Bivalirudin vs Heparin in NSTEMI and STEMI in Patients on Modern Antiplatelet Therapy in SWEDEHEART

Inclusion Criteria: * Patients with a diagnosis of NSTEMI as judged by the physician in accordance with current guideline definitions (positive troponin) or, patients with a diagnosis of STEMI as defined by chest pain suggestive for myocardial ischemia for at least 30 minutes before hospital admission, time from onset of symptoms of less than 24 hours, and an ECG with new ST-segment elevation in two or more contiguous leads of ≥0.2 mV in leads V2-V3 and/or ≥0.1 mV in other leads or a probable new-onset left bundle branch block. * PCI of culprit lesion is intended (therapeutic PCI, not primarily diagnostic PCI). * Treated with bolus dose of ticagrelor or prasugrel before start of PCI. See 2.6 * Ability to provide informed consent * Age 18 years or older Exclusion Criteria: * Previous randomization in the VALIDATE-SWEDEHEART trial. * Known terminal disease with life expectancy less than one year. * Patients with known ongoing bleeding * Patients with uncontrolled hypertension in the opinion of the investigator * Patients with known subacute bacterial endocarditis * Patients with known severe renal (GFR \< 30 ml/min) and/or liver dysfunction * Patients with known thrombocytopenia or thrombocyte function defects * Any other contraindication for the study medications. * Heparin \> 5000U Before arriving to PCI lab or \> 3000 U given during angiography before randomization. * GpIIb/IIIa inhibitors have been given or are pre-planned to be given during the procedure.