Peripheral Endarterectomy

Definition
Purpose
Demographics
Description
Diagnosis/Preparation
Aftercare
Risks
Normal results
Morbidity and mortality rates
Alternatives

Definition

A peripheral endarterectomy is the surgical removal of fatty deposits, called plaque, from the walls of arteries other than those of the heart and brain. The surgery is performed when plaque blocks an artery and obstructs the flow of blood and oxygen to other parts of the body, most commonly the legs but also the arms, kidneys, or intestines. The peripheral arteries most often treated with endarterectomy are those that supply the legs, especially the aortoiliac arteries in the pelvic area. Other arteries that may be treated with endarterectomy include the femoral arteries in the groin, the renal arteries that supply the kidneys, and the superior mesenteric arteries that supply the intestines.

Purpose

Endarterectomy surgeries are performed to treat advanced peripheral arterial disease (PAD). PAD most often occurs as a result of atherosclerosis, a condition characterized by the gradual build up of fats, cholesterol, cellular waste, calcium, and other substances on the inner walls of large and medium-sized arteries. Plaque, the hardened, waxy substance that results from this build up, can cause narrowing (stenosis) of an artery and block the flow of blood and oxygen. Peripheral enarterectomies are performed to reopen blocked arteries and to restore blood flow in the body (revascularization). helping to prevent heart attack, stroke, the amputation of a limb, organ failure, or death.

Demographics

People who have been diagnosed with PAD caused by atherosclerosis are at high risk of arterial blockage (occlusion) and are candidates for peripheral endarterectomy. Occlusive arterial disease is found in 15 to 20% of men and women older than age 70. When found in people younger than 70, it occurs more often in men than in women, particularly in those who have ever smoked or who have diabetes. Women with PAD live longer than men with the same condition, which accounts for the equal incidence in older Americans. African- Americans have been shown to be at greater risk for arterial occlusion than other racial groups in the United States.

Description

PAD is a progressive occlusive disease of the arteries, common in older people who have ever smoked or who have diabetes. Although there are other forms of arterial disease that affect peripheral arteries (Buerger’s disease, Raynaud’s disease, and acrocyanosis), PAD in most people is caused by wide spread artherosclerosis, the accumulation of plaque on the inner lining (endothelium) of the artery walls. Most commonly, occlusive PAD develops in the legs, including the femoral arteries that supply the thighs with blood or in the common iliac arteries, which are branches of the lower abdominal aorta that also supply the legs. The arteries that supply the shoulders and arms are less commonly affected. Branches of the aorta that deliver blood to the kidneys, the infrarenal aorta and renal arteries, can become narrowed as a result of artherosclerosis, but are only rarely blocked suddenly and completely, a condition requiring immediate surgery. Even more rare is blockage of the branches that supply the liver and spleen.

The development of atherosclerosis and PAD is influenced by heredity and also by lifestyle factors,

KEY TERMS

Atheroma— A collection of plaque (lesion) blocking a portion of an artery.

Atherosclerosis (arteriosclerosis)— A process of thickening and hardening of large and medium-sized arteries as a result of fatty deposits on their inner linings.

Ischemia— An inadequate blood supply (circulation) in an area of the body when arteries in the area are blocked.

Peripheral arterial disease (PAD)— An occlusive disease of the arteries most often caused by progressive artherosclerosis.

Peripheral endarterectomy— The surgical removal of fatty deposits, called plaque, from the walls of arteries other than those of the heart and brain.

Plaque— A collection of wax-like fatty deposits on the insides of artery walls.

Restenosis— The repeat narrowing of blood vessels that may occur after surgical removal of plaque when preventive measures are not taken.

Revascularization— Retoring normal blood flow (circulation) in the body’s vascular (veins and arteries) system.

