Venous disorders: disease mechanism

Venous disorders are characterized by impaired flow of blood from the veins of the legs back to the heart. The insufficient venous drainage can result from pooling and reflux of blood, obstruction, venous wall scarring, and muscle pump dysfunction, either alone or in combination. Compression therapy plays a fundamental role in the treatment concept of venous disorders.


In the average sized adult, about 4 to 6 liters of blood are pumped through the body almost 1500 times a day. Thus, with approximately 7000 liters of blood that need to be returned to the heart every day, the heart and the venous system have a difficult job to do, especially because they must overcome the force of gravity to pump the blood upwards.

Leg veins can dilate for different reasons, venous hypertension being one of them. If the leg veins are dilated, the vein valves can’t close properly anymore. A venous reflux occurs when the blood leaks downwards and stagnates in the vein.

Persistent venous reflux and venous hypertension can further damage the internal walls of the leg veins and this can lead to chronic venous insufficiency that indicates the more advanced forms of venous disorders.

Acute manifestations of venous disease usually occur without pre-existing conditions, but can also be triggered by chronic venous disease and require medical treatment.

In both cases, chronic and acute venous disorders, compression therapy plays a fundamental role in the treatment concept.

Lifestyle-related obesity

Obesity is an important risk factor for the development of vascular disorders, including all types of lower limb venous diseases.

Sedentary lifestyle

Reduced physical activity can lead to frequently occurring leg symptoms like heaviness, pain, and swelling, and to more severe venous disease like deep vein thrombosis (DVT), which is when a blood clot forms in one or more of the deep veins in your body, usually in the legs.

When your legs are inactive, the leg muscle pump system is not working and therefore not supporting the upward venous blood return. This can result in pooling, or even clotting of blood in the veins of your legs, if a venous insufficiency i.e. defective venous valves, exists. 


Smoking is not only damaging to the lungs, but also to the legs. It is an important risk factor for peripheral arterial disease and the development of lower limb venous insufficiency.

Compression wear can help

Besides avoiding these negative lifestyle factors, compression wear might help to support your leg health by revitalizing your legs, relieving early symptoms like pain, heaviness and swelling, and by increasing the venous return.

Advanced age and family history

The risk of developing venous disorders increases with age as the cells in the vascular system are aging as well. Age-related changes of venous walls and valves can lead to a decline in valve function. If one of your family members suffers from venous disease, you have a higher risk of becoming affected at some point in your life due to genetic predisposition. This is because specific genetic variations that can be inherited enhance the likelihood of a person to develop chronic venous insufficiency or varicose veins.

Gender and hormonal change

Women are twice as likely to develop varicose veins than men. The sex hormone progesterone, an endogenous steroid, is the main active ingredient in contraceptive medication and naturally involved in the menstrual cycle and pregnancy. It leads to a loss of venous wall tonicity (progesterone causes the vein walls to dilate).

Furthermore, the risk of developing deep vein thrombosis (DVT) increases by taking contraceptive medication and during pregnancy.  

Pregnancy enhances the risk of thrombosis four-fold to five-fold. One reason for this increased risk is hypercoagulability, which has most probably evolved to protect women against the bleeding challenges associated with childbirth and miscarriage. The risk continues after birth until the woman’s hormonal levels return to their pre-pregnancy state. The risk is at its highest in the days and weeks after birth.

Research studies show a strong association between a history of pregnancy and varicose veins. Consequently, many mothers-to-be experience common symptoms such as heavy, tired, aching legs, and swollen feet and ankles. 30 percent of women pregnant for the first time and 55 percent of women who have had two or more full-term pregnancies develop varicose veins, according to a report by «Swiss Medical Weekly».

In postmenopausal women with chronic venous insufficiency, venous pain seems to be a common symptom. This is due to hormonal fluctuations and due to the fact that pain perception is generally increased during menopause.

Compression wear helps

Compression wear is a preventive measure to help improve overall circulation. If you have a feeling of pain, heaviness, or swelling in the affected leg, compression wear can help you to relieve the symptoms.

