Chronic venous insufficiency

Author : Dr Ralph Gonzales Professor of Medicine University of California San Francisco

2008-07-19

Chronic venous insufficiency : Swelling in the Lower Legs

What Is Chronic Venous Insufficiency?

Chronic venous insufficiency (CVI) is by far the most common cause of lower leg swelling, affecting up to 2% of the entire population, and up to 20% of elderly persons. About 2.5 million people in the US suffer from CVI. Chronic swelling in the lower leg predisposes the person to decreased oxygen deliver to the skin, which can lead to increased susceptibility for skin rashes, infection and leg sores. One in five people with CVI will develop a lower leg ulcer (sore) at some point in time. Once they develop, leg sores can be very difficult to heal, some taking months to years to heal with intensive treatments.

Both right and left ankle and lower leg swelling is generally present in all patients with CVI; it tends to be the symptom that leads to the diagnosis. Patients with CVI also frequently report “heavy legs,” itching, and gnawing discomfort or pain. Symptoms tend to be worse towards the end of the day, and best upon awakening in the morning.

Skin changes develop in stages in relation to the severity and duration of CVI. A bronze tanning due to hyperpigmentation (where patches of skin become darker than the surrounding skin) is commonly seen in the early stages of CVI, as is statis dermatitis, which refers to inflamed skin that frequently scales and itches. As the condition progresses, tiny white patches call “atrophie blanche” can appear over the areas of hyperpigmentation, and in the final stages of disease a process called lipodermatosclerosis develops. This is where thick brawny skin eventually leads, in advanced cases, to the lower leg resembling an inverted champagne bottle.

Venous valve

What Causes Chronic Venous Insufficiency?

Chronic venous insufficiency is due to insufficient return of blood from the lower leg to the heart. Due to gravity, as the blood pools in the legs the pressure increases within the system of veins through which blood flows as it returns to the heart. When standing, normal venous pressure in the legs is 80 mm Hg in deep veins and 20–30 mm Hg in surface veins (the ones often referred to as varicose veins when they develop venous insufficiency). The reason that the surface veins in the leg normally have lower blood pressure than the deep leg veins is because there are one-way valves that allow the body to push the blood back to the heart and lungs, and protect the surface veins and skin from high pressures. While the one-way valves keep the blood moving one direction, it’s the calf and other leg muscles that do the majority of work of returning venous blood from the legs to the heart by squeezing the veins during walking or contraction.

When the valves and/or muscles fail, venous hypertension results. Chronic exposure to elevated venous pressure in the lower legs leads to leakage of fluid, inflammation and decreased oxygen delivery to the skin. These changes account for the brawny, fibrotic skin changes observed in patients with CVI, and the predisposition toward skin ulceration (sores), particularly on the inside ankle area.

While aging is the most common cause of CVI, leg clots (deep venous thrombosis or DVT) are another important cause, especially when CVI has developed in just one leg. Other risk factors that increase a person’s chances for developing CVI besides a history of blood clots in the legs include family history of varicose veins, obesity, pregnancy and previous leg injury. Studies have not been conclusive about prolonged standing or sitting as risk factors for developing CVI.

  

When Should I See a Doctor If I Have Developed New Leg Swelling?

The development of new lower leg swelling is a condition that should be evaluated by a health care provider. In general, the slow and gradual onset of leg swelling at the end of the day that is absent upon awakening is very likely to represent venous insufficiency. However, one should seek evaluation more urgently if the swelling has developed more rapidly (such as hours-to-days), and especially if the swelling involves only one leg and is not due to an obvious injury. Lower legs can swell in response to increased pressure in the venous or lymphatic systems, to conditions that increase the leakiness of capillaries (the tiny vessels that connect arteries to veins), to low levels of protein in the blood, and to local injury or infection.

Besides CVI, other causes of new leg swelling include:

· Deep venous thrombosis (leg clot)

· Cellulitis (skin infection)

· Baker’s cyst rupture (located behind the knee)

· Calf muscle tear or rupture

· Lymphedema (fluid retention caused by a compromised lymphatic system)

· Congestive heart failure

· Liver failure with cirrhosis

· Kidney failure, particularly nephritic syndrome (which excretes protein in the urine)

· Drug reactions, especially to calcium channel blockers, minoxidil, or thioglitazones.

Swelling of the entire leg or swelling of one leg three centimeters more than the other suggests deep venous obstruction or clot. (In normal persons, the left calf is slightly larger than the right as a result of normal anatomy.) Because many of the conditions above can be life-threatening, it is important to be evaluated by a medical provider as quickly as possible.

How Do You Diagnose Chronic Venous Insufficiency?

An ultrasound test can identify many causes of lower leg swelling, including CVI. Persons without an obvious cause of new leg swelling in a single limb (e.g., calf strain) should have an ultrasound performed, since leg clots can be diagnosed with ultrasound and are difficult to exclude on clinical grounds alone. It is common to also perform a urine test to look for protein losses in the urine, and blood tests to examine kidney and liver function. In patients with suspected heart disease, an echocardiogram (an ultrasound of the heart) might be ordered to assess for congestive heart failure.

