Preventing venous thrombosis: medical experts give advice

What is deep vein thrombosis (DVT)?

Deep vein thrombosis is a condition in which a blood clot forms in a deep vein, usually in the legs or pelvis. These veins are responsible for transporting blood back to the heart and a thrombus can significantly impede this process. The clot can partially or completely block the blood flow, causing a range of symptoms and potential complications.

Anatomy of the veins and the importance of vein health

To understand the development of DVT, it is important to familiarize yourself with the anatomy and function of the veins.
The body’s veins are blood vessels that carry blood back to the heart.
Unlike arteries, which carry blood away from the heart, veins rely on the support of muscles and special valves to ensure the return flow of blood.
These valves prevent the blood from flowing backwards, especially in the legs, when it is transported to the heart against the force of gravity.

Varicose veins occur when these venous valves no longer function properly and the blood accumulates in the superficial veins.
This leads to dilation of the veins, which is not only a cosmetic problem but can also increase the risk of DVT. People with varicose veins have an increased risk, as these dilated veins allow the blood to flow more slowly, which can promote the formation of clots.

Causes and risk factors of deep vein thrombosis

Causes

The development of DVT is favored by several factors, which together are known as the Virchow triad.
This triad includes blood flow disorders (stasis), damage to the vessel walls and an increased tendency of the blood to clot.

• Long-term immobility: One of the main causes of DVT is immobility, as occurs during long air travel, bedriddenness or after surgery.
  If the muscles are inactive for long periods of time, the blood in the legs can stagnate, which increases the risk of clots forming.
• Injuries or operations: Any injury or operation that affects the veins can damage the vessel walls.
  This leads to an inflammatory reaction, which increases the blood’s tendency to clot and thus promotes the formation of a thrombus.
• Hormonal influences: Certain hormonal changes, such as those that occur during pregnancy, when taking oral contraceptives or during hormone replacement therapy, can increase the risk of DVT.
  These hormonal influences often act by increasing the coagulation factors in the blood.

Risk factors

In addition to the direct causes, there are a number of risk factors that increase the likelihood of DVT.
These can be divided into non-modifiable and modifiable risk factors.

Non-modifiable risk factors

• Age: The risk of DVT increases with age.
  This is due to a general decrease in vein function and an increased tendency for blood clotting.
• Genetic predisposition: Certain genetic factors can increase blood clotting and thus increase the risk of DVT.
  People with known hereditary coagulation disorders, such as the factor V Leiden mutation, have a significantly higher risk.
• Gender: Women have a higher risk of DVT than men due to hormonal influences, especially when taking contraceptive pills or during pregnancy.

Modifiable risk factors

• Smoking: Smoking has a harmful effect on the blood vessels and increases the risk of thrombosis.
  It causes constriction of the blood vessels and damage to the vessel walls, which promotes thrombus formation.
• Overweight and obesity: Being overweight increases the pressure on the leg veins and can obstruct blood flow, which increases the risk of DVT.
  Losing weight can significantly reduce the risk.
• Inactivity: A sedentary lifestyle also contributes to the stagnation of blood in the veins.
  Regular exercise promotes blood circulation and reduces the risk of thrombosis.

Symptoms of deep vein thrombosis

The symptoms of DVT can be subtle and non-specific, making diagnosis difficult.
They vary depending on the size and location of the clot and the degree of blockage in the vein.

Main symptoms

• Swelling: One of the most common manifestations of DVT is sudden swelling, usually in one leg.
  This often occurs in the lower leg or ankle and can worsen over the course of the day.
• Pain and tenderness: The pain is usually localized in the calf area and can range from a slight pressure sensation to severe pain that is aggravated by walking or standing.
• Redness and discoloration of the skin: The skin over the affected vein may be reddish or bluish in color, often accompanied by a feeling of warmth or heat in the affected area.
• Feeling of heaviness: Those affected often report a feeling of heaviness in the affected leg, which occurs particularly after long periods of inactivity.

Atypical symptoms

In some cases, the symptoms may be more subtle and manifest as general malaise, fatigue or diffuse pain in the leg, making the diagnosis of DVT more difficult.
It is important to consider medical evaluation even in the presence of non-specific symptoms, especially if risk factors are present.

Diagnosis of deep vein thrombosis

The diagnosis of DVT is based on a combination of clinical examination, imaging techniques and laboratory tests.
Early and accurate diagnosis is crucial to avoid complications.

