The study would enrolled a total of 2100 AMI patients undergoing PCI to one of three antithrombotic regimens: bivalirudin alone, or unfractionated heparin alone, or unfractionated heparin plus a glycoprotein IIb/IIIa inhibitor.

All enrolled patients would be followed-up to 30 days, 6 months, and 1 year. The purpose of the study is to evaluate the efficacy and safety of bivalirudin in AMI patients with DES.

This is a prospective, randomized, single-blind, active drug controlled multicenter clinical research and the study would enrolled a total of 2100 AMI patients undergoing percutaneous coronary intervention (PCI) to one of three antithrombotic regimens: bivalirudin alone, or unfractionated heparin alone, or unfractionated heparin plus a glycoprotein IIb/IIIa inhibitor. All enrolled patients would be followed-up to 30 days, 6 months, and 1 year. The purpose of the study is to evaluate the efficacy and safety of bivalirudin in AMI patients with DES.

Inclusion Criteria:

1. Age 18 to 80 years old
2. Planned emergency PCI for acute myocardial infarction (STEMI or NSTEMI) Symptom onset within 12h for STEMI (or within 24 h for patients have unrelieved chest pain, continuous ST elevation or new developed LBBB) Symptom onset within 72h for NSTEMI
3. Avoid to undergoing revascularization for non-culprit vessels within 30 days after index procedure.
4. Provide written informed consent.

Exclusion Criteria:

1. Unsuitable for PCI; treatment by thrombolysis within 72 hours of acute ST-elevation myocardial infarction; left main coronary artery disease; cardiogenic shock.
2. Any anticoagulant agents were used 48 h before randomization.
3. Active bleeding or bleeding constitution, bleeding tendency, including the recent retina or vitreous hemorrhage (1 months), GI or urinary tract hemorrhage (3 months), cerebral hemorrhage (6 months) or cerebral infarction history (3 months), etc.;
4. Other disease may lead to vascular lesions and secondary bleeding factors (such as active gastric ulcer, active ulcerative colitis, intracranial aneurysm, etc.),
5. Deep puncture or major surgery (including eye or brain surgery) within 1 month.
6. Suspicious aortic dissection, pericarditis and subacute bacterial endocarditis.
7. Untreated or uncontrolled hypertension > 180/110 mmHg.
8. Hemoglobin < 100 g/L or platelet count < 100 * 109 / L.
9. Elevated AST, ALT level higher than three times of the normal upper limit.
10. severe renal insufficiency (eGFR < 30 mL/min / 1.73 m2).
11. Heparin induced thrombocytopenia.
12. Known allergy to the study drugs and instruments (UFH, bivalirudin, aspirin and clopidogrel, stainless steel, contrast agents, etc.), or those allergic constitution.
13. Pregnancy or lactation.
14. Researchers think that doesn't fit to participate in this study.