Deep venous thrombosis

How does deep vein thrombosis occur

The venous system is formed by a set of veins that collect blood from the entire body allowing its return to the heart. In the lower limbs it consists of a deep venous system, a superficial venous system and a communicating venous system.

The thrombus or clot occurs due to three fundamental events that are stagnation of the blood, the damage to the wall of the blood vessels and an increase in the coagulability of the blood (hypercoagulability).

In addition, there are a series of factors that favor the appearance of a venous thrombus and that include previous surgery, tumors, kidney diseases, prolonged immobilization (more than 8 days), pregnancy and postpartum, consumption of oral contraceptives, blood disorders that produce hypercoagulability and age.

When the thrombus forms, it remains lodged inside the vein, hindering the venous flow through it.

Sometimes, especially if the thrombus is very large and / or fragile, it can fragment and travel through the venous system through the inferior vena cava reaching the lungs, producing a pulmonary embolism which is a serious disease.

Another complication related to DVT is the post-thrombotic syndrome that occurs when the blood vessels become obstructed by the thrombus and also the venous valves that allow venous return are damaged. The blood accumulates, causing swelling, pain and even skin ulcers in the affected leg area.

Symptoms

In most cases, DVT has no symptoms and is discovered due to the appearance of its complications, such as pulmonary embolism.

When it gives symptoms, they can be noticed in the lower extremities: pain, swelling, inflammation, changes in skin color and skin temperature.

Diagnosis

The test of choice that allows the diagnostic confirmation of a DVT is Doppler ultrasound, being the technique of choice. It allows to see the venous system, the location of the thrombus and the functioning of the venous circulation.

Other complementary tests can be carried out aimed at studying diseases that produce hypercoagulability in the blood through, generally, a series of specific parameters are requested in an analysis.

Treatment

Treatment is based on anticoagulation. For this, anticoagulant drugs are used that reduce the risk of complications (pulmonary embolism and post-thrombotic syndrome). The drug used is heparin, which is administered by subcutaneous injections and is started in all patients with suspected DVT.

Maintenance anticoagulant treatment (since the duration of treatment is between 6 and 12 months depending on the clinical situation) is carried out with oral anticoagulants (acenocoumarol or warfarin).

Elevation and use of compression stockings help decrease swelling and pain and prevent post-thrombotic syndrome. They are indicated from the moment of diagnosis up to a minimum of one year.

In patients in whom anticoagulants are contraindicated or who present recurrent DVT despite correct anticoagulant treatment, placement of a filter in the inferior vena cava may be indicated. It is a procedure in which a filter is placed inside the cava to trap a clot as it moves through the bloodstream and prevent it from reaching the lungs.

Prevention of deep vein thrombosis

In people with risk factors and especially before surgery, anticoagulant treatment may be indicated.

It is recommended to move your legs frequently and drink fluids on long trips or in situations that require sitting or lying down for long periods of time. Early mobilization after surgery or illness is important to avoid blood stagnation and thrombus formation.