Early Single Antiplatelet Therapy After IVUS-Guided PCI in Acute Coronary Syndrome

Early Single Antiplatelet Therapy With a Potent P2Y12 Inhibitor After Intravascular Ultrasound-Guided PCI in Patients With Acute Coronary Syndrome: A Multicenter Randomized Controlled Trial

This is a prospective, open-label, multicenter, randomized, phase IV clinical trial designed to evaluate the safety and efficacy of early aspirin discontinuation followed by potent P2Y12 inhibitor monotherapy after intravascular ultrasound (IVUS)-guided drug-eluting stent implantation in patients with acute coronary syndrome. A total of 1,900 patients who achieve complete revascularization after IVUS-guided percutaneous coronary intervention (PCI) and meet the predefined successful IVUS-guided PCI criteria will be randomized in a 1:1 ratio to either the early single antiplatelet therapy group (Early SAPT: ticagrelor or prasugrel monotherapy) or the standard dual antiplatelet therapy group (Standard DAPT: aspirin plus ticagrelor or prasugrel). Randomization will be performed within 96 hours after completion of PCI, and clinical follow-up will be conducted at 1 month, 3 months, 6 months, and 12 months after randomization. The primary endpoints are major adverse cardiovascular events, defined as a composite of all-cause death, myocardial infarction, ischemia-driven target vessel revascularization, and definite or probable stent thrombosis occurring up to 12 months after randomization, and clinically relevant bleeding, defined as Bleeding Academic Research Consortium (BARC) type 2, 3, or 5 bleeding occurring up to 12 months after randomization. This study aims to determine whether early P2Y12 inhibitor monotherapy is non-inferior to standard dual antiplatelet therapy (DAPT) for ischemic events and is superior in reducing clinically relevant bleeding.

The study population will consist of patients diagnosed with acute coronary syndrome (ACS) who undergo percutaneous coronary intervention (PCI), achieve complete revascularization (CR) of all clinically significant coronary lesions under intravascular ultrasound (IVUS) guidance, and meet the imaging criteria predefined in this study.

Patients who meet all inclusion criteria and none of the exclusion criteria will be randomized within 96 hours after completion of PCI for CR, provided that no additional revascularization procedure is considered necessary. Before randomization, appropriate antiplatelet therapy including aspirin and a P2Y12 inhibitor may be administered according to the standard practice of each participating center. If staged PCI is planned, study enrollment and randomization will be allowed only after completion of all planned procedures. After the operator confirms successful procedural completeness based on final angiographic and IVUS images, eligible participants will be randomized in an open-label manner in a 1:1 ratio.

After randomization, the treatment strategy will be as follows. In the early single antiplatelet therapy (Early SAPT) group, aspirin will be discontinued immediately after randomization once CR has been confirmed, and potent P2Y12 inhibitor monotherapy will be administered as prasugrel 10 mg once daily or ticagrelor 90 mg twice daily. In the standard dual antiplatelet therapy (Standard DAPT) group, aspirin 100 mg once daily will be administered in combination with prasugrel 10 mg once daily or ticagrelor 90 mg twice daily. All patients will continue standard cardiovascular preventive therapy, including high-intensity statin therapy, beta-blockers, angiotensin-converting enzyme inhibitors (ACE inhibitors), or angiotensin receptor blockers (ARBs), as appropriate. A proton pump inhibitor (PPI) may be used at the discretion of the treating physician in patients at risk of gastrointestinal bleeding.

All randomized study participants will undergo clinical follow-up at 1 month, 3 months, 6 months, and 12 months after randomization.

Inclusion Criteria:

1. Age >=18 years
2. Diagnosis of acute coronary syndrome, including ST-segment elevation myocardial infarction (STEMI), non-ST-segment elevation myocardial infarction (NSTEMI), or unstable angina (UA)
3. Successful IVUS-guided PCI with drug-eluting stent implantation
4. Randomization within 96 hours after PCI
5. Written informed consent

Exclusion Criteria:

1. Planned staged PCI or CABG
2. PCI failure, including no-reflow, major dissection, or thrombosis
3. Need for oral anticoagulation
4. Major bleeding within 30 days
5. History of hemorrhagic stroke or ischemic stroke within 6 months
6. Platelet count <100,000/mm3 or WBC count <3,000/mm3
7. Contraindication to aspirin, ticagrelor, or prasugrel
8. Life expectancy <1 year
9. Current or potential pregnancy
10. Investigator deems participation inappropriate