Bear in mind that not all persons with lower leg swelling need an ultrasound test. If the swelling is on both sides, mild (restricted to feet and ankles), gets better with leg elevation or sleep, and is associated with skin changes such as hyperpigmentation or stasis dermatitis, then it is reasonable to assume this is CVI and see how it responds to treatment with compression stockings (see below).

Treatment of Chronic Venous Insufficiency

1. Behavioral treatments

a. Leg elevation. Persons should try to elevate legs above the heart for 15 to 30 minutes, two to three times daily, as well as in bed.

b. Walking. Regular walking and exercise can help to improve the return of venous blood to the heart.

2. Compression Therapy

a. Elastic compression. This is the main treatment for uncomplicated CVI. Graduated compression stockings work by increasing the pressure in your leg tissues and veins in order to counteract the increased pressure that has developed as a result of the faulty vein valves. They tend to have the highest pressure at the ankle (where ulcers are most prone to develop), and the pressure tapers down to normal as it reaches the knee.
      
A wide variety of stockings are effective in decreasing leg swelling. Some stockings have zippers that make them easier to apply for elderly or debilitated patients and some have an open-toe. Compression stockings should be put on with awakening in the morning, before venous pressures rise and cause swelling, and removed at night. Compression stockings should generally be replaced every 4-6 months if used every day, or every 6-9 months if used with an alternate pair.

Although you can buy stockings from many drug stores and medical supply companies, your doctor should provide you with a “prescription” that includes the amount of tension to be applied by the compression, the size (based on your calf circumference) and the length.

Severity of venous insufficiency                     Ankle Tension

· Swelling without complications                     20-30 mm Hg

· Swelling with complications                            30-40 mm Hg

(such as dermatitis or prior ulcer)

· Swelling with recurrent ulcers                        40-50 mm Hg



Calf Circumference                                               Stocking Size*

· 12 inches                                                                     Small

· 15 inches                                                                     Medium

· 17.5 inches                                                                 Large

*These are based on T.E.D. hose. Other scales might be used by different manufacturers.

For most people, knee-high stockings are all they will need. Thigh-high stockings are appropriate for persons with swelling that affects the entire leg, but these are much more difficult to keep in place.

b. Unna Boot. The most common initial treatment for lower leg sores due to CVI is a foot/lower leg cast popularly known as an “Unna Boot” (named after a German dermatologist). These are easy-to-apply paste-gauze boots (like a cast) that are impregnated with zinc or other compounds. They harden within a few minutes to hours of application, and they are replaced weekly until the ulcer is healed. Elastic compression stockings with bandages around the leg ulcer could also be used for the purpose of promoting wound healing, but the advantage of the Unna Boot is that it is easier to apply constant pressure and medication (zinc) over several days without requiring dressing changes.

In addition, because the Unna Boot is essentially a rigid cast, it only applies pressure in an amount that is equal to the severity of leg swelling. Therefore, if the swelling decreases substantially at night (which is common), the Unna Boot doesn’t continue to apply pressure. In contrast, compression stockings still continue to apply some pressure at night, which could be dangerous for patients that also have peripheral arterial disease, ie, blockage of blood vessels that deliver blood to the lower leg.

c. Other Types of Compression. There are other types of compression devices that include compression pumps and orthosis devices, but these are expensive, bulky and limit mobility. They are primarily used under unique circumstances that preclude the use of compression stockings.

3. Systemic Therapy (pills)

a. Diuretics (water pills). It is best to avoid diuretic therapy (such as hydrochlorothiazide or furosemide (Lasix), unless the patient has medical conditions that cause the body to retain water, such as congestive heart failure, pulmonary hypertension, cirrhosis, or nephrotic syndrome. This is because while the legs appear swollen and overloaded with fluid, the actual circulation (blood flow) is relatively underloaded, because fluid is leaking from the circulatory system to the tissues in the legs. Therefore, use of diuretics under these conditions, which reduce blood volume and blood pressure, may lead to dizziness, low blood pressure and reduced blood flow to the kidneys causing acute kidney failure.

b. Horse chestnut seed extract (Venostat). Available over-the-counter in health food stores, horse chestnut seed extract has been shown in well-performed studies to be equivalent to compression stockings and can be quite useful in patients who are not able to walk or exercise. It is believed to work by reducing the inflammation that results when blood pools in the legs for too long. While appearing safe in these studies, we do not have long-term safety experience with this therapy.

c. Hydroxyethlylrutosides (Venorutin). Although not studied as extensively as horse chestnut seed extract, there is ample evidence that these therapies also help reduce swelling.

4. Invasive Treatments.

Invasive treatments, particularly those requiring surgery, are generally reserved for patients failing the more conservative therapies above. With the exception of valve reconstruction, all of these treatments involve with superficial venous system.

a. Vein removal (stripping) or ablation. Vein removal can be accomplished surgically (i.e., “stripping”), but is now more frequently performed using heat or laser ablation as an outpatient or office procedure. Heat and laser ablation basically destroy the veins that are insufficient, sending venous blood to veins with normal functioning valves. All procedures have fairly high success rates for controlling leg swelling when the deep vein valves have normal function, and there are no head-to-head trials that demonstrate one method of removal/ablation is superior to the other.

