Underlying Cause of Out-of-Hospital Cardiac Arrests in Japan in Survivors Versus Nonsurvivors.

backgroundThe causes underlying out-of-hospital cardiac arrest (OHCA) are rarely investigated. This study aimed to investigate causes of OHCA in CRITICAL (Comprehensive Registry of In-Hospital Intensive Care for OHCA Survival), a multicenter OHCA registry in Osaka, Japan.

methodsNontraumatic patients with OHCA (by CARES [Cardiac Arrest Registry to Enhance Survival] criteria) aged 18 to 90 years between July 1, 2012 and December 31, 2020 were included. By Japanese law, all patients with OHCA (resuscitated or not) must be transported to the emergency department where death is declared if resuscitation is unsuccessful; this latter group was considered presumed sudden cardiac deaths whereas those surviving to hospitalization were considered resuscitated OHCA. We compared underlying causes of OHCA in presumed sudden cardiac deaths, survivors of OHCA (alive 30 days after the event), and nonsurvivors of OHCA (died during hospitalization). Causes were confirmed when autopsy or postresuscitation hospital workup was performed and probable when determined by attending physician impression (partial workup).

resultsOf 12 252 total OHCAs, 8005 (65.3%) were. presumed sudden cardiac deaths, 4247 (34.7%) were resuscitated, and 1293 (10.6%) were survivors. Resuscitated OHCA cardiac causes comprised 73.2% (n=3110) and noncardiac causes 26.8% (n=1137). Cardiac cause, most commonly acute coronary syndrome, was more prevalent in survivors of OHCA than nonsurvivors (85.7% [n=1137] versus 67.8% [n=2002];

conclusionsCardiac cause was more common in survivors than cases dying in the emergency room (sudden deaths) or in hospital after initial resuscitation (nonsurvivors of OHCA). Causes in nonsurvivors of OHCA who died in hospital were more heterogeneous than those of survivors of OHCA, especially cerebrovascular emergencies.