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Peripheral artery disease (PAD)

Definition

Peripheral artery disease, also known as peripheral arterial disease, is a common circulatory problem in which narrowed arteries reduce blood flow to your limbs.

When you develop peripheral artery disease (PAD), your extremities — usually your legs — don't receive enough blood flow to keep up with demand. This causes symptoms, most notably leg pain when walking (intermittent claudication).

Peripheral artery disease is also likely to be a sign of widespread accumulation of fatty deposits in your arteries (atherosclerosis). This condition may be reducing blood flow to your heart and brain, as well as your legs.

Often, you can successfully treat peripheral artery disease by quitting tobacco if you smoke, exercising and eating a healthy diet. Early diagnosis and treatment can prevent peripheral artery disease from getting worse and also help you reduce your risk of heart disease and stroke.

Symptoms

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Intermittent claudication In peripheral artery disease, the arteries that supply blood to the legs are narrowed, typically because of atherosclerosis, causing a cluster of pain symptoms called intermittent claudication. With proper treatment, new, collateral blood vessels may form, allowing blood to circulate around the damaged areas.

Intermittent claudication

While many people with peripheral artery disease have mild or no symptoms, about one in 10 experiences leg pain when walking (intermittent claudication).

Intermittent claudication is characterized by muscle pain or cramping in your legs or arms that's triggered by activity, such as walking, but disappears after a few minutes of rest. The location of the pain depends on the location of the clogged or narrowed artery. Calf pain is most common.

The severity of intermittent claudication varies widely, from mild discomfort to debilitating pain. Severe intermittent claudication can make it hard for you to walk or do other types of physical activity.

Signs and symptoms of peripheral artery disease include:

• Painful cramping in your hip, thigh or calf muscles after walking or climbing stairs (intermittent claudication)
• Leg numbness or weakness
• Coldness in your lower leg or foot, especially when compared with the other leg
• Sores on your toes, feet or legs that won't heal
• A change in the color of your legs
• Hair loss on your feet and legs
• Changes in your toenails

If peripheral artery disease progresses, pain may even occur when you're at rest or when you're lying down (ischemic rest pain). It may be intense enough to disrupt sleep. Hanging your legs over the edge of your bed or walking around your room may temporarily relieve the pain.

Causes

The most common cause of peripheral artery disease is atherosclerosis. In atherosclerosis, fatty deposits (plaques) build up in your artery walls and reduce blood flow.

Although the heart is usually the focus of discussion of atherosclerosis, the disease can and usually does affect arteries throughout your body. When it occurs in the arteries supplying blood to your limbs, it causes peripheral artery disease.

Less commonly, the cause of PAD may be blood clots in your arteries, injury to your limbs, unusual anatomy of your ligaments or muscles, or infection.

Risk factors

Factors that increase your risk of developing peripheral artery disease include:

• Smoking
• Diabetes
• Obesity (a body mass index over 30)
• High blood pressure (140/90 millimeters of mercury or higher)
• High cholesterol (total blood cholesterol over 240 milligrams per deciliter or 6.2 millimoles per liter)
• Increasing age, especially after reaching 50 years of age
• A family history of peripheral artery disease, heart disease or stroke
• Excess levels of homocysteine, a protein component that helps build and maintain tissue
• Excess levels of C-reactive protein, a general marker of inflammation

People who smoke or have diabetes have the greatest risk of complications from PAD — such as tissue death (gangrene) in a leg due to reduced blood flow.

When to seek medical advice

If you have leg pain, numbness or other symptoms, don't dismiss them as a "normal part of aging." Call your doctor and make an appointment.

Early diagnosis and treatment of peripheral artery disease is important not only to preserve the health of your limbs but also to decrease your risk of heart disease, stroke and other health problems.

