Clinical Outcomes in Patients With Delayed Hospitalization for Non-ST-Segment Elevation Myocardial Infarction

Abstract

Background: Recently, the number of patients presenting with non-ST-segment elevation myocardial infarction (NSTEMI) has reduced, whereas increased mortality was reported. A plausible explanation for increased mortality was prehospital delay because of patients' reticence of their symptoms.

Objectives: The purpose of this study was to investigate the association between prehospital delay and clinical outcomes in patients with NSTEMI METHODS: Among 13,104 patients from the Korea-Acute-Myocardial-Infarction-Registry-National Institutes of Health, the authors evaluated 6,544 patients with NSTEMI. Study patients were categorized into 2 groups according to symptom-to-door (StD) time (<24 or ≥24 hours). The primary outcome was 3-year all-cause mortality, and the secondary outcome was 3-year composite of all-cause mortality, recurrent MI, and hospitalization for heart failure.

Results: Overall, 1,827 (27.9%) patients were classified into the StD time ≥24 hours group. The StD time ≥24 hours group had higher all-cause mortality (17.0% vs 10.5%; P < 0.001) and incidence of secondary outcomes (23.3% vs 15.7%; P < 0.001) than the StD time <24 hours group. The higher all-cause mortality in the StD time ≥24 hours group was observed consistently in the subgroup analysis regarding age, sex, atypical chest pain, dyspnea, Q-wave in electrocardiogram, use of emergency medical services, hypertension, diabetes mellitus, chronic kidney disease, left ventricle dysfunction, TIMI (Thrombolysis In Myocardial Infarction) flow, and the GRACE risk score. In the multivariable analysis, independent predictors of prehospital delay were the elderly, women, nonspecific symptoms such as atypical chest pain or dyspnea, diabetes, and no use of emergency medical services.

Conclusions: Prehospital delay is associated with an increased risk of 3-year all-cause mortality in patients with NSTEMI. (iCReaT Study No. C110016).