Clinical examination

The first step in the diagnosis of DVT is a thorough medical history and physical examination.
The doctor will ask about specific symptoms and look for risk factors.
This includes examining the affected leg for swelling, tenderness and skin changes.
A positive Homans sign (pain in the calf on dorsiflexion of the foot) can be an indication of DVT, but is non-specific.

Imaging procedures

The diagnosis is usually confirmed by imaging procedures.
The most common methods include

• Doppler ultrasound: Doppler ultrasound is the preferred method for diagnosing DVT.
  It uses sound waves to visualize the blood flow in the veins.
  A clot is indicated by an interruption or slowing of the blood flow.
• Phlebography: Phlebography is an invasive procedure in which a contrast agent is injected into the vein.
  An X-ray is then taken to assess the blood flow and the structure of the veins.
  This method is usually used when ultrasound does not provide clear results.
• Magnetic resonance venography (MRV): MRV is an advanced imaging technique that provides detailed images of the veins.
  It is mainly used in complex cases where other imaging techniques do not provide a clear diagnosis.

Laboratory tests

In addition to imaging procedures, laboratory tests can be used to support the diagnosis:

• D-dimer test: The D-dimer test measures the breakdown products of fibrin, a protein that is produced when blood clots form.
  An elevated D-dimer value can indicate a DVT, but is not specific and should be confirmed by imaging procedures.
• Coagulation profiles: If a congenital or acquired coagulation disorder is suspected, specific blood tests can be carried out to assess the blood’s tendency to clot.
  These tests can provide indications of thrombophilia, such as factor V Leiden mutation, antithrombin III deficiency or the presence of antiphospholipid antibodies.
  A precise determination of the coagulation tendency is particularly important in the case of repeated thromboses or a family history.

Differential diagnosis

A careful differential diagnosis is crucial, as various other conditions can cause symptoms similar to DVT.
These include

• Muscle injuries or muscle cramps: Muscle injuries or cramps can cause similar pain and swelling, especially after physical exertion.
• Cellulitis: A bacterial infection of the skin and underlying tissue that causes redness, swelling and pain and can easily be mistaken for DVT.
• Superficial vein thrombosis (thrombophlebitis): An inflammation and thrombosis of the superficial veins that causes similar but usually milder symptoms than DVT.
• Lymphoedema: A chronic swelling of the tissue caused by a disruption of lymphatic drainage.
  In contrast to DVT, lymphoedema frequently affects both legs and is often associated with chronic swelling.

A precise differentiation of these conditions is important in order to initiate the correct treatment and avoid unnecessary complications.

Management and treatment of deep vein thrombosis

The treatment of deep vein thrombosis aims to prevent the formation of further clots, dissolve or stabilize the existing clot and prevent complications such as pulmonary embolism.
The therapeutic approaches range from drug treatments and compression therapy to surgical interventions in severe cases.

Drug treatment

Anticoagulation therapy

Anticoagulation is the basis of DVT treatment and aims to inhibit blood clotting and prevent the formation of further thrombi.

• Heparin: Heparin, an anticoagulant, is often used as first-line therapy.
  It can be administered intravenously or subcutaneously and acts quickly to inhibit clotting.
  Heparin is often used in the first few days of treatment before switching to oral anticoagulants.
• Low molecular weight heparin (NMH): NMH is administered subcutaneously and has a longer half-life than unfractionated heparin.
  It is easier to dose and does not require constant monitoring of blood clotting, making it the preferred choice for many patients.
• Oral anticoagulants: After initial heparin therapy, patients are often switched to oral anticoagulants such as warfarin or newer oral anticoagulants (NOACs) such as apixaban, rivaroxaban or dabigatran.
  These drugs inhibit the formation of clotting factors and are administered for several months or even for life, depending on the individual risk of recurrent thrombosis.

Thrombolytic therapy

In certain cases, particularly in the case of extensive thrombosis or in patients at high risk of pulmonary embolism, thrombolytic therapy may be considered.
This therapy aims to dissolve the clot by administering drugs such as streptokinase, urokinase or recombinant tissue plasminogen activator (rt-PA).
However, thrombolytic therapy carries a considerable risk of severe bleeding and is therefore only used in selected cases.

Thrombectomy

In rare and severe cases, particularly in the case of impending gangrene or large thrombi that do not respond to drug therapy, surgical thrombectomy may be necessary.
In this procedure, the blood clot is surgically removed in order to restore blood flow.

Compression therapy

Compression therapy is an important addition to the medical treatment of DVT.
Wearing compression stockings improves venous return and reduces the risk of developing complications such as post-thrombotic syndrome.

