Angiomax® or Unfractionated Heparin for Patients Undergoing Percutaneous Coronary Intervention

Inclusion Criteria: 1. The patient is male or female ≥ 18 years of age. 2. The patient presents with stable angina pectoris, or silent ischemia (positive stress test without chest pain). 3. The patient is scheduled for coronary angiography, with possible angioplasty. 4. The patient is able to tolerate dual anti-platelet therapy with aspirin and clopidogrel for a minimum of 30 days and is on those medications at the time of the PCI (clopidogrel may be administered during PCI or within 30 minutes post PCI). 5. The patient is able and willing to conform to the requirements of the study and voluntarily signs an Informed Consent. 6. The patient does not present with any form of illness or condition that in the investigator's opinion would impair the results of the study. 7. Women of child bearing potential must have a negative urine or serum pregnancy test prior to enrollment. Exclusion Criteria: 1. Patients in cardiogenic shock. 2. Patients with acute coronary syndrome, which includes unstable angina, non-ST-elevation MI or STEMI. 3. Known history of heparin-induced thrombocytopenia. 4. Contraindication to unfractionated heparin, bivalirudin, or any anticoagulant or antithrombotic pharmacological agent. 5. Any significant medical condition, which in the investigator's opinion, may interfere with the patient's optimal participation in the study. 6. Pregnant women or nursing mothers.