Impact of center volume on in-hospital mortality in adult patients with out‑of‑hospital cardiac arrest resuscitated using extracorporeal cardiopulmonary resuscitation: A secondary analysis of the SAVE-J II study

Abstract Background:Recently, patients with out-of-hospital cardiac arrest (OHCA) refractory to conventional resuscitation have started undergoing extracorporeal cardiopulmonary resuscitation (ECPR). However, the mortality rate of these patients remains high. This study aimed to clarify whether a center ECPR volume was associated with the survival rates of adult patients with OHCA resuscitated using ECPR. Methods: This was a secondary analysis of a retrospective multicenter registry study, the SAVE-J II study, involving 36 participating institutions in Japan. The centers were divided into three groups according to the tertiles of the annual average number of patients undergoing ECPR: high-volume (≥21 sessions per year), medium-volume (11–20 sessions per year), or low-volume (<11 sessions per year). The primary outcome was survival rate at the time of discharge. Patient characteristics and outcomes were compared among the three groups. Moreover, a multivariable-adjusted logistic regression model was applied to study the impact of center ECPR volume. Results: A total of 1,740 patients were included in this study. The center ECPR volume was strongly associated with survival rate at the time of discharge; furthermore, survival rate was best in high-volume compared with medium- and low-volume centers (33.4%, 24.1%, and 26.8%, respectively; P=0.001). After adjusting for patient characteristics, undergoing ECPR at high-volume centers was associated with an increased likelihood of survival compared to middle- (adjusted odds ratio 0.657; P=0.003) and low-volume centers (adjusted odds ratio 0.983; P=0.006). Conclusion: The annual number of ECPR sessions was associated with favorable survival rates and lower complication rates of the ECPR procedure. IRB information: The present study was approved by the institutional review board of Kagawa University (approval number: 2018-110) Clinical trial registration: https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000041577 (unique identifier: UMIN000036490, Registered 15 April 2019, retrospectively registered)