• Compression stockings: Patients are often advised to wear class II or III medical compression stockings to reduce swelling and promote blood circulation.
  These stockings should be worn daily, especially during long periods of standing or sitting.
• Intermittent pneumatic compression: In some cases, particularly with immobilized patients, intermittent pneumatic compression (IPC) can be used.
  This uses inflatable cuffs to exert pressure on the legs, which promotes blood flow in the deep veins.

Long-term management and secondary prevention

After the initial treatment of DVT, it is crucial to take measures to prevent recurrences.
This includes both drug and non-drug approaches.

Continued anticoagulation

In many cases, long-term anticoagulation is necessary to minimize the risk of recurrent thrombosis.
The duration of anticoagulation depends on various factors, including the cause of the initial thrombosis, the presence of risk factors and the response to the initial therapy.
Patients with recurrent thrombosis or certain coagulation disorders may require lifelong anticoagulation.

Lifestyle changes and prevention

Long-term prevention strategies are crucial to reduce the risk of recurrent thrombosis:

• Weight management: Being overweight increases the pressure on the veins and promotes the formation of thrombosis.
  Losing weight can therefore significantly reduce the risk.
• Regular exercise: Physical activity improves blood circulation and reduces the risk of thrombosis.
  Exercises that activate the leg muscles, such as walking, swimming or cycling, are particularly beneficial.
• Avoid prolonged immobilization: During long journeys or after operations, measures should be taken to promote blood flow, such as wearing compression stockings or getting up and moving regularly.
• Smoking cessation: Smoking is a significant risk factor for thrombosis. Quitting smoking significantly reduces the risk and improves overall vascular health.

Complications of deep vein thrombosis

The complications of DVT can be both acute and chronic.
Early diagnosis and treatment are crucial to minimize the risk of serious complications.

Pulmonary embolism

One of the most dangerous complications of DVT is pulmonary embolism.
It occurs when part of the blood clot breaks off and travels into the pulmonary arteries, where it blocks the blood supply.
The symptoms of a pulmonary embolism can occur suddenly and include

• Shortness of breath: Sudden shortness of breath is the most common symptom of a pulmonary embolism and should always be considered an emergency.
• Chest pain: The pain may be stabbing or pressing and worsen when you inhale.
• Coughing: Coughing, sometimes with bloody sputum, can be another sign of pulmonary embolism.
• Cyanosis: A bluish discoloration of the lips or skin may indicate an insufficient oxygen supply.

A pulmonary embolism is a medical emergency that requires immediate treatment.
If left untreated, it can lead to severe oxygen deficiency, shock and even death.

Post-thrombotic syndrome (PTS)

Post-thrombotic syndrome is a chronic complication that can occur after a DVT.
It is caused by persistent vein damage that leads to chronic venous insufficiency.

Symptoms of post-thrombotic syndrome

• Chronic swelling: A common symptom of PTS is persistent swelling of the affected leg, which may worsen during the day.
• Pain and heaviness: Patients often report pain, a feeling of heaviness or fatigue in the affected leg, which is exacerbated by prolonged standing or sitting.
• Skin changes: Skin changes include hyperpigmentation, hardening and, in severe cases, the development of venous ulcers, which are difficult to treat.
• Varicose veins: Secondary varicose veins can develop in the affected leg and worsen the symptoms.

Treatment of post-thrombotic syndrome (PTS)

Post-thrombotic syndrome (PTS) is a major challenge in the long-term management of patients who have suffered a deep vein thrombosis.
Treatment aims to alleviate symptoms, improve quality of life and slow down the progression of the disease.

Compression therapy

Compression therapy remains the most important treatment method for post-thrombotic syndrome.
Class II or III compression stockings, which increase the pressure on the veins, can reduce swelling and promote blood circulation.
Patients should wear these stockings daily, especially during the day when standing or sitting.
In some cases, intermittent pneumatic compression can be used as a complementary measure to support venous circulation.

Movement therapy

Regular exercise plays a crucial role in the treatment of PTS.
Specific exercises that strengthen the muscles of the legs can improve venous pump efficiency and thus alleviate symptoms.
Targeted physiotherapy programs that include stretching exercises and specific leg muscle exercises are particularly effective.
Patients should also take care to avoid long periods of sitting or standing and take regular breaks for exercise.

Skin care and treatment of ulcers

The skin over the affected area is often susceptible to damage, especially if there is chronic swelling and congestion.
Careful skin care is crucial to avoid complications such as ulcers (open wounds).
Daily moisturizers can help keep the skin supple and reduce the risk of cracks and ulcers.

