This prospective, multicenter, randomized, controlled, open-label clinical study has a target enrollment of 240 subjects. It will explore whether STEMI patients transferred to a PCI center following thrombolytic therapy and expected to have stent implantation might benefit from an alternative treatment strategy and the use of new technologies designed to improve myocardial protection throughout the medical care process.

Eligible patients with STEMI who meet the Inclusion/Exclusion Criteria will receive thrombolytic therapy, and then be transferred to the PCI center for coronary angiography (CAG). Patients having a target vessel with TIMI grade 3 flow as shown by CAG, and and ≥ 50% angiographic stenosis after thrombus aspiration, will be randomized in a 1:1 ratio to either an immediate stenting group or a deferred stenting group. Patients assigned to the immediate stenting group will undergo appropriate stent implantation based on characteristics of the lesions. Patients assigned to the deferred stenting group will be sent back to the ward after PCI to receive standard anticoagulant and antiplatelet therapies, and the CAG will be repeated 5 to 7 days after initial intervention, followed by treatment with stent implantation.

All subjects will be recorded postoperative microcirculation perfusion and ST-segment drop of electrocardiogram and followed up by telephone or in the clinic at 1, 6, and 12 months after discharge from the hospital to obtain information including their general condition, chief complaints or discomforts, details of taking their oral medications, recent relevant test results, and to evaluate the primary endpoint, secondary endpoints.

Inclusion Criteria:

• Inpatients who meet all of the following criteria can be included in the study:

  1. Age: 18-75 years old;
  2. A confirmed diagnosis of STEMI with symptom onset within 12 h;

STEMI criteria:

1. Patient has a history of chest pain/discomfort;
2. ST elevation ≥ 0.1 mV in at least two contiguous leads of an ECG on admission (> 30 minutes; ≥ 0.2 mV required for V2 and V3 ) or the development of new left bundle branch block (LBBB);
3. an increase in cardiac biomarkers (troponin, CK-MB) above the 99th percentile of the laboratory upper reference limit; 3. Time from FMC to wire crossing estimated to be > 120 min; 4. Has a target vessel with TIMI grade 3 flow shown as by CAG and ≥ 50% angiographic stenosis after thrombus aspiration; 5. Has culprit lesions identified as primary lesions; 6. Signed the written informed consent form.

Exclusion Criteria:

• Patients are not eligible for enrollment if they meet any of the following criteria:

  1. A contraindication to thrombolysis;
  2. An estimated survival time ≤ 12 months;
  3. Known heart failure of Killip class III or above, or mechanical complications such as heart rupture;
  4. Known to be participating in any other clinical trial;
  5. Pregnant or lactating women, or women experiencing their menstrual period;
  6. Weight < 40 Kg or > 125 Kg;
  7. Known allergies to drugs that are required during the study such as contrast agents, antiplatelet drugs, and anticoagulants;
  8. A target vessel with TIMI grade 0-2 flow as revealed by the initial CAG;
  9. Having lesions located in the LMCA or root of the LAD, or with severe multiple vessel disease.

This study is a prospective, multicenter, randomized, controlled, open-label clinical study.