Like coronary artery disease (CAD), peripheral arterial disease (PAD) is a form of atherosclerosis, a progressive disease that involves the hardening and narrowing of the arteries due to a gradual buildup of plaque. Whereas CAD involves the coronary arteries, PAD occurs in arteries outside the heart (e.g., in the kidneys, legs and/or feet). It can also affect the carotid arteries (which supply blood to the brain), increasing the risk of stroke.

There are four major areas where peripheral arterial disease (PAD) produces symptoms:

• In the arteries supplying blood to the brain. Cerebrovascular disease (including carotid artery disease) is the number one cause of stroke and disability in the United States.
  
  
• In the arteries supplying blood to the arteries of the kidneys. PAD of the renal arteries (renal artery stenosis) is one of the causes of high blood pressure and renal failure.
  
  
• In the arteries supplying blood to the legs. PAD of the lower extremities is a major cause of diminished ability to walk and advanced cases can lead to leg amputation.
  
• In the arteries supplying blood to the intestines. PAD of the mesenteric arteries (mesenteric arterial disease) is less frequent but can cause severe pain, weight loss and death from intestinal gangrene.

A separate condition, abdominal aortic aneurysm (AAA) is also associated with PAD. AAA is the bulging or ballooning out of part of the wall of the abdominal aorta, a section of the blood vessel that carries oxygen-rich blood from the heart to the body.

The diagnosis and treatment of PAD depends on where it occurs and the complications associated with that form of the disease. In the lower extremities, for example, diagnosis of PAD typically involves a painless measurement called an ankle-brachial index (ABI). Elsewhere, the diagnosis may involve the use of more complex testing such as duplex imaging, magnetic resonance angiogram (MRA) and/or an angiogram. If PAD is diagnosed in one part of the body, it's highly likely that other arteries will be affected because atherosclerosis tends to be a systemic disease, or one that affects multiple areas of the body.

Treatment for PAD depends on the symptoms and possible complications. In the legs, where PAD may cause pain and impair the ability to walk, the goal is to restore blood flow to the tissues beyond the blockage. In the neck and head, the goal is to prevent stroke. In general, treatment for PAD often involves new and improved medications (e.g., antiplatelets), risk factor modification and other more specialized measures. More invasive treatments, such as catheter-based procedures and bypass surgery, are also available, depending on where the disease is located.

Like coronary disease, there are both controllable and uncontrollable risk factors for PAD. Risk factors for this condition that are not controllable include gender, age, ethnicity and family history. Risk factors that can be modified include smoking, lack of regular exercise, eating a high fat diet, obesity, uncontrolled diabetes or hypertension, stress or anger, and high LDL cholesterol and low HDL cholesterol.