Peripheral artery disease (PAD), known in the past as peripheral vascular disease, is a disorder that affects the arteries of the circulatory system. The arteries are the blood vessels that carry oxygen-rich blood away from the heart to the body. With PAD, the arteries become narrowed, which is usually caused by atherosclerotic plaque.
Healthy arteries have a smooth lining that prevents blood from clotting and promotes steady blood flow. In PAD, the arteries become slowly narrowed or blocked, as plaque forms inside the artery walls (shown in Figure). This blockage is from “atherosclerosis”, also known as hardening of the arteries; it can affect arteries throughout the entire body. The symptoms depend on which part of the body is involved. When the leg arteries are blocked, the condition is called PAD.