J Korean Soc Emerg Med.  2025 Apr;36(2):54-62.

Comparison of complications in patients with NSTEMI according to the timing of invasive intervention: early versus delayed

• Seo CW
• Park HY
• Kim HB
• Ko JW
• Lee JB
• Hwang YJ
• Hwang TS

Abstract

Objective
Acute coronary syndrome often requires urgent intervention. The 2023 European Society of Cardiology guidelines recommend invasive procedures within 24 hours for high-risk cases. Nevertheless, there have been limited studies on non-ST-segment elevation myocardial infarction (NSTEMI) in South Korea. This study compared the risk of complications based on the timing of intervention.
Methods
A retrospective observational study was conducted on patients with chest pain and elevated high-sensitivity troponin T from January to December 2021 in the emergency department. Patients were categorized into early (≤24 hr) and late (>24 hr) intervention groups. Primary outcomes (death, restenosis, or stroke) at 12 months were compared. Survival and subgroup analyses were performed to examine the factors affecting the outcomes in the two groups.
Results
Three hundred seventy six patients were enrolled in the study, and 115 patients were excluded. Among 261 patients, 106 and 155 patients were in the early intervention group (≤24 hr), and late intervention group (>24 hr), respectively. The primary outcome (death or restenosis) showed no significant difference (hazard ratio [HR] in the early intervention group at 12 mo; 1.03; 95% confidence interval [CI], 0.63-1.70; P=0.905). However, risk of stroke was lower in the early intervention group (HR in the early, 0.08; 95% CI, 0.00-0.66; P=0.013). Subgroup analysis showed no significant advantage for early intervention.
Conclusion
In NSTEMI patients, early intervention does not reduce death or restenosis but lowers stroke incidence. No specific risk factors favored early intervention.

Keyword

Acute coronary syndrome; Non-ST elevated myocardial infarction; Coronary angiography; Time factors; Complications