Association of advanced age and aetiology of cardiac arrest with outcomes in patients with out-of-hospital cardiac arrest receiving extracorporeal cardiopulmonary resuscitation: a secondary analysis of multicentre registry study in Japan

Background Data on extracorporeal cardiopulmonary resuscitation (ECPR) in older patients, particularly those aged ≥75 years, remain limited and inconsistent. In this study, we investigated the association between advanced age and outcomes in patients receiving ECPR and determined differences in outcomes by aetiology of out-of-hospital cardiac arrest (OHCA) to identify older patients who may benefit from ECPR. Methods This secondary analysis of a retrospective multicentre cohort study in Japan included adult patients with OHCA who received ECPR between 2013 and 2018. The study outcomes were unfavourable neurological outcomes at discharge, in-hospital mortality and ECPR-related complications. The study cohort was categorised by age groups, and the association between age group and outcomes was investigated. We also compared patient characteristics between favourable and unfavourable outcome groups and performed subgroup analysis to gain insights regarding the group of older patients who could benefit from ECPR. Results Of the 1904 included patients, 1106 were aged <65 years, 547 were 65–74 years, and 251 were ≥75 years. Patients aged 65–74 years and those aged <65 years had comparable rates of unfavourable neurological outcomes and in-hospital mortality. However, patients aged ≥75 years had significantly higher rates of unfavourable neurological outcomes and in-hospital mortality than those aged <65 years. Subgroup analysis of crude mortality rates revealed relatively high survival rates for patients with pulmonary embolism (54.5%) or hypothermia (25%) compared to those with other causes of arrest in the ≥75 years group. Conclusions Patients with OHCA aged ≥75 years and receiving ECPR are at higher risk of unfavourable neurological outcomes and in-hospital mortality than those aged <65 years. However, neurological outcomes and in-hospital mortality in patients aged ≥75 years vary with the causes of OHCA. ECPR outcomes in super-geriatric patients with OHCA may be comparable to those in younger patients for specific aetiologies.