Compression wear helps against morning sickness

Did you know that compression hosiery also helps against morning sickness? A recent study has shown that compression stockings alleviate nausea and vomiting symptoms during early pregnancy. Order our Mendoza one-pager by e-mail for more information!

Surgery, trauma, and traveling increase risk of thrombosis

Research shows that surgery, trauma, and long-distance traveling are associated with increased risk of venous thrombosis. Poor blood circulation during surgery or long-distance traveling or even a trauma can lead to the formation of a blood clot (thrombosis). The blood clot in some cases can migrate to the lungs, resulting in a pulmonary embolism. If left untreated, this can be fatal.

Constrained movement restricts the blood circulation in the legs, which in consequence can lead to heavy legs, leg pain, swollen feet, and swollen ankles.

Compression wear helps after surgery

Wearing compression stockings has been recommended to reduce the risk of DVT following surgery. For more information, watch our video on compression and hospitalization.   

The discomfort and risk of DVT applies to all types of long-distance travel by car, train, or bus, and it can happen to anyone regardless of age, weight, or lifestyle. A simple and comfortable way to help relieve the symptoms of heavy legs, leg pain, swollen feet and ankles during travel is to wear graduated compression stockings.

Venous insufficiency

Constant standing or sitting impedes the flow of blood towards the heart. Under certain circumstances, this can lead to venous insufficiency, which is characterized by improperly functioning vein valves that interfere with venous return and cause the blood to pool in the veins.

If left untreated, venous insufficiency can result in the formation of serious disorders, including phlebitis, pulmonary embolism, or ulcers. According to the 2003 Bonn Vein Study, it is estimated that one out of every six men and one out of every five women suffer from chronic venous insufficiency

Despite the fact that the severity of chronic venous insufficiency has diminished over the past 20 years, the data of this study clearly shows that venous disorders are still very common throughout the population. Watch our movie to learn more about venous disorders.

Disturbed venous system

In patients with chronic venous disease, the internal walls of the leg veins are subjected to pathological changes due to hypertension or other reasons and deteriorate. This causes the leg veins to dilate, thereby preventing the valves from closing properly. This, in turn, causes a reflux, which is when the blood leaks downwards and stagnates in the vein, thereby leading to further venous hypertension and more advanced forms of chronic venous disorders. This condition is known as chronic venous insufficiency (CVI) which may result in edema, skin change and, in some cases, ulcerations

What is CEAP Classification?

In order to standardize the reporting and treatment of the diverse manifestations of chronic venous disorders, a comprehensive classification system (CEAP) was developed to allow uniform diagnosis and comparison of patient populations. Created by an international ad hoc committee of the American Venous Forum in 1994, it has been endorsed throughout the world and is now an accepted standard for classifying chronic venous disorders.

The fundamentals of the CEAP classification include a description of the clinical class (C) based upon objective signs, the etiology (E), the anatomical (A) distribution of reflux and obstruction in the superficial, deep and perforating veins, and the underlying pathophysiology (P), whether due to reflux or obstruction (1).

Designed to be a document that would evolve over time, CEAP underwent its first official review and revision by an international panel under the auspices of the American Venous Forum in 2004 (2). The revised document retains the basic CEAP categories but improves the underlying details.

CEAP: Seven clinical classes of chronic venous disorders

According to the CEAP classification, chronic venous disorders can be divided into seven clinical classes C0 to C6 with specific signs:

C0: No visible or palpable signs of venous disease

C1: Telangiectasis (spider veins) or reticular veins

C2: Varicose veins

C3: Edema

C4: Skin changes (pigmentation, eczema, induration)

C5: Healed venous ulcer

C6: Active venous ulcer

References: (1) Porter JM, Moneta GL. Reporting standards in venous disease: an update. International Consensu Committee on Chronic Venous Disease. J Vasc Surg 1995;21:635-45. (2) Eklof B, Rutherford RB, Bergan JJ, Carpentier PH, Glovicski P, Kistner RL, et al. Revision of the CEAP classification for chronic venous disorders: consensus statement. J Vasc Sur 2004;40:1248-52.

