Drug-eluting Stents to Treat Unprotected Coronary Left Main Disease

Inclusion Criteria: * Patients older than age 18 with ischemic symptoms or evidence of myocardial ischemia in the presence of ≥ 50 % stenosis located in unprotected LMCA who are unable to undergo CABG because of cardiac surgeons' refusal (poor surgical candidates) or their own unwillingness. * Pretreatment with a loading dose of 600 mg clopidogrel. * Informed, written consent by the patients or her/his legally-authorized representative for participation in the study. Exclusion Criteria: * Cardiogenic shock. * ST-segment elevation acute myocardial infarction (ST-segment ≥ 0.1 mV elevation in ≥ 2 contiguous ECG leads persisting for at least 20 minutes) within 48 hours from symptom onset. * In-stent restenosis. * Malignancies or other comorbid conditions with life expectancy less than one year or that may result in protocol non-compliance. * Prior coronary artery bypass surgery with revascularization of LAD and/or LCx. * Planned staged PCI procedure within 30 days from index procedure or prior PCI within the last 30 days. * An elective surgical procedure is planned that would necessitate interruption of clopidogrel during the first six months post enrollment. * Known allergy to the study medications: aspirin, clopidogrel, UHF; sirolimus, paclitaxel; true anaphylaxis after prior exposure to contrast media. * Pregnancy (present, suspected or planned). * Patient's inability to fully cooperate with the study protocol.