Difficulty in enrolling the required number of participants has made it impractical to proceed with the trial.

Vulnerable plaque characterized by thin fibrous cap and large lipid core is an independent risk factor for most of acute cardiac event. Current clinical data showed that thin-cap fibroatheroma was more frequently observed in patients with ACS than SAP. Further OCT study indicated that patients with ACS had significantly higher incidence of incomplete neointimal coverage and malapposition after DES implantation than those with SAP. These findings imply that initial native lesion characteristics may be related to different vessel response (neointimal coverage and malapposition) after stenting. However, there is little data on the relationship between plaque characteristics and vascular response to DES after stent implantation evaluated by OCT.

Therefore, this study was designed to investigate the relationship between initial plaque characteristics and stent surface coverage or late malapposition after SES implantation. The investigators will use high resolution OCT to assess the initial culprit plaque morphology and subsequent vascular response after SES stenting at the time points of post-stenting, 6 months and 12 months. IVUS will also be performed to evaluate the tissue protrusion, malapposition, vessel remodeling at the same time points.

Vulnerable plaque characterized by thin fibrous cap and large lipid core is an independent risk factor for most of acute cardiac event. Current clinical data showed that thin-cap fibroatheroma was more frequently observed in patients with ACS than SAP. Further OCT study indicated that patients with ACS had significantly higher incidence of incomplete neointimal coverage and malapposition after DES implantation than those with SAP. These findings imply that initial native lesion characteristics may be related to different vessel response (neointimal coverage and malapposition) after stenting. However, there is little data on the relationship between plaque characteristics and vascular response to DES after stent implantation evaluated by OCT.

Therefore, this study was designed to investigate the relationship between initial plaque characteristics and stent surface coverage or late malapposition after SES implantation. The investigators will use high resolution OCT to assess the initial culprit plaque morphology and subsequent vascular response after SES stenting at the time points of post-stenting, 6 months and 12 months.

Inclusion Criteria

General Inclusion Criteria：

1. Age:18-75Y
2. Patients with stable angina or acute coronary syndrome considered suitable for coronary revascularization.
3. Patient or legal guardian understands and agrees to comply with all specified study requirements and provides written informed consent.

Angiographic Inclusion Criteria：

1. Significant coronary de novo lesion (> 70% by visual estimation).
2. Target lesion is de novo native coronary artery lesion that can be treated with 1-2 stents.
3. Reference vessel diameter of 2.5 to 4.0 mm.

Exclusion Criteria：

General Exclusion Criteria：

1. ST-segment elevation myocardial infarction within 7 days prior to the index procedure.
2. Previous CABG.
3. Life expectancy <12 months due to another medical condition.
4. Contraindication to antiplatelet therapy
5. Creatinine level more than 2.0mg/dL or ESRD.
6. Severe hepatic dysfunction (more than 3 times normal reference values).
7. Planned surgery procedure ≤ 6 months post-index procedure.
8. Known allergy to stainless steel or a history of hypersensitivity to sirolimus or structurally related compounds.
9. Female of childbearing potential with a positive pregnancy test within 7 days before the index procedure, or lactating, or intends to become pregnant during the 12 months post index procedure.
10. Patient is not clinically appropriate for OCT evaluation in the opinion of the investigator.

Angiographic Exclusion Criteria：

1. Study lesion is ostial in location (within 3.0 mm of vessel origin).
2. Study lesion involving arterial segments with highly tortuous anatomy.
3. Complex lesion morphologies (aorto-ostial, bifurcation needs two stents technique, left main, severe thrombi, heavy calcification).