30-Day Outcomes Post Veno-Arterial Extra Corporeal Membrane Oxygenation (VA-ECMO) After Cardiac Surgery and Predictors of Survival

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is sometimes needed for post-cardiotomy cardiogenic shock (PCCS). There is little data regarding outcomes in the Australian context, particularly in a non-cardiac transplant centre. Our aim was to report on 30-day outcomes after patients with PCCS treated with VA-ECMO in an Australian non-cardiac transplant tertiary centre, and to determine risk factors for non-survival in this population. A retrospective analysis was performed on all adults treated with VA-ECMO for PCCS between August 2001 and September 2016 at our centre. Univariate analysis with adjustment for multiplicity identified risk factors for non-survival. Area under the receiver operating characteristics (AUROC) method was used to assess their predictive value. We identified 64 patients out of 5,502 open-heart surgery cases of which three patients did not meet inclusion criteria. Mean (SD) age was 63 (14) years. Survival to hospital discharge or 30 days post VA-ECMO occurred in 27/61 (44%) patients. VA-ECMO was able to be weaned in 44/61 patients (72%); 54/61 patients (89%) had at least one major complication. Prior to VA-ECMO initiation, no statistically significant differences between survivors and non-survivors could be determined. After VA-ECMO initiation, only 24-hour nadir lactate and 48-hour nadir lactate levels were significantly different between survivors and non-survivors (1.50 mmol/L vs 3.20 mmol/L p=0.001; and 1.20 mmol/L vs. 1.90 mmol/L p=0.001 respectively). For mortality prediction, 24- and 48-hour nadir lactate levels had AUROCs of 0.775 and 0.782, respectively. VA-ECMO is associated with acceptable survival rates but significant morbidity. Nadir lactate levels in the first 24 and 48 hours after VA-ECMO initiation may be useful in predicting early survival.