Prevention of venous thromboembolism

Being unwell and going into hospital increases your risk of developing deep vein thrombosis (DVT) and pulmonary embolism (PE), and although blood clots can cause deaths in hospital, they can largely be prevented. Prophylaxis is the term given to a treatment given or action taken to prevent disease. Thromboprophylaxis refers to the preventative measures taken to avoid thrombosis.

Figure: prevention of DVT and PE is an important consideration for doctors when patients are admitted to hospital. On admission to hospital, every patient should be risk assessed to determine their likelihood of developing venous thromboembolism (VTE) to allow the doctors to decide what preventive measures can be taken.


There are two forms of thromboprophylaxis—taking low doses of anticoagulants, which alter the clotting cascade and make it less likely that the blood will clot, and mechanical forms of prophylaxis including compression stockings, which are designed to improve blood flow in the legs and reduce the chance that a DVT will form.

Surgery and recent immobility after an acute medical illness are common reasons for a hospital stay and such patients are routinely assessed for their risk of DVT and thromboprophylaxis is prescribed if the risk is high and the probability of complications such as bleeding is low.

For example, patients undergoing hip replacement surgery have a high risk of DVT and are usually given small doses of anticoagulants around the time of the operation and for several days after. Clinical guidelines recommend that this is continued after hospital discharge in certain high-risk patients including those who have undergone hip surgery.

Figure: in the UK, doctors follow the National Institute of Health and Care Excellence (NICE) clinical guidelines for prevention of VTE to decide the type and duration of treatment to prevent DVT. This is determined on a case-by-case basis, taking into account the existing relevant risk factors of VTE and the chance that thromboprophylaxis may cause a side effect such as bleeding.