CVD subtypes

To distinguish the different manifestations of CVD, the CEAP classification system is applied.

C0S: Heavy legs, feeling of swelling and leg pain

With C0S stadium, patients often describe a sensation of heavy legs, characterized by a feeling of discomfort, tiredness, and achiness in the legs. These symptoms are often experienced after sitting or standing for prolonged hours and occur in the evening – usually, they are not present in the morning or after waking.

In summer, the symptoms may increase due to the heat, and are typically associated with swollen feet and ankles. No visible or palpable signs of venous disease are yet present at this early stage of venous disorders.

Treatment and care of heavy legs 

  • To avoid heavy, painful, and tired legs, try Sigvaris compression solutions. 
  • Elevation of the legs usually lets the symptoms disappear.
  • A broad range of creams and gels is available to alleviate symptoms of heavy legs.

C1: Spider veins and reticular veins

Medical illustration of a leg with spider veins

Spider veins (also called reticular veins or telangiectasia) are small, dilated, superficial veins that correspond to a confluence of dilated intradermal venules less than 1 mm in caliber. They can be found in different areas of the leg. Reticular veins are dilated bluish subdermal veins, usually 1 mm to less than 3 mm in diameter. They are usually tortuous. This excludes normal visible veins in persons with thin, transparent skin.

Treatment and care of spider veins

Important to know: Before any treatment of spider veins is considered, it is essential to have a duplex ultrasonography done to assess if an underlying venous reflux is present or not. 

C2: Varicose veins

Medical illustration of a leg with varicose veins

Varicose veins are subcutaneous, dilated, and tortuous veins 3 mm in diameter or larger. They have defective valves, causing venous stasis. Varicose veins can be found on the foot, calf, thigh, or entire leg, and affect nearly 30% of the world’s population.

Varicose veins can be painful or, on the contrary, totally painless. When symptoms are present, they include ankle and leg swelling, heaviness or fullness, aching, restlessness, fatigue, pain, cramps, and itching. There are many causes known for the development of varicose veins, such as age > 50 years, working for prolonged time in standing or sitting position, physical inactivity, obesity, heredity, pregnancy, and menopause.

Early diagnosis is essential to prevent worsening of venous disease. If left untreated, complications can include thrombophlebitis (inflammatory process causing a blood clot to form) and variceal bleeding

Treatment and care of varicose veins

Online recommendations for people with varicose veins 

Varicose veins are damaged veins in which the venous valves do not close properly.

C3: Edema

Venous edema

Edema is defined as a perceptible increase in volume of fluid in skin and subcutaneous tissue, characteristically indented with pressure. Venous edema usually occurs in the ankle region, but it may extend to the leg and foot.

There are many causes of edema, such as standing or sitting for long periods of time, physical inactivity, chronic venous disease, lymphedema, filariasis, heredity, pregnancy, surgery, and trauma.

Edemas of venous origin occur when blood stagnates in the veins, thereby preventing the capillaries from properly functioning and causing excessive fluid (water, electrolytes, proteins, dissolved substances) to build up in the skin and subcutaneous tissue.

Treatment and care of edema

C4a: Erythematous dermatitis (eczema)

Eczema is an inflammatory reaction of the skin induced by blood stagnation in the veins. It is most often located near varicose veins, but it can be found anywhere on the leg. If left untreated, it can progress to blistering, weeping, or scaling eruption of the skin on the leg.

Treatment and care of eczema

Appropriate anti-inflammatory treatment should be provided if deemed necessary by the treating physician.

C4a: Pigmentation

Medical illustration of a leg with venous discoloration

Pigmentation is defined by a brownish darkening of the skin due to the leakage of erythrocytes from the vein into the surrounding tissue. It usually occurs in the ankle region, but it may extend to the leg and foot.

Treatment and care of pigmentation

Important to know: Pigmentation usually remains even after removal of the responsible varicose veins by surgery or sclerotherapy.

