Peripheral Arterial Disease
- peripheral atherosclerosis
- chronic peripheral arterial occlusive disease
- peripheral vascular disease
Peripheral vascular disease refers to diseases of blood vessels (both arteries and veins) outside the heart and brain. There are two types of these circulation disorders:
What is going on in the body?
Atherosclerosis is a condition in which fatty deposits form inside blood vessel walls. This causes the walls to become thick and less elastic. The thickened areas are called plaques.
When these plaques grow large enough or break apart, they can block the flow of blood through the arteries. The tissues that receive blood from these arteries then begin to suffer damage from a lack of oxygen. In the arms and legs, this phenomenon results in PAD.
Atherosclerosis can also cause symptoms from narrowed arteries to the heart (coronary artery disease) or the brain (cerebrovascular disease).
Because atherosclerosis typically occurs throughout the body, persons with PAD have risks for coronary and cerebrovascular disease that range from three to six times that of others.
What are the causes and risks of the disease?
Peripheral arterial disease is generally caused by atherosclerosis
. Atherosclerosis is caused by an injury to the inside layer of the artery. It usually occurs where the artery bends or branches. Damage to the walls of the artery may be caused by a number of factors, including:
- high blood pressure
- high cholesterol
Atherosclerosis is more common in men than in women. A person's risk of atherosclerosis goes up as he or she ages. People who are sedentary are also at higher risk. PAD may also be caused by a blood clot that lodges in an artery of the arm or leg. Less commonly, PAD may be caused by a blood clot that lodges in an artery of the arm or leg.
What can be done to prevent the disease?
A person may reduce his or her risk for developing atherosclerosis
and peripheral arterial disease by:
- controlling blood cholesterol
- controlling diabetes
- controlling high blood pressure
- exercising regularly
- eating a heart-healthy diet
- not smoking
How is the disease diagnosed?
Diagnosis of PAD begins with a medical history and physical exam. The healthcare provider may detect weak or absent pulses in the affected arm or leg. With a stethoscope, the provider can often hear a "whooshing" sound of blood moving through a narrowed artery.
The provider may order a Doppler ultrasound. This special imaging method uses sound waves to detect reduced blood flow through narrow arteries. If the diagnosis is in doubt or if surgery is being considered, an angiogram may be performed. A contrast agent is injected, and with a special imaging technique the provider can see the inside of the affected arteryand measure how narrowed it is.
Long Term Effects
What are the long-term effects of the disease?
Over time, PAD can cause loss of sensation or weakness in the affected arm or leg. The artery can become so narrowed that the person has pain at rest. When the artery becomes very narrow or blocked, tissue death can set in. This is known as gangrene. When tissue in the limb begins to die, the limb usually has to be amputated.
What are the risks to others?
PAD is not contagious and poses no risk to others.
What are the treatments for the disease?
Over time, exercise can double the amount of exertion a person can take before claudication occurs. This works because the increased demand on the muscle stimulates the development of smaller arteries serving the same muscle ("collateral" circulation).
Any exercise program should be discussed first with the healthcare provider. In general, someone with PAD should walk 30 minutes a day. The person should walk until the pain is uncomfortable. After a brief rest to allow the pain to go away, the person should continue walking.
Medicines are sometimes helpful in relieving symptoms of PAD. These include:
aspirin to thin the blood
antiplatelet drugs like clopidogrel (i.e., Plavix)
pentoxifylline (i.e., Trental) or Cilostazol (i.e., Pletal) to improve the oxygen supply to the muscles
anticoagulants like warfarin (i.e., Coumadin)
- Statins to prevent the progression of atherosclerosis
For severe narrowing of arteries, several procedures are helpful. These include angioplasty, stent placement, and bypass surgery. Angioplasty is a procedure in which a tube with a balloon is inserted into the blocked artery and inflated. This is 90% successful in reopening the artery and allowing blood to flow.
After 5 years, however, almost half of these arteries close up again. Stents are rigid tubes like tiny drinking straws. They can be placed at the reopened area of the artery and reduce the rate of narrowing. Surgery can also be done to bypass the narrowed area. Bypass operations are 70% to 85% successful. Their success depends on which artery is being bypassed and the specific method used to bypass it.
What are the side effects of the treatments?
Medicines used to treat PAD may cause nausea, rash, and allergic reactions. Surgery may be complicated by bleeding, infection, or an allergic reaction to the anesthetic.
What happens after treatment for the disease?
If treatment is successful in opening the artery, the individual will have fewer symptoms. However, the problem can recur or develop in other arteries. It is important to work on lowering risk factors for atherosclerosis.
How is the disease monitored?
Persons with PAD often need regular visits with the healthcare provider. Any new or worsening symptoms should be reported to the provider.
Scientific American Medicine 2000 (updated monthly); Medical Knowledge Self Assessment Program (MKSAP 11) 1998