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Deep Vein Thrombosis
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What is a

Deep Vein Thrombosis (DVT)?

What is a Deep Vein Thrombosis (DVT)?

Deep vein thrombosis (DVT) is a condition whereby blood clots are formed commonly in the veins in the legs or pelvis. It can also occur in the arm if there is a compression syndrome of the major draining vein of the arm.

It occurs as a result of provoking factors like surgery, immobility, long plane journeys, dehydration and cancer, which makes the blood more likely to clot.

Once the blood clots occur in the deep veins, it can propagate further north into the major body veins (IVC) and migrate into the lungs and heart, which is potentially fatal.

What are the symptoms and signs to look for in a DVT?

What are the symptoms and signs to

look for in a DVT?

Common symptoms include sudden onset of swelling and pain in the leg/arm. It is more common to occur in one limb but it can sometimes occur in both simultaneously.

You can also detect warmth and redness on the back of the calf of the affected leg.

It can also be totally asymptomatic, especially for DVTs in the below the knee region.


Causes and risk factors

DVT occurs due to 3 main factors (Virchow triad):
1. Problem with the flow of blood
2. Problem with the components of the blood
3. Problem within the vessel wall

All 3 factors causing blood to stagnate and then clots can form inside the vessel.

Problem with flow of blood normally occurs in situations like travelling on the plane or sitting or lying for a long time (hospital patients).

Problem with the components of the blood occurs in dehydration when the blood becomes very viscus or thick.

Problem with the vessel wall occurs when it is compressed such as by the overlying artery in the leg (May-Thurner Syndrome) or in the arm by the first rib (Paget Schrotter Syndrome). This causes the flow of the blood inside the vein to significantly slow down and promote clot formation.

Smoking and dehydration also make the blood more prone to clot.

Why do we need to treat a DVT?

The main goals of treatment are to:

  • Keep the clot from getting bigger and involving other veins.
  • Prevent the clot from breaking off in your vein and moving to your lungs (pulmonary embolism). This condition is potentially life-threatening as it prevents oxygen transfer to the venous blood.
  • Lessen the risk of another blood clot.
  • Prevent long-term complications from the blood clot, such as chronic venous insufficiency and post-thrombotic syndrome (PTS).

What treatments are available for


Treatments include medications called anticoagulants (blood thinners), compression stockings and elevating your affected leg(s) at different times throughout the day.

In a minority of cases, when the DVT is extensive (normally with the clot extending above the groin or arm), minimally invasive surgery (catheter-based procedures) may be required to remove the clot directly to improve outcome for the leg or arm.

Related Information

How to make a diagnosis of DVT?

DVT can be diagnosed usually from a good history and examination with a high index of suspicion and this condition should be seen by a vascular specialist. Appropriate investigations should be performed in the hospital setting.

It can be excluded by a simple blood test (D-Dimer). A simple Duplex ultrasound scan confirms the diagnosis. A vascular specialist may also consider performing a CT scan of your abdomen or pelvis if he/she believes that the clot has extended above the groin.

DVT Treatment

Get treatment immediately in order to prevent potentially serious complications. Some patients with a DVT may need to be treated in the hospital. Others may be able to have outpatient treatment alone.

Treatments for DVT include:
– Medicines
– Compression Stockings
– and Keyhole Surgery.

Be patient with your treatment – you may need to take medicine for at least a few months and potentially wear compression stockings for the medium term.

What can I expect if I have DVT?

A DVT can take several months to a year to resolve, so you’ll need to keep taking blood thinning medicines as instructed and keep wearing compression stockings until your specialist tells you to stop.

You may need blood tests to make sure you’re getting the right dose of blood thinners. Your provider may want to do more ultrasounds later to find out if your blood clot is still in the same place, improving or getting larger.

DVT prevention

DVT can be prevented by simple measures like good hydration on long haul flights.

When patients are having surgery, they are normally given special stockings (TED) to prevent clots forming in the legs. Regular exercise and mobilisation are essential after any major surgery.

When travelling on the plane, you can buy compression stockings to help with vein circulation. Smoking cessation also helps. For female patients undergoing any surgery, the oral contraceptive