This is a randomized, open label, cohort study, in which a total of 100 patients will be enrolled and randomly assigned to receive bivalirudin or heparin in a 1:1 ratio during short-term intervention of non-infarction related artery for acute ST-segment elevation myocardial infarction after emergency percutaneous coronary intervention.

NACE, MACE, any type of BARC bleeding, stent thrombosis will be evaluated in 30 days and 6 months after recruitment.

The 2017 guideline gives a class IIA recommendation ('should be considered') for complete revascularisation in patients presenting with STEMI and multivessel disease, which is approximately 50% of the STEMI population. Staged multivessel PCI during hospitalization (3-5 days after PPCI) is common in contemporary practice.

Patients undergoing primary PCI should receive enhanced antithrombotic therapy, includes DAPT and and parenteral anticoagulant, which caused an increased bleeding risk. In addition, repeated use of heparin in a short time may increase the incidence of HIT. Direct thrombin inhibitor bivalirudin, demonstrated a reduced risk of bleeding and an overall favorable profile including reduced NACE.

This is a randomized, open label, cohort study, which is aimed to investigate the safety and efficacy of bivalirudin during short-term intervention of non-infarction related artery for acute ST-segment elevation myocardial infarction after emergency percutaneous coronary intervention.

Inclusion Criteria:

• Age ≥ 18 years.
• Acute STEMI (including patients within 12 h of symptom onset, or 24-48 h with recurrent or ongoing chest pain chest pain, persistent ST-segment elevation or new left bundle branch block.
• Staged intervention of non-infarction related artery within 5 days after PPCI during Hospitalization.
• Signed informed consent.

Exclusion Criteria:

• Cardiogenic shock.
• Received thrombolytic therapy or used any anticoagulant drugs within 48 hours before randomized.
• Active bleeding, recent bleeding events or bleeding tendency.
• History of surgery in the last 1 month.
• Suspicious symptoms of aortic dissection, pericarditis and endocarditis.
• Blood pressure > 180/110 mmHg.
• Hemoglobin < 100 g/L, Platelet count <100×10(9)/L, Transaminase 3 times upper limit of normality or Creatinine clearance <30ml/min.
• History of Heparin-Induced Thrombocytopenia.
• Allergic to any research drug or device.
• Pregnancy or lactation.
• Any condition that makes the patient unsuitable for PCI or may interfere with the study.
• Patient disagrees or fails to sign the written informed consent.