Atherosclerosis, sometimes called "hardening of the arteries," occurs when cholesterol, calcium, and other substances build up in the inner lining of the arteries, forming a material called plaque. Over time, plaque may narrow the artery and reduce blood flow through it.

Coronary artery disease is atherosclerosis in the heart (coronary) arteries. Peripheral arterial disease of the legs is atherosclerosis in the leg arteries. If atherosclerosis affects the brain arteries (carotid or cerebral arteries), a stroke can occur.