Atherosclerosis is a condition in which an artery wall thickens as the result of a build up of fatty materials such as cholesterol. This build up of plaque can lead to impairment of blood flow resulting in an infarction of the tissue downstream of the diseased artery (examples are coronary or carotid atherosclerosis leading to a heart attack or stroke).

Atherosclerosis http://www.web-books.com/eLibrary/Medicine/Cardiovascular/Atherosclerosis.htm