Wednesday, December 30, 2009

Many diabetic foot amputations are preventable

It costs $1,400 to cover the oozing sore on the diabetic's foot with a piece of artificial skin, helping it heal if patients keep pressure off that spot. So when Medicare paid for the treatment but not the extra $100 for a simple walking cast to protect it, an artificial skin maker last year started giving free casts to some needy patients.

Without the right cushioning, "the person will walk to the bus stop and destroy it," fumes Dr. David G. Armstrong of the Southern Arizona Limb Salvage Alliance.

Limb-salvage experts say many of the 80,000-plus amputations of toes, feet and lower legs that diabetics undergo each year are preventable if only patients got the right care for their feet. Yet they're frustrated that so few do until they're already on what's called the stairway to amputation, suffering escalating foot problems because of a combination of ignorance -- among patients and doctors -- and payment hassles.

"There's no magic medicine right now for the diabetic foot," says specialist Dr. Lawrence Lavery of Texas A&M University, who bemoans that simple-but-effective preventive care just isn't attention-getting.

"People come in (saying), 'Hey, my wife noticed a bloody trail today as I was walking across the linoleum in the kitchen. What should I do?'"

President Barack Obama got a drubbing from surgeons this month after a confusing comment about how they're paid for foot amputations that cost $30,000 or more. That tab is the total cost, including hospitalization; surgeon fees range from about $750 to $1,000.

Obama's larger argument: Better payment for early-stage diabetes treatment, or even care to prevent diabetes, could save the nation money.

The money part's hard to prove but it's a lot of misery saved if it's your foot, and the spat highlights a huge problem. Some 24 million Americans have diabetes, meaning their bodies can't properly regulate blood sugar, or glucose. Over years, high glucose levels gradually damage blood vessels and nerves.

One vicious result: About 600,000 diabetics get foot ulcers every year. Poor blood flow in the lower legs makes those ulcers slow to heal. And loss of sensation in the feet, called neuropathy, makes patients slow to notice even small wounds that rapidly can turn gangrenous.

A mere nick while clipping nails, or a blister from an ill-fitting shoe, can begin the march toward amputation -- and about half of patients who do lose a foot die within five years.

Saving those feet isn't cheap. Treating a slow-to-heal diabetic foot ulcer can cost up to $8,000. If it gets infected, $17,000. Worse, a fraction of patients gets multiple slow-to-heal ulcers each year.

What helps?

--Routine foot checkups. There's great variability in how insurers pay for foot screenings before someone's deemed at high risk, says Dr. Harry Goldsmith, a consultant on podiatric reimbursement. Yet some simple tests, like one that measures blood pressure at the ankle to predict circulation clogs, can signal later risk of ulcers. Medicare patients who do develop certain risk factors qualify for the next step, regular clinic visits to have a technician trim nails or smooth calluses, time that should include a quick check for any wounds, Goldsmith says.

--Gadgets like $20 telescoping mirrors let diabetics who can't move well check their numb soles for wounds between doctor visits, and infrared foot thermometers that cost up to $100 can detect changes in temperature that mean an ulcer's brewing before the skin breaks. Again, insurance payment varies.

--Taking pressure off the foot is key, starting with supportive shoes or insoles that target weak spots before an ulcer strikes. Medicare will help pay for certain therapeutic shoes although paperwork limits the diabetics who try them, says Lavery. He finds that an athletic shoe checked by a foot specialist for proper fit can help many patients.

When an ulcer demands more advanced care like grafting that artificial skin, Armstrong says removable walking casts -- to-the-calf Velcro boots that injured athletes often wear -- ease pressure best but seldom are covered. Worried that doctors wouldn't prescribe its wound healer Dermagraft if patients crushed it before it could work, Tennessee-based Advanced BioHealing has provided nearly 1,900 of the boots through a patient-assistance program since last year, said vice president Dean Tozer.

--The "toe and flow" approach, diabetic limb-salvage teams that pair specialists who otherwise seldom work side-by-side, like podiatrists and vascular surgeons. Wound care won't work well until clogged leg arteries are cleared to improve blood flow, notes Armstrong, whose team at the University of Arizona, Tucson, documented a drop in amputations in its first nine months. Such teams can eliminate some of the time diabetics wait for appointments to treat a festering foot, plus stress prevention.