Another technique of vein ablation is called injection sclerotherapy, where the clinician injects a toxic substance into the vein that plugs-up the interior of the vessel and it eventually dissolves. Scientific studies support the use of injection sclerotherapy for recurrent varicose veins following surgery and for tiny “spider” or “thread” veins.

b. Ligation and stripping. This surgical procedure involves ligating (or tying-off) the saphenous vein in the thigh where it enters the deep venous system (saphenofemoral junction). This procedure has been the standard treatment for severe CVI for many years, and is effective at controlling symptoms, swelling and ulcer recurrence. By removing the insufficient vein, blood in the leg that needs to return to the heart pursues other routes of return such as the perforator veins.

c. Valve reconstruction. This is a fairly intensive procedure that is reserved for patients with severe CVI who have difficulty controlling ulcers and symptoms.

d. Subfascial endoscopic perforator surgery (SEPS). This procedure is useful for patients with difficult-to-control CVI who have incompetent perforator veins in the calf. The perforator veins are one of the communication points between the high pressure deep venous system and the normally low pressure superficial venous system. Clinical trials have shown it to be effective at reducing ankle ulcer recurrence when the main cause of CVI is due to incompetent perforator veins. This surgical technique is performed through a small endoscope (tube) that is introduced at a site far away from the affected tissue so that problems with wound healing are less likely to develop than with local surgery, and basically ligates (ties-off) the incompetent perforator veins which reduces the transmission of the high pressure from the deep venous system to the superficial system.

Complications

Ulcers. Lower leg ulcers (sores) are common in patients with advanced CVI, often occurring over the inside ankle bone. Any skin breakdown in a patient with CVI needs to be evaluated by a healthcare provider.

Typical venous ulcers are shallow, can become quite large, and are located on the lower 1/3 of the lower leg. Ulcers or wounds that are very painful, deep, or that occur in the foot or in the top half of the lower leg may be due to other causes, such as infection, arterial insufficiency, or diabetes. Venous ulcers should be treated in partnership with a wound specialist. They often require long-term treatment with Unna Boot’s and dressing changes, and may take several months to heal. Patients with non-healing ulcers and recurrent venous ulcers may require vein surgery in order to achieve prolonged control of the ulcer.

The best preventive measures that patients with CVI can perform to reduce their risk of leg ulcers is to exercise and elevate their legs daily, and to wear compression stockings that have the appropriate tension.

Infection (skin and/or bone). Chronic swelling of the lower leg leads to changes that weaken the immune system in the legs, and increases the potential for skin infections. Infections can develop after a minor nick or injury introduces germs to the area, or they can develop as a secondary infection of a leg sore. Signs of infection include severe pain, deep tissue involvement and fever. Untreated infections can lead to deeper, recalcitrant infections of bone or muscle, and can also lead to more severe blood stream infections (sepsis). Treatment usually includes topical or oral antibiotics, and meticulous wound care to keep the area protected and clean around leg sores, when present.

Prevention Of Chronic Venous Insufficiency

No studies have demonstrated that regular walking, exercise or routine use of compression stockings prevent the develop of CVI in persons with normal venous systems and no symptoms of CVI, with the exception of one important group—those with deep venous thrombosis.

Prevention of post-thrombotic syndrome and CVI. There is very good evidence that about 30% to 50% of persons who develop a confirmed deep venous thrombosis in the leg (particularly the thigh) are at increased risk for development of post-thrombotic syndrome which includes chronic pain, swelling and immobility of the affected limb over the next 2 years. The use of compression stockings in persons with deep venous thrombosis has been shown to decrease the development of post-thrombotic syndrome by as much as 50%.

Prevention of CVI in persons with prolonged sitting or standing all day. For all other groups of patients at risk for CVI, we have little additional evidence to guide recommendations for prevention.

Compression stockings (12–18 mm Hg at the ankle) are effective in preventing lower leg swelling and asymptomatic thrombosis (clotting) associated with long airline flights in low- to medium-risk persons, as well as in women with pregnancy associated varicose veins. Compression stockings have also been shown to reduce lower leg venous pressure and reactive oxygen stress in persons with jobs that require prolonged standing. However, studies have been inconclusive about whether use of compression stockings prevents the actual development of CVI (i.e., venous valvular incompetence) among persons at increased risk for future development of CVI.

Similarly, studies have not shown that regular walking or leg elevation prevent CVI in persons with normal venous systems (although of clear benefit once CVI has developed). Nonetheless, regular walking and exercise have important health benefits for the prevention of heart disease, diabetes and obesity.

References

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Barwell JR et al. Comparison of surgery and compression with compression alone in chronic venous ulceration (ESCHAR study): randomised controlled trial. Lancet. 2004 Jun 5;363 (9424):1854–9.

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Bergan JJ et al. Chronic venous disease. N Engl J Med. 2006 Aug 3;355(5):488–98.

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Palfreyman SJ et al. Dressings for healing venous leg ulcers. Cochrane Database Syst Rev. 2006 Jul 19;3:CD001103.

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