<unk>  refers to the narrowing of the ostium part of the coronary arteries.  An<unk>  lesion is defined as a lesion which begins within 3-5 mm of the origin of a major epicardial artery.<unk>  lesions represent a challenge to the interventional cardiologist because they often involve the wall of the aorta, they are often calcified, they may not fully dilate and they are prone to restenosis. A key issue in the treatment of an<unk>  lesion is to assure that the stent is inserted proximal enough to fully cover the aorto-ostial junction (particularly in the right coronary artery). Essentially the operator must realize that the aortic wall is being stented as well.
Coronary ostial stenosis
Coronary artery tortuosity
Multivessel coronary artery disease
Coronary artery irregularity
Coronary artery ulceration
Coronary artery dual ostia
Coronary artery thrombus
Penetrating atherosclerotic aortic ulcer