1 Foot 2 Foot

There's a good chance you've never heard of peripheral arterial disease, or PAD. But this blockage of the leg arteries affects an estimated 8-12 million people in the U.S. alone. The condition can lead to painful leg symptoms, but most people experience no symptoms at all, and the disease is dangerously underdiagnosed.

1Foot 2Foot is taking a proactive role by providing in- office vascular screening to diagnose PAD. This simple and painless test is covered by most insurance plans and provides information that can be lifesaving.

Vascular specialists understand that PAD is both underdiagnosed and undertreated. The statistics are staggering: the prevalence of PAD is higher than that of stroke and similar to that of MI. Between 3 and 5 million Americans have intermittent claudication or exertional leg pain due to vascular disease, and between 8 and 10 million have PAD. Mortality for established PAD is estimated at 4-6% per year. For those with critical limb ischemia and the lowest ankle-brachial index (ABI), the outcomes are even worse. This group has an annual mortality rate approaching 10%. Failure to diagnose PAD in its early stages leads to increased morbidity and mortality, as well as a marked decrease in quality of life. The strong correlation between PAD and coronary artery disease (CAD) also makes PAD a reliable indicator of CAD in otherwise asymptomatic patients.

These statistics have prompted recent efforts by vascular specialists to identify patients at risk for PAD, confirm the diagnosis, and refer them for the optimal treatment at earlier stages of the disease. Yet most patients are not referred to a vascular specialist until their disease has progressed, at which point treatment options become limited. These patients may have signs or symptoms of PAD, but due to lack of knowledge by their primary physicians, are not treated until their disease has reached advanced stages. The principal challenge for vascular specialists is to help referring physicians accurately detect the symptoms of the disease earlier, when multiple treatment options are available.

Fewer than 50% of patients with symptoms and PAD have classic symptoms of intermittent claudication. Classic (Rose) claudication is defined as onset of symptoms in a major muscle group of a limb that begins at reproducible distances and resolves when the patient stops and stands still. The majority present with atypical symptoms, describing discomfort after walking variable distances or sometimes while at rest. These patients also must sit or lay down for relief of their symptoms.

A thorough pulse exam and the ABI are important components of the diagnosis for these patients. Patients should remove their shoes, socks, and slacks. All four pulses should be palpated in a limb, and the feet should be examined for skin breakdown, ulcers, paleness, and other indicators. It is a misconception that all PAD patients present with cold feet, no hair on their legs, and dystrophic toenails. Many with normal circulation present this way, while others with advanced PAD may not have these signs.

An ABI should also be obtained. The ABI is our single best screening test for cardiovascular disease. It is even better than the EKG, a common test performed by primary care physicians. The ABI is superior to a cholesterol level, blood sugar, or hemoglobin A1C test in identifying significant risk of MI, stroke, and risk of cardiovascular death. ABI testing is simple, and medical assistants can be taught onsite how to perform this test in 15 minutes or so. The ABI result identifies whether the patient has PAD, but also establishes his or her risk of heart attack and stroke, and ultimately, mortality. If an ABI value is abnormal, but symptoms do not support a diagnosis of PAD, the mere presence of an abnormal ABI remains vitally important because of its value in predicting heart attack, stroke, and death. The 5-year mortality rate approaches 30%, so it is quite possible that 30% of these patients with an abnormal ABI will die in 5 years. The ABI is also noninvasive, can be performed quickly, and is easily performed by all primary care physicians in their practices.

Who Should Be Tested?

The ABI should be a standard diagnostic test for many patients. A formal program of PAD detection should include testing any patient over 50 years of age with a history of tobacco use or has diabetes, or anyone over age 70 regardless of risk factors (PARTNERS Study, Hirsch, AT, et al. JAMA 2001;286). You should expect that one in three of these patients will have PAD, either isolated or in combination with CAD.

Is the ABI Accurate?

Forty percent of PAD patients will have diabetes mellitus. Diabetics and many elderly patients have stiff, noncompliant arteries at the ankles due to calcium in the walls that cannot be compressed with a blood pressure cuff. If the examiner can still hear a Doppler signal at a pressure level of 250 mm Hg or more, the patient should be referred to a specialist. Despite the “supranormal” ankle pressures, these patients probably have PAD.

Another limitation is in patients with aortoiliac disease, or disease above the groin. In this case, patients may have normal ABIs at rest. In fact, you can feel their pulses in their feet, but the history suggests claudication. These could even be patients reporting classic symptoms of exertional (Rose) leg pain. Even with a normal ABI at rest and a normal pulse, these patients should be exercised and can be referred to a specialist to have a stress ABI performed. After stress testing, the ABI will likely fall, and they will lose their palpable pulse.