Arterial Plaque Can Affect Legs and Feet, Too

One of the scourges facing aging Baby Boomers is plaque - that fatty stuff that builds up inside the arteries that carry blood from the heart to the head, limbs and other structures. When plaque in the coronary arteries restricts blood flow, it's called coronary artery disease, or CAD, which can lead to chest discomfort or a heart attack. When plaque builds up in the carotid arteries of the neck, it's called cerebrovascular disease, and can trigger a stroke. When the arteries of the legs have limited blood flow due to plaque, it's called peripheral artery disease, or PAD - and if left untreated, it can result in leg pain or even amputation.

The risks from PAD, CAD and cerebrovascular disease are similar, says David S. Marks, MD, Associate Professor of Medicine at the Medical College of Wisconsin and director of the Cardiac Catheterization Laboratory at Froedtert & Medical College Clinics.

"Atherosclerosis (the medical term for arterial plaque deposits) is common," he says. "Patients with PAD are also at significant risk of coronary artery disease (CAD) and for carotid artery disease. We know those diseases run together and affect many people living in industrial societies. About 50% of patients with coronary artery disease also have either PAD or carotid artery disease."

Linked to Heart Disease
According to the National Heart, Lung and Blood Institute (NHLBI), "A person with PAD has a six to seven times greater risk of CAD, heart attack, stroke or transient ischemic attack (also called a 'mini stroke') than the rest of the population. If a person has heart disease, he or she has a 1 in 3 chance of having blocked arteries in the legs."

The American Heart Association estimates between 8 and 12 million Americans have PAD, and about 100,000 end up losing a foot or leg to amputation each year. Once regarded as a disease that affected men primarily, PAD is expected to increase among women, who tend to live longer than men and experience vascular problems later in life.

A common symptom, Dr. Marks says, is claudication, also called angina of the legs. Because blood flow to the lower limbs is restricted, patients can experience severe pain, numbness, tingling or weakness in the leg, typically the calf, or foot; in some cases, patients experience symptoms in the buttocks. Some patients with extreme leg pain may have difficulty walking short distances.

"Another symptom of PAD," he adds, "is non-healing ulcers on the legs or toes and feet. PAD can also be implicated in erectile dysfunction."

Diagnostic Exams and Tests
Diagnosing PAD is fairly straightforward, Dr. Marks says: "We begin with a good health history and physical exam. We order tests, including an ABI - arterial brachial index - which compares blood pressure in the arms to blood pressure in the ankles." The test is performed while the patient is resting, and in some cases it's followed by a second test after the patient walks on a treadmill. Additional tests could include a CT or MRI scan. In some cases, a patient might undergo an angiogram, but that test is used less for PAD than it is for coronary artery disease, he says.

Treatment Is Based on Lifestyle Changes
"With many PAD patients, we know we're treating a lifestyle disease, so treatment is conservative or non-invasive," Dr. Marks says. "We begin patients on a walking program; that's very important. Walking every day is a better way to increase blood flow and improve the efficiency of oxygen delivery than even riding a bike or swimming." Like CAD, PAD is in part a self-inflicted disease, a consequence of lifestyle choices such as overeating, living a sedentary lifestyle and smoking.

According to the NHLBI, smoking increases the risk of developing PAD three to five times. By quitting smoking, the risk for coronary artery disease and PAD decreases rapidly - 40% within five years of stopping smoking - "and for most patients, coronary artery disease is their major life-threatening risk," Dr. Marks says.

Medications
Because many PAD patients also have hypertension, high cholesterol or diabetes (or a combination), it's critical that those conditions are well managed by medication or very aggressive lifestyle change, Dr. Marks says. Other medications may be specifically prescribed for PAD - aspirin, Plavix, cholesterol-lowering drugs - but he describes these as "marginally effective in reducing claudication - but very effective in reducing overall cardiovascular risk." In some cases, vasodilators - drugs that cause blood vessels to dilate or expand - may be helpful.

Interventional Techniques
For many patients, making lifestyle changes and managing hypertension and diabetes medically can reduce their risk of PAD and CAD, he says. But in some cases, intervention beyond medication or lifestyle may be necessary.

Like CAD, PAD can be treated with bypass surgery, or angioplasty with or without stenting. But these techniques, which work well with CAD, do not necessarily have the same success rate with PAD, Dr. Marks notes. PAD patients who undergo angioplasty can later experience high rates of restenosis, or recurrence of some blockages. Stents that are placed in peripheral arteries specifically in the legs tend to twist or flex, which may make them less effective.

Bypass surgery and grafting can be successful, depending on the location and type of blockage - whether it's a single blockage or there is additional blockage beyond the bypass graft. Restenosis can also occur after PAD bypass procedures. Another technique is catheter-based excision, or atherectomy, which involves cutting away blockages from inside the vessel. This can be effective in well-chosen patients, Dr. Marks says.

"Like so many developments in medicine," he notes, "we sometimes get excited about procedures. We're pleased to perform interventions when they're needed. But the reality for most PAD patients is that it's the hard, mundane work - lifestyle changes and the overall medical management of risk factors - that make a difference."

Although PAD is a distressing diagnosis and a serious health condition, Dr. Marks says, "it's important primarily because it can be the first symptoms of atherosclerosis a patient may become aware of. It's important to treat the whole patient, because in treating PAD, you're also helping to prevent heart disease, which is life-threatening. For most patients, the best treatment is to quit smoking, start walking, and control conditions like diabetes and hypertension that also affect heart disease. It's a matter of doing the right thing for your health."

Barbara Abel
HealthLink Contributing Writer

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.