Claudication: Symptoms, Causes, and Treatment

Pain and cramping in the legs is the main symptom of claudication.

Claudication is pain and/or cramping in the lower leg due to inadequate blood flow to the muscles. The pain usually causes the person to limp. The word "claudication" comes from the Latin "claudicare" meaning to limp. Claudication typically is felt while walking and subsides with rest. It is commonly referred to as "intermittent" claudication because it comes and goes with exertion and rest. In severe claudication, the pain is also felt at rest.

Pain and cramping in the legs is the main symptom of claudication. Pain can be sharp or dull, aching or throbbing, or burning. The severity of the peripheral artery disease, the location of the plaque, and the activity of the muscles determine the severity of symptoms and the location of the pain. Calf pain is the most common location for leg cramps. This is because the atherosclerotic plaques often begin in the arteries farthest from the heart. If the blockage or plaque formation is farther up the leg, the pain from claudication may be felt in the thigh. If the blockage is in the aorta (the main artery from the heart to the legs) then symptoms may include pain in the buttocks or groin or erectile dysfunction.

The severity of the peripheral artery disease, the location of the plaque, and the activity of the muscles determine the severity of symptoms and the location of the pain.

Several medical problems can cause claudication, but the most common is peripheral artery disease. Peripheral artery disease (PAD) is caused by atherosclerosis, which is a hardening of the arteries from the accumulation of cholesterol plaques that form on the inner lining of the arteries. This is especially common at branching points of the arteries in the legs. The blockage of the arteries from these plaques causes low blood flow to the muscles in the legs. When walking or exercising the muscles in the legs require more blood flow to increase oxygen to the cells. Atherosclerotic plaques cause decreased blood flow and decreased oxygen. The muscles of the legs can ache and burn as a result of inadequate oxygen. This is felt as cramping in the legs.

Intermittent claudication can be due to temporary artery narrowing due to spasm of the artery (vasospasm), permanent artery narrowing due to atherosclerosis, or from the complete blockage of an artery of the leg.

The usually intermittent nature of the pain of claudication is due to a temporary inadequate supply of oxygen to the muscles of the leg. The poor oxygen supply is a result of narrowing of the arteries that supply the leg with blood. This limits the supply of oxygen to the leg muscles and is especially noticeable when the oxygen requirement of these muscles rises with exercise or walking. Claudication that comes and goes is often referred to as intermittent claudication.

Intermittent claudication is more common in men than in women. The condition affects 1% to 2% of the population under 60 years of age, increasing in incidence with age, to affect over 18% of persons over 70 years of age, according to the American Academy of Family Physicians.

Risk factors for peripheral artery disease and claudication include:

• Smoking
• Diabetes
• High blood pressure
• High cholesterol
• African American descent
• Heart disease

A physician will take a history and the diagnosis will be based on the patient's symptoms.

Testing for claudication may include:

• Ultrasound is most commonly used to determine location and severity of the narrowing in the blood vessels.
• Ankle-arm index measures the blood pressure at the ankle compared with the blood pressure in the arm. An abnormal result is an indication of peripheral artery disease.
• Segmental blood pressure measures blood pressure in different parts of the leg (calf, low thigh, high thigh) to detect a blockage that is causing decreased blood flow.
• Computed tomography (CT) and magnetic resonance angiography (MRA) are other noninvasive tests that can help a doctor map the blood flow in the affected areas. These tests may be considered if the patient's doctor thinks that a procedure (revascularization) to treat peripheral artery disease may be helpful.

There are two main ways to treat claudication: medication and a surgical treatment, called revascularization.

Medication therapies are often used initially as they are non-invasive. The two most commonly used medications include:

• Cilostazol (Pletal) reduces the pain of intermittent claudication by widening (dilating) the arteries, thereby improving the flow of blood and oxygen to the legs.
• Pentoxifylline (Trental) decreases the "stickiness" (viscosity) of blood and thereby improves its flow through arteries. This increases the flow of blood and oxygen to muscles.

There are several drugs being investigated to treat claudication. These medications are not yet approved for use in treating this condition. These medications include:

• ACE (angiotensin converting enzyme) inhibitors
• Antichlamydophila therapy –- roxithromycin
• Propionyl-L-carnitine
• Defibrotide
• Prostaglandins

A surgical procedure called a revascularization is used in patients who do not respond to medications. There are two types of revascularization procedures: endovascular (inside the blood vessel) and surgically grafting or bypassing the artery.

• Endovascular procedures include:
  • Angioplasty: A balloon is placed in the blocked area and inflated to widen the diameter of the artery and increase blood flow
  • Stenting: Wire mesh used to hold a blood vessel open after angioplasty and prevents scar tissue from narrowing the blood vessel
• Surgical grafting or bypassing an artery involves an open surgery with an incision and sewing in a graft using either the patient's vein or a synthetic tube to increase blood flow around the blocked area.
• Compression therapy can also be used as a noninvasive way to treat symptoms of claudication. Intermittent calf compression has been shown in studies to improve symptoms-free walking distance.

The prognosis of claudication is generally favorable with treatment. Without treatment, 26% of patients worsen over time. Over 5 years, 4% to 8% will progress to require a revascularization procedure.

The underlying cause of claudication, peripheral vascular disease, does put patients at risk for other atherosclerotic diseases. A finding of claudication or peripheral artery disease should be considered a warning sign of other potential atherosclerotic blockages in the body.

Some of the risk factors for claudication are behaviors that can be modified such as:

• quit smoking,
• managing diabetes and high blood pressure, and
• maintaining a healthy diet to keep cholesterol levels normal.

Medications that help thin the blood can be used to help prevent symptoms of claudication, but they do not treat the underlying cause. Medications include:

• aspirin,
• clopidogrel (Plavix),
• ticlopidine (Ticlid), and
• dipyridamole (Permole, Persantine, Aggrenox).

Exercise is recommended for patients with claudication symptoms. Frequent exercise, especially walking, greatly reduces symptoms and increases symptom-free walking distance and is one of the most effective preventive measures.