Peripheral Vascular Disease
Claudication is the development of pain deep in the muscles of the leg (calves, thighs, or buttocks) during activity; the pain is relieved by resting the legs. Claudication, which literally means “to limp,” is one of the symptoms of lower extremity peripheral artery disease (PAD), which is when blockages in the arteries prevent blood from easily flowing through.
Although other underlying medical problems can also cause claudication, PAD is the most common cause. PAD is caused by deposits of fatty plaques (atherosclerosis) within the vessel walls. These plaques grow with time and result in narrowing or completely block blood flow in the leg arteries and blood flow to the muscles and skin.
Another important, but less common, cause of claudication is a complication of an aneurysm in the abdomen or leg. An aneurysm is an abnormally dilated (bulging) artery, which is often filled with debris or blood clots. These clots or clumps of debris can break off and clog arteries in the leg, sometimes causing claudication as a first symptom.
In younger adults, claudication may be due to something called “popliteal entrapment syndrome,” an uncommon condition in which a band of muscle compresses the popliteal artery (an artery located behind the knee in each leg). In other cases, it can result from the compression of the popliteal artery due to a cyst in the arterial wall.
Risk Factors for Peripheral Arterial Disease
The major risk factors for developing peripheral artery disease (PAD) include:
- Cigarette smoking – the most significant risk factor for developing PAD
- Hyperlipidemia (elevated blood levels of lipids, including cholesterol and triglycerides)
- Hypertension (high blood pressure)
- Physical inactivity
The pain and discomfort associated with claudication from PAD varies from person to person. It is usually described as a gradually restrictive, cramp-like pain in the calf or thigh that occurs with activity and is relieved with rest. It can also present with gradually restrictive, cramp-like buttock pain that occurs with activity and is relieved with rest. Some people have severe, debilitating discomfort while others have minimal symptoms.
The severity of your symptoms will depend upon several factors, including how many arteries are affected, how narrowed your arteries are, how well your circulation compensates for the blockage(s), how quickly you walk, how much weight you carry, and whether you walk up an incline or stairs.
The location of your pain depends on the location of PAD.
- Buttock pain – Pain in the hips or thighs results from blockage of the main artery of the abdomen (the aorta) or its branches (the iliac arteries), which are located in the abdomen. When symptomatic, people with a blockage in the aorta complain of buttock, hip, or thigh pain. The pain is often described as aching, and there may also be weakness while walking up stairs. Other physical signs include loss of muscle mass and hair loss on the lower extremities. Erectile dysfunction (ED) in men may also occur when the aorta or iliac arteries are blocked.
- Thigh pain – Thigh claudication often results from the narrowing of the artery in the groin (the common femoral artery) or midthigh (the superficial femoral artery) but can also be caused by blockage of the vessels above the groin (the aorta and iliac arteries).
- Calf pain – The calf is the most common location for pain. It is usually described as a gradually restrictive, cramp-like pain that commonly occurs with activity and is relieved with rest. Claudication pain in the upper two-thirds of the calf is usually due to the narrowing of the artery in the mid-thigh (the superficial femoral artery), whereas pain in the lower third of the calf is due to disease in the artery behind the knee (the popliteal artery).
- Foot pain – Foot claudication can occur from narrowing of an artery in the lower part of the leg below the knee (the tibial or peroneal artery).
Diagnosis of Peripheral Arterial Disease
The diagnosis of claudication is based upon the signs and symptoms described above. Doctors can do noninvasive tests to confirm the diagnosis and estimate the severity of the disease.
- Ankle-brachial index — The ankle-brachial index (ABI), also called the ankle-arm index, is used to confirm the diagnosis of PAD. The ABI measures the resting blood pressure at the ankle compared with the blood pressure in the arm. Doctors can diagnose PAD based on the result of this measurement. If the result is normal at rest in a person with symptoms of claudication, it is often repeated following exercise (eg, after the person walks on a treadmill or does several heel raises) and the results compared.
- Segmental blood pressure — Blood pressure can be measured at other levels in the legs (calf, low thigh, high thigh) to determine the level and extent of PAD. These measurements are called “segmental limb pressures.”
- Imaging — Ultrasonography (ultrasound) is a noninvasive test that can be used to measure the blood flow and allow doctors to see the location and severity of the narrowing of the arteries. Computed tomographic and magnetic resonance angiography are other noninvasive ways of looking at blood vessels; these tests are usually used if symptoms are unusual, do not improve with medical treatment, or if they suddenly get worse. In this situation, invasive imaging tests (ie, arteriography, which involves injecting dye into a blood vessel and then looking at it with an X-ray) may also be considered, especially if your doctor thinks you are a candidate for a procedure called revascularization.
Anyone with PAD-related claudication should receive treatment. This generally includes making lifestyle changes (such as quitting smoking) to reduce your risk of cardiovascular disease, participating in an exercise program, and often taking medications.
If medications and lifestyle changes are not sufficient to reduce symptoms, and your pain continues to interfere with your ability to work or do your normal daily activities, you may be a candidate for a procedure called “revascularization” to restore blood flow to the blocked arteries.
Reduce risk factors — As mentioned above, the main risk factors for PAD are cigarette smoking, diabetes, high blood pressure, high cholesterol or lipids, and morbid obesity. All people with claudication should work to control these risk factors.
- Lowering your cholesterol level can prevent worsening of PAD and reduce symptoms of claudication. Treatment may include lifestyle changes (diet and exercise) and/or lipid-lowering medications such as statins. For people with claudication, taking a statin can lower the risk of cardiovascular events (such as heart attack or stroke) even if they do not have high cholesterol.
- Quitting smoking and keeping diabetes or high blood pressure well controlled may also improve claudication symptoms (ie, pain) but, even more importantly, helps to reduce the risk of coronary heart disease.
- Antiplatelet agents (such as aspirin or clopidogrel) are medications that reduce blood clotting and are recommended for all patients with coronary heart disease equivalents, which include PAD. While these medications may only modestly improve claudication symptoms, treatment reduces the need for surgery and decreases the risk of cardiovascular complications (such as heart attack or stroke) and death.
- Exercise — Exercise programs reduce the symptoms of claudication, for example, by allowing you to increase the distance and time you can walk before developing symptoms. People who respond to an exercise program can expect improvement within two months. Motivated patients who are supervised by a professional achieve the best results. The benefits of exercise diminish when exercise training stops.
If you have severe lifestyle-limiting claudication (ie, the leg pain interferes with your ability to carry out daily activities successfully), particularly if medication has been unsuccessful in relieving symptoms, your doctor may recommend a procedure to increase the amount of blood flow to your legs.