A Study Evaluating the Efficacy and Safety of Abciximab, an Anti-Platelet Therapy, in Patients With Unstable Angina Not Responding to Standard Medical Therapy Who Are Eligible for Coronary Angioplasty

Inclusion Criteria: * Patients with refractory angina as evidenced by at least one episode of ischemia (chest pain and/or ST-T changes) despite bed rest and at least 2 hours of treatment with oral or intravenous nitrates and intravenous heparin, or persistent newly developed negative T-waves occurring or continuing after at least 2 hours of treatment with oral or intravenous nitrates and intravenous heparin * Having clinical signs and symptoms of angina at rest or minimal exertion with dynamic ST-segment and/or T-wave changes * Having an episode of chest pain within 48 hours prior to the start of study agent administration * Having a culprit lesion in a single native coronary vessel suitable for angioplasty on the qualifying angiogram Exclusion Criteria: * Patients who have had a recent myocardial infarction, unless CK has returned to less than twice the upper limit of normal * Having features of ongoing ischemia that would require immediate intervention, or had a percutaneous transluminal coronary angioplasty (PTCA) within the past 24 hours * Having an unprotected occlusion of the main left coronary artery \> 50%, a culprit lesion located in a venous or arterial bypass graft, or recent bleeding or a condition associated with increased bleeding risk * Receiving concurrent administration of oral anticoagulants at the time of study entry, administration of intravenous dextran (prior to or planned for use during angioplasty), or planned administration of thrombolytic agent prior to or during angioplasty * Having persistent hypertension at admission despite treatment, or a platelet count less than 100,000 per millimeter cubed