The Study to Evaluate Patient Outcome Using Distal Protection Combined With the BX Velocity. (DISCOVER)

Inclusion Criteria: Unstable angina pectoris (Braunwald classification B & C, I-II-III, native vessels) or lesion located in the SVG; Single de novo or restenotic lesion requiring treatment in a major native coronary artery or saphenous vein graft; The vessel diameter to place the AngioGuard™ device in must be > 3 and < 5.5 mm (6.5 when the 7mm AngioGuard™ is available); Target lesion stenosis is >50% and <100% (TIMI 1). Exclusion Criteria: A Q-wave or non-Q-wave myocardial infarction within the preceding 72 hours unless the CK and CK-MB enzymes are back to normal; More than one coronary artery is 100% occluded; Patient has unprotected left main coronary disease with > 50% stenosis; Patient has an ostial target lesion; Significant (>50%) untreated stenosis proximal or distal to the target lesion that will be treated during the procedure, since this may require revascularization or impede runoff; Ejection fraction <30%; Totally occluded vessel (TIMI 0 Level).