The OCT examination will be analyzed according to OCT consensus standard definitions. Intima can be recognized as a uniform signal-rich bright layer and media as a signal-poor darker layer due to low backscatter. The lumen, intima, and media layers will be traced automatically with manual correction to obtain average thickness and areas for every frames. The only segment without any signs of coronary atherosclerosis on coronary angiography will be used for OCT examination. Following indices will be analyzed: