Very early vs delayed invasive strategy in high-risk NSTEMI patients without hemodynamic instability: Insight from the KAMIR-NIH.

Background: High-risk non-ST-elevation myocardial infarction (NSTEMI) patients' optimal timing for percutaneous coronary intervention (PCI) is debated despite the recommendation for early invasive revascularization. This study aimed to compare outcomes of NSTEMI patients without hemodynamic instability undergoing very early invasive strategy (VEIS, ≤ 12 hours) versus delayed invasive strategy (DIS, >12 hours).

Methods: Excluding urgent indications for PCI including initial systolic blood pressure under 90 mmHg, ventricular arrhythmia, or Killip class IV, 4,733 NSTEMI patients were recruited from the Korea Acute Myocardial Infarction Registry-National Institutes of Health (KAMIR-NIH). Patients were divided into low and high- global registry of acute coronary events risk score risk score (GRS) groups based on 140. Both groups were then categorized into VEIS and DIS. Clinical outcomes, including all-cause death (ACD), cardiac death (CD), recurrent MI, and cerebrovascular accident at 12 months, were evaluated.

Results: Among 4,733 NSTEMI patients, 62% had low GRS, and 38% had high GRS. The proportions of VEIS and DIS were 43% vs. 57% in the low GRS group and 47% vs. 53% in the high GRS group. In the low GRS group, VEIS and DIS demonstrated similar outcomes; however, in the high GRS group, VEIS exhibited worse ACD outcomes compared to DIS (HR = 1.46, P = 0.003). The adverse effect of VEIS was consistent with propensity score matched analysis (HR = 1.34, P = 0.042).

Conclusion: VEIS yielded worse outcomes than DIS in high-risk NSTEMI patients without hemodynamic instability in real-world practice.