Peripheral artery disease results in reduced blood flow in the arteries of the trunk, arms, and legs.
Most often, doctors use the term peripheral artery disease to describe poor circulation in the arteries of the legs that results from atherosclerosis. However, peripheral artery disease can affect other arteries, such as those in the arms, and can have other causes. Disorders of arteries that supply the brain with blood are considered separately as cerebrovascular disease. Disorders that reduce blood flow of arteries in the abdomen are considered separately as abdominal aortic branch occlusion.
Causes
Peripheral artery disease may be described as:
Occlusive peripheral artery disease is due to something that physically narrows or blocks arteries. The most common cause is atherosclerosis caused by buildup of plaque in the walls of the arteries. Plaque is made up of cholesterol, fatty material, and fibrin (a clotting protein). Fibromuscular dysplasia is an example of occlusive peripheral artery disease caused by abnormalities in the cells in the vessel wall rather than atherosclerosis.
In functional peripheral artery disease, blood flow is decreased because the arteries do not function properly. Normally, the arteries of the arms and legs widen (dilate) and narrow (constrict) in response to changes in the environment, such as a change in temperature, changes in blood flow, or signals from the brain. Functional peripheral artery disease usually occurs when the normal mechanisms that dilate and constrict these arteries are exaggerated. The affected arteries constrict more tightly and more often. Sometimes, this occurs as a sudden, abnormal contraction of the muscles (spasm) within the walls of the blood vessels. The spasm causes a temporary narrowing that reduces blood flow. More rarely, the condition is due to abnormal relaxation of the muscles within the walls of the blood vessels, leading to a widening (vasodilation) of arteries. These changes in constriction can be caused by:
An inherited defect in the blood vessels
Disturbances of the nerves that control the dilation and constriction of arteries (sympathetic nervous system)
Injuries
Medications
Acrocyanosis, erythromelalgia, and Raynaud syndrome are examples of functional peripheral artery diseases.
