Peripheral Vascular Disease / Peripheral Arterial Disease

What is peripheral vascular disease?

Peripheral vascular disease is a term doctors use to describe diseases of the blood vessels that carry blood to and from the body excluding those that carry blood to and from the heart and brain.  Two types of peripheral vascular diseases exist, functional and organic.  Functional vascular diseases, like Raynaud’s disease are usually short term and involve muscle spasms that come and go.  Organic vascular diseases like peripheral arterial disease, however, involve structural problems in blood vessels like inflammation and tissue damage.

What is peripheral arterial disease?

Peripheral arterial disease is the most common form of peripheral vascular disease, and doctors often use the two terms interchangeably.  In this condition, the blood vessels that carry blood away from the heart (arteries) become hardened and restricted due to fatty deposits that build up on their walls, a disease process called atherosclerosis or arteriosclerosis.  This condition is closely associated with coronary and carotid artery diseases, diseases in which the arteries supplying the heart and brain become narrowed by the same atherosclerotic process that affects peripheral arteries.  Arteries of the legs, arms, and kidneys are most often affected by peripheral arterial disease, but the disorder can limit blood flow to any organ.

What are the risk factors for peripheral arterial disease?

This disease affects approximately 10 million people in the U.S. and usually occurs in patients 50 years and older.  With 5% of people over 50 and 20% of people over 70 affected, peripheral arterial disease is the most significant cause of disability among the elderly.  Smokers are 3-4 times more likely to have peripheral arterial disease than nonsmokers.  In addition to age and smoking history, risk factors for the condition include a family history of atherosclerosis or coronary artery disease, obesity, diabetes, physical inactivity, high blood pressure, kidney disease requiring hemodialysis, high LDL and low HDL cholesterol, and high cholesterol or high saturated fat diets. 

What causes peripheral arterial disease?

Peripheral arterial disease usually occurs due to atherosclerotic narrowing in the arteries of the body.  Atherosclerosis will often affect the blood vessels of the arms and legs before affecting those of the heart and brain.  Atherosclerosis occurs when fatty substances combine with cholesterol, cellular waste, and calcium to form a plaque that builds, lining an artery and causing it to become narrow and hard.  This plaque can inhibit blood flow and can break off and lodge in smaller blood vessels.  Atherosclerosis occurs by a complex process of damage beginning in childhood and continuing to develop throughout adult life.   Blood vessel damage because of an arm or leg injury or infection may also cause peripheral arterial disease.

What are the symptoms, dangers, and complications of peripheral arterial disease?

Many people are diagnosed with peripheral arterial disease even though they have no symptoms.  The symptoms of peripheral arterial disease vary according to the body part or organ affected.  Ischemia occurs when a part of the body does not get the oxygen it needs because of limited blood flow.  If ischemia occurs in the legs or arms, it can cause coldness, bluing, or even tissue death called gangrene.  If it occurs in the heart, it causes a heart attack; in the brain, it causes a stroke.  Symptoms of peripheral vascular disease in the arms and legs include the following: leg pain called intermittent claudication that occurs when a patient walks but stops when the patients rests; numbness in the arms, legs, or feet at rest; loss of hair on the legs or feet; paleness or cyanosis of the legs; and faint or absent pulse in a limb.  Complications can usually be prevented with adequate treatment, but may include limb injury or infection, open sores called ischemic ulcers, and impotence.  Smoking, uncontrolled diabetes, and hypertension can accelerate the progression of this disease.  Patients with peripheral arterial disease should, if they have not already been diagnosed with a heart condition, be cautious because of this condition’s close association with cardiac problems.  Seventy five percent of people with peripheral arterial disease, when they die, die of a coronary or cerebrovascular event, generally a heart attack or stroke.

How do doctors diagnose peripheral arterial disease?

If a patient presents with symptoms or a decreased pulse in the extremities, a doctor may want to see if there is an abnormal difference between the blood pressure in the ankle and arm; the result of this test is a ratio called the ankle/brachial index (ABI).  A normal ABI would indicate that the blood pressure in the arteries of the ankles is at least 90% of the blood pressure in the arm.  Additionally, he may want to see the results of a doppler ultrasound in the affected extremity.  A Doppler ultrasound is noninvasive and uses sound waves to measure flow rates in blood vessels in order to detect narrowing or blockages.  An angiogram may help him by showing him a picture of the arteries so that he can see the extent of the damage and investigate options for treatment. To obtain an angiogram, a doctor injects dye into an artery to see it in an x-ray. 

What are the treatment options for peripheral arterial disease?

For many patients, lifestyle changes alone are sufficient to manage peripheral arterial disease.  For other patients, dieting, exercising, and quitting smoking will not be enough to help their symptoms or stop the progression of their artery disease, and they may need to take medications or have a procedure.  Medications can help a patient lower his LDL cholesterol and blood pressure, prevent or dissolve blood clots, and reduce leg pain.  Statins are drugs that can help lower cholesterol.  Angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), beta blockers, calcium channel blockers, and diuretics can help lower blood pressure.  Cilostazol and pentoxifylline are drugs that can help a patient walk longer without leg pain by increasing the amount of blood that can reach legs. 

If arterial damage is severe and blood flow to a limb is considerably blocked such that symptoms are disabling, pain from inadequate circulation to an extremity occurs at rest, or limb loss is imminent, a patient may need to have a procedure to restore blood flow (revascularization procedure).  In serious cases when a blockage in an artery extends over a long portion, a surgeon may perform a bypass grafting surgery by either using a synthetic (man-made) blood vessel or removing a vein from another part of the body and placing it as an alternative route so that blood can bypass an occluded artery.  Catheter-based procedures are less invasive methods that can be used in many cases instead of an open surgery bypass graft.  To access the blocked artery, a doctor makes a small incision through which he inserts a thin wire to thread to the site of the problem.  At the blocked point, the doctor can perform what is called an angioplasty by inflating a small balloon at the end of the wire to force the blood vessel to become larger.  Doctors usually place a small, netted tube called a stent at the blocked point to help keep the artery open.  A patient may need thrombolytic therapy if his artery has been blocked by a blood clot.  This procedure is similar to angioplasty, but instead of inflating a balloon at the narrowed point, the doctor will inject drugs that are designed to dissolve clots in order to clear the artery and restore circulation to a restricted limb.

The most important therapy for patients with peripheral arterial disease is exercise.  Patients afflicted with this condition should start slowly if necessary but should begin a program in which they exercise at least 3-4 times a week.  When exercising, people with intermittent claudication need to alternate exercise and rest periods as they try to increase the amount of time that they can exercise without having to stop because of leg muscle pain.