If venous ulcers occur, a combined therapy of compression, wound care and, if necessary, surgical measures is required.
Special dressings and wound dressings can promote healing, while careful monitoring and, if necessary, antibiotic therapy are necessary to prevent infection.

Drug therapy

In addition to compression therapy, medication can be used to alleviate the symptoms of PTS:

• Venotonics: These drugs, such as diosmin or hesperidin, are intended to strengthen the vein wall, improve microcirculation and thus reduce the symptoms of PTS.
  However, their effectiveness varies and they are often used as a supplement to compression therapy.
• Anti-inflammatory medication: For pain and inflammation, non-steroidal anti-inflammatory drugs (NSAIDs) or corticosteroid creams can be used to relieve discomfort.
• Anticoagulants: In some cases, prolonged anticoagulation therapy may be necessary to reduce the risk of new thromboses, especially if the PTS is severe.

Surgical options

In severe cases where conservative measures are not sufficient, surgical interventions may be considered.
Options include:

• Vein reconstruction: Surgical intervention to restore venous drainage can be considered for severely damaged veins.
  However, this is a highly specialized technique that is only performed in selected cases and by experienced surgeons.
• Venous bypass: In some cases, a bypass of the affected vein may be necessary to restore blood flow and relieve symptoms.
• Stenting: In cases of severe venous obstruction, particularly in the pelvic region, a stent can be inserted to keep the affected vein open and improve blood flow.

Prevention of deep vein thrombosis

Prevention of deep vein thrombosis is crucial, especially in patients with known risk factors.
Through a combination of lifestyle adjustments, medical interventions and awareness raising, many cases of DVT can be prevented.

Primary prevention

Primary prevention aims to prevent the development of a first thrombosis.
The most important measures include

Weight management and healthy eating

Being overweight is a significant risk factor for the development of DVT.
A healthy diet and regular physical activity can reduce body weight and thus reduce the risk of thrombosis.
A balanced diet rich in fiber, fruits and vegetables and low in saturated fats and sugars supports overall vascular health.

Regular physical activity

Physical activity promotes venous return and prevents stagnation of blood in the legs.
It is recommended to do at least 30 minutes of moderate physical activity most days of the week.
Activities such as walking, swimming and cycling are particularly beneficial.

Avoidance of immobility

Long-term immobility, such as bedriddenness or long journeys, significantly increases the risk of DVT.
Measures to prevent immobility, such as getting up and moving regularly, wearing compression stockings during long journeys and staying hydrated, can significantly reduce the risk.

Education and awareness-raising

Comprehensive education about the risk factors and signs of DVT is crucial, especially for patients who belong to the at-risk groups.
This includes counseling patients on the importance of exercise, the risks of smoking and obesity, and the benefits of compression therapy.

Secondary prevention

Secondary prevention is aimed at patients who have already suffered a DVT in order to minimize the risk of a recurrence.

Long-term anticoagulation

Patients with a high risk of recurrent thrombosis, such as those with thrombophilia or recurrent thrombosis, may benefit from prolonged anticoagulation therapy.
The decision on the duration of anticoagulation should be made on an individual basis and reviewed regularly.

Monitoring and regular checks

Regular follow-up examinations with a specialist in vascular medicine are essential to monitor the condition of the veins and to be able to react in good time to signs of complications or new thromboses.
This includes both clinical examinations and occasional imaging procedures.

Use of compression stockings

Regular use of compression stockings can reduce the symptoms of post-thrombotic syndrome and reduce the risk of new thromboses.
Patients should wear these stockings consistently, especially in situations that increase the risk of thrombosis.

Summary and outlook

Deep vein thrombosis is a serious and potentially life-threatening condition that requires early diagnosis and appropriate treatment. With advances in medical diagnostics and therapy, including the availability of newer anticoagulants and modern imaging techniques, patients can now be treated effectively and complications minimized.

Prevention plays a central role in the management of DVT, both in primary prevention for patients at risk and in secondary prevention for those who have already suffered a thrombosis.
The risk can be significantly reduced through a combination of a healthy lifestyle, regular exercise, drug prophylaxis and compression therapy.

Going forward, it remains important to raise awareness of the risk factors and symptoms of DVT among the general public and healthcare professionals in order to improve early detection and prevent serious complications.
Research and innovation in the field of venous disease promises continued progress that will further improve treatment options and patients’ quality of life.