Adult Health Library

Peripheral Arterial Disease

What is peripheral arterial disease (PAD)?

Peripheral arterial disease (PAD) is a slow and progressive circulation disorder. It may involve disease in any of the blood vessels outside of the heart and diseases of the lymph vessels - the arteries, veins, or lymphatic vessels. Organs supplied by these vessels such as the brain, heart, and legs, may not receive adequate blood flow for ordinary function. However, the legs and feet are most commonly affected, thus the name peripheral arterial disease.

Conditions associated with PAD that affect the veins include deep vein thrombosis (DVT), varicose veins, and chronic venous insufficiency. Lymphedema is an example of PAD that affects the lymphatic vessels.

When PAD occurs in the arteries outside the heart, it may be referred to as peripheral vascular disease (PVD). However, the terms "peripheral vascular disease" and "peripheral arterial disease" are often used interchangeably. In the US, about 8 million people have peripheral artery disease. It is frequently found in people with coronary artery disease, because atherosclerosis, which causes coronary artery disease, is a widespread disease of the arteries.

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Conditions associated with PAD may be occlusive (occurs because the artery becomes blocked in some manner) or functional (the artery either constricts due to a spasm or expands). Examples of occlusive PAD include peripheral arterial occlusion and Buerger's disease (thromboangiitis obliterans). Examples of functional PAD include Raynaud's disease and phenomenon and acrocyanosis.

What causes peripheral arterial disease?

PAD is often characterized by a narrowing of the vessels that carry blood to the leg and arm muscles. The most common cause is atherosclerosis (the buildup of plaque inside the artery wall). Plaque reduces the amount of blood flow to the limbs and decreases the oxygen and nutrients available to the tissue. Clots may form on the artery walls, further decreasing the inner size of the vessel and potentially blocking off major arteries.

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Other causes of peripheral arterial disease may include trauma to the arms or legs, irregular anatomy of muscles or ligaments, or infection. Persons with coronary artery (arteries that supply blood to the heart muscle) disease are frequently found to also have peripheral arterial disease. 

What are conditions associated with peripheral arterial disease?

The term "peripheral arterial disease" encompasses several different conditions. Some of these conditions include, but are not limited to, the following:

• atherosclerosis -  the build-up of plaque inside the artery wall. Plaque is made up of deposits of fatty substances, cholesterol, cellular waste products, calcium, and fibrin. The artery wall then becomes thickened and loses its elasticity. Symptoms may develop gradually, and may be few, as the plaque builds up in the artery. However, when a major artery is blocked, a heart attack, stroke, aneurysm, or blood clot may occur, depending on where the blockage occurs. 

• Buerger's disease (thromboangiitis obliterans) -  a chronic inflammatory disease in the peripheral arteries of the extremities leading to the development of clots in the small- and medium-sized arteries of the arms or legs and eventual blockage of the arteries. Buerger's disease most commonly occurs in men between the ages of 20 and 40 who smoke cigarettes. Symptoms include pain in the legs or feet, clammy cool skin, and a diminished sense of heat and cold.  

• chronic venous insufficiency -  a prolonged condition in which one or more veins do not adequately return blood from the lower extremities back to the heart due to damaged venous valves. Symptoms include discoloration of the skin and ankles, swelling of the legs, and feelings of dull aching pain, heaviness, or cramping in the extremities. 

• deep vein thrombosis (DVT) -  a clot that occurs in a deep vein, and has the potential to dislodge, travel to the lungs, occlude a lung artery (pulmonary embolism), and cause a potentially life-threatening event. It is found most commonly in those who have undergone extended periods of inactivity, such as from sitting while traveling or prolonged bed rest after surgery. Symptoms may be absent or subtle, but include swelling and tenderness in the affected extremity, pain at rest and with compression, and raised vein pattern.

• Raynaud's phenomenon -  a condition in which the smallest arteries that bring blood to the fingers or toes constrict (go into spasm) when exposed to cold or as the result of emotional upset. Raynaud's most commonly occurs in women between the ages of 18 and 30. Symptoms include coldness, pain, and pallor (paleness) of the fingertips or toes. 

