ABSTRACT
Atherosclerosis is a degenerative process of the major human elastic and muscular arteries. It is characterized by the formation of intimal plaques consisting of lipid accumulations, smooth-muscle and inflammatory cells, connective tissue fibers, and calcium deposits. Morbidity associated with atherosclerosis arises from plaque enlargement or degeneration. Plaque enlargement may obstruct the lumen, resulting in stenosis and impairment of blood flow. Sudden obstruction of the lumen may result from the dissection of blood from the lumen into or under the plaque or hemorrhage within the plaque from vasa vasorum. Plaque ulceration may result in embolization of plaque elements or thrombus formation on the disrupted intima. Thrombosis may also occlude atherosclerotic vessels without obvious plaque disruption due to local modifications of flow. Finally, atrophy of the media, often associated with atherosclerotic disease, may result in weakening of the artery wall with aneurysmal dilatation, mural thrombosis, and rupture.
