Peripheral Artery Disease is caused by a thickening of the inside walls of the arteries of your legs. This thickening, called atherosclerosis, narrows the space through which blood can flow, decreasing the supply of oxygen and nutrients to the legs and feet. It can affect both legs, but most often symptoms begin in one leg.
Atherosclerosis usually occurs when a person has high levels of cholesterol, a fat-like substance, in the blood. Cholesterol and fat, circulating in the blood, build up on the walls of the arteries. When the level of cholesterol in the blood is high, there is a greater chance that it will be deposited onto the artery walls. Plaque formations can grow large enough to significantly reduce the blood's flow through an artery. When a plaque formation becomes brittle, it may rupture, triggering a blood clot to form. A clot may either further narrow the artery, or completely block it. When that blockage occurs in a coronary artery, it can cause a heart attack. When it occurs in a carotid artery, it can cause a stroke. If the blockage remains in the peripheral arteries, it can cause pain, changes in skin color, sores or ulcers and difficulty walking. Total loss of circulation to the legs and feet can cause gangrene and loss of a limb.
Some patients with peripheral artery disease experience cramping in the arms or legs while moving the extremity. This cramping is called claudication. Claudication comes from the Latin word claudicare meaning to limp. The discomfort usually occurs in large muscles in one or both legs during physical activity, such as walking. Not every person with PAD experiences leg pain. Some people may feel a tightness, heaviness, cramping, or weakness of the leg.