• thrombophlebitis -  a blood clot in an inflamed vein, most commonly in the legs, but it can also occur in the arms. The clot can either be close to the skin (superficial thrombophlebitis) or deep within a muscle (deep vein thrombosis). It may result from pooling of blood, venous wall injury, and altered blood coagulation. Symptoms in the affected extremity include swelling, pain, tenderness, redness, and warmth.

• varicose veins -  dilated, twisted veins caused by incompetent valves (valves that allow backward flow of blood) allowing blood to pool. It is most commonly found in the legs or lower trunk. Symptoms include bruising and sensations of burning or aching. Pregnancy, obesity, and extended periods of standing intensify the symptoms. 

What are the risk factors for peripheral arterial disease?

A risk factor is anything that may increase a person's chance of developing a disease. It may be an activity, diet, family history, or many other things. Risk factors for peripheral arterial disease include factors which can be changed or treated and factors that cannot be changed.

Risk factors that cannot be changed include the following:

• age (especially older than 50)

• history of heart disease

• male gender

• diabetes mellitus (type 1 diabetes)

• postmenopausal women

• family history of dyslipidemia (elevated lipids in the blood, such as cholesterol), hypertension, or peripheral arterial disease

Risk factors that may be changed or treated include:

• coronary artery disease

• impaired glucose tolerance

• dyslipidemia

• hypertension (high blood pressure)

• obesity

• physical inactivity

• smoking or use of tobacco products

Those who smoke or have diabetes mellitus have the highest risk of complications from peripheral arterial disease because these risk factors also cause impaired blood flow. 

What are the symptoms of peripheral arterial disease?

Approximately half the people diagnosed with peripheral arterial disease are symptom free. For those experiencing symptoms, the most common first symptom is intermittent claudication in the calf (leg discomfort described as painful cramping that occurs with exercise and is relieved by rest). During rest, the muscles need less blood flow, so the pain disappears. It may occur in one or both legs depending on the location of the clogged or narrowed artery.

Other symptoms of peripheral arterial disease may include:

• changes in the skin, including decreased skin temperature, or thin, brittle shiny skin on the legs and feet

• diminished pulses in the legs and the feet

• gangrene (dead tissue due to lack of blood flow)

• hair loss on the legs

• impotence

• non-healing wounds over pressure points, such as heels or ankles

• numbness, weakness, or heaviness in muscles

• pain (described as burning or aching) at rest, commonly in the toes and at night while lying flat

• pallor (paleness) when the legs are elevated

• reddish-blue discoloration of the extremities

• restricted mobility

• severe pain

• thickened, opaque toenails

The symptoms of peripheral arterial disease may resemble other conditions. Consult your physician for a diagnosis. 

How is peripheral arterial disease diagnosed? 

In addition to a complete medical history and physical examination, diagnostic procedures for peripheral arterial disease may include any, or a combination, of the following:

• angiogram -  an x-ray of the arteries and veins to detect blockage or narrowing of the vessels. This procedure involves inserting a thin, flexible tube into an artery in the leg and injecting a contrast dye. The contrast dye makes the arteries and veins visible on the x-ray.

• ankle-brachial index (ABI) -  a comparison of the blood pressure in the ankle with the blood pressure in the arm using a regular blood pressure cuff and a Doppler ultrasound device. To determine the ABI, the systolic blood pressure (the top number of the blood pressure measurement) of the ankle is divided by the systolic blood pressure of the arm. 

• blood lipid profile -  a blood test to measure the levels of each type of fat in your blood: total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, and others.

• Doppler ultrasound flow studies -  uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs. Doppler technique is used to measure and assess the flow of blood. Faintness or absence of sound may indicate an obstruction in the blood flow.

• magnetic resonance angiography (MRA) -  a noninvasive diagnostic procedure that uses a combination of a large magnet, radiofrequencies, and a computer to produce detailed images of organs and structures within the body. An MRA is often used to examine the heart and other soft tissues and to assess blood flow.

