The hypothesis in this study was that ticagrelor switched to 60 mg after 1 month of standard dose, with antiplatelet activity that is not inferior to the standard dose and better than 75 mg clopidogrel for patients with ACS after PCI.

Inclusion Criteria:

• Agree to sign the Informed Consent;
• Male or female, ≥ 18 years of age, and ≤ 70 years of age
• Patient presents with acute coronary syndrome (ACS)
• Planned to undergo PCI
• Planned to DAPT for 1 year after PCI

Exclusion Criteria:

• Treatment with other investigational agents (including placebo) or devices within 30 days prior to randomization or planned use of investigational agents or devices prior to the Day 30 visit.
• Patients cannot use ticagrelor or clopidogrel due to contraindications or other reasons.
• Patients with active pathological hemorrhage or a history of intracranial hemorrhage
• Patient unable to receive 12 months of dual anti-platelet therapy
• Patient developing procedure-related complications such as stent thrombosis, coronary dissection, coronary perforation, cardiac tamponade or no-reflow during PCI
• Patient or physician refusal to enroll in the study
• History of intracranial hemorrhage
• Patient has a history of bleeding diathesis or coagulopathy
• Patient has an active pathological bleeding, such as active gastrointestinal (GI) bleeding
• Patient is pregnant, breastfeeding, or planning to become pregnant within 12 months
• Patient is receiving chronic oral anticoagulation therapy (i.e., vitamin K antagonist, direct thrombin inhibitor, Factor Xa inhibitor)
• Patient with cardiogenic shock or mechanical circulatory assist devices placed
• Patient with active liver diseases
• Patient with severe renal insufficiency (eGFR <30ml/min/1.73m2 based on simplified MDRD equation or CrCl <30ml/min based on Cockcroft-Gault equation)
• Patient has a malignancy or a life expectancy of less than one year
• Platelet count <100 000/μL, or hematocrit <32% or >52%, or white blood cell count <3000/μL
• Any other condition deemed by the investigator to place the patient at excessive risk of bleeding with ticagrelor