2010-10-09 / Columnists

Maintaining Your Health on Mackinac

Peripheral Arterial Disease Affects Circulation in Legs, Feet
By Yvan Silva, M.D.

Peripheral arterial disease, commonly referred to as PAD, is a condition affecting blood circulation to the lower extremities, especially the legs and feet. Arteries carry blood pumped by the blood throughout the body. The arterial system has a smooth lining that provides optimal blood flow and prevents clotting. As arteriosclerosis sets in, hardening the walls of the arteries and fatty deposits, called plaques, build up in the walls, arteries slowly narrow and may become blocked, compromising blood flow.

Several factors play a role in development of this disease process. Smoking is the predominant risk factor. Stopping smoking is essential in the treatment process, since even one or two cigarettes a day can affect it adversely. Diabetes is also a significant risk factor. Strict control of sugar is very important in preventing progression. High blood pressure and high cholesterol levels are also known risk factors, as is aging – PAD occurs more frequently after age 55.

Painful cramping of the hip muscles or calf muscles in the legs during walking can become severe enough to hinder walking. As demand by the leg muscles increases during walking, insufficient blood flow leads to pain; this is relieved by stopping to rest and is called intermittent claudication (claudicare: to limp.) Weakness, numbness, and heaviness of the legs without pain can be indicative. Color changes in skin of the legs and feet and poor healing of wounds, chronic sores that do not heal promptly are important signs. Burning or aching of the feet and toes, especially when lying flat, is experienced in late stages.

PAD affects approximately 20% of adults over the age of 55 years. It is estimated that 27 million people are affected in the United States and Europe. It is important to recognize that approximately half the people with PAD have no symptoms. The occurrence of PAD increases with age, prolonged exposure to smoking, diabetes and hypertension, and among people of advanced age with these risk factors, the prevalence may approach 50%. Establishing a diagnosis of PAD is important in order to prevent further deterioration and to treat the existing condition.

The usual physical examination for this condition includes the assessment of arterial pulses in the groin, behind the knees, and the feet. The presence of abnormal sounds heard with the stethoscope in these areas, called bruits, may be suggestive of narrowing in these locations, however, further testing is required to determine the degree of disease that may be present. The most widely accepted and objective definition of PAD is measurement of ankle blood pressure by a Doppler device, which amplifies blood flow. The ratio of the ankle systolic blood pressure to that measured in the brachial artery (above the elbow) should be 0.90. This ankle-brachial index (ABI) is the ratio, and when less than that, it is suggestive of PAD. Testing for PAD is becoming increasingly available in vascular laboratories in clinic and hospital settings. In severe cases, when the narrowing or obstruction threatens the viability of the extremity, dye studies of the arteries with bypass grafts are indicated to restore circulation.

After the diagnosis of PAD is made, the best treatment to stop or reverse build-up of plaque in the arteries is instituted. Symptoms of leg claudication, ability to walk increasing distances, and quality of life can be improved by smoking cessation, a structured exercise program, control of blood sugar and hypertension, and other indicated medications. There is a strong correlation between PAD and the incidence of disease in the coronary arteries and the cerebrovascular circulation. Testing of these systems may be warranted.

Dr. Silva is a professor of surgery at Wayne State University and a resident of Woodbluff on Mackinac Island.

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