Hypercholesterolemia is one of the major risk factors for cardiovascular disease. Treatment with statins to lower cholesterol is important for the secondary prevention of cardiovascular disease. In addition to the effect of reducing cholesterol synthesis and decreasing low-density lipoprotein-cholesterol (LDL-C), It has been known that statins has several pleotropic effects including anti-inflammatory effect, antithrombotic effect, and improvement of endothelial function. It has been proven to reduce the atherosclerotic lesion and inhibit the progression. Therefore, the ACC/AHA guidelines recommend high-intensity statins for coronary artery disease and the ESC recommends a reduction of LDL-C of less than 70 mg / dL or more than 50% of baseline. However, long-term use of high-intensity statins increases the incidence of diabetes mellitus, liver damage, and musculoskeletal injuries. Therefore, there are many concerns about the use of high-intensity statins, especially in elderly patients. There is a lack of information about side effects.
Ezetimibe reduces serum cholesterol level by inhibiting its absorption in the small intestine. It reduces LDL-C by 15-25% when used in combination with statins. In a recently published study of patients with acute coronary syndrome (IMPROVE-IT), the combination of simvastatin and ezetimibe significantly reduced LDL-C levels compared to simvastatin alone. In addition, the combination of atorvastatin and ezetimibe showed a significant reduction of LDL-C and coronary atherosclerosis compared to statin alone in the study of coronary intravascular ultrasonography.
To date, studies have shown that LDL-C is additionally reduced when ezetimibe is combined with statin, which has beneficial effects such as prevention of cardiovascular events and reduction of atherosclerotic plaques. However, when LDL-C is reduced to similar levels using high-intensity statins, it is unclear whether statin and ezetimibe combination treatments will have similar effects to high-intensity statins. 
This study investigates whether the combination of statin and ezetimibe shows similar results compared with high-intensity statins, indicating that this combination therapy may be an effective alternative in patients with high-intensity statins.

Treatment

This clinical trial was designed with a single organ, random assignment, comparator comparison, parallel design, and open study. For patients who have performed coronary artery interventions, patients who meet the selection and exclusion criteria for clinical trials with minor and secondary stenosis diseases that do not require intervention are evaluated as ultrasound in the vessel, and a random assignment (Table 1) is used for 1:1 random assignment in two groups:
Group I: atorvastatin 10 mg + ezetimibe 10 mg once daily
Group II: atorvastatin 40 mg once daily
The institution intends to assess the quantitative and qualitative changes of the lithospheric plates by conducting a follow-up examination on the 3M,6M,9M after registration and on the 12M, ± 8weeks of coronary artery contrasting.

Arm Label

Target Number of Participant

Arm Type

Arm Description

Atozet tab (atorvastatin 10 mg + ezetimibe 10 mg) once a day for 1year

Arm Label

Target Number of Participant

Arm Type

Arm Description

atorvastatin 40 mg  once a day for 1year

Gender

Age

Description

Inclusion criteria

1) Patients with coronary artery disease who were 19 years of age or older and needed coronary angiography
2) Patients who needed percutaneous coronary intervention for coronary artery disease
3) Intermediate coronary artery stenosis (diameter stenosis ≥30% to ≤60% by visual estimation, diameter ≥2.0 mm to ≤4.0 mm, de novo lesion in native coronary artery) in which intravascular ultrasound could be feasible
4) Baseline serum LDL-C ≥ 70mg/dL
5) Patients who gave written informed consent

Exclusion criteria

1) Cardiogenic shock
2) Heart failure with symptoms of New York Heart Association class III/IV or left ventricular ejection fraction <35%
3) Renal dysfunction (creatinine level ≥1.7 mg/dL or dependence of dialysis
4) Pregnancy or breast-feeding women
5) Psychotic patient
6) Hepatic dysfunction (transaminase level > 3 times of normal within limit)
7) Patients with difficulty in assessing intravascular ultrasonography for the following reasons: severe calcification, severe tortuous vessels, total occlusion
8) Patients who can not receive adequate antiplatelet therapy
9) Thrombocytopenia (platelet count < 70x109/L)

Percent atheroma volume of intermediate in the vascular wall of the mild and intermediate  stenosis lesion after 12months Lipid-lowering Drug

for 12 months

Percent atheroma volume in the vascular wall

for 12 months

Lipid core burden index

for 12 months

Absolute and percent changes in the lipid, glycemic and inflammatory profiles

for 12 months

Not applicable