Pre-Hospital Delay and Outcomes in Myocardial Infarction With Nonobstructive Coronary Arteries

Background and Objectives: Real-world evidence on the relationship between delayed hospitalization and outcomes in myocardial infarction with nonobstructive coronary arteries (MINOCA) is lacking. Hence, we aimed to evaluate the clinical characteristics of patients with MINOCA and the 2-year mortality outcomes in this patient population according to the symptom-to-door time (SDT). Methods: Overall, 861 patients with MINOCA from 2 Korean nationwide observational registries (2011-2020) were included and categorized as early or late presenters. Late presentation was defined as SDT >= 12 hours in patients with ST-segment elevation myocardial infarction (STEMI) and SDT >= 24 hours in patients with non-STEMI. The primary outcome was 2-year all-cause mortality. Propensity score matching (PSM) and age-sex adjusted analysis were used to determine whether late presentation independently affected mortality. Multivariate logistic regression analysis was used to examine the independent factors correlated with late presentation. Results: In unadjusted data, late presenters had a notably higher risk of 2-year all-cause mortality than early presenters (hazard ratio [HR], 2.44; 95% confidence interval [CI], 1.47-4.08). This trend persisted in age-sex adjusted analysis (adjusted HR, 2.29; 95% CI, 1.36-3.84) and PSM-adjusted analysis (adjusted HR, 2.18; 95% CI, 1.05-4.53). The positive independent factors for late presentation included female sex, no emergency medical service use and high creatinine level, whereas the negative independent factor was a dyslipidemia. Conclusions: Late presentation is associated with higher mortality in patients with MINOCA. Multidisciplinary efforts are needed to reduce pre-hospital delay, thereby improving the clinical outcomes in these patients.