Compression stockings

Compression stockings are a specialized hosiery, designed to help prevent the occurrence of, and guard against further progression of venous disorders^[1] such as edema, phlebitis and thrombosis. Compression stockings are elastic garments worn around the leg, compressing the limb. This reduces the diameter of distended veins and causes an increase in venous blood flow velocity and valve effectiveness. Compression therapy helps decrease venous pressure, prevents venous stasis and impairments of venous walls, and relieves heavy and aching legs.

Knee High Compression Hose are used not only to help increase circulation, but to also help prevent the formation of blood clots in the lower legs, as well as aiding in the treatment of ulcers of the lower legs. “The majority of venous ulcers heal with compression bandages, however ulcers frequently recur. Clinical guidelines therefore recommend that people continue to wear compression, usually in the form of hosiery (tights, stockings, socks) after their ulcer heals, to prevent recurrence.” [1] “Optimal gradient pressure is 18mmHg at the ankle, 14mmHg at the calf, and 10mmHg at the knee.” [2] Although, according to an article published by JAMA, it was concluded that “non-custom-made graded elastic stockings with 24 mm Hg of pressure at the ankle are effective in decreasing volume, circumference, and symptoms in the lower leg in patients with minimal problems during a one-week period.” [3] “Graded elastic compression stockings on the lower leg were evaluated for their ability to (1) decrease leg volume, (2) decrease circumference, and (3) alleviate discomfort.” [4] The measurement used for compression stockings, is mmHg, otherwise known as millimeters of mercury. Millimeter of mercury (mmHg) is a non-SI unit of pressure. It is the atmospheric pressure that supports a column of mercury 1 millimeter high. The unit is named after Evangelista Torricelli, Italian physicist and mathematician, for his discovery of the principle of the barometer in 1643. [5]

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Unlike traditional dress or athletic stockings and socks, compression stockings use stronger elastics to create significant pressure on the legs, ankles and feet. Compression stockings are tightest at the ankles and gradually become less constrictive towards the knees and thighs. By compressing the surface veins, arteries and muscles, the circulating blood is forced through narrower circulatory channels. As a result, the arterial pressure is increased, which causes more blood to return to the heart and less blood to pool in the feet.

There are two types of compression stockings, gradient and anti-embolism.^[3]

Medical uses

Treatment is usually prescribed by a physician to relieve all manifestations of chronic venous disease and prevent venous troubles. Compression stockings are recommended under the following conditions:

Tired, aching legs

Tired, aching legs occur when the blood flow slows down in the legs (can be an indicator of deep vein thrombosis).

Edema

When any combination of blood or tissue fluid, pool in the legs and feet due to poor circulation.

Chronic peripheral venous insufficiency

This is when the veins cannot pump deoxygenated blood to the heart.

Varicose veins

Varicose veins are saccular and distended veins which can expand considerably and may cause painful venous inflammation. Once developed, will not disappear on its own. The formation of varicose veins is an externally visible sign of venous weakness.

Spider Veins (mild varicosities)

Spider Veins are the smallest cutaneous blood vessels which shimmer bluish or reddish through the skin.

Deep vein thrombosis

Deep vein thrombosis occurs when blood flow decreases (especially in the lower extremities), causing blood to pool in the legs and leading to blood clot (thrombus) formation.

Lymphedema

When a body part swells due to an abnormal accumulation of lymph fluid, occurring when there is interference with the normal drainage of lymph fluid back into the blood, commonly swelling the arm, leg, neck or abdomen.

Phlebitis

Inflammation and clotting in a vein, most often a leg vein, due to infection, inflammation, or trauma. People with varicose veins are more often affected. Inflammation occurs suddenly, causing the thrombus to adhere firmly to the vein wall, which can clog a superficial vein.

Economy class syndrome (ECS)

Occurs on long flight, due to traveler's inactivity, gravity, and cramped seating, which slows down the blood flow through veins.^[1]

Lipodermatosclerosis

Inflammation of subcutaneous fat, form of panniculitis.

Pregnancy

Hormones released during pregnancy and the expanding uterus (pressure on the inferior vena cava - the major vein returning blood up to the heart) can affect leg veins.^[4]

The use of elastic compression stockings can reduce volumetric variations during standing hours. The use of stockings for the entire day is more effective than just half the day or not using compression stockings at all. ^[5] Many physicians and vein specialists recommend wearing compression stockings after varicose vein stripping, but studies show that wearing an elastic compression has no additional benefit following elastic bandaging for three days in post-operative care after stripping of the great saphenous vein as assessed by control of limb, oedema, pain, complications and return to work.^[6]

Economy class stroke syndrome

There is a possible link between a common physical defect in the heart and potentially deadly stroke that could occur during long airplane flights.^[7] The connection, called "economy class stroke syndrome," has been reported in healthy, young travelers who suffered ischemic strokes during or shortly after long air trips. Prolonged sitting associated with air travel is known to be a cause of clots forming in the legs. Upwards of 30 percent of the population is estimated to have patent foramen ovale (PFO), a common condition where a small hole exists between the right and left sides of the heart. PFO rarely causes any adverse medical condition and can only be determined through specific diagnostic tests such as an echocardiogram.

Gradient compression stockings

These stockings are designed to remedy impaired "Musculovenous pump" performance caused by incompetent leg vein valves. They are woven in such a way that the compression level is highest around the ankle and lessens towards the top of the hose.

Doctors will typically recommend these stockings for those who are prone to blood clots, lower limb edema, and blood pooling in the legs and feet from prolonged periods of sitting or inactivity.

They are worn by those who are ambulatory in most cases, where they assist the calf muscles to perform their pumping action more efficiently to return blood to the heart. In some cases, they are worn by those at increased risk of circulatory problems, such as diabetics, whose legs are prone to excessive swelling. A common indicator for the prescription of such stockings is chronic peripheral venous insufficiency, caused by incompetent perforator veins. Low pressure compression stockings are available without prescription in most countries, and may be purchased at a pharmacy or medical supply store. Stockings with a higher pressure gradient, say, above 25-30mmHg, may require a prescription from a doctor.

There are several crucial cautionary steps that need to be taken before using compression stocking:

1. A patient's ABI (Ankle Brachial Index) must be >1.0 per leg to wear compression stockings, otherwise the stockings may obstruct the patient's arterial flow. The ABI indicates how unobstructed a patient's leg and arm arteries are. Any competent doctor or nurse can measure and calculate a patient's ABI.
2. It is crucial that compression stockings are properly sized. The compression should gradually reduce from the highest compression at the smallest part of the ankle, until a 70% reduction of pressure just below the knee.

Vascular doctors & nurses may use special pads to ensure uniform higher pressure around the circumference of the ankle (to smooth out the irregular cross-sectional profile.) Self-prescription is reasonably safe assuming that the compression gradient is 15-20 mmHg, the ABI (for both legs) is >1.0 and that the stockings fit correctly. "Firm" gradient stockings (20-30 mmHg and 30-40 mmHg) should generally be worn only on medical advice.

Although current research reports mixed results of compression socks on athletic performance,^[8][9] there is anecdotal evidence from athletes that they can benefit from such stockings.

Anti-Embolism Compression Stockings

These stockings are commonly referred to as TED hose, short for thromboembolism-deterrent hose. They are used to support the venous and lymphatic drainage of the leg.^[10]

Like gradient compression stockings, anti-embolism stockings deliver a distributed amount of compression at the ankle and up the leg. This compression, when combined with the muscle pump effect of the calf, aids in circulating blood and lymph fluid through the legs (in non-ambulatory patients).

Compression wear has also been adopted by the sports science industry. Various garments have been developed to improve the efficiency of muscles by stabilising muscles and improving circulation/ lactic acid removal. Today, compression stockings are available in a wide range of opacities, colors, styles and sizes, making them virtually indistinguishable from regular hosiery or socks.

Contraindications

Caution should be used in those with advanced peripheral obstructive arterial disease, heart failure, septic phlebitis, oozing dermatitis and advanced peripheral neuropathy in regards to wearing compression stockings.^[11]

Compression classes

Compression stockings are constructed using elastic fibers or rubber. These fibers help compress the limb, aiding in circulation.

Compression stockings are offered in different levels of compression. The unit of measure used to classify the pressure of the stockings is mmHg. They are often sold in one of the following pressure ranges:

Support - over-the-counter

• 10-15 mmHg
• 15-20 mmHg

With the advice or prescription of a physician or medical professional and proper sizing from a trained fitter:

• 20-30 mmHg
• 30-40 mmHg
• 40-50 mmHg
• 50+ mmHg

Compression levels used by some manufacturers for custom made, flat knitted products in the US and Europe:

• 18-21 mmHg
• 23-32 mmHg
• 34-46 mmHg
• >50 mmHg

Styles

• Knee-high (AD)
• Thigh-high (AG)
• Pantyhose (AT)
• Maternity Pantyhose
• Waist Attachment/CHAPS

Commonly used terms for compression stockings

• Anti-embolism - Worn when non-ambulatory or post-surgical to help prevent pooling of blood in the legs that could lead to a venous thrombosis.
• Custom - uniquely made for a specific individual.
• Circular Knit - Seamless stockings that offer greater aesthetic appeal.
• Flat Knit - Stockings made with a seam that can be constructed in virtually any shape or size. Most often used in higher compression classes.
• Silver - Stockings constructed using special silver textile fibers. Silver offers natural anti-microbial protection.
• Lymphedema - compression stockings used to manage edema resulting from the onset of Lymphedema
• Support - mild compression stockings sold over-the-counter and without a physician's prescription

See also

Wikimedia Commons has media related to Compression stockings.

• Diabetic socks, which prevents compression
• Compression sportswear

References