In-hospital mortality and successful weaning from venoarterial extracorporeal membrane oxygenation: analysis of 5,263 patients using a national inpatient database in Japan

BACKGROUND: The mortality rate of severely ill patients treated with venoarterial extracorporeal membrane oxygenation (VA-ECMO) remains unknown because of differences in patient background, clinical settings, and sample sizes between studies. We determined the in-hospital mortality of VA-ECMO patients and the proportion weaned from VA-ECMO using a national inpatient database in Japan. METHODS: Patients aged ≥19 years who received VA-ECMO during hospitalization for cardiogenic shock, pulmonary embolism, hypothermia, poisoning, or trauma between 1 July 2010 and 31 March 2013 were identified, using The Japanese Diagnosis Procedure Combination national inpatient database. RESULTS: The primary outcome was in-hospital mortality and the secondary outcome was the proportion weaned from VA-ECMO. A total of 5263 patients received VA-ECMO during the study period. The majority of patients had cardiogenic shock (n = 4,658). The number of patients weaned from VA-ECMO was 3389 (64.4 %) and in-hospital mortality after weaning from VA-ECMO was 1994 (37.9 %). In-hospital mortality without cardiac arrest in the cardiogenic shock group was significantly lower than that in patients with cardiac arrest (70.5 % vs. 77.1 %, p <0.001). In the multivariable logistic regression including multiple imputation, higher age and greater or smaller body mass index were significantly associated with in-hospital mortality, whereas hospital volume was not associated with such mortality. CONCLUSIONS: The present nationwide study showed high mortality rates in patients who received VA-ECMO, and in particular in patients with cardiogenic shock and in patients with cardiac arrest. Weaning from VA-ECMO did not necessarily result in survival. Further studies are warranted to clarify risk-adjusted mortality of VA-ECMO using more detailed data on patient background.