Patients will receive either bivalirudin given as a 0.75 mg/kg bolus followed immediately by a 1.75-mg / kg per hour infusion for 30 minutes prior to primary PCI and continued for 4 hours after the end of the procedure at the reduced dose of 0.25 mg/kg per hour , or heparins at guideline-recommended doses , with or without routine or bailout glycoprotein IIb/IIIa inhibitor treatment according to local practice .