The vast majority of peripheral arterial disease is caused by arteriosclerosis obliterans (ASO), a progressive occlusive disease of the arteries. ASO is believed to begin by the formation of a fatty streak in the artery called atherosclerosis. These fatty streaks localize in the wall of the blood vessel and harden over time forming ASO. Complete occlusion of the artery results in disruption of blood flow to the target organ.

Arterial foot and leg ulcers occur as a result of advanced peripheral arterial disease. Occlusion of the arteries of the leg and foot impair healing resulting in ulcerations. Males are more predisposed to ASO and are subsequently more inclined to develop problems with PAD. Other contributing factors include mechanical stress, lipid disorders and high blood pressure. Tobacco use, whether smoking, snuff or chew is a significant contributing factor. Circulating levels of nicotine make the blood more acidic. As a result, nicotine makes the artery wall much more permeable to atherosclerotic plaque, increasing the likelihood of ASO.

Wagner described the classification used to describe arterial ulcers and wounds used most commonly today.

Wagner Grade 0 - Irritation of the skin with no break in the skin.

Wagner Grade 1 - Superficial wound with no infection. Skin is intact but erythematous.

Wagner Grade 2 - Partial to full thickness erosion of the skin. Infection possible. No deep tissue or bone involvement.

Wagner Grade 3 - Full thickness, deep tissue involvement. Wound is infected with probably bone infection.

Wagner Grade 4 - Deep, extensive infection with gangrene.

Diagnosis of peripheral arterial disease begins with a history and physical exam.  Patients with peripheral arterial disease will describe achy pain in the foot and leg.  Painful cramps at night, called nocturnal claudication, are one symptom of compromised arterial circulation.  Another finding of PAD would include an inability to walk distances.  This symptom is called intermittent claudication.  Patients with intermittent claudication describe pain when trying to walk for any distance.  Intermittent claudication is also described as a heaviness of the leg with activity.  Many patients with advanced peripheral arterial disease find it difficult to raise their feet to sit in a recliner chair or lay in bed.  With compromised arterial flow, blood has a difficult time ascending the leg.  Therefore, many patients with PAD will sleep with their foot hanging off the edge of the bed.

The physical exam in cases of peripheral arterial disease starts with the palpation of pedal pulses.  Their are two pulses in each foot.  The dorsalis pedis (DP) pulse is found on the top of the foot while the posterior tibial pulse (PT) is found behind medial malleolus (inside ankle bone).  Pulses are graded 4/4 (good)  to 0/4 (poor).  Patients with advanced PAD will exhibit additional physical exam findings to include loss of hair growth and thin, shiny skin turgor.  Turgor is the appearance of the skin.  Delayed capillary refill time (CFT) is suggestive of small artery disease.  Normal CFT is less than 3 seconds.  Delayed CFT is considered suggestive of PAD.

Vascular testing for PAD is initially performed by office based Doppler exams.  Doppler exams measure arterial blood flow to the foot and leg.  The waveforms created by the Doppler can be used to assess hardening of the artery.  The Doppler is also used to measure the blood pressure in the leg.  The blood pressure of the leg is compared to the blood pressure in the arm.  This arm to leg relationship is called an ankle brachial index (ABI).  The ABI is very important in establishing a quantitative measure of the blood flow to the foot.  If ABI testing shows a significant decrease in arterial flow, x-ray studies using dye in the artery, called an arteriogram,  is used to determine the exact location of arterial blockage of the leg. 

Treatment of Peripheral Arterial Disease and Ischemic Ulcers

The underlying cause of arterial foot and leg ulcerations is ischemia (lack of blood flow). Treatment of ischemia may include medical or surgical care. Patients who are smokers will benefit greatly from smoking cessation. Increased exercise may contribute to collateral circulation and may improve blood flow to the ulcer.

Several oral medications are used to treat peripheral arterial disease. Calcium channel blockers (Verapamil, Calan), although primarily used as antihypertensive agents, may be used to increase small vessel peripheral blood flow. Trental (pentoxifylline) is an oral medication that is used to treat PAD decreasing the viscosity of the blood. Trental coats the red blood cell so that it becomes slippery and able to travel through occluded vessels. Pletal (cilostazol) is another oral medication used to treat PAD.  Pletal inhibits cellular phosphodiesterase resulting in dilation of arterial vascular beds. Recent studies have shown a significant reduction in intermittent claudication symptoms with the use of Pletal.

Arterial bypass surgery is a common procedure but may only be used on the medium to large vessels of the leg. Until recently, revascularization was limited to bypass grafting with harvested grafts or synthetic grafts. During the past ten years there have been significant advances in endovascular techniques used to revascularization the leg and foot  Endovascular techniques focus on cleaning the blockage of the leg by using balloons to compress plaque or devices to ream plaque, re-opening occluded vessels.

Wound care is also important for arterial ulcerations. Treatment of infection any be necessary with antibiotics, whether topical, oral or IV. Protection of the wound is essential. Many devices have been invented for this purpose to act as a cradle or pad for the wound. Many physicians use topical enzymes for wound debridement or wound growth factors.

Unfortunately, amputation is still all too common for advanced cases of peripheral arterial disease.  The level of amputation is dictated by vascular testing that includes Doppler exam and/or aortic arteriogram.