LOwer Maintenance Dose TICagrelor in Acute Coronary Syndrome Patients Undergoing Percutaneous Coronary Intervention

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