Peripheral artery disease
Overview
Peripheral artery disease (PAD) is a common circulatory problem in which narrowed arteries reduce blood flow to your limbs. When you develop peripheral artery disease, 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 (claudication).
Pathophysiology
Peripheral artery disease is often caused by atherosclerosis. In atherosclerosis, fatty deposits (plaques) build up on your artery walls and reduce blood flow. Although the heart is usually the focus of discussion of atherosclerosis, this 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 peripheral artery disease may be blood vessel inflammation, injury to your limbs, unusual anatomy of your ligaments or muscles, or radiation exposure.
Risk Factors
Factors that increase your risk of developing peripheral artery disease include:
- Smoking
- Diabetes
- Obesity (a body mass index, or BMI, over 30)
- High blood pressure
- High cholesterol
- Increasing age, especially after reaching 50 years of age
- A family history of peripheral artery disease, heart disease or stroke
- High levels of homocysteine, a protein component that helps build and maintain tissue
People who smoke or have diabetes have the greatest risk of developing peripheral artery disease due to reduced blood flow.
Symptoms
While many people with peripheral artery disease have mild or no symptoms, some people have leg pain when walking (claudication). Claudication symptoms include 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 the most common location.
The severity of claudication varies widely, from mild discomfort to debilitating pain. Severe claudication can make it hard for you to walk or do other types of physical activity.
Peripheral artery disease symptoms include:
- Painful cramping in one or both of your hips, thighs or calf muscles after certain activities, such as walking or climbing stairs (claudication)
- Leg numbness or weakness
- Coldness in your lower leg or foot, especially when compared with the other side
- Sores on your toes, feet or legs that won't heal
- A change in the color of your legs
- Hair loss or slower hair growth on your feet and legs
- Slower growth of your toenails
- Shiny skin on your legs
- No pulse or a weak pulse in your legs or feet
- Erectile dysfunction in men
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.
Complications
If peripheral artery disease is left untreated, you may develop:
- Critical limb ischemia: This condition begins as open sores that don't heal, an injury, or an infection of your feet or legs. Critical limb ischemia occurs when such injuries or infections progress and can cause tissue death (gangrene), sometimes requiring amputation of the affected limb.
- Stroke and heart attack: The atherosclerosis that causes the signs and symptoms of peripheral artery disease isn't limited to your legs. Fat deposits also build up in arteries supplying your heart and brain.
Diagnosis
To diagnose peripheral artery disease, your doctor may rely on a physical exam, a Doppler ultrasound, or angiography.
During a physical exam, your doctor may find:
- Weak or absent pulses in the lower limbs.
- Whooshing sounds (bruits) over the arteries that may indicate atherosclerosis.
- Poor wound healing in the lower limbs.
- Changes in the skin of the lower limbs, including loss of hair, paleness, bluish discoloration (cyanosis), and thickened nails.
- Lower blood pressure in your affected limb.
Ankle-brachial index (ABI) is one of the most commonly used tests for peripheral artery disease. 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 is a noninvasive method to capture images of your blood vessels. A Doppler ultrasound may help your doctor evaluate blood flow through your blood vessels and identify blocked or narrowed arteries.
In angiography, a dye injected into your blood vessels makes them visible under X-ray. This test allows your doctor to view blood flow through your arteries as it happens. With the help of local anesthesia, a small hollow tube (catheter) can be threaded through your blood vessels to deliver the dye. Angiography allows direct viewing of disruptions in blood flow and arterial blockages.
Treatment
Treatment for peripheral artery disease has two major goals:
- Manage symptoms, such as leg pain, so that you can resume physical activities.
- 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 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.
Prevention
The best way to prevent claudication is to maintain a healthy lifestyle. That means:
- Quit smoking if you're a smoker.
- If you have diabetes, keep your blood sugar in good control.
- Exercise regularly. Aim for 30 minutes several times a week after you've gotten your doctor's OK.
- Lower your cholesterol and blood pressure levels, if applicable.
- Eat foods that are low in saturated fat.
- Maintain a healthy weight.