In patients with acute myocardial infarction without ST-segment elevation on ECG (non-STEMI), previous studies have indicated that routine invasive treatment confers more benefit as compared to selective invasive approach. The benefits of routine invasive coronary intervention have been the most evident in patients with higher baseline risk profile. However, the question of optimal timing of routine invasive intervention remains unsolved.

Immediate invasive intervention early after admission for non-STEMI may limit myocardial necrosis by securing the patency of the culprit coronary artery. Nevertheless, several previous studies reported higher levels of biomarkers of myocardial injury in patients undergoing early PCI. The question of earlier versus delayed procedure in non-STEMI patients may thus amount to whether the risk of intervening on an unstable plaque is greater than the risk of new ischemic events while waiting for the invasive procedure.

The purpose of the present study is to compare effects of immediate coronary intervention, within 2 hours of admission, versus delayed intervention, within 2-72 hours after admission, in patients witn non-STEMI.

Inclusion Criteria:

1. episode of chest pain occurring no longer than 24 hours prior to admission
2. elevation of cardiac troponin I above the upper limit of normal (ULN)
3. new ST-segment depression at least 1 millivolt (mV) and/or T-wave inversion or transient ST-segment elevation in ≥ 2 contiguous leads

Exclusion Criteria:

1. age < 18 years
2. persistent ST-segment elevation
3. hemodynamic instability
4. cardiogenic shock on admission
5. life-threatening ventricular arrhythmias on admission
6. refractory angina on admission
7. active bleeding
8. any contraindication for the use of dual antiplatelet therapy (DAPT)
9. presence of comorbidities with life expectancy < 6 months