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Friday, September 19, 2014

Peripheral Arterial Disease: A Patient Guide

What is Peripheral Arterial Disease?

Peripheral arterial disease (PAD) is due to atherosclerosis – a progressive disease that involves the hardening and narrowing of the arteries due to a gradual buildup of plaque (fatty deposits). PAD occurs in the arteries outside of the heart (called peripheral arteries). Peripheral arterial disease (PAD) affects millions of people in the United States, most of whom are not aware that they have the disease. PAD interferes with lifestyle by decreasing walking ability, and slowing healing to the affected areas. As blood flow and therefore oxygen supply progress, the affected area becomes less able to cope with the activities of ordinary everyday life, more amenable to scratches, infections, and eventually to cell death (gangrene).

Atherosclerosis affects the whole body, and people with PAD also have a markedly increased risk of heart attack, stroke and death. A patient with PAD has about five times the risk of dying of a heart attack or stroke over the next ten years as the patient who does not have peripheral arterial disease. Long term risk of patients with peripheral arterial disease is worse than patients with only coronary artery disease.

Which arteries are most affected by PAD?

The major areas where atherosclerosis produces symptoms in the peripheral artery beds are:

  • Cerebrovascular, or brain arteries (e.g., carotid and vertebral arteries) – Cerebrovascular disease (including carotid artery disease) is the leading cause of stroke and disability in the United States.
  • Renal, or kidney arteries – Renal artery stenosis (PAD of the renal arteries) is a major cause of high blood pressure and renal failure requiring dialysis or transplant.
  • Lower extremity, or leg arteries – Lower extremity PAD is a major cause of diminished ability to walk. Advanced cases lead to gangrene, ulcers and amputation of the feet or legs.
  • Mesenteric, or intestinal arteries – Mesenteric arterial disease (PAD of the mesenteric arteries) is less common but can cause severe pain, weight loss, and even death from intestinal gangrene.
  • Abdominal aorta – Weakening of the wall of this major vessel that leads to the lower extremities can result in aneurysm, renal failure, gangrene, ulcer, amputation and the problems of mesenteric and intestinal artery blockage.

What are the symptoms of PAD?

PAD rarely offers warning signs to its estimated 8 to 12 million victims, who are generally older adults. Only a third of the afflicted have leg pain from PAD, two-thirds of people really don't have symptoms. Symptoms, however, can include: pain, ache, cramp or severe fatigue in one or both legs when walking (this pain will subside upon resting, but returns after walking a similar distance) – so that those affected slacken their walking pace, or stop altogether. In later stages of progression, leg circulation may be so poor that pain occurs in the toes and feet during periods of inactivity, especially at night. This is known as rest pain. Rest pain commonly worsens when the legs are elevated and is relieved by lowering the legs (due to the effects of gravity on the leg circulation). As the condition worsens the integrity of the skin is affected with easy bruising, infections (cellulites) and ulcers may form. Due to the inadequacy of the circulation, antibiotics often are not sufficient to cure infections in compromised legs and gangrene may require amputation.

Isn’t PAD part of the normal aging process and, therefore, not preventable?

No. Although the likelihood of acquiring PAD increases with age the vast majority of diagnosed patients are able to control this progressive condition with proper medical treatment.

What are the risk factors for PAD?

Risk factors for PAD are much the same as for cardiovascular or cerebrovascular disease. They are age, smoking, hypertension, hyperlipidemia, diabetes, obesity, physical inactivity, and family history. Of these, by far the most important is cigarette smoking – especially for those smoking more than 15 cigarettes a day.

How is PAD diagnosed?

The diagnosis of PAD is relatively easy when a patient is having classic symptoms. A common presentation is the person that goes to the physician for recurring calf discomfort after a certain distance of walking, that disappears with rest, and reappears when walking the identical distance again. A physician can also make the diagnosis by noting the absence or diminution of a pulse on examination, or by hearing a noise called a bruit over a blood vessel with a stethoscope. This is why the doctor checks your pulses in places like your feet, or listens to the blood vessels in your neck.  Sometimes however, pulses are normal and there are no bruits. For this reason, several different types of tests may be used.

The ABI is a measurement performed with an electronic stethoscope and a simple office blood pressure cuff. This test measures the blood pressure at the ankle and at the arm, and the physician can easily compare the pressure at these two sites. A blood pressure that is lower in the ankle than the arm implies a blockage in the artery between the heart and the leg. Such a blockage represents peripheral arterial disease.

Several other examinations may be required to diagnose and determine the extent of the disease:

  • Medical history and physical exam
  • Ankle-brachial test
  • Treadmill exercise test
  • Reactive hyperemia test
  • Segmental pressure measurements
  • Pulse volume waveform analysis
  • Duplex arterial imaging or ultrasound imaging
  • Magnetic resonance angiography
  • Computerized tomographic angiography
  • Arteriogram

How can PAD be prevented?