Stenosis— The narrowing of a blood vessel.

such as dietary habits and levels of exercise . The risk factors for atherosclerosis include:

• high levels of blood cholesterol and triglycerides
• high blood pressure
• cigarette smoking or exposure to tobacco smoke
• diabetes, types I and II
• obesity
• inactivity, lack of exercise
• family history of early cardiovascular disease

Just as coronary artery disease (CAD) can cause a heart attack when plaque blocks the arteries of the heart, or blockage in the carotid artery leading to the brain can cause a stroke, blockage of the peripheral arteries can create life-threatening conditions. When peripheral arteries have become narrowed by plaque accumulation (atheroma), the flow of oxygen-carrying blood to the arms, legs, or body organs will be interrupted, which can cause cell death from lack of oxygen (ischemia) and nutrition. Normal growth and cell repair cannot take place, which can lead to gangrene in the limbs and subsequent amputation. When blood flow is blocked to internal organs, such as the kidneys or intestines, the result of tissue death can be the shut-down of the affected organ system and systemic (whole body) poisoning from waste accumulation. Death can result if emergency surgery is not performed to correct the blockage.

In some cases, the body will attempt to change the flow of blood when a portion of an artery is blocked by plaque. Smaller arteries around the blockage will begin to take some of the blood flow. This adaptation of the body (collateral circulation) is one reason for a lack of symptoms in some people who actually have PAD. Symptoms usually occur when the blockage is over 70% or when complete blockage occurs as a result of a piece of plaque breaking off and blocking the artery. Blockage in the legs, for example, will reduce or cut off circulation, causing painful cramping in the legs during walking (intermittent claudication) and pain in the feet during rest, especially during the night. When an artery gradually becomes narrowed by plaque, the symptoms are not as severe as when sudden, complete blockage occurs. Sudden blockage does not offer time for collateral vessels to develop and symptoms can be equally sudden and dramatic. Possible symptoms of reduced blood flow in the most typically affected arteries include:

• Arteries of the arms and legs: Gradual blockage creates muscle aches and pain, cramping, and sensations of tiredness or numbness; sudden blockage may cause severe pain, coldness and numbness. A leg or arm may become blue (cyanotic) from lack of oxygen. No pulse will be felt. Paralysis may occur.
• Lower aorta, femoral artery, and common iliac arteries: Gradual narrowing causes intermittent claudication affecting the buttocks and thighs. Men may become impotent. Sudden blockage will cause both legs to become painful, pale, and cold. No pulse will be felt. Legs may become numb. The feet may become painful, infected, or even gangrenous when gradual or complete blockage limits or cuts off circulation
• Renal arteries: Gradual narrowing may produce no symptoms and no change in kidney function. Sudden, complete blockage may cause sudden pain in the side and bloody urine. This is an emergency situation.
• Superior mesenteric artery: Gradual narrowing causes steady, severe pain in the middle of the abdomen about 30 to 60 minutes after a meal. Nutrients are lost and weight loss is common. Sudden, complete blockage causes severe abdominal pain, vomiting, and the urge to move the bowels. Blood pressure falls, intestinal gangrene may develop, and the patient may go into shock. This is an emergency situation.

Sudden, complete occlusion of an artery can also happen when a clot (thrombus) forms in an already narrowed artery. Clot formation (thrombosis) can occur anywhere in the body and travel to a narrowed portion of an affected artery and become lodged (embolism), blocking blood flow. Clots can sometimes be dissolved with anticoagulant drug therapy. When this therapy is not effective or a life-threatening blockage occurs suddenly, clots can be surgically removed using thromboendarterectomy, a procedure similar to peripheral endarterectomy.

Early treatment for PAD may include medical treatment to reduce the underlying causes: lowering cholesterol, lowering blood pressure, stopping smoking, increasing exercise, and reducing the likelihood of clot formation. Clot-dissolving drugs (thrombolytic drugs) may also be used to remove a clot medically rather than to perform surgery. When these measures are not effective, or an artery becomes completely blocked, peripheral endarterectomy may be performed to remove the blockage (see also angioplasty and peripheral vascular bypass surgery ). Treatment of risk factors must continue, because surgery only corrects the immediate problem, not the underlying causes.

