Lower Extremity Atherosclerosis
What is it?
Atherosclerosis is a condition in which fatty materials collect under the inner lining of the arterial wall.
As the amount of fatty material increases, it forms a thickened area, called plaque, in the artery’s inner lining. This plaque narrows and blocks the artery. Lower extremity atherosclerosis affects the arteries of the legs. Atherosclerosis is also known as hardening of the arteries.
Who gets it?
High blood pressure, high blood cholesterol levels, high stress levels, diabetes mellitus, cigarette smoking, obesity, lack of exercise, and advanced age increase a person’s chances of developing lower extremity
atherosclerosis.
What causes it?
Any one of the risk factors for atherosclerosis can cause damage to the layer of cells that lines the artery. When this happens, white blood cells, called monocytes, move from the bloodstream into the arterial wall to try to repair the damage. While there, they are transformed into cells that accumulate fatty materials, and plaque develops. Arteries that are affected by atherosclerosis lose their elasticity, and the arteries stiffen and narrow. With time, the plaque can rupture and cause blood clots, which can break away and travel to the brain, causing a stroke.
What are the symptoms?
Generally, people with lower extremity atherosclerosis have no symptoms until the artery is extremely narrowed. At this point, the most common symptom is pain in the calf muscle during exercise, called intermittent
claudication. This occurs because the blood flow can’t keep up with the muscles’ demand for oxygen. However, as the disease progresses, the patient may even feel leg pain when at rest. The pain is often worse when the leg is elevated. As the artery becomes increasingly obstructed, the lack of blood flow to the leg and foot causes the foot to feel cold and numb. The skin becomes extremely dry, and the toenails and leg hair may stop growing. The lack of blood flow can cause sores on the toes, heel, or lower leg. After a period of time, gangrene, or tissue death, can set in. Often, patients with lower extremity atherosclerosis also have other types of vascular disease, so they are at a greater risk for stroke and heart attack.
How is it diagnosed?
Your doctor will perform a careful physical examination and ask about your medical history, particularly any history of vascular disease, diabetes mellitus, high blood pressure, or high cholesterol. Your doctor may suspect lower extremity atherosclerosis based upon your description of symptoms and a physical examination of the lower leg area. By listening with a stethoscope, a doctor can hear diminished or absent pulse sounds below a certain point in the leg. There are also a number of tests that can help the doctor determine the amount of blood flow to the legs. One commonly used test is the ankle-brachial index (ABI), which is used to check the systolic blood pressure in the ankle area. Blood pressure is recorded in two values. The systolic is the top number, and is taken when the heart contracts. Doctors may measure the ankle blood pressure before and after exercise by having you walk on a treadmill in the office. Someone with intermittent claudication will not maintain a normal ankle systolic pressure after exercise. To confirm the diagnosis, your doctor may perform a test called a Doppler study to check the blood flow in your legs. Blood pressure cuffs are placed at four different locations on your legs to measure the blood pressure from the top of your leg to your ankle. The sound of the blood flow tells the doctor if there is an obstruction and how severe it is. A fifth blood pressure cuff on your arm allows your doctor to compare its blood pressure with the blood pressures in your leg. Normal blood pressure at the ankle is 90 percent of the arm pressure, but it will be less if there is narrowing of the leg arteries. If your doctor feels your treatment will require surgery, he or she may also recommend a color Doppler study, which is an ultrasound technique that creates a picture of the narrowed artery, with different colors to show different blood flow rates. Another method of seeing the rate of blood flow and any narrowing is through an arteriography or angiography. After a dye is injected into the artery, an x-ray is taken. The x-ray shows the path the dye is able to take, so your doctor can see any blockages. Doctors often use a test called the toe systolic pressure index to check blood pressure in the extremities of patients with diabetes.
What is the treatment?
Treatment for lower extremity atherosclerosis depends upon your symptoms. It can be as simple as taking medication to reduce blood clotting or to relax the blood vessels. Lifelong aspirin therapy is usually effective in thinning the blood of patients with intermittent claudication. In patients with intermittent claudication and high serum cholesterol levels, doctors often recommend a drug called an HMG-CoA reductase inhibitor. Your doctor will also recommend lifestyle changes to try to halt or reverse artherosclerosis. This includes not smoking, following a healthy diet to lower your cholesterol level, and carefully monitoring your blood sugar level if you have diabetes. If you have intermittent claudication, your doctor will recommend a regular exercise program. To begin, he or she will ask you to exercise at least 30 minutes each day. If the pain occurs during exercise, you should simply stop and rest until the pain is gone, then gradually begin again. Because exercise improves your muscle tone and endurance, it can help make other blood vessels that supply the muscle grow larger and take on some of the work of the narrowed artery. In some cases, your doctor may prescribe a drug that helps improve the delivery of oxygen to the muscles. Surgery is recommended when claudication is severe, the arteries are extremely narrowed, and non-surgical treatment has failed. One commonly used surgical procedure is called balloon angioplasty, where a catheter with a balloon on the tip is inserted into the narrowed artery. The balloon is then inflated to clear the blockage. Amputation, the surgical removal of part of the leg or foot, may be necessary if the blood flow has been cut off for too long, especially if gangrene has set in.
Self-care tips
Your can lower your risk of lower extremity atherosclerosis by controlling your blood pressure and cholesterol levels. Eat a healthy low fat, high fiber diet; stop smoking; exercise regularly, and follow your doctor’s recommendation for treatment of diabetes, if you have this condition.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
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