Endeavor Zotarolimus - Eluting Stent in the Treatment Lesions in Small Native Coronary Arteries.

GENERAL INCLUSION CRITERIA: * The patient is ≥18 years of age. * The patient has clinical evidence of ischemic heart disease, stable or unstable angina, silent ischemia, or positive functional study. * The patient is an acceptable candidate for Percutaneous Transluminal Coronary Angiography (PTCA), stenting, and emergent Coronary Artery Bypass Grafting (CABG) surgery. * Female patients of childbearing potential must have a negative pregnancy test within 7 days before the procedure. * The patient or patient's legal representative has been informed of the nature of the study and agrees to its provisions and has provided written informed consent as approved by the Institutional Review Board of the respective clinical site. * The patient agrees to return to same research facility for all required post-procedure follow-up visits. ANGIOGRAPHIC INCLUSION CRITERIA 1\. The target lesion/vessel must meet the following criteria: 1. The patient requires treatment of either: * A single de novo lesion located in a native coronary artery amenable to treatment with a 2.25mm, 2.5mm or 2.75mm stent, or * Two de novo lesions located in separate target vessels, with at least one of the target lesions amenable to treatment with a 2.25mm, 2.5mm, or 2.75mm stent and the second lesion amenable to treatment with a 2.25mm, 2.5mm, or 2.75mm stent or a 3.0mm or 3.5mm approved Endeavor stent. 2. The lesion(s) must be ≤ 27mm in length. 3. The lesion(s) must have a stenosis of ≥ 50% and \< 100%. 4. The vessel(s) has (have) a thrombolysis in myocardial infarction (TIMI) flow 2 or greater. 5. The target vessel reference diameter must be ≥ 2.25mm and ≤ 2.75mm and the second target vessel reference diameter, if present, must be ≥ 2.25mm and ≤ 3.5mm. 6. All target lesions can be treated with a Medtronic Endeavor stent. GENERAL EXCLUSION CRITERIA: 1. Known hypersensitivity or contraindication to aspirin, heparin, bivalirudin, ticlopidine, clopidogrel, cobalt, nickel, chromium, molybdenum, polymer coatings, or sensitivity to contrast media, which cannot be adequately pre-medicated 2. History of allergic reaction or significant sensitivity to drugs such as zotarolimus, rapamycin, tacrolimus, everolimus, or any other analogue or derivative 3. Platelet count \<100,000 cells/mm³ or \>700,000 cells/mm³, or white blood cell count \<3,000 cells/mm³ 4. Serum creatinine level \>2.0 mg/dl within 7 days prior to index procedure 5. Evidence of acute MI within 72 hours of intended index procedure 6. Planned PCI of any vessel within 30 days pre or post-index procedure and/or planned PCI of the target vessel(s) within 12 months post-procedure. 7. During the index procedure, the target lesion(s) requires treatment with a device other than PTCA prior to stent placement 8. History of stroke or transient ischemic attack (TIA) within prior 6 months 9. Active peptic ulcer or upper gastrointestinal (GI) bleeding within prior 6 months. 10. History of bleeding diathesis or coagulopathy or patient will refuse blood transfusions. 11. Concurrent medical condition with life expectancy of less than 12 months. 12. Any previous or planned treatment of target vessel with anti-restenotic therapies including but not limited to brachytherapy. 13. Currently participating in an investigational drug or another device study that has not completed primary endpoint or that clinically interferes with current study endpoints; or requires coronary angiography, IVUS or other coronary artery imaging procedures. 14. Documented left ventricular ejection fraction (LVEF) \<30% at most recent evaluation. 15. Inability to comply with protocol required medication regimen ANGIOGRAPHIC EXCLUSION CRITERIA 1\. Target lesion(s) located in native vessel distal to anastomosis with saphenous vein graft or a left/right internal mammary artery bypass with \>40% diameter stenosis anywhere within graft. 2\. Previous stenting in the target vessel(s) unless the following conditions are met: a. It has been at least 9 months since the previous stenting, and b. The target lesion(s) is/are at least 15mm away from the previously placed stent. 3\. Target vessel has other lesions with \>40% diameter stenosis based on visual estimate or on-line QCA 4. Target vessel(s) has/have evidence of thrombus 5. Target vessel(s) is excessively tortuous (two bends ≥90º to reach target lesion) 6. Target lesion has any of the following characteristics: 1. Location is aorto-ostial, an unprotected left main lesion, or within 5 mm of the origin of the left anterior descending (LAD), left circumflex (LCX), or right coronary artery (RCA) 2. Involves a side branch \>2.0 mm in diameter 3. Is at or distal to a \>45º bend in the vessel 4. Is severely calcified 5. Involves a bifurcation 7. Unprotected left main coronary artery disease