Peripheral endarterectomy works best in narrow areas like the leg where the artery can be easily accessed, or when there is complete blockage of an artery by an atheroma that is short in length. Endarler arteries lower in the leg or in the foot or arm. Drug therapy, angiography , stent placement, or surgical bypass may be used to treat blockages of the arteries in these are

Patients undergoing peripheral endarterectomy will typically be given general anesthesia. The surgery is an open surgical procedure in which a vascular surgeon makes a relatively large incision in the outer skin to access the obstructed artery being treated. In order to perform the surgery, the blood that normally flows through the artery must first be rerouted through a tube connecting the blood vessels below and above the surgical site. The surgeon will then cut the obstructed artery lengthwise and will use surgical tools to clean away the accumulation of plaque. The hard, waxy substance comes out fairly easily, sometimes in a single piece. The artery will then be sutured closed or patched with a piece of a vein, usually from the patient’s leg, to enlarge the repaired artery and prevent later narrowing from post-operative scarring. The entire procedure will take about one hour if there are no complications.

Diagnosis/Preparation

A complete patient history is essential to diagnosis, particularly information about family members who may have had diabetes or early cardiovascular disease. Symptoms will be important diagnostic indicators, letting the physician know what areas of the body may have reduced blood flow. Blood pressure will be taken in the arms and legs. Pulses will be measured in the arms, armpits, wrists, groin, ankles, and behind the knees. This will show where blockages may exist, since the pulse below a blockage is usually absent. Additionally, a stethoscope will be used to listen for abnormal sounds in the arteries that may indicate narrowing. Blood flow procedures may be performed, including:

• Doppler ultrasonography—direct measurement of blood flow and rates of flow, sometimes performed in conjunction with stress testing (exercise between tests).
• Angiography—an x-ray procedure that provides clear images of the affected arteries before surgery is performed.
• Blood tests—routine tests such as cholesterol and glucose, as well as tests to help identify other causes of narrowed arteries, such as inflammation, thoracic outlet syndrome, high homocycteine levels, or arteritis.
• Spiral computed tomography (CT angiography) or magnetic resonance angiography (MRI)—less invasive forms of angiography.

If ultrasonography or angiography procedures were not performed earlier to diagnose arterial blockage, these tests will be performed before surgery to evaluate the amount of plaque and the extent and exact location of narrowing. Aspirin therapy or other clot-prevention medication may be prescribed before surgery. Any underlying medical condition, such as high blood pressure, heart disease, or diabetes will be treated prior to peripheral endarterectomy to help get the best result from the surgery. Upon admission to the hospital, routine blood and urine tests will be performed.

Aftercare

After the peripheral endarterectomy, the patient’s blood pressure, temperature, and heart rate will be monitored in a hospital recovery room for an hour or more, and the surgical site will be checked regularly. The patient will then be transferred to a concentrated care unit to be observed for any sign of complications. The total hospital stay may be two to three days. When the patient returns home, activities can be resumed gradually. Walking and strenuous activity may be restricted, especially if surgery was performed on the groin or leg. During recuperation, the patient may be given pain medication as needed and clot prevention (anticoagulant) medication. Patients will be advised to reduce the risk factors for artherosclerosis in order to avoid repeat narrowing or blockage of the arteries. Repeat stenosis (restenosis) has been shown to occur frequently in people who do not make the necessary changes in lifestyle, such as changes in diet, exercise, and quitting smoking. The benefits of the surgery may only be temporary if underlying disease, such as arther-osclerosis, high blood pressure, or diabetes, is not also treated.