Strategies to prevent PAD are similar to those that prevent coronary artery disease. They include:

  • Eat a heart-healthy diet. While certain vitamins and minerals have been shown to be helpful to heart health, fats and oils such as saturated fat and tropical oils (palm and coconut oil) have been shown to be particularly harmful, because they can speed up the development of PAD, atherosclerosis, and obesity.
  • Improve cholesterol level. This is especially important if you have a family history of vascular disease. A person's total cholesterol level should be no more than 200 milligrams per deciliter and no more than five times the HDL level (HDL is the “good cholesterol”). The LDL cholesterol (the “bad” cholesterol) should be no more than 130. For people that already have PAD we now recommend that the target LDL cholesterol should be around 70. Key strategies to improve cholesterol ratios include a heart-healthy diet, regular exercise, limited alcohol use, and prescription cholesterol-reducing drugs (if needed, almost all people that already have PAD documented will benefit from cholesterol lowering medications).
  • Exercise regularly. Exercise is an excellent tool in the prevention of vascular complications of PAD. It can slow or even reverse the process of atherosclerosis, as well as lower blood pressure and reduce cholesterol levels (consult with your physician before beginning any exercise program).
  • Control diabetes. Persons with diabetes are more likely to develop the complications of vascular disease. Diabetes is the leading cause of amputation as well as a need for renal replacement therapy in the US. Inadequacy of diabetes control is the leading cause of complications among diabetic patients.
  • Control high blood pressure (hypertension). Individuals with high blood pressure are at greater risk of developing vascular problems. Hypertension can be controlled through blood pressure-lowering medications, self-monitoring, eating a heart-healthy and low-salt diet, and engaging in regular exercise. Certain blood pressure medications are particularly helpful in increasing walking distance of patients with PAD. Likewise, some blood pressure medications may aggravate this condition.
  • Control weight. Obesity and being overweight are major risk factors for a host of serious health conditions, including PAD, high blood pressure, diabetes, heart attack, and stroke.
  • Quit smoking (or don’t start to smoke). Tobacco smoking is a major cause of PAD and stroke. Tobacco causes vasoconstriction to the peripheral arterial vessels. Since these vessels are the ones affected by PAD, there is further decrease in flow to the areas that need it most. The vasoconstrictor effects of tobacco can still be measured 24 hours after even one cigarette.

How is PAD treated?

Early intervention is very important. If patients stop smoking, if their diabetes is well controlled, if their blood pressure is normalized with either diet or medication, if their cholesterol is normalized with diet or medication – these things can help to greatly change the progression of the disease and significantly reduce the likelihood that the patient will be limited by vascular disability, require an amputation, bypass procedure or suffer a heart attack or stroke.

What are the current drug therapies for PAD?

For every PAD patient, reducing risk should be the primary goal of treatment, and healthy lifestyle changes are the first step. Medications also play a key role in treatment, with several types of drugs working together to reduce stroke and heart attack risk. One class of drugs called antiplatelet agents includes a common household medication – aspirin – that prevent platelets from sticking together and forming clots in the artery. There is also a prescription antiplatelet called clopidogrel (Plavix).

Everyone who has atherosclerosis – including patients with PAD – should be on a cholesterol lowering medication. Most patients should be on a statin. Statins lower both total cholesterol and LDL cholesterol (bad cholesterol).

Blood pressure also needs to be monitored in PAD patients and, in many cases, lowered. For patients with evidence for PAD an ACE (angiotensin converting enzyme) inhibitor, or angiotensin receptor blocker should decrease the rate of heart attack, stroke and renal (kidney) insufficiency and increase walking distance capability. Also, patients with high blood sugar should be put on antidiabetic drugs, since this condition can also lead to heart attack and stroke.

What treatments are used to specifically address leg pain?

The aforementioned types of medications, combined with the right lifestyle changes, can reduce a patient’s stroke and heart attack risk. But none of these therapies address the leg pain of PAD called claudication, which requires its own treatment strategy. Pain from intermittent claudicating is caused when leg muscles do not receive the oxygen rich blood required during exercise. The pain can be severe enough to hinder a person from walking.

There are three major options available:

  1. Discontinue cigarette smoking completely and permanently. This not only prevents the progression of the atherosclerosis, but also may improve walking tolerance.
  2. Begin a structured exercise program that includes walking on a treadmill or walking outside for about 30 to 40 minutes a day (rest when leg pain begins and resume walking when pain subsides).
  3. Begin medication. There are two drugs available in the United States: Pentoxifylline (Trental), which has been available for several years, and a drug called cilostazol (Pletal), which was approved in 1999. Cilostazol has been shown to be effective in increasing the walking distance in patients who have exertional calf discomfort. Your physician can tell you if either medication is right for you or in combination with exercise therapy or other treatments.

What other treatment options are available?

PAD can be treated with angioplasty alone or in combination with stenting, and with bypass surgery. In extreme cases (3-6%) amputation of the affected limb may be necessary.

How common is continued leg pain after a bypass?

It is quite common for claudication to persist after surgery but ideally this symptom should be less severe. This is because it is usually not possible for the surgeon to bypass all of the many blockages that exist in patients with PAD.. Recommended care and management is to embark on an exercise rehabilitation program in a supervised setting. Such a program usually involves treadmill walking at least three times a week. These programs are often administered by vascular specialists, or at the Vascular or Cardiac Rehab centers usually located in nearby hospitals. A vascular internist or cardiologist should supervise the care.

What treatment options are in development for PAD?

Multiple combination therapies have been proposed for the treatment of PAD including  combinations of drug and laser therapy.  Several trials of growth factors to grow new vessels have not yielded additional satisfactory treatments.  If bypass and angioplasty are no longer options, eligibility for current trials should be considered.

For further information from the U.S. Department of Health and Human Services: www.aboutpad.org

Finding a Physician

The Society for Vascular Medicine and Biology will let you search their database of qualified vascular specialists. This website is located at http://www.svmb.org/directory.cgi

The Society of Cardiovascular and Interventional Radiology offers a service called "Find An Interventional Radiologist Near You" that can be found at this link: http://www.scvir.org/locate/index.htm

The American Association of Vascular Surgeons offers a service called "Find A Physician" that can be found at this link: http://www.vascularweb.org.


Sources

Drug Treatment of Peripheral Artery Disease. Available at: http://www.jr2.ox.ac.uk/bandolier/band29/b29-4.html.

Peripheral Artery Disease. Available at: http://www.understandingpad.com.

Vascular Disease Foundation, Peripheral Artery Disease. Available at: http://www.vdf.org.