Anfibatide Treatment in STEMI Patients

Inclusion Criteria: 1. Aged 18-75 years; 2. Fulfill the standard of direct PCI: ST Segment Elevation Myocardial Infarction occurred \< 12 hours (ST Segment Elevation or New Left Bundle Branch Block (LBBB), combined myocardial ischemia chest pain medical history or the dynamic change of cardiac marker (troponin and/or CK-MB); 3. Patients who will receive PCI and suitable for angioplasty and stent placement; 4. Patients, or their family or guardian give signed informed consent forms. Exclusion Criteria: 1. Patients with weight \< 50kg; 2. Patients with severe hepatic or renal dysfunction, alanine aminotransferase (ALT) exceeds 3 times the normal maximum reference level, creatinine clearance level \< 30ml/min or serum creatinine ≥ 200μmol/L or ≥2.5mg/dl; 3. Patients with severe hemodynamic instability; 4. Patients who will receive 2 times or more PCI treatment; 5. Patients with heart function in decompensatory phase (Killip grade 3-4) or cardiac shock; 6. Patients with untreated hypertension (SBP \> 180mmHg or DBP \> 110mmHg) or hypotension shock (SBP \< 90mmHg); 7. Patients received GPIIb/IIIa receptor antagonists and/or thrombolytic therapy before randomization; 1. Used eptifibatide and tirofiban in the past 12 hours before the randomization; 2. Used abxicimab in the past 7 days before the randomization; 3. Have received thrombolytic therapy before the randomization; 8. Patients who need a long-term treatment of clopidogrel; 9. Patients who have received enoxaparin sodium injection before the surgery; 10. Patients who have hemorrhage risk: 1. Suffered from ischemic stroke or transient ischemic attack (TIA) in the past 12 months; 2. Suffered from hemorrhage stroke, or other life-long neuronal dysfunction; 3. Suffered from tumor, arteriovenous malformation in brain and aneurysms; 4. Suffered from traumatic brain injury in the past 3 months, or received major surgery; 5. Received percutaneous coronary intervention (PCI) in the past 6 months; 6. Have received coronary artery bypass graft therapy (CABG); 7. Receiving long-term oral anticoagulants therapy; 8. Suffered from active peptic ulcer, urinary and reproductive tract hemorrhage, or other active hemorrhage. 11. Patients with coagulation disorder: 1. Known as international normalized ratio \> 2\*; 2. Patients with coagulation abnormalities or other hemorrhagic tendency (including inherited hemorrhagic diseases, e.g. Von Willebrand disease or hemophilia; acquired hemorrhagic diseases; and other clinically identified hemorrhagic diseases with unsolved rationale); 3. Hematology test shows platelet count \< 100x109mm3/L, or hemoglobin \< 100g/L; 4. Recorded clopidogrel-related thrombocytopenia or agranulocytosis; 12. Life expectancy \< 1 year; 13. Patients who have implemented with pacemaker, and contraindicated to MRI examination; 14. Patients who are allergic constitution or allergic to any component of aspirin, clopidogrel, creatinine, antiplatelet thrombolysin and investigational product; 15. Women in pregnant or lactation period, or women of child-bearing age do not take efficient contraception measures; 16. Patients who are participating or will be participating in other clinical trials; 17. Patients who have participated in clinical trials of antiplatelet thrombolysin or other related trials; 18. Patients who are not suitable for participating in this clinical trial according to the investigator's judgment, including who are unable or unwilling to follow the protocol; 19. Patients who participated in other clinical trials in the past 3 months.