C4b: Lipodermatosclerosis (LDS)

Lipodermatosclerosis (LDS) refers to a localized chronic inflammation and fibrosis of the skin and subcutaneous tissues of the lower leg that occurs in patients who have severe chronic venous disorders. LDS is sometimes preceded by diffuse inflammatory edema of the skin, which may be painful and is often referred to as hypodermitis. LDS must be differentiated from lymphangitis, erysipelas, or cellulitis by their characteristically different local signs and systemic features.

Treatment and care of LDS

Appropriate anti-inflammatory treatment should be provided if deemed necessary by the treating physician

C4b: White atrophy

Medical illustration of a leg with white atrophy

White atrophy, also called atrophie blanche, is a type of scar localized on the lower leg or foot. It is an often circular, whitish, and atrophic skin area surrounded by dilated capillaries and sometimes hyperpigmentation. It is a sign of severe CVD and represents late sequelae of lipodermatosclerosis where the skin has lost its nutrient blood flow.

Treatment and care of white atrophy

C5 and C6: Healed and active leg ulcer

Medical illustration of a leg with active venous leg ulcer

C6: Active leg ulcer

Medical illustration of a leg with healed venous leg ulcer

C5: Healed leg ulcer

A venous leg ulcer is a full-thickness defect of the skin, most frequently in the ankle region, that fails to heal spontaneously and is sustained by CVD. An active leg ulcer is classified C6, while healed leg ulcers are classified C5 by means of the CEAP classification.

Venous leg ulcers are painful open lesions on the lower leg that occur in the presence of severe venous disease. The wound itself is often irregular and there may be weeping discharge as the tissue fluid seeps from the wound.

It is important to know that ulcers do not heal spontaneously, but that treatment options for this severe and often painful disease exist.

A venous leg ulcer is one of the most serious results of the progression of chronic venous insufficiency. 

Treatment and care of leg ulcer

A venous leg ulcer may take months to heal.

  • Primary treatment includes healing the wound and controlling a possible infection.
  • Managing pain, minimizing the swelling, and protecting the healthy skin are also crucial steps during the treatment.
  • Short-stretch compression or a special ulcer stocking system delivering a pressure of > 40 mmHg are applied until healing of the venous leg ulcer. 
  • Other measures: inelastic compression wraps
  • Other interventional measures: endothermal ablation (laser/radiofrequency), chemical ablation (ultrasound-guided foam sclerotherapy), and shave therapy (excision of the affected tissue)

Important to know: Nearly 80% of venous leg ulcers can be healed with good wound management. Once it has healed, the patient should wear a minimum of 30-40 mmHg Sigvaris medical graduated compression stockings for life to promote non-recurrence of the ulcer. Daily walks, a healthy diet, and weight control are also key in patient caring.

Sigvaris solutions for leg ulcer

SIGVARIS Ulcer X Kit and Sigvaris 500 are dual stocking systems. They consist of a low-compression underliner (15-20 mmHg) and an overstocking (23-32 mmHg). The underliner is made with an inner layer of cotton and a smooth exterior that allows easy donning of the overstocking. It keeps the wound dressing in place, especially at night when the overstocking is removed to help the patient rest more comfortably.

During daily activities, the 23-32 mmHg overstocking and the 15-20 mmHg underliner provide the necessary compression needed to heal the venous ulcer. The Ulcer X Kit has been proven to be the superior treatment choice for the successful healing of venous ulcers. 

Complete wound closure achievement: 96,2% with Ulcer X kit as compared to 70% with traditional bandages.

Ulcers with diameter of up to 4 cm healed twice as fast with the Ulcer X Kit as compared to bandages; Ulcers >4 cm healed equally fast as with bandages.

Pain at night/morning was reported in the bandage group, but absent in the Ulcer X Kit group.

Other benefits of the Ulcer X kit include the ease of application that promotes compliance, increased activity and thereby a better quality of life. 

Acute venous disorders

Acute manifestations of venous disorders usually occur without pre-existing conditions, but they can also be triggered by chronic venous disorders. In any case, medical treatment is immediately required.

