Peripheral Artery Disease - Dr. Kashif Syed

CLAUDICATION OVERVIEW

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.

Lastly, pain in the legs can be related to nerve compression in the spine; the medical term for this is “neurogenic claudication” or “pseudoclaudication.” A rare but important cause of hip pain with walking may be inflammation of the fluid spaces around the hip muscles; this is called “bursitis.”

PERIPHERAL ARTERY DISEASE RISK FACTORS

The major risk factors for developing peripheral artery disease (PAD) include:

Cigarette smoking is the most significant risk factor for developing PAD.

CLAUDICATION SYMPTOMS

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) (ie, development of collaterals), how much or 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 mid-thigh (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).

CLAUDICATION DIAGNOSIS

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."

CLAUDICATION TREATMENT

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 and limb events.

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. Clopidogrel had a modest but significant advantage over aspirin for reducing the risk for cardiovascular events in a large randomized trial, particularly among patients with PAD. A combination of antiplatelet and low-dose antithrombotic therapy may benefit patients with PAD. Rivaroxaban, an oral anticoagulant, at 2.5 mg twice a day plus aspirin reduced the risk for major adverse cardiovascular events and major adverse limb events compared with aspirin alone; however, rivaroxaban plus aspirin increased the risk of major bleeding.

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 [1]. People who respond to an exercise program can expect improvement within two months. The exercise programs should be individually prescribed where possible. All patients should aim for at least 30 min of aerobic activity, at least three times a week, ideally in the form of walking exercise to near-maximal claudication pain [2]. The benefits of exercise diminish when exercise training stops.

Motivated patients who are supervised by a professional achieve the best results. In May 2017, the Center for Medicare and Medicaid Services in the United States announced a decision to provide coverage for supervised treadmill exercise for people with PAD. Supervised exercise training involves walking on a treadmill or a track for 45 to 60 minutes at least three times per week. The sessions are supervised by an exercise physiologist, physical therapist, or nurse. The exercise program can be adjusted based on the presence of other cardiovascular problems (such as an abnormal heart rhythm or chest pain).

Although encouraged, nonsupervised walking programs generally do not result in the same amount of improvement. However, in a systematic review, there was no clear difference comparing alternative exercise modes (eg, cycling, upper extremity ergometry, resistance training) and supervised walking exercise for improving the maximum and pain‐free walking distance in patients with intermittent claudication.

Medication to improve walking distance — Several different medications can help improve walking distance (ie, how far and how long you can walk without having pain) in people with claudication. Your doctor may suggest medication if lifestyle changes and exercise haven’t been sufficient in relieving your symptoms.

Cilostazol — Cilostazol is the most effective medication for treatment of claudication symptoms, particularly when combined with exercise. Your healthcare provider may also recommend cilostazol if your ability to walk is limited.

Cilostazol should be taken one-half hour before or two hours after eating because high-fat meals increase the amount of drug absorbed by the body. Certain medications and foods (grapefruit juice) can also change the way cilostazol is absorbed, and your dose may need to be adjusted, so be sure to discuss possible interactions with your doctor. Cilostazol may be taken safely with aspirin and/or clopidogrel. Potential side effects of cilostazol include headache, loose or soft stools, diarrhea, dizziness, and palpitations. Cilostazol is not used in people with significant heart failure.

Statin therapy — Statins are medications used to lower cholesterol. Statin therapy may slow progression of PAD and help with claudication symptoms, even in people who do not have high cholesterol.

Unproven or ineffective treatments for reducing pain — Many other drugs have been tried for treating claudication pain but are either much less effective than the therapies listed above or are ineffective. These include pentoxifylline, herbal remedies (Ginkgo biloba, Padma 28), and others. Some treatments may be harmful (eg, chelation therapy, which involves injecting a substance with the goal of removing heavy metals from the body). Many other treatments are still being studied and are not yet recommended for reducing pain (eg, angiotensin inhibitors, antioxidants, bosentan, prostanoids, other phosphodiesterase inhibitors, and gene therapy).

Revascularization — If you have severe lifestyle-limiting claudication (ie, the leg pain interferes with your ability to carry out daily activities successfully), and if medication has been unsuccessful in relieving symptoms, your doctor may recommend a procedure to increase the amount of blood flow to your legs.

Revascularization procedures can be generally divided into two general categories: “catheter-based” endovascular procedures, which are done without incisions (eg, balloon angioplasty with or without stenting, atherectomy, recanalization), and “surgery” (eg, bypass, endarterectomy). Increasingly, revascularization may involve a combination of multiple techniques and devices, called “hybrid” procedures, all with the objective of improving blood flow. The selection of revascularization technique depends upon a variety of factors, such as your particular anatomy, severity of symptoms, prior interventions, suitability for anesthesia, and the experience of your physician, as well as your personal preferences. There is no one single revascularization procedure for claudication.

Endovascular — Endovascular intervention (without incisions) is generally attempted before surgery since it is less invasive and has fewer cardiovascular risks. Endovascular procedures are performed through a catheter (thin tube) placed into the femoral artery through the skin in the groin region. Balloon angioplasty involves threading a guidewire through the narrowed or blocked vessel. A deflated balloon is placed over the wire, and the balloon is inflated and then deflated. This opens the vessel and allows blood to flow more freely.

A stent is often used to hold the vessel open after angioplasty. A stent is an expandable tube made of a wire mesh. The goal of a stent is to prevent restenosis, which is when the vessel becomes narrowed again. Stents work better in some vessels compared with others.

Angioplasty and stenting are most successful for treating single, short blockages, but advancements in technology have allowed treatment of multiple, longer, and even completely blocked artery segments. However, restenosis is more common when longer or blocked segments are treated.

Atherectomy uses a specialized device to remove the plaque that is causing the blockage by cutting or burning it. Another technique uses a special catheter to open up completely blocked vessels.

Surgery — Surgical revascularization involves sewing in a graft (usually a vein, but sometimes man-made material) to go around (bypass) the narrowed or blocked area of the blood vessel, which improves blood flow to the rest of the leg. The best candidates for surgery are those who are younger, do not have diabetes, and have little disease in the vessels below the knee. Many older individuals and those with diabetes are able to have successful surgery, but it is important for these patients to understand that they have a higher risk for postoperative complications.