How To Detect Peripheral Arterial Disease

Author(s): 
By Peter A. Blume, DPM, Jonathan J. Key, DPM, Bauer E. Sumpio, MD, PhD

Peripheral arterial disease (PAD) affects 12 million people in the United States.1 More than half of the patients with PAD are asymptomatic or have atypical symptoms.2 PAD is a narrowing of blood vessels characterized by atherosclerotic occlusive disease of the lower extremities, restricting blood flow. There are many causes of PAD. In addition to a major risk factor like smoking, diseases such as diabetes, Buerger’s disease, hypertension and Raynaud’s disease predispose patients to developing PAD.
Inadequate perfusion to the lower extremity will always result in a non-healing wound, which often leads to infection, tissue loss and amputation. Tissue loss in the lower extremity can be due to PAD, which reduces the supply of oxygen, nutrients and soluble mediators involved in the tissue repair and maintenance process. A lack of tissue perfusion decreases tissue resilience, leads to rapid death of tissue and impedes wound healing.3
Podiatric physicians play a pivotal role in assessing the disease and can often be the first to recognize and diagnose either the onset or advanced stages of PAD.

What You Should Know About The Common Symptoms
In order to identify risk factors for PAD, one must obtain a thorough patient history and perform a complete physical examination. These patients may experience pain in the lower extremity musculature due to inadequate perfusion. Early symptoms include an achy, tired sensation of affected muscles, usually in the legs. Intermittent claudication is the most common and classic symptom of PAD. Patients will describe it as pain, cramping or aching in the calves, thighs or buttocks that occurs when walking and is relieved by rest.1

Complaints of pain may be acute or chronic in onset. The sudden onset of extremity pain may be associated with coolness and/or numbness resulting from acute thrombosis of distal vasculature. Patients presenting with chronic pain may relate symptoms of burning pain that are relieved by elevation and aggravated by dependency. These patients are deemed to have rest pain. Critical limb ischemia, which involves the development of tissue loss or gangrene in the lower extremity, is a more critical manifestation of PAD.1
Obtaining a thorough history will influence the decision process when treating patients who have PAD. Past medical, past surgical, social, ambulatory status and nutritional histories all play an important role in arriving at an appropriate course of treatment for the patient.

Essential Keys To The Vascular Examination
The vascular examination begins with the two most important components, visual inspection and palpation of lower extremity pulses. One should note and evaluate the color and integrity of the skin. When patients have a pallor upon elevation and rubor upon dependency, this is often the first indicator of vascular insufficiency. After elevation of the extremity, keep in mind that it normally takes less than 20 seconds for the return of blood to the dependent extremity. This is a useful marker in evaluating the severity of the vascular deficit.
One should also inspect the skin for trophic changes. When patients have PAD, the integument becomes dry, shiny, fissured and hairless. You may also note brittle and dystrophic nails. Also be sure to inspect the interdigital spaces for maceration and ulcerations.

Proceed to assess the skin temperature of the affected limb and compare it to the contralateral limb, noting any coolness. Temperature is a good indicator of blood flow in the dermal vessels.3 One should palpate the femoral, popliteal and pedal pulses routinely in every physical examination. However, keep in mind that palpable pulses do not preclude the presence of limb threatening ischemia.4 Also be aware that the dorsalis pedis has been reported to be absent in 8.1 percent of healthy individuals and the posterior tibial pulse is absent in 2.0 percent of the population as a whole.1 Therefore, there is a high false positive and false negative rate when it comes to evaluating pulses by palpation.1 If the pulses are nonpalpable, proceed to assess the pulses with a hand-held Doppler.

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