The study is to evaluate the effect of optimized 12-month step-down antiplatelet therapy (APT) compared with standard 12-month dual antiplatelet therapy in clinical net adverse events, cardiovascular and cerebrovascular adverse events and reducing clinical related bleeding events in the patients with acute coronary syndrome (ACS) who are not the predominant coronary artery disease after percutaneous coronary intervention (PCI).

This is a prospective, multi- center, randomized, parallel-group trial designed to evaluate the effect of optimized 12-month step-down antiplatelet therapy compared with standard 12-month dual antiplatelet therapy in clinical net adverse clinical events, cardiovascular and cerebrovascular adverse events and reducing clinical related bleeding events in the patients with acute coronary syndrome who are not the main coronary artery disease.2020 subjects will be enrolled. After PCI,eligible patients will be randomly assigned in a 1:1 ratio to either the optimized antiplatelet therapy group（O-APT）or the standard antiplatelet therapy group（S-APT）. The primary efficacy end points are clinical net adverse clinical events ,or the event rate of the composite of cardiovascular death, non-fatal myocardial infarction, stent thrombosis, ischemia driven coronary revascularization and stroke at 12 months. The primary safety end point is the incidence of PLATO major bleeding or Bleeding Academic Research Consortium (BARC) type 2, 3 or 5 bleeding at 12 months.

Inclusion Criteria:

• Patients admission for coronary artery disease treatment with non-emergency percutaneous intervention with stent deployment

• Enrollment into the study will require meeting at least one of these clinical syndromes.

  1. Unstable angina
  2. Non-ST elevation myocardial infarction (NSTEMI)
  3. ST elevation MI (STEMI)

• Non predominant coronary artery disease, it is defined as: exclusion of left main artery disease or left main artery bifurcated disease or ostial left anterior descending disease by coronary angiography imaging, and other high-risk vascular diseases considered by surgeons

• Patients understands the study requirements and the treatment procedures and provided informed consent before the procedure

Exclusion Criteria:

• Complications during stenting for coronary artery disease
• Stroke within 3 months or any permanent neurologic deficit, and prior intracranial bleed, or any intracranial disease such as aneurysm or fistula
• Any planned surgery within 6 months
• any reason why any antiplatelet therapy might need to be discontinued within 12 months
• Severe chronic kidney disease defined as an estimated glomerular filtration rate (eGFR) < 15ml/min/1.73m^2
• Need for chronic oral anticoagulation (warfarin/coumadin or direct oral anticoagulants)
• Platelet count < 100,000 mm^3
• Contraindication to aspirin
• Contraindication to ticagrelor
• Liver cirrhosis
• Women of child-bearing potential
• Life expectancy < 1 year
• Any condition likely to interfere with study processes including medication compliance or follow-up visits (e.g. dementia, alcohol abuse, severe frailty, long distance to travel for follow-up visits, etc.)