The purpose of this study is to evaluate the effectiveness and safety of abciximab (an anti-platelet therapy) versus placebo in patients undergoing high risk coronary angioplasty.

This is a randomized, double-blind, placebo-controlled, multicenter study evaluating the efficacy and safety of abciximab, an anti-platelet therapy, in patients undergoing high risk coronary angioplasty. The primary outcomes of the study include any of the following: the number of deaths from any cause, or myocardial infarctions and recurrent ischemic events requiring urgent intervention (e.g., repeat angioplasty, coronary artery bypass surgery, intracoronary stent placement, or intra-aortic balloon pump).

Patients receive an abciximab bolus, abciximab bolus plus infusion, or placebo.

Inclusion Criteria:

• Patients referred for elective or urgent coronary balloon angioplasty or atherectomy with an FDA-approved device in one of the following settings: unstable angina or non-Q wave myocardial infarction, acute Q-wave myocardial infarction, or high-risk clinical/morphological characteristics

Exclusion Criteria:

• Patients with a history of hemorrhagic diathesis - Having had major surgery or clinically significant gastrointestinal or genitourinary bleeding within 6 weeks of study enrollment
• Having had a stroke within 2 years prior to enrollment or any stroke with significant residual neurological deficit
• Having occlusion of the left main coronary artery greater than 50% or a history of vasculitis
• Treated with oral anticoagulants within 7 days (unless prothrombin time is =< 1.2 times control) or intravenous dextran (before or planned for during the treatment angioplasty)