It is a multi-center randomized clinical trial (RCT) which will enroll 3746 patients with acute coronary syndrome (ACS) concomitant non-valvular atrial fibrillation (NVAF) and undergoing new generation drug eluting stent (DES) implantation at 70 centers nationwide in China and contains two sub-studies.

In the OPTIMA-3 sub-study, 2274 subjects who choose warfarin as anticoagulant will randomly receive triple antithrombotic therapy (warfarin with targeted INR 2.0-3.0, clopidogrel 75 mg od and aspirin 100 mg od) for 1 month or 6 months in a 1:1 ratio then quit aspirin till 12 months after percutaneous coronary intervention (PCI). The primary endpoint of the OPTIMA-3 is a composite of cardiovascular death, myocardial infarction, ischemic stroke, systemic thromboembolism and unplanned revascularization up to 12 months; the major secondary endpoint is the International Society of Thrombosis and Hemostasis (ISTH) major bleeding or clinically relevant non-major bleeding (CRNMB).

In the OPTIMA-4 sub-study, 1472 subjects who prefer dabigatran will be randomly assigned in a 1:1 ratio to a dual antithrombotic therapy of dabigatran 110 mg twice daily with ticagrelor 90 mg twice daily or with clopidogrel 75 mg od for 12 months after PCI. The primary safety endpoint of the OPTIMA-4 is ISTH major bleeding or CRNMB at 12 months; the primary efficacy endpoint is a composite of cardiovascular death, myocardial infarction, ischemic stroke, systemic thromboembolism and unplanned revascularization.

Other secondary endpoints comprise death (cardiovascular, non- cardiovascular), MI (fatal or non-fatal, Q-wave or non-Q-wave), unplanned revascularization (target or non-target vessel, target or non-target lesion), stent thrombosis (possible, probable, definite), stroke (hemorrhage or ischemic), all bleeding (ISTH and BARC criteria) and net adverse events.

All endpoints will be collected and compared between subgroups and sub-studies during hospitalization and in 1 month (± 7 days), 6 months (± 7 days) and 12 months (± 7 days) for office visits and in 2 weeks (± 7 days), 2 months (± 7 days) and 3 months (± 7 days) for phone call visits.

Inclusion Criteria:

• ≥ 18 years;
• ACS patients concomitant non-valvular AF (paroxysmal, persistent and permanent) underwent PCI and new-generation DES implantation;
• CHA2DS2-VASc score ≥ 2;
• Acceptable risk of bleeding at the discretion of the researchers (e.g. HAS-BLED score ≤ 2)
• Consent to participate in the trial

Exclusion Criteria:

• DES implanted in the left main coronary artery
• Cardiogenic shock or Killip III-IV
• STEMI patients with malignant arrhythmias or underwent electrodefibrillation or CPR or with cardiac mechanical complications (heart rupture, ventricular septal perforation, nipple muscle fracture, etc.)
• History of gastrointestinal or intracranial hemorrhage; active bleeding, trauma or major surgery within one month; suspected or diagnosed aortic dissection
• Ischemic stroke with limb dysfunction or dysphasia
• Known allergy or intolerance to the study medications: warfarin, clopidogrel, aspirin, dabigatran, ticagrelor and heparin
• Participating in other ongoing trials
• Planned surgery in 12 months requiring to withdraw the antiplatelet agents
• Planned RFCA or left atrial appendage occlusion in the next 12m
• Abnormal liver or kidney function (ALT ≥ 3 ULN; estimated CrCl < 30 ml/min calculated by Cockcroft-Gault equation); diagnosed liver cirrhosis
• Hematological disease with bleeding tendency; hemoglobin < 100 g/L, platelet count < 100 × 10^9 /L
• Malignancies or life expectancy less than 1 year
• Pregnant (present, suspected, or planned) or lactating woman
• Patients who are taking drugs which may interact with study agents, such as miconazole, ketoconazole, fluconazole, voriconazole, itraconazole, posaconazole, efinaconazole, and rifampicin, etc.
• Patients with any other conditions that may not be suitable to participate in the trial at the discretion of the researchers.