There are limited data on the causes of death in patients undergoing extracorporeal cardiopulmonary resuscitation (ECPR). This study aimed to analyse the causes of death among patients who received ECPR following out-of-hospital cardiac arrest (OHCA).

In this post-hoc analysis of a prospective registry, the causes of death were categorized using a predefined method specifically developed for cardiac arrest patients. Two investigators independently assigned each patient to one of five predefined categories of death, with interrater reliability measured using Fleiss’ kappa.

From January 2012 to December 2023, a total of 1,219 OHCA patients were admitted to the hospital, of whom 210 underwent ECPR. Among these, 152 (72.3%) patients died during their index hospitalization. The median age of deceased patients was 57 years, with 80.9% being male, and the median time to ECPR initiation was 62 min (IQR: 53–72). Interrater agreement was 0.81. The most common primary cause of death was refractory shock (75/152 patients, 49.3%), followed by neurological injury (69/152 patients, 45.3%), rearrest (7/152 patients, 4.6%), and comorbidities (1/152 patients, 0.6%).

Refractory shock was the leading cause of death among our cohort of ECPR patients, followed closely by neurological complications, while other causes were rare.