OCT or Angiography Guided De-escalation of DAPT

Inclusion Criteria: 1. 18 \~ 85 years old adult patients; 2. Patients diagnosed with STEMI and undergoing PCI. 3. Patients able and willing to give written informed consent and to comply with the requirements of this study protocol. Exclusion Criteria: 1. Prior history of intracranial hemorrhage or ischemic stroke during the past 6 months； 2. Allergy to aspirin or clopidogrel or ticagrelor; 3. Occurrence of major adverse cardiovascular event (MACE) within 30 days after undergoing PCI; 4. Platelet count \< 50 × 109/L; 5. Major bleeding during the past 12 months; 6. Any form of oral, long-term anticoagulation therapy; 7. Pregnancy or lactation; 8. Suspected aortic dissection; 9. Coronary CT-negative patients; 10. Life expectancy \<1 year; 11. Uncontrolled hypertension, systolic blood pressure (SBP) ≥180 mmHg, and/or diastolic blood pressure (DBP) ≥110 mmHg; 12. Comorbid conditions included the presence of any of the following: cardiogenic shock, chronic congestive heart failure with NYHA classes III or IV, left ventricular ejection fraction (LVEF) \< 35% at transthoracic echocardiography, hypotension with SBP \< 90mmHg and/or DBP \< 60mmHg, severe arrhythmia (including high-degree AV block, sick sinus syndrome, sustained ventricular tachycardia), severe pulmonary insufficiency, pulmonary embolism, hepatic insufficiency due to non-cardiac causes (ALT or AST more than three times the upper limit of the institution's normal reference ranges), cirrhosis, severe renal failure (eGFR \< 30ml/min/1.73m2); 13. Surgery plan within 30 days; 14. Psychiatric abnormalities or alcohol dependence; 15. Patients who are participating in other clinical trials; 16. Unable to tolerate 1 month of DAPT; 17. Angiographic triple vessel disease coronary disease; 18. Other situations judged by the investigators not to be suitable for the clinical trial.