AP Online delivered by Newstex

Monday, December 14, 2009

Chronic Critical Limb Ischemia

Chronic critical limb ischemia is manifested by pain at rest, non-healing wounds and gangrene. Ischemic rest pain is typically described as a burning pain in the arch or distal foot that occurs while the patient is recumbent but is relieved when the patient returns to a position in which the feet are dependent. Objective hemodynamic parameters that support the diagnosis of critical limb ischemia include an ankle-brachial index of 0.4 or less, an ankle systolic pressure of 50 mm Hg or less, or a toe systolic pressure of 30 mm Hg or less. Intervention may include conservative therapy, revascularization or amputation. Progressive gangrene, rapidly enlarging wounds or continuous ischemic rest pain can signify a threat to the limb and suggest the need for revascularization in patients without prohibitive operative risks. Bypass grafts are usually required because of the multilevel and distal nature of the arterial narrowing in critical limb ischemia. Patients with diabetes are more likely than other patients to have distal disease that is less amenable to bypass grafting. Compared with amputation, revascularization is more cost-effective and is associated with better perioperative morbidity and mortality. Limb preservation should be the goal in most patients with critical limb ischemia.

Atherosclerosis underlies most peripheral arterial disease. Narrowed vessels that cannot supply sufficient blood flow to exercising leg muscles may cause claudication, which is brought on by exercise and relieved by rest. (For a review of the diagnosis and management of claudication, see the article by Santilli, et al., in the March 1996 issue of American Family Physician.1) As vessel narrowing increases, critical limb ischemia can develop when the blood flow does not meet the metabolic demands of tissue at rest. While critical limb ischemia may be due to an acute condition such as an embolus or thrombosis, most cases are the progressive result of a chronic condition, most commonly atherosclerosis.
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An ankle systolic pressure of 50 mm Hg or less or a toe systolic pressure of 30 mm Hg or less suggests the presence of critical limb ischemia.
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Chronic critical limb ischemia is defined not only by the clinical presentation but also by an objective measurement of impaired blood flow. Criteria for diagnosis include either one of the following (1) more than two weeks of recurrent foot pain at rest that requires regular use of analgesics and is associated with an ankle systolic pressure of 50 mm Hg or less, or a toe systolic pressure of 30 mm Hg or less, or (2) a nonhealing wound or gangrene of the foot or toes, with similar hemodynamic measurements.2 The hemodynamic parameters may be less reliable in patients with diabetes because arterial wall calcification can impair compression by a blood pressure cuff and produce systolic pressure measurements that are greater than the actual levels.

Risk Factors:
Chronic critical limb ischemia is the end result of arterial occlusive disease, most commonly atherosclerosis. In addition to atherosclerosis in association with hypertension, hypercholesterolemia, cigarette smoking and diabetes,3,4 less frequent causes of chronic critical limb ischemia include Buerger's disease, or thromboangiitis obliterans, and some forms of arteritis.5
Figure 1a
FIGURE 1A. Right heel ulcer in a 56-year-old patient with diabetes. The ulcer failed to heal after three months of conservative treatment.

Diabetes is a particularly important risk factor because it is frequently associated with severe peripheral arterial disease. Atherosclerosis develops at a younger age in patients with diabetes and progresses rapidly. Moreover, atherosclerosis affects more distal vessels in patients with diabetes; the profunda femoris, popliteal and tibial arteries are frequently affected, while the aorta and iliac arteries are minimally narrowed. These distal lesions are less amenable to revascularization. Atherosclerosis in distal arteries in combination with diabetic neuropathy contributes to the higher rates of limb loss in diabetic patients compared with nondiabetic patients.6,7

Clinical Presentation:
The development of chronic critical limb ischemia usually requires multiple sites of arterial obstruction that severely reduce blood flow to the tissues.7,8 Critical tissue ischemia is manifested clinically as rest pain, nonhealing wounds (because of the increased metabolic requirements of wound healing) or tissue necrosis (gangrene).

Ischemic rest pain is classically described as a burning pain in the ball of the foot and toes that is worse at night when the patient is in bed. The pain is exacerbated by the recumbent position because of the loss of gravity-assisted flow to the foot. Ischemic rest pain is located in the foot, where tissue is farthest from the heart and distal to the arterial occlusions.1 Patients with ischemic rest pain often need to dangle their legs over the side of the bed or sleep in a recliner to regain gravity-augmented blood flow and relieve the pain. Patients who keep their legs in a dependent position for comfort often present with considerable edema of the feet and ankles.

