The purpose of this study is to compare coronary endothelium function in patients with a zotarolimus-eluting versus a sirolimus-eluting or a everolimus-eluting stents with optical coherence tomography, vasoconstriction in response to acetylcholine, and coronary biomarker level.

Inclusion Criteria:

• Significant coronary de novo lesion (> 70% by quantitative angiographic analysis)
• Patients with stable or acute coronary syndrome considered for coronary revascularization
• Reference vessel diameter of 2.5 to 3.5 mm by operator assessment

Exclusion Criteria:

• Contraindication to anti-platelet agents
• Ostial lesion within 5 mm from ostium
• Different DES in other vessel simultaneously
• Creatinine level 2.5 mg/dL
• Left main stenosis more than 50%.
• vein graft lesion
• Triple vessel disease with stenosis more than 50% in 3 epicardial coronary arteries
• Life expectancy 1 year
• Reference vessel < 2.5 mm or > 4.0 mm diameter by visual
• Long lesion that require more than three stents