Tests and diagnosis

Some of the tests your doctor may rely on to diagnose peripheral artery disease:

• Physical exam. Your doctor may find signs of PAD during a physical examination, such as a weak or absent pulse below a narrowed area of your artery, whooshing sounds (bruits) over your arteries that can be heard with a stethoscope, evidence of poor wound healing in the area where your blood flow is restricted, and decreased blood pressure in your affected limb.
• Ankle-brachial index (ABI). This is one of the most common tests used to diagnose PAD. It compares the blood pressure in your ankle with the blood pressure in your arm. To get a blood pressure reading, your doctor uses a regular blood pressure cuff and a special ultrasound device to evaluate blood pressure and flow. You may walk on a treadmill and have readings taken before and immediately after exercising to capture the severity of the narrowed arteries during walking.
• Ultrasound. Special ultrasound imaging techniques, such as Doppler ultrasound or duplex scanning, can help your doctor evaluate blood flow through your blood vessels and identify blocked or narrowed arteries.
• Angiography. By injecting a dye (contrast material) into your blood vessels, this test allows your doctor to view blood flow through your arteries as it happens. Your doctor is able to trace the flow of the contrast material using imaging techniques such as X-ray imaging or procedures called magnetic resonance angiography (MRA) or computerized tomography angiography (CTA). Catheter angiography is a more invasive procedure that involves guiding a catheter through an artery in your groin to the affected area and injecting the dye that way. Although invasive, this type of angiography allows for simultaneous diagnosis and treatment - finding the narrowed area of a blood vessel and then widening it with an angioplasty procedure or administering medication to improve blood flow.
• Blood tests. A sample of your blood can be used to measure your cholesterol and check levels of homocysteine and C-reactive protein.

Complications

Peripheral artery disease can lead to open sores that don't heal, injury, or infection of your feet and legs, especially if you also have diabetes. Critical limb ischemia (CLI) is the extreme state of this condition and can cause tissue death (gangrene), sometimes requiring amputation of the affected limb.

Stroke and heart attack are among the more serious and common complications of peripheral artery disease. Atherosclerosis causing signs and symptoms of peripheral artery disease is not limited to your legs. Fat deposits also build up in arteries supplying your heart and brain. As a result, you have a greater risk of coronary artery disease and stroke.

Treatments and drugs

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Graft bypass A graft is used to redirect blood flow around a blocked or narrowed artery. A graft can be a blood vessel from another part of the body or a man-made substitute.

Graft bypass

Treatment for peripheral artery disease has two major goals. The first is to manage symptoms, such as leg pain, so that you can resume physical activities. The second is to stop the progression of atherosclerosis throughout your body to reduce your risk of heart attack and stroke.

You may be able to accomplish these goals with lifestyle changes. If you smoke, quitting is the single most important thing you can do to reduce the progression of the blockage and reduce your risk of complications.

If lifestyle changes are not enough, you need additional medical treatment. Your doctor may prescribe medicine to prevent blood clots, lower blood pressure and cholesterol, and control pain and other symptoms.

Medications

• Cholesterol-lowering medications. You may take a cholesterol-lowering drug called a statin to reduce your risk factor for heart attack and stroke. The goal for people who have peripheral artery disease is to reduce low-density lipoprotein (LDL) cholesterol, the "bad" cholesterol, to less than 100 milligrams per deciliter (mg/dL), or 2.6 millimoles per liter (mmol/L). The goal is even lower if you have additional major risk factors for heart attack and stroke, especially diabetes or continued smoking.
• High blood pressure medications. If you also have high blood pressure, your doctor may prescribe medications to lower it such as beta blockers or ACE inhibitors. The goal of this therapy is to reduce your systolic blood pressure (the top number of the two numbers) to 140 millimeters of mercury (mm Hg) or lower and your diastolic blood pressure (the bottom number) to 90 mm Hg or lower. If you have diabetes, the blood pressure targets are even lower.
• Medication to control blood sugar. If you also have diabetes, it becomes even more important to control your blood sugar (glucose) levels.
• Medications to prevent blood clots. Because peripheral artery disease is related to reduced blood flow to your limbs, it's important to reduce your risk of blood clots. A blood clot can completely block an already narrowed blood vessel and cause tissue death. Your doctor may prescribe daily aspirin therapy or another medication that helps prevent blood clots, such as clopidogrel (Plavix).
• Symptom-relief medications. The drug cilostazol (Pletal) increases blood flow to the limbs both by preventing blood clots and by widening the blood vessels. It specifically helps the symptom of claudication, leg pain, for people who have peripheral artery disease. An alternative to cilostazol is pentoxifylline; however, it's less effective.