Risks

The risks associated with peripheral endarterectomy primarily involve the underlying conditions that led to blockage of arteries in the first place. Embolism is the most serious postoperative risk; a clot or piece of tissue from the endarterectomy site that may travel to the heart, brain, or lungs can cause heart attack, stroke, or death. Restenosis, the continuing build-up of plaque, can occur within months to years after surgery if risk factors are not controlled. Other complications may include:

• reactions to anesthesia
• breathing difficulties
• changes in blood pressure
• nerve injury
• postoperative bleeding

Normal results

The outcomes of peripheral endarterectomy as a treatment for arterial blockage are usually good. Blood flow can be restored quickly to relieve symptoms and help prevent heart attack, stroke, organ failure, or limb amputation.

Morbidity and mortality rates

Morbidity and mortality depend upon the artery involved, the extent of the blockage, and the patient’s overall condition, which directly influences response to the surgery. Time is also a factor. In cases of sudden and complete blockage of the mesenteric arteries, for example, only immediate surgery can save the person’s life. Although death does not frequently occur during peripheral endarterectomy surgery, patients with widespread atherosclerosis and PAD have been shown to have increased morbidity and mortality associated with

WHO PERFORMS THE PROCEDURE AND WHERE IS IT PERFORMED?

Peripheral endarterectomy is performed in a hospital operating room by a vascular surgeon.

coronary artery disease, because of the common risk factors, such as cigarette smoking, high blood pressure, and diabetes. PAD patients with diabetes are shown to represent 50% of all amputations. However, only a small percentage of patients undergoing peripheral endarterectomy will suffer limb loss or associated disability and reduced quality of life.

Alternatives

Peripheral endarterectomy removes plaque directly from blocked arteries; there is no alternative way to mechanically remove plaque. However, there are alternative ways to prevent plaque build-up and reduce the risk of narrowing or blocking the peripheral arteries. Certain vitamin deficiencies in older people, for example, are known to promote high levels of homocysteine, an amino acid that contributes to atherosclerosis and a higher risk for PAD. Some nutritional supplements and alternative therapies that are recommended to help promote good vascular health include:

• Folic acid can help lower homocysteine levels and increase the oxygen-carrying capacity of red blood cells.
• Vitamins B₆ and B₁₂ help lower homocysteine levels.
• Antioxidant vitamins C and E work together to promote healthy blood vessels and improve circulation.
• Angelica, an herb that contains Coumadin, a recognized anticoagulant, may help prevent clot formation in the blood.
• Essential fatty acids, as found in flax seed and other oils, can help reduce blood pressure and cholesterol, and maintain elasticity of blood vessels.
• Chelation therapy may be used to break up plaque and improve circulation.

Resources

BOOKS

Cranton, Elmer MD., ed. Bypassing Bypass Surgery: Chelation Therapy: A Non-Surgical Treatment for Reversing Arteriosclerosis, Improving Blocked Circulation, and Slowing the Aging Process. Hampton Roads Pub. Co., 2001.

QUESTIONS TO ASK THE DOCTOR

• Why do I need this surgery?
• How will the surgery improve my condition?
• What kind of anesthesia will I be given?
• What are the risks of having this surgery?
• How many of these procedures have you performed? How many of the surgery patients had complications after surgery?
• How can I expect to feel after surgery? How long will it take me to recover?
• What are my chances of developing this problem again after the surgery?
• What can I do to help prevent developing this condition again?

McDougal, Gene. Unclog Your Arteries: How I Beat Artherosclerosis. 1st Books Library, Nov 2001.

ORGANIZATIONS

American Heart Association (AHA). 7272 Greenville Ave., Dallas, TX 75231. (800) 242-8721. http://www.americanheart.org.

Vascular Disease Foundation. 3333 South Wadsworth Blvd. B104-37, Lakewood, CO 80227. (303) 949-8337; (866) PADINFO (723-4636). http://www.vdf.org.

OTHER

Hirsch, Alan T. MD. “Occlusive Peripheral Arterial Disease.” The Merck Manual of Medicine. Home Edition [cited July 7, 2003]. http://www.merck.com/pubs.

“Patient Information: Frequently Asked Questions.” Peripheral Vascular Surgery Society [cited July 7, 2003]. http://www.pvss.org.

L. Lee Culvert