Deep vein thrombosis

Overview: What is deep vein thrombosis?

Veins are the blood vessels in which blood flows from the body back to the heart. Here, a distinction is made between a superficial and a deep system. The deep system forms the main veins and transports most of the blood back to the heart. For a variety of reasons, a blood clot can develop in the deep veins of the arms, legs or pelvis. Most often, the blood clot develops in the deep veins of the leg and pelvis, most commonly in the deep muscle layers of the lower leg. This is called deep vein thrombosis, abbreviated DVT.

In DVT, the vein may be partially or completely occluded. Due to the blockage in the vessel, blood can no longer flow freely from the extremity back to the heart and lungs. It backs up behind the clot and causes swelling. Typical complaints are pain in the calf, thigh or hip, which increases when walking or standing. Swelling, hyperthermia or reddish-bluish discoloration of the skin can also be indications of venous thrombosis. However, venous thrombosis often goes unnoticed and the body dissolves the blood clot itself.

Thrombosis is always an emergency and you must seek medical advice immediately! The main goal is to prevent the growth of the blood clot, restore blood flow, and avoid life-threatening complications such as pulmonary embolism.

Venous thrombosis: Causes and risk factors

Three mechanisms (“Virchow triad”) lead to blood clots:

1. Reduced flow rate of the blood: In case of lack of movement due to bed confinement, severe illnesses, longer journeys or after operations.
2. Increased tendency of the blood to clot: The composition of the blood may be altered, for example in the case of coagulation disorders, cancer or the use of hormonal contraceptives.
3. Injuries: Changes or inflammation of the innermost layer of the vein wall, such as in varicose veins

Risk factors

• Recent surgery
• Prolonged bedriddenness
• Age 60 and above
• Pregnancy and the period immediately after childbirth
• Active cancer; especially if currently being treated by chemotherapy or radiation.
• Previous thrombosis
• Longer trips by plane, car, bus or train
• Smoking
• Taking estrogens, for example, contraceptives or hormone replacement therapy.
• Hereditary or non-hereditary coagulation disorders (thrombophilia)
• Strong varicose veins
• Pronounced obesity (adiposity)
• Severe cardiac insufficiency (heart failure)

Some people also have several of these risk factors at the same time – in which case the risk of venous thrombosis increases further.

Symptoms: recognize venous thrombosis and act correctly

In many cases, deep vein thrombosis causes no symptoms and goes unnoticed. The organism dissolves the blood clot itself. Other people, on the other hand, develop symptoms that require us to act immediately. If part of the blood clot in the leg vein becomes dislodged, it is washed away with the blood flow and can block a vessel at another site. Often, the clot ends up in the lungs. This is called a (pulmonary) embolism. A pulmonary embolism can be a life-threatening consequence and, in the worst case, fatal.

You can recognize a venous thrombosis by the following symptoms:

• Pain in the leg (especially calf, but also foot) or pelvis/back – especially with physical exertion and when stepping. When elevating the legs, the pain often improves.
• Pressure sensitivity in the affected region
• Feeling of heaviness and tension
• Reddened or bluish discolored skin
• Swelling
• Overheating of the affected part of the body
• “Warning veins”: superficial veins protrude because blood seeks other routes due to vascular blockage.

Diagnosis venous thrombosis

In the case of venous thrombosis, rapid diagnosis is important so that the correct treatment can be started promptly.

Specific questions about your medical history (anamnesis):

• What symptoms do you experience? Where, since when and how pronounced?
• Do the symptoms improve or worsen in certain situations?
• Have you ever had a thrombosis?
• Have you recently been bedridden for an extended period of time?
• Do you smoke? How much and since when?
• Are you taking any medications, such as hormonal contraceptives or hormone replacement therapy?
• Are you pregnant or have you recently given birth?
• Do you suffer from diseases – for example cancer or coagulation disorders

Examinations for venous thrombosis

If deep vein thrombosis is suspected, the following examinations follow:

• Physical examination: palpation of skin and extremities
• Blood test: Determination of blood coagulation values and other blood values, such as D-dimers. These substances are fragments of the protein fibrin. They occur when a blood clot is broken down. Elevated D-dimer levels are virtually always found in thrombosis, but can also occur in other conditions. In order to exclude this and to confirm the diagnosis, an ultrasound examination is therefore also performed if the D-dimer test is positive. On the other hand, negative D-dimer values are used to exclude thrombosis. If the values are negative, an ultrasound examination is usually no longer necessary.
• Color-coded duplex sonography: A special ultrasound examination that can be used to visualize both flowing blood and thrombosis (clotted blood) in the veins. Color-coded duplex ultrasonography provides an accurate assessment of the extent of venous thrombosis and helps plan therapy.
• Phlebography: This is an X-ray examination of the veins using contrast medium. A blood clot is clearly visible on the images. This method is used, for example, in the treatment of acute or chronic pelvic vein thrombosis.
• Computed tomography (CT) and magnetic resonance imaging (MRI) are also used. CT uses X-rays, while MRI uses magnetic fields. Both methods produce high-resolution, detailed cross-sectional images of the body and vessels (also: veins). This reveals the exact extent of blood clots.

Venous thrombosis: Prevention, early detection, prognosis

You can prevent thrombosis by eliminating existing risk factors. Some tips for thrombosis prophylaxis that will protect you from blood clots:

• Move as much as possible in everyday life and exercise regularly – preferably endurance sports such as swimming, hiking or cycling.
• Standing or sitting for long periods of time is not good for the veins.
• Strengthen your veins, for example by doing foot exercises (even when traveling!) or by regular cold-warm castings.
• Try to lose weight if you are overweight.
• Refrain from smoking. Smoking and hormonal contraception increase the risk of thrombosis.
• You should have pronounced varicose veins treated. We will be happy to advise you and can offer you a wide range of treatment options.
• Sometimes blood thinning agents are necessary (for example after surgery, in case of plaster cast) – always consult with us.

Prevent travel thrombosis – tips for protection

Travel thrombosis is most common in people who have experienced previous thrombosis or have extensive varicose veins. Travelers who bring other risk factors or who have known thrombophilias are also at risk. On air, car or train journeys lasting longer than four hours, it is therefore advisable to take preventive measures to protect against thrombosis (thromboprophylaxis). Some general tips for travel:

• Wear compression stockings, which exert pressure on the veins from the outside.
• Be sure to stay hydrated – drink plenty of water or tea. This applies to everyday life, but also when traveling.
• Be sparing in the consumption of coffee and alcoholic beverages, as in excess they can dehydrate the body and increase the tendency of blood to clot.
• If possible, do not take sleeping pills.
• Get up at least once an hour for a few minutes.
• Only take blood thinners if you have already suffered a thrombosis or pulmonary embolism or if you have been advised by a doctor to take prophylaxis.

Course and prognosis in venous thrombosis

The course and prognosis for thrombosis depend on the location and size of the blood clot. Existing diseases can also influence the course. However, thrombosis is easily treatable if we diagnose and treat it quickly.

A feared consequence of deep vein thrombosis is pulmonary embolism. In the process, part of the blood clot (thrombus) breaks loose and is washed away with the blood flow toward the heart and lungs. There it occludes a pulmonary vessel. This does not always have to be life-threatening. About half of people with fresh leg vein thrombosis have a minor pulmonary embolism without realizing it. However, if it is a larger thrombus that occludes a larger vessel, the pulmonary embolism can have fatal consequences.

Weeks, months or years later, the thrombosis may also develop into postthrombotic syndrome. In this case, the vessel walls and venous valves are so severely damaged that permanent blood stasis occurs in the leg. The consequences are swelling, heaviness and pain in the leg. This is often accompanied by skin discoloration, itching and rashes. If the postthrombotic syndrome is very severe, it can also lead to chronic wounds and an open leg.

The risk of developing postthrombotic syndrome is highest with extensive thrombosis involving the great iliac vein. Therefore, to prevent the disease in patients with thrombosis of the iliac vein, surgical treatment is sometimes necessary.

Venous thrombosis: Treatment must begin quickly

We must treat a deep vein thrombosis immediately so that the blood clot does not continue to grow, it does not break loose and no complications such as a pulmonary embolism develop. As a rule, deep vein thrombosis of the arms and legs is treated with blood thinning medication for at least three months. The duration of blood-thinning therapy depends, among other things, on whether thrombosis has occurred provoked or unprovoked. In the case of venous thrombosis in the pelvic region, additional surgical intervention may be required.

In addition, treatment should prevent the onset of post-thrombotic syndrome, which can occur weeks to years later.