What is peripheral arterial disease (PAD)?
Peripheral arterial disease (PAD) -- also known as peripheral vascular disease, atherosclerosis or hardening of the arteries -- is a disorder that occurs in the arteries of the circulatory system. Arteries are the blood vessels that carry oxygen and nutrient-rich blood from the heart to all areas of the body. PAD occurs in the arteries that carry blood to the arms and legs.
Healthy arteries have a smooth lining that prevents blood from clotting and promotes steady blood flow. In PAD, the arteries slowly become narrowed or blocked when plaque gradually forms inside the artery walls. Plaque is made of excessive fat, cholesterol and other substances floating through the bloodstream, such as inflammatory cells, proteins and calcium. If the arteries become narrowed or blocked, blood cannot get through to nourish organs and other tissues, causing damage to the tissues and eventually tissue death.
The rate at which PAD progresses varies with each individual and depends on many factors, including where in the body the plaque has formed and the person’s overall health.
What are the conditions associated with PAD?
If left untreated, patients with PAD can develop serious health problems, including:
- Heart attack: permanent damage to the heart muscle caused by a lack of blood supply to the heart for an extended time
- Stroke: interruption of the blood flow to the brain
- Transient ischemic attack (TIA): a temporary interruption in the blood supply to the brain)
- Renal artery disease or stenosis: a narrowing or blockage of the artery that supplies blood to the kidney
- Amputation: the removal of part or all of the foot or leg (rarely the arm), especially in people who also have diabetes
Development of Peripheral Arterial Disease
Your arteries are shaped like hollow tubes. Inside, they are smooth and elastic, allowing blood to flow freely.
Peripheral arterial disease starts when fatty deposits start streaking the blood vessel walls. The fatty matter builds up. This causes slight injury to your blood vessel walls. In an attempt to heal itself, the cells release chemicals that make the walls stickier. Other substances floating through your bloodstream start sticking to the vessel walls, such as inflammatory cells, proteins and calcium. The fat and other substances combine to form a material called plaque or atherosclerosis. The plaque builds up and narrows the artery.
Over time, the inside of the arteries develop plaques of different sizes. Many of the plaque deposits are hard on the outside and soft and mushy on the inside. The hard surface can crack or tear, exposing the soft, fatty inside. When this happens, platelets (disc-shaped particles in the blood that aid clotting) come to the area, and blood clots form around the plaque. The artery narrows further. Symptoms occur.
The artery may become completely blocked by plaque or a blood clot that lodges in a narrowed artery. If this occurs, the tissue below the blockage is permanently damaged and may die (gangrene). This most often occurs in the toes and feet.
PAD in Women
Have you ever had to cut short a day of shopping or sightseeing because of severe leg pain? Maybe you’ve given up golf because you can no longer walk the course.
Pain or discomfort in the legs is a common symptom of a disease called peripheral arterial disease (PAD). Up to 8-12 million Americans have PAD. Peripheral arterial disease is atherosclerosis that develops in the arteries of the legs or, less commonly, the arms. Like atherosclerosis in the heart (coronary) arteries, PAD is caused by the accumulation of fatty plaque in the blood vessel walls. As plaque builds up, the blood vessels get narrower and narrower, until they become blocked. In the coronary arteries, atherosclerosis causes chest pain or a heart attack. In the legs, atherosclerosis can cause pain, weakness, or fatigue while walking.
The dangers of PAD extend well beyond difficulties in walking, and the consequences can be far worse than missing a shopping trip or golf game. Peripheral artery disease increases the risk of developing a non-healing sore of the legs or feet. In cases of severe PAD, these sores can develop into areas of dead tissue (gangrene) that ultimately require amputation of the foot or leg.
The effects of PAD can extend beyond the affected limb. The body’s circulatory system is interconnected. Patients with atherosclerosis of the legs commonly have atherosclerosis in other parts of the body. Therefore, it’s not surprising that patients with peripheral artery disease are at increased risk for having a heart attack, stroke, transient ischemic attack (“mini-stroke,”) or problems with the kidney (renal) arteries.
Who Gets PAD?
Although PAD is a different condition than coronary artery disease, the two are related. People who have one are likely to have the other: the National Institutes of Health estimates that a person with PAD has a six to seven times higher risk of coronary artery disease, heart attack, stroke or a transient ischemic attack than the general population; a person with heart disease has a 1 in 3 chance of having peripheral artery disease in the legs (1).
Not surprisingly, the two diseases also share some common risk factors. This is because these risk factors cause the same changes in arteries in the arms and legs as they do in the coronary arteries.
PAD risk factors include:
- Age over 50
- High blood pressure
- High cholesterol
- Abdominal obesity
- Kidney disease (both a risk factor and a consequence of PAD)
Other risk factors for PAD include race – African Americans have about two times the risk for PAD as Caucasians or Asians – and a family history of heart disease or PAD.
Both woman and men are at risk for developing PAD.
As in coronary artery disease, many of these risk factors are out of your control. But, according to researchers at Cleveland Clinic (2), smoking is the single most important modifiable (changeable) risk factor for PAD and its complications. Smoking increases the risk for PAD by 400 percent and brings on PAD symptoms almost 10 years earlier. Compared with non-smokers of the same age, smokers with PAD are more likely to die of heart attack or stroke, have poorer results with heart bypass surgery procedures on the legs and are twice as likely to have a limb amputated.
Diabetes is another strong risk factor for PAD in women. When combined with other, common conditions related to diabetes such as heart disease, nerve problems in the legs and feet, visual problems, obesity and depression, adding PAD to the mix increases the likelihood that a diabetic woman will have serious mobility problems.
What are the symptoms of peripheral arterial disease?
PAD can build up over a lifetime, and the symptoms may not become obvious until later in life. For many people, the outward symptoms will not appear until the artery has narrowed by 60 percent or more.
The first noticeable symptom of PAD may be intermittent claudication -- leg discomfort, pain or cramping that develops with activity, is relieved with rest, and recurs upon resuming activity. The pain is often noticed in the calf, but may also be felt in the buttocks or thighs. Intermittent claudication symptoms may also include numbness, weakness, heaviness or fatigue in the leg muscles when walking that are relieved at rest. The pain can be severe enough to interfere with normal walking. This type of cyclical pain is caused by reduced blood flow to the leg muscles and goes away at rest because the muscles require less blood flow at rest.Other symptoms of advanced PAD may include:
- A burning or aching pain in the feet and toes while resting, especially at night while lying flat
- Cool skin in the feet
- Redness or other color changes of the skin
- Increased occurrence of infection
- Toe and foot sores that do not heal
Many people with PAD do not have any symptoms.