Non-healing wounds are usually found in areas of foot trauma caused by improperly fitting shoes or an injury. A wound is generally considered to be nonhealing if it fails to respond to a four- to 12-week trial of conservative therapy such as regular dressing changes, avoidance of trauma, treatment of infection and debridement of necrotic tissue.

Gangrene is usually found on the toes. It develops when the blood supply is so low that spontaneous necrosis occurs in the most poorly perfused tissues.

Patients with diabetes develop atherosclerotic lesions in the more distal leg vessels, which are less amenable to revascularization.
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The presence of rest pain can sometimes be difficult to discern in patients with other chronic leg pain, such as that caused by peripheral neuropathy. Labeling a wound as non-healing can also be a subjective assessment. However, a number of physical findings and objective hemodynamic parameters can be used to substantiate a diagnosis of chronic critical limb ischemia. Typical physical findings include absent or diminished pedal pulses, shiny smooth skin of the feet and legs, and muscle wasting of the calves.

An objective measurement of blood flow is easily accomplished with the use of a hand-held Doppler probe and a blood pressure cuff.1 The cuff is inflated until the pulse distal to the cuff is no longer heard by Doppler. The cuff is then slowly deflated until the pulse is again detected. This measurement is recorded as the systolic pressure. As previously mentioned, an ankle systolic pressure of 50 mm Hg or less or a toe systolic pressure of 30 mm Hg or less suggests the presence of critical limb ischemia.

University of Minnesota School of Medicine
Minneapolis, Minnesota

Peripheral Arterial Disease

Your arteries carry blood rich in oxygen and nutrients from your heart to the rest of your body. When the arteries in your legs become blocked, your legs do not receive enough blood or oxygen, and you may have a condition called peripheral artery disease (PAD), sometimes called leg artery disease.

PAD can cause discomfort or pain when you walk. The pain can occur in your hips, buttocks, thighs, knees, shins, or upper feet. Leg artery disease is considered a type of peripheral arterial disease because it affects the arteries, blood vessels that carry blood away from your heart to your limbs. You are more likely to develop PAD as you age. One in 3 people age 70 or older has PAD. Smoking or having diabetes increases your chances of developing the disease sooner.

The aorta is the largest artery in your body, and it carries blood pumped out of your heart to the rest of your body. Just beneath your belly button in your abdomen, the aorta splits into the two iliac arteries, which carry blood into each leg. When the iliac arteries reach your groin, they split again to become the femoral arteries. Many smaller arteries branch from your femoral arteries to take blood down to your toes.

Your arteries are normally smooth and unobstructed on the inside but, as you age, they can become blocked through a process called atherosclerosis, which means hardening of the arteries. As you age, a sticky substance called plaque can build up in the walls of your arteries. Plaque is made up of cholesterol, calcium, and fibrous tissue. As more plaque builds up, your arteries narrow and stiffen. Eventually, enough plaque builds up to reduce blood flow to your leg arteries. When this happens, your leg does not receive the oxygen it needs. Physicians call this leg artery disease. You may feel well and still have leg artery disease or sometimes similar blockages in other arteries, such as those leading to the heart or brain. It is important to treat this disease not only because it may place you at a greater risk for limb loss but also for having a heart attack or stroke.

What are the symptoms?
You may not feel any symptoms from peripheral artery disease at first. The most common early symptom is intermittent claudication (IC). IC is discomfort or pain in your legs that happens when you walk and goes away when you rest. You may not always feel pain; instead you may feel a tightness, heaviness, cramping, or weakness in your leg with activity. IC often occurs more quickly if you walk uphill or up a flight of stairs. Over time, you may begin to feel IC at shorter walking distances. Only about 50 percent of the people with leg artery disease have blockages severe enough to experience IC.

Critical limb ischemia is a symptom that you may experience if you have advanced peripheral artery disease. This occurs when your legs do not get enough oxygen even when you are resting. With critical limb ischemia, you may experience pain in your feet or in your toes even when you are not walking.

In severe peripheral artery disease, you may develop painful sores on your toes or feet. If the circulation in your leg does not improve, these ulcers can start as dry, gray, or black sores, and eventually become dead tissue (called gangrene).

In extreme cases, especially if your leg has gangrene and is not salvageable, your surgeon may recommend amputating your lower leg or foot. Amputation is a treatment of last resort. Vascular surgeons usually only perform it when the circulation in your leg is severely reduced and cannot be improved by the methods discussed already. More than 90 percent of patients with gangrene who are seen by vascular specialists can avoid amputation or have it limited to a small portion of the foot or toes.

~ VascularWeb ~