• treadmill exercise test -  a test that is given while a patient walks on a treadmill to monitor the heart during exercise.

• photoplethysmography (PPG) -  an examination comparable to the ankle brachial index except that it uses a very tiny blood pressure cuff around the toe and a PPG sensor (infrared light to evaluate blood flow near the surface of the skin) to record waveforms and blood pressure measurements. These measurements are then compared to the systolic blood pressure in the arm.

• pulse volume recording (PVR) waveform analysis -  a technique used to calculate blood volume changes in the legs using a recording device that displays the results as a waveform.

• reactive hyperemia test -  a test similar to an ABI or a treadmill test but used for people who are unable to walk on a treadmill. While a person is lying on his or her back, comparative blood pressure measurements are taken on the thighs and ankles to determine any decrease between the two sites. 

• segmental blood pressure measurements -  a means of comparing blood pressure measurements using a Doppler device in the upper thigh, above and below the knee, at the ankle, and on the arm to determine any constriction in blood flow. 

What is the treatment for peripheral arterial disease?

There are two main goals for treatment of peripheral artery/vascular disease: control the symptoms and halt the progression of the disease to lower the risk of heart attack, stroke, and other complications. 

Specific treatment will be determined by your physician based on:

• your age, overall health, and medical history

• extent of the disease

• your signs and symptoms

• your tolerance for specific medications, procedures, or therapies

• expectations for the course of the disease

• your opinion or preference

Treatment may include:

• lifestyle modifications to control risk factors, including regular exercise, proper nutrition, and smoking cessation

• aggressive treatment of existing conditions that may aggravate PAD, such as diabetes, hypertension, and hyperlipidemia (elevated blood cholesterol)

• medications for improving blood flow, such as antiplatelet agents (blood thinners) and medications that relax the blood vessel walls

• angioplasty - a catheter (long hollow tube) is used to create a larger opening in an artery to increase blood flow. Angioplasty may be performed in many of the arteries in the body. There are several types of angioplasty procedures, including:

  • balloon angioplasty - a small balloon is inflated inside the blocked artery to open the blocked area

  • atherectomy - the blocked area inside the artery is "shaved" away by a tiny device on the end of a catheter

  • laser angioplasty - a laser used to "vaporize" the blockage in the artery

  • stent - a tiny coil is expanded inside the blocked artery to open the blocked area and is left in place to keep the artery open

• vascular surgery - a bypass graft using a blood vessel from another part of the body or a tube made of synthetic material is placed in the area of the blocked or narrowed artery to reroute the blood flow

With both angioplasty and vascular surgery, an angiogram is often performed prior to the procedure. 

What are the complications of peripheral arterial disease? 

Complications of peripheral arterial disease most often occur because of decreased or absent blood flow. Such complications may include:

• amputation (loss of a limb)

• heart attack

• poor wound healing

• restricted mobility due to pain or discomfort with exertion

• severe pain in the affected extremity

• stroke (three times more likely in persons with PAD)

By following an aggressive treatment plan for peripheral arterial disease, complications such as these may be prevented.

Prevention of peripheral arterial disease:

Steps to prevent PAD are primarily aimed at management of the risk factors for PAD. A prevention program for PAD may include:

• smoking cessation, including avoidance of second hand smoke and use of tobacco products

• dietary modifications including reduced fat, cholesterol, and simple carbohydrates (such as sweets), and increased amounts of fruits and vegetables

• treatment of dyslipidemia (high blood cholesterol levels) with medications as determined by your physician

• weight reduction

• moderation in alcohol intake

• medications as determined by your physician to reduce your risk of blood clot formation

• exercise plan of a minimum of 30 minutes daily

• control of diabetes mellitus

• control of hypertension (high blood pressure)

A prevention plan for PAD may also be used to prevent or lessen the progress of PAD once it has been diagnosed. Consult your physician for diagnosis and treatment.