Peripheral artery disease (PAD), also called peripheral vascular disease (PVD) or peripheral artery occlusive disease (PAOD), is a narrowing of blood vessels that restricts blood flow. It mostly occurs in the legs, but is sometimes seen in the arms and can affect blood flow to the head and organs. The disease can cause serious health problems and adversely affect the ability to walk. The best way to reduce one's risk from PAD is to regularly exercise and eat a healthy diet.
PAD includes a group of diseases in which blood vessels become restricted or blocked. Typically, the patient has PAD from atherosclerosis, a disease in which fatty plaques form on the inside walls of blood vessels. Other processes, such as blood clots, further restrict blood flow in the blood vessels. Both veins and arteries can be affected, but the disease is usually arterial.
All the symptoms and consequences of PAD are related to restricted blood flow. PAD is a progressive disease that can lead to gangrene of the affected area. It can also occur suddenly if an embolism occurs or when a blot clot rapidly develops in a blood vessel already restricted by an atherosclerotic plaque, and the blood flow is quickly cut off.
About 12%–14% of the general population has PAD. However, only one in four people has been diagnosed with it and is receiving treatment. More than 8 million Americans age 40 and over have PAD. As an individual ages, the risk of developing PAD increases. About 20% of people over age 70 have PAD. Generally, PAD affects about one in three people with diabetes who are older than age 30.
There are many causes of PAD. One major risk factor is smoking cigarettes; this includes both firsthand and secondhand exposure to tobacco products. Diseases that can increase the chance of developing PAD are diabetes (diabetes mellitus), dyslipidemia, hypertension (high blood pressure), Buerger's disease, and Raynaud's disease.
The risk of developing PAD is two to four times greater for people with diabetes than the general population. And the mix of smoking and diabetes worsens PAD and heart disease. Dyslipidemia occurs when a person has high low-density-lipoprotein (LDL, or “bad”) cholesterol and low high-density-lipoprotein (HDL, or “good”) cholesterol. These individuals have an increased chance of developing PAD as well. Elevated blood pressure, called hypertension, also causes an increased incidence of PAD. The risk for hypertension, tobacco smoking, high total cholesterol, and diabetes can be reduced by living a healthy lifestyle, including eating a diet low in fat and high in fruits and vegetables, and exercising on a regular basis.
At the most severe stage of the disease, when the blood flow is greatly restricted, gangrene can develop in those areas lacking blood supply. In some cases, PAD occurs suddenly. This happens when an embolism rapidly blocks blood flow to a blood vessel. The patient experiences a sharp pain, followed by a loss of sensation in the affected area. The limb becomes cold and numb and loses color (pale) or turns bluish. If only one leg is affected, it is noticeably different in color from the other leg.
PAD can be diagnosed with a physical examination. The doctor compares blood pressures taken above and below the point of pain. The area below the pain (downstream from the obstruction) has a much lower or undetectable blood pressure reading. One such method is an ankle brachial pressure index (ABPI/ABI), which compares blood pressure in an arm to blood pressure in the ankle of the leg that shows symptoms of PAD. Ultrasonography also is used to diagnose and define this disease, and Doppler ultrasound can help spot blocked blood flow in an artery. CT angiography (CTA) or magnetic resonance angiography (MRA) are tests that can show images of the arteries of the legs and feet. Catheter angiography might be used to pinpoint blockages. The procedure involves inserting a long, thin tube called a catheter into an artery through a tiny incision and imaging to see blood flow.
If a person smokes or otherwise uses tobacco products, it is important to stop immediately. Exercise is essential to treating this disease. Guidelines released in 2016 emphasized that people with PAD should participate in structured exercise programs. The patient should walk until pain appears, rest until the pain disappears, and then resume walking. The amount of walking a patient can do should increase gradually as the symptoms improve. Ideally, the patient should walk 30–60 minutes per day. Infections in the affected area should be treated promptly. A change of diet is also recommended. It should include plenty of foods such as fruits, vegetables, and grains and eliminate foods containing substantial amounts of fats and sugars.
In some cases, doctors must intervene to open the blocked artery and allow blood to flow through it. A catheter also can be used in this case. The doctor guides the catheter through the arteries to the blocked area and inflates a small balloon attached to the catheter to open the artery or uses a laser or tiny blade to clean away plaque. Sometimes, a stent also is placed in the artery. Stents are small metal implants that keep arteries open. If a clot is causing the blockage, the doctor can insert a drug through the catheter that helps dissolve the clot. These catheter techniques are less invasive than surgery, requiring only a small incision. Bypass surgery might be required for severely blocked arteries. Limbs with gangrene must be amputated to prevent the death of the patient.
The prognosis depends on the underlying disease and the stage at which PAD is diagnosed. Patients should control and remove risk factors, such as smoking, immediately. In many cases, PAD can be treated successfully, but cardiovascular problems that exist with PAD may ultimately prove to be fatal. Persons with PAD have an increased risk of cardiovascular problems, such as heart disease and heart attacks. Those with PAD and claudication have an increased risk of amputation of the affected limb.
PAD can be prevented by getting help from a medical professional. Quitting smoking as quickly as possible is advised because tobacco use is the biggest risk factor for PAD. Several stop-smoking programs are available to help people quit the habit. In addition, blood pressure and cholesterol should be checked and lowered to normal levels, if necessary. A healthy lifestyle that includes plenty of fruits, vegetables, and whole grains each day is very beneficial. People with PAD should use low-fat or nonfat milk products. Foods containing saturated fats, trans fat, cholesterol, sodium (salt), and added sugar should be avoided. If overweight, it is advised to begin a program to lose weight. An exercise program can improve one's overall health, well-being, and fitness level. The risk from PAD can be reduced when the person's lifestyle is healthy.
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American College of Cardiology, Heart House, 2400 N St. NW, Washington, DC, 20037, (202) 375-6000, Fax: (202) 375-7000, (800) 253-4636, email@example.com, http://www.acc.org .
American Heart Association, 7272 Greenville Ave., Dallas, TX, 75231, (301) 223-2307, (800) 242-8721, http://www.heart.org .
Centers for Disease Control and Prevention, 1600 Clifton Rd., Atlanta, GA, 30333, (800) 232-4636, firstname.lastname@example.org, http://www.cdc.gov .
National Coalition for Promoting Physical Activity, 1100 H St. NW, Suite 510, Washington, DC, 20005, (202) 454-7521, Fax: (202) 454-7598, http://www.ncppa.org .
National Heart, Lung, and Blood Institute, P.O. Box 30105, Bethesda, MD, 20824-0105, (301) 592-8573, Fax: (240) 629-3246, http://www.nhlbi.nih.gov .
John T. Lohr, PhD
Revised by Laura Jean Cataldo, RN, EdD
Revised by William A. Atkins, BB, BS, MBA
Revised by Teresa G. Odle, BA, ELS