Effect of Atorvastatin on Fractional Flow Reserve in Coronary Artery Disease

The patients who have intermediate CAD (30-80% diameter stenosis by visual estimation) with FFR≥0.80, or nonculprit coronary artery disease with FFR≥0.8 after culprit coronary artery disease intervention will be enrolled. FFR, IVUS(optional) and index of microcirculatory resistance (IMR) should be performed simultaneously. Atorvastatin 20mg is a starting dose, then up-titration will be done twice within each 4\~6weeks until LDL target goal (① LDL\<70mg/dl, or ② statin naive: \>50% reduction from baseline LDL, current statin user: \>30% reduction from baseline LDL). First titration will be atorvastatin 40mg, second will be atorvastatin 80mg. If patients have any adverse effect on atorvastatin, the dose of atorvastatin can be adjusted by investigator's decision. Official clinical follow-up except visit for statin dose titration will occur at 1, 12 months after index procedure. Follow-up coronary angiography, FFR,IMR,and IVUS(optional) will be performed 12 months after index procedure.