BackgroundBleeding is the most common complication in out-of-hospital cardiac arrest (OHCA) patients receiving extracorporeal cardiopulmonary resuscitation (ECPR). No studies comprehensively described the incidence rate, timing of onset, risk factors, and treatment of bleeding complications in OHCA patients receiving ECPR in a multicenter setting with a large database. This study aimed to analyze the risk factors of bleeding during the first day of admission and to comprehensively describe details of bleeding during hospitalization in patients with OHCA receiving ECPR in the SAVE-J II study database.MethodsThis study was a secondary analysis of the SAVE-J II study, which is a multicenter retrospective registry study from 36 participating institutions in Japan in 2013–2018. Adult OHCA patients who received ECPR were included. The primary outcome was the risk factor of bleeding complications during the first day of admission. The secondary outcomes were the details of bleeding complications and clinical outcomes.ResultsA total of 1,632 patients were included. Among these, 361 patients (22.1%) had bleeding complications during hospital stay, which most commonly occurred in cannulation sites (14.3%), followed by bleeding in the retroperitoneum (2.8%), gastrointestinal tract (2.2%), upper airway (1.2%), and mediastinum (1.1%). These bleeding complications developed within two days of admission, and 21.9% of patients required interventional radiology (IVR) or/and surgical interventions for hemostasis. The survival rate at discharge of the bleeding group was 27.4%, and the rate of favorable neurological outcome at discharge was 14.1%. Multivariable logistic regression analysis showed that the platelet count (< 10 × 104/μL vs > 10 × 104/μL) was significantly associated with bleeding complications during the first day of admission (adjusted odds ratio [OR]: 1.865 [1.252–2.777], p = 0.002).ConclusionsIn a large ECPR registry database in Japan, up to 22.1% of patients experienced bleeding complications requiring blood transfusion, IVR, or surgical intervention for hemostasis. The initial platelet count was a significant risk factor of early bleeding complications. It is necessary to lower the occurrence of bleeding complications from ECPR, and this study provided an additional standard value for future studies to improve its safety.