By: Michael Jaff
Peripheral arterial disease (PAD), a condition commonly correlated with diabetes, affects at least one in every three diabetics over the age of 501 and approximately eight million Americans over the age of 40. Although PAD is common among diabetic and senior populations, current data show that public and physician knowledge of the disease is startlingly low, with only 25 percent of the affected population seeking treatment.2
People with diabetes are at the greatest risk for developing severe PAD and experiencing complications from the disease, as they have difficulty properly processing the sugar they ingest. As a result, plaque (fatty deposits) accumulates in the arteries, triggering changes in internal blood vessel size and elasticity that cause subsequent circulation problems.
Plaque buildup causes a narrowing and hardening of the arteries and can eventually decrease the blood flow to the lower extremities. When blood flow to the legs becomes limited or restricted, the propensity for developing infections, chronic foot ulcers, gangrene and leg lesions dramatically increases. Not only that, but these foot wounds have difficulty healing. In severe cases, the affected limb is so damaged that amputation is required if other treatments fail. Problems with the feet are one of the most common causes of diabetes-related hospitalizations. In fact, people with diabetes are up to 15 times more likely to endure lower limb amputation than those without diabetes.3 Fortunately, new medical devices and drugs are being developed, and in many cases amputation can be avoided or limited.
Although a common indicator of PAD is extreme leg or buttock pain caused by walking or exercising, as many as 40 percent of people with PAD never complain of this symptom4 – and those who do commonly mistake the discomfort for aging pains and fail to seek treatment, allowing the condition to worsen. PAD is highly treatable in its early stages, but as the disease remains undiagnosed, the likelihood of complications greatly increases, as does the probability of heart attack or stroke.
The following are risk factors for PAD:
- Being older than 50 years old (1 in 20 Americans over the age of 50 has PAD)
- Being a current or former smoker (both have an up to four times greater risk of developing PAD)
- Having high blood pressure (high blood pressure increases the likelihood of plaque build-up in the arteries)
- Having a history of heart disease (chances of contracting PAD increase to one in three patients suffering from heart disease)
- Having high cholesterol (excess cholesterol and fat in the blood contribute to the formation of plaque in the arteries)
- Being African American (African Americans, for reasons not yet fully understood, are twice as likely to have PAD as their Caucasian counterparts)
Individuals who have PAD may also have plaques in the arteries to the brain and heart, which could cause stroke or heart attack, respectively. Early detection and treatment of PAD is essential to improve quality of life and reduce the risk of heart attack, stroke, and amputation among diabetics with the condition.
Several symptoms are warning signs and potential indicators of PAD, including:
- Fatigue or cramping in the leg muscles (known as claudication) when walking
- Pain in the legs and/or feet that disturbs sleep
- Wounds on toes, feet or legs that heal slowly, poorly, or not at all
- Color changes in the skin of the feet (paleness or blueness)
- A lower temperature in one leg compared to the other leg
- Poor nail growth and decreased hair growth on toes and legs
Physicians can quickly and easily test for peripheral arterial disease, which can allow patients to undergo treatment for the condition and effectively arrest the progression of the disease. The most common test is the ankle-brachial index (ABI), a noninvasive process that compares the blood pressure in the ankles with the blood pressure in the arms. An ABI can help determine if someone has PAD, but it cannot identify the location and degree of the obstruction in the artery. A Doppler test, which is also noninvasive, can check a specific artery for blockage. The Doppler test uses ultrasound waves to measure blood flow in arteries within the lower extremities.
Once a clogged artery is identified, patients can consider several treatment options with their physician. Angioplasty is a nonsurgical procedure that is used to widen arteries with constricted or blocked blood flow. During the procedure, a catheter with a balloon on its tip is inserted into the narrowed artery and inflated. Once the artery widens, the balloon is deflated and the catheter is withdrawn, often restoring blood flow.
Another option in certain arteries such as the iliac is a stenting procedure. In this process, a stent (a wire mesh tube) is inserted into the artery, where it is expanded to act as a “scaffold” to hold the artery open and allow blood flow to resume. The procedure is minimally invasive, as the stent is guided into the restricted artery with a catheter inserted through a small opening in the artery. Drug-eluting stents, which are coated with medicine that is slowly released into the artery, were created to prevent plaque from growing around the stent due to inflammation and forming scar tissue, a process called restenosis. These devices have shown clinical effectiveness in treating coronary artery disease.
An investigational device for PAD with this characteristic is the new Zilver PTX Drug-Eluting Stent (www.zilverptxtrial.com) from Cook Medical. Currently in clinical trial for use in the superficial femoral artery (SFA), the largest artery in the leg, the Zilver stent is coated with paclitaxel, a drug used as an anti-cancer agent and used successfully with coronary stents to reduce the recurrence of narrowing in the coronary arteries. The Zilver PTX stent was created to reduce arterial reblockage in the nearly 40 percent of patients who now must endure repeat procedures when arteries renarrow. The Zilver PTX Trial is currently enrolling patients having PAD in the artery between the groin and knee in clinical trial locations around the world, and has commercial approval in New Zealand, Singapore and Hong Kong. Future PAD studies will be conducted to examine the effectiveness of treating obstructions in arteries below the knee to the foot with this technology.
In situations where large sections of an artery are narrowed, arterial bypass is a surgical option. During leg bypass surgery, a vein from another part of the body or a fabricated blood vessel is sewn above and below the clogged area of the artery to detour blood flow around the blockage. Bypass surgery is a largely successful treatment option, but can be risky for patients who suffer from other disorders such as diabetes or high blood pressure.
People who have experienced any of the aforementioned symptoms or are at increased risk for PAD, especially those with diabetes, should speak to their healthcare professional immediately to schedule testing. Identification and diagnosis of peripheral arterial disease is critical, as early treatment can ultimately save a life.
1 National Institute of Health Peripheral Arterial Disease Fact Sheet – NIH Publication No. 06-5837 • August 2006
2 Becker GJ, et al. The importance of increasing public and physician awareness of peripheral arterial disease. J Vasc Interv Radiol 2002;13:7–11
3 Diabetes Health: “The Double Whammy: When Peripheral Artery Disease Complicates Peripheral Neuropathy” by Linda von Wartburg May 8, 2007
4 Hirsch AT, et al. Peripheral arterial disease, detection, awareness, and treatment in primary care. JAMA 2001; 286:1317-24