Impact of IntraVascular UltraSound Guidance on Outcomes of Xience Prime Stents in Long Lesions (IVUS-XPL Study)

Inclusion Criteria: * Age 20 years old or older * Patients with typical chest pain or evidences of myocardial ischemia (e.g., stable, unstable angina, silent ischemia and positive functional study or reversible changes in the electrocardiogram (ECG) consistent with ischemia * Non-emergent conditions * Patients with signed informed consent * Stent length ≥28 mm by angiography estimation * Significant coronary artery stenosis (\> 50% by visual estimate) considered for coronary revascularization with stent implantation * Reference vessel diameter of 2.5 to 4.0 mm by operator assessment Exclusion Criteria: * Acute ST elevation myocardial infarction within 48 hours * Contraindication to anti-platelet agents \& bleeding history within prior 3 months * Known hypersensitivity or contraindication to any of the following medications: Heparin, Aspirin, Clopidogrel, Zotarolimus or other -limus group * Prior history of the following presentations * Cerebral vascular accident (not including transient ischemic attack) * Peripheral artery occlusive diseases * Thromboembolic disease * Stent thrombosis * Age \> 80 years old * Severe hepatic dysfunction (3 times normal reference values) * Significant renal dysfunction (Serum creatinine \> 2.0 mg/dl) * Significant leucopenia, neutropenia, thrombocytopenia, anemia, or known bleeding diathesis * Cardiogenic shock * LVEF \< 40% * Pregnant women or women with potential childbearing * Life expectancy \< 1 year * Left main disease requiring PCI * Bifurcation lesion with 2-stent technique * Chronic total occlusion * Presence of previously implanted DES within 6-month * In-stent restenosis lesion