Bivalirudin is widely used as an anticoagulant during percutaneous coronary intervention (PCI) for coronary heart disease. Prolonging infusions may decrease myocardial damage associated with bivalirudin use during primary PCI . However, whether prolonging infusions of bivalirudin could prevent ischemic complications is unknown. The investigators examined the effects of prolonged drug infusion after elective PCI. The investigators hypothesized that continuing the bivalirudin infusion commenced during the procedure at the PCI recommended dose for 4 hours would prevent myocardial damage.