The disorder is characterized by a buildup of fatty deposits, called plaques , on the inner walls of arteries. These yellowish plaques consist of materials such as cholesterol, lipids, and cellular debris. They lead to a loss of elasticity in the artery and to ischemia, or a narrowing of the blood's passageway. The resulting decrease in smooth blood flow may ultimately deprive a vital organ, such as the heart or brain, of its blood supply. Loss of circulation to a limb may also occur.
Atherosclerosis is the most common cause of coronary heart disease, including heart attacks.
It is also a major cause of stroke. Half the mortality in Western societies results from heart and blood-vessel diseases, of which atherosclerosis, the most common lethal disease, is the major cause. The causes of atherosclerosis are not yet fully understood, but certain characteristics called risk factors tend occur in persons prone to atherosclerosis. These include high blood pressure, or hypertension, and high blood-cholesterol levels. Resistance to these factors appears to diminish with age, especially when accompanied by obesity and cigarette smoking.