Coronary artery disease is associated with substantial morbidity and mortality worldwide. Percutaneous coronary intervention (PCI) is a pivotal procedure for the treatment of coronary artery disease. Although coronary angiography (CA) is the standard imaging modality used for coronary stent implantation, it provides only two-dimensional images of the coronary arteries. Intravascular ultrasound (IVUS) can provide additional information on plaque characteristics and vessel morphology, which may facilitate optimal stent sizing and procedural optimization. However, IVUS requires additional time and cost and may increase procedural complexity. Evidence regarding the clinical benefit of IVUS-guided PCI in patients with acute coronary syndrome (ACS) remains limited.

This study is a prospective, multicenter, randomized controlled trial designed to compare IVUS-guided PCI versus angiography-guided PCI in patients with ACS. A total of 1,500 participants will be randomized 1:1 to either the IVUS-guided group or the angiography-guided group. Participants will be recruited from 15 PCI centers in Korea. The primary outcome is target vessel failure at 2 years.

Coronary artery disease is a condition characterized by a high incidence and mortality rate globally. Percutaneous coronary intervention (PCI) stands as a pivotal procedure in the diagnosis and treatment of this disease. Although coronary angiography (CA) is the standard imaging used in coronary stent implantation, it has a limitation in that it only provides two-dimensional images of the coronary arteries. To overcome this limitation, intravascular ultrasound (IVUS) can be utilized, allowing for the visualization of three-dimensional images such as intravascular plaque and morphological characteristics within the vessel, thereby offering more detailed information essential for optimal stent placement. Theoretically, IVUS-guided drug-eluting stent insertion could bring about a reduction in major cardiac events in patients with complex lesions and those at high risk, but most studies have excluded patients with acute coronary syndrome (ACS). The utilization of IVUS demands additional costs and time and might escalate the risk of intravascular complications in certain circumstances. However, the use of IVUS can facilitate a more accurate evaluation of plaque properties and morphology, assisting in determining more effective treatment strategies, and potentially contributing to lowering the risk of major cardiac events in patients suffering from acute myocardial infarction.

The objective of this study is to observe and compare the clinical impact between IVUS-guided drug-eluting stent insertion and angiography-guided drug-eluting stent insertion in patients with ACS over a span of 24 months. To this end, the investigators have planned a prospective, multi-institutional, randomized controlled trial, setting the primary outcome measurement as the target vessel failure rate over two years. The study will encompass 1500 patients, who will be assigned randomly at a 1:1 ratio to either the IVUS-guided or angiography-guided groups. The study participants will be recruited from 15 leading domestic PCI centers.

This research intends to chart the future course of ACS treatment, aspiring to surmount the current limitations of the technologies being employed. It is anticipated that in patients with ACS, IVUS-guided stent insertion during drug-eluting stent implantation might present superior clinical long-term prognoses compared to simple angiography-guided insertion.

Inclusion Criteria:

1. Patients 19 years of age or older
2. Patients with unstable angina pectoris, and acute MI including NSTEMI or STEMI.
3. Coronary artery disease defined as >70% stenosis (reference vessel diameter 2.5 - 5.0 mm based on operator assessment) with identifiable culprit lesion indicated stent implantation
4. All lesions must be suitable for treatment with the Synergy stent system, or other Synergy platform iteration
5. The patient or guardian agrees to the study protocol and the schedule of clinical and angiographic follow-up, and provides informed, written consent, as approved by the appropriate Institutional Review Board/Ethical Committee of the respective clinical site.

Exclusion Criteria:

1. Age >90 years
2. Subject has known hypersensitivity or contraindication to device material and its degradants (everolimus, poly(L-lactide), poly(DL-lactide), lactide, lactic acid) and cobalt, chromium, nickel, platinum, tungsten, acrylic, and fluoro polymers that cannot be adequately premedicated.
3. Absolute contraindications or allergy that cannot be pre-medicated, to iodinated contrast or to antiplatelet drugs, including both aspirin and P2Y12 inhibitors
4. An elective surgical procedure is planned that would necessitate interruption of antiplatelet drugs within 6 m after the procedure.
5. Cardiogenic shock
6. Restenotic lesions
7. Compromised left ventricular dysfunction (LVEF <30%)
8. At the time of screening, the subject has a malignancy that is not in remission
9. Non-cardiac co-morbidities with a life expectancy less than 1 year
10. Patients who are actively participating in another drug or device investigational study, which have not completed the primary endpoint follow-up period.
11. Subject belongs to a vulnerable population (per investigator's judgment) or subject unable to read or write
12. Concern for inability of the patient to comply with study procedures and/or follow-up (e.g., alcohol or drug abuse)
13. Pregnancy

Individual participant data will not be publicly available because of institutional policy and patient confidentiality considerations.