulation lactate levels (OR 1.20 per mmol/L increase, 95 % CI 1.04-1.36, p = 0.008) were independently associated with all-cause in-hospital mortality. 8-h post-cannulation lactate levels ≥5.3 mmol/L demonstrated high specificity for in-hospital mortality (90.0 %), while levels ≥7.8 mmol/L were demonstrated high specificity for VA-ECMO death (91.1 %). These thresholds were significantly associated with 30-day all-cause mortality (p < 0.001).

Conclusion: Pre-cannulation SAVE and SOFA scores are useful prognostic tools in patients with CS. 8-h post-cannulation serum lactate levels are a pragmatic biomarker and can further assist in prognostication of patients on VA-ECMO, and the cutoffs of 5.3 mmol/L and 7.8 mmol/L have high specificity for all-cause mortality and VA-ECMO mortality, respectively. The development of accurate prognostic tools is critical in managing and optimizing care for patients with CS.