Synergistic Effect of Combination Therapy With Cilostazol and Probucol on Plaque Stabilization and Lesion Regression: Serial Intravascular Ultrasound and Virtual Histology Study(SECURE Study)

Inclusion Criteria: 1. Patients treated with PCI with stent 2. Male or female over 20 years of age 3. Presence of at least one PCI target lesion(lesion length ≤26mm) with ≥50% diameter stenosis that can be covered with a single Endeavor Sprint stent(Medtronic) 4. Other PCI target lesions also should be treated with Endeavor Sprint stents 5. Presence of an intermediate non-PCI target lesion with luminal narrowing of ≥30% and ≤70% by visual estimation 6. Signed written informed consent to participate in the study Exclusion Criteria: 1. Intermediate (non-PCI target) lesions that might provide difficulty for IVUS evaluation because of following reasons: heavy calcification (\>90° Arc), tortuous vessel with sever angulation, total occlusion, or bifurcation lesions 2. Previous PCI in the last 6 months 3. Previous CABG 4. Patients with AMI undergoing primary PCI or rescue PCI after thrombolysis 5. Cardiogenic shock 6. Inability to take adequate anti-platelet therapy 7. Thrombocytopenia (platelet count \<70 x 109/l) 8. Known hypersensitivity or contraindication to any of the following medications: Heparin, aspirin, clopidogrel, cilostazol, probucol, statin, contrast media\* \*Patients with documented sensitivity to contrast media which can be effectively pre-medicated with steroids and diphenhydramine \[e.g. rash\] may be enrolled. Those with true anaphylaxis to prior contrast media, however, should not be enrolled. 9. History of severe ventricular arrhythmia 10. Significant QTc prolongation (≥470 ms) on ECG 11. NYHA class III/IV heart failure or LV ejection fraction ≤35% 12. Familial hypercholesterolemia 13. Uncontrolled hypertriglyceridemia (\>400 mg/dL) 14. Chronic renal failure with serum creatinine level ≥2mg/dL 15. Severe liver disease or transaminase level ≥3 times the upper limit of normal. 16. Pregnant or breastfeeding