Sequential MonotherApy of TicagrElor and Clopidogrel After Coronary Intervention

Inclusion Criteria: 1. Age 18-80 years old; 2. Acute coronary syndrome was diagnosed upon admission; 3. Administered ticagrelor for at least 30 days after successful PCI with implantation of a current-generation drug-eluting stent(s) 4. Agree to the study protocol and the schedule of clinical follow-up, and provides informed, written consent Exclusion Criteria: 1. Implanted with first-generation DES or bioabsorbable stent(s) during hospitalization; 2. Patients with active pathological bleeding (such as peptic ulcer or intracranial hemorrhage); 3. History of intracranial hemorrhage, intracranial neoplasms, intracranial vascular malformations or hemangioma 4. High potential risk of major bleeding, such as acute or chronic gastrointestinal ulcers or other gastrointestinal diseases, alignant tumors, etc.; 5. Thrombolytic therapy within 24 hours of index PCI; 6. Planned coronary revascularization (surgical or percutaneous) within 30 days; 7. Allergic to ticagrelor, clopidogrel or aspirin and any excipients; 8. Inability to tolerate 12-month DAPT (ticagrelor+aspirin) for any reason; 9. Cardiogenic shock or hemodynamic instability; 10. Diagnosed as active hepatitis or liver cirrhosis upon admission; 11. Suffer from a known serious progressive disease (e.g. progressive cancer, chronic obstructive lung disease, etc.;) or estimated survival time\<12 months ; 12. Platelet count\<100000 /mm3; 13. Dialysis-dependent renal failure； 14. Required use of oral anticoagulation (warfarin or other factor II or factor X inhibitors); 15. Pregnant or plan to be pregnant within 1 year; 16. Any condition that may interfere with any study procedures, such as dementia, immobility, alcohol use, etc; 17. Participating in any other clinical trial of an investigational drug or device that has not met its primary endpoint.