Angioplasty and surgery
In some cases, angioplasty or surgery may be necessary to treat peripheral artery disease that's causing intermittent claudication:

• Angioplasty. In this procedure, a small hollow tube (catheter) is threaded through a blood vessel to the affected artery. There, a small balloon on its tip is inflated to reopen the artery and flatten the blockage into the artery wall, while at the same time stretching the artery open to increase blood flow. Your doctor may also insert a mesh framework called a stent in the artery to help keep it open. This is the same procedure doctors use to open heart arteries.
• Bypass surgery. Your doctor may create a graft bypass using a vessel from another part of your body or a blood vessel made of synthetic fabric. This technique allows blood to flow around — or bypass — the blocked or narrowed artery.
• Thrombolytic therapy. If you have a blood clot blocking an artery, your doctor may inject a clot-dissolving drug into your artery at the point of the clot to break it up.

Supervised exercise program
In addition to medications or surgery, your doctor may prescribe a supervised exercise training program to increase the distance you can walk pain-free. Regular exercise improves symptoms of PAD by a number of methods, including helping your body use oxygen more efficiently.

Lifestyle and home remedies

Many people can manage the symptoms of peripheral artery disease and stop the progression of the disease through lifestyle changes, especially quitting smoking. To stabilize or improve PAD:

• Stop smoking. Smoking contributes to constriction and damage of your arteries and is a significant risk factor for the development and worsening of PAD. If you smoke, quitting is the most important thing you can do to reduce the progression of the blockage and reduce your risk of complications.
• Exercise. This is a key component. Success in treatment of PAD is often measured by how far you can walk without pain. Proper exercise helps condition your muscles to use oxygen more efficiently. Your doctor can help you develop an appropriate exercise plan. He or she may refer you to a claudication exercise rehabilitation program.
• Eat a healthy diet. A heart-healthy diet can help control your blood pressure and cholesterol levels, which contribute to atherosclerosis. Preliminary research indicates foods with omega-3 fatty acids may have some beneficial effects on peripheral artery disease symptoms. Omega-3 fatty acids, which also appear to improve the treatment and prevention of coronary artery disease, can be found in fatty cold-water fish, such as salmon, mackerel and herring. Lesser amounts are in flaxseeds, walnuts, soybeans and canola oil.

Careful foot care
In addition to the above suggestions, take good care of your feet. People with peripheral artery disease, especially those who also have diabetes, are at risk of poor healing of sores on the lower legs and feet. Poor blood circulation can postpone or prevent proper healing and increases the risk of infection. Follow this advice to care for your feet:

• Wash your feet daily and moisturize them well and often to prevent cracks that can lead to infection.
• Wear well-fitting shoes and thick, dry socks.
• Promptly treat any fungal infections of the feet, such as athlete's foot.
• Take care when trimming your nails.
• Avoid walking barefoot.
• See your doctor at the first sign of a sore or injury to your skin.

Alternative medicine

Some studies suggest that the blood thinning effects of ginkgo may allow people with intermittent claudication to walk longer distances with less pain. However, this herbal remedy can cause bleeding when taken in high doses, and it could be dangerous if paired with anti-platelet medications, including aspirin, which are commonly prescribed to people with PAD. Talk to your doctor before you consider taking ginkgo for relief from leg pain.