Superficial thrombophlebitis (ST)

Superficial thrombophlebitis (ST) is a relatively common inflammatory process associated with a blood clot (thrombus) that affects the superficial veins (veins that are close to the surface of the body). Symptoms and signs include local pain, itching, tenderness, reddening of the skin, and hardening of the surrounding tissue.

Treatment and care of ST 

  • Appropriate anti-inflammatory and anticoagulant medication as prescribed by the treating physician
  • Surgical interventions (thrombectomy, ligation)
  • Non-invasive care with Sigvaris compression solutions 

Deep vein thrombosis (DVT)

Deep vein thrombosis (DVT) is a blood clot that usually forms in the deep vein system, mainly of the lower leg and which can block the venous return. The blood clot inside the vein can hold onto the vein wall, or it can be floating inside the vein.

DVT is caused by a combination of various pathophysiological factors, to  including vein wall damage, stasis, and hypercoagulability. Risk factors for the development of DVT include, amongst others, pregnancy, contraceptive medication, cancer, surgery, injuries, CVI, and travel.  

Some DVT cases have no recognized symptoms. For those who do show symptoms, they can include:

  • Pain
  • Warmth
  • Redness
  • Swelling

Complications of DVT include

  • Pulmonary embolism: If the clot breaks loose and travels through the vessel to the arteries located in the lungs, it significantly blocks blood flow through the lungs, which is a potentially fatal condition.
  • Post-thrombotic syndrome: Up to one half of patients with DVT develop a long-term complication known as post-thrombotic syndrome (PTS). This condition can show up as chronic pain, swelling, heaviness, edema, and skin changes in the affected limb. In severe cases, venous ulcers may develop.

Diagnosis of DVT

When symptoms described above occur, the patient must see a doctor quickly to confirm the diagnosis which can be made with a simple ultrasound scan. Early diagnosis and treatment can greatly reduce your risk of serious complications. 

Treatment and care of DVT

  • DVT treatment consists in taking anticoagulant drugs and wearing medical compression stockings to improve the venous blood return and to prevent PTS. 
  • It can also include thrombectomy to remove the clot. 

Important to know: Treatment should eliminate the symptoms rapidly and durably, but also allow to stay mobile and pursue every day activities.

Illustration deep vein thrombisis

The symptoms of DVT can go unrecognized.

Pulmonary embolism

Pulmonary embolism occurs when a blood clot, or part of it (emboli), detaches itself and migrates to the lung arteries. Pulmonary embolism is one of the most serious consequences of DVT because it may be fatal. The signs of embolism are non-specific and can include difficult breathing, chest pain, cough, fever, or blood expectorations.

Because these symptoms are also common with other medical conditions, pulmonary embolism may not be recognized right away. Only specific tests will enable a correct diagnosis such as lung scan (computer tomography). In case of such symptoms, emergency medical assistance must be sought at once.

Treatment and care of pulmonary embolism

Treatment can include

  • hemodynamic and respiratory support
  • anticoagulant medication
  • thrombolytic treatment
  • surgical embolectomy
  • catheter-directed treatment 
  • Sigvaris compression solutions 

Post-thrombotic syndrome

Up to one half of patients with DVT develop a long-term complication known as post-thrombotic syndrome (PTS).

This condition can show up as chronic pain, swelling, heaviness, edema, and skin changes in the affected limb. In severe cases, venous ulcers may develop.

Treatment and care of PTS

Treatment can include

  • anticoagulant medication
  • thrombolysis and medical compression

Variceal bleeding

Variceal bleeding is defined as bleeding from varicose veins. It is associated with a traumatized superficial varicosity, but significant bleeding can also happen from an area of ulceration. The resulting blood loss may be profound and even life threatening.

Treatment and care of variceal bleeding

  • To stop the bleeding, the leg should be elevated, and a constant pressure should be exerted on the wound.
  • Medical advice should be sought at once to receive the appropriate treatment.

Further reading