<qa>  What is the calcurated by coronary pressure and flow velocity?Subjects are patients who are planned to do percutaneous coronary intervention for coronary stenosis in the left circumflex artery without other stenosis in the left ascending artery and the right coronary artery, or a patient with normal coronary artery. Immediately after coronary angiography or percutaneous coronary intervention, the investigators will evaluate for coronary hemodynamics by distribution of wave intensity which is calcurated by coronary pressure and flow velocity with Combowire in each coronary segment. Also, they will assess coronary morphology by View It in each coronary segment. 