This multicenter, randomized controlled trial in China aims to enroll 2,400 patients with ST-segment elevation myocardial infarction undergoing percutaneous coronary intervention (PCI) within 24 hours post-fibrinolysis. Participants will be randomly assigned in a 1:1 ratio to receive either bivalirudin or heparin, with follow-up at 30 days and 1 year. The primary endpoint is a composite of all-cause mortality and Bleeding Academic Research Consortium (BARC) type 3 or 5 bleeding at 30 days.

Bivalirudin is a direct thrombin inhibitor that exhibits a reversible and transient anticoagulant effect. Randomized trials have shown conflicting results for bivalirudin in reducing the risk of bleeding for ST-segment elevation myocardial infarction (STEMI) patients undergoing primary PCI (PPCI) compared to heparin. Recently, the BRIGHT-4 study, which assigned 6016 STEMI patients to bivalirudin with a prolonged high dose infusion or heparin during PPCI, showed bivalirudin decreased the risk of a composite endpoint of all-cause mortality and bleeding. However, few studies have focused on the safety and efficacy of bivalirudin in PCI post-fibrinolysis. We therefore aim to conduct the Bivalirudin With Prolonged Infusion During PCI Versus Heparin Following Fibrinolytic Therapy (BRIGHT-FIT) trial to examine whether bivalirudin with a high-dose infusion in PCI after fibrinolysis in superior to heparin in reducing mortality and major bleeding.

Inclusion Criteria:

• Any age
• STEMI patients received fibrinolysis therapy within 12h of symptom onset and are planned to undergo PCI within 24h of symptom onset.
• Dual antiplatelet drugs must be administrated according to guidelines before PCI (loading doses and maintenance doses of aspirin and clopidogrel or ticagrelor)
• Patients requiring staged revascularization of non-culprit vessels within 30 days may be enrolled. In such cases the same antithrombotic agents and PCI procedures must be used in the staged procedure consistent with the index procedure PCI, in particular the assigned antithrombin agent heparin vs. bivalirudin);
• The subject or legal representative has been informed of the nature of the study, understood the provisions of the protocol, was able to ensure adherence, and signed informed consent.

Exclusion Criteria:

• Not suitable for PCI;
• Mechanical complications (such as ventricular septal rupture, papillary muscle rupture with acute mitral regurgitation, etc.);
• Cardiogenic shock(Killip IV)
• Known allergy or contraindications to heparin, bivalirudin, aspirin, or both clopidogrel and ticagrelor
• Patients who underwent PCI in past 30 days
• Patients in whom the investigators consider inappropriate to participate in this study (eg, have participated in another drug/instrument study or undergoing another drug/instrument study, pregnancy).