Incidence and Long‐Term Outcomes of Acute Myocardial Infarction Among Survivors of Out‐of‐Hospital Cardiac Arrest

Abstract

Background Despite the increasing long‐term survival after out‐of‐hospital cardiac arrest (OHCA), the risk of subsequent acute myocardial infarction (AMI) remains poorly understood. We aimed to determine the incidence, predictors, and long‐term outcomes of AMI among survivors of OHCA. Methods and Results We assembled a retrospective cohort of 882 patients with OHCA who survived to 30 days or discharge from the hospital between 2010 and 2019. Survivors of OHCA had an increased risk of subsequent AMI, defined as AMI occurring 30 days after index OHCA or following discharge from the hospital after OHCA, compared with the general population when matched for age and sex (standardized incidence ratio, 4.64 [95% CI, 3.52–6.01]). Age‐specific risks of subsequent AMI for men (standardized incidence ratio, 3.29 [95% CI, 2.39–4.42]) and women (standardized incidence ratio, 6.15 [95% CI, 3.27–10.52]) were significantly increased. A total of 7.2%, 8.3%, and 14.3% of survivors of OHCA had a subsequent AMI at 3 years, 5 years, and end of follow‐up, respectively. Age at OHCA (hazard ratio [HR], 1.04 [95% CI, 1.02–1.06]) and past medical history of prior AMI, defined as any AMI preceding or during the index OHCA event (HR, 1.84 [95% CI, 1.05–3.22]), were associated with subsequent AMI, while an initial shockable rhythm was not (HR, 1.00 [95% CI, 0.52–1.94]). Survivors of OHCA with subsequent AMI had a higher risk of death (HR, 1.58 [95% CI, 1.12–2.22]) than those without. Conclusions Survivors of OHCA are at an increased risk of subsequent AMI compared with the general population. Prior AMI, but not an initial shockable rhythm, increases this risk, while subsequent AMI predicts death. Preventive measures for AMI including cardiovascular risk factor control and revascularization may thus improve outcomes in selected patients with cardiac pathogenesis.