STEMI represents the subtype of ACS with the worst prognosis, associated with high mortality and an elevated risk of complications. The use of IVI guidance holds the potential to reduce the incidence of MACE. In previous studies, there has been limited research on intravascular imaging in the context of primary revascularization procedures for STEMI, and no large-scale cohort study has compared the differences in clinical outcomes between IVI-guided and angiography-guided primary revascularization. Therefore, we conducted this large-scale randomized controlled trial to compare IVI-guided primary PCI versus coronary angiography-guided primary PCI in patients with STEMI.

This study is a prospective, multicenter, randomized controlled, superiority clinical trial. Eligible subjects who meet the inclusion/exclusion criteria will be randomly assigned in a 1:1 ratio to either the IVUS-guided strategy (experimental group) or the conventional coronary angiography-guided strategy (control group). The study plans to enroll at least 2488 subjects, with 1244 subjects in each of the experimental and control groups. Zhongshan Hospital, Fudan University serves as the lead center. A competitive enrollment approach will be adopted, with the number of cases enrolled by the lead center not exceeding 50% of the total sample size.

In the IVUS group, intravascular ultrasound (IVUS) will be used for guidance; the use of high-frequency intravascular ultrasound (resolution ≥ 50 MHz) is encouraged, though not mandatory.

Inclusion criteria

1. Patients diagnosed with acute ST-segment elevation myocardial infarction (STEMI) who have an indication for emergency interventional therapy;
2. Subjects who are eligible to undergo primary percutaneous coronary intervention (PCI);
3. Subjects or their authorized family members voluntarily agree to participate in the clinical trial and sign the written informed consent form;
4. The IVUS catheter is expected to pass through the target lesion to complete the examination.

Exclusion Criteria

1. Patients with cardiogenic shock or severe heart failure (Killip class IV);
2. Patients who have previously undergone coronary artery bypass grafting (CABG);
3. Patients with coma or disturbance of consciousness;
4. Patients who are expected to be intolerant to long-term antiplatelet therapy;
5. Pregnant women;
6. Life expectancy < 1 year;
7. Currently participating in another drug/device clinical trial and not having reached the primary endpoint;
8. Poor compliance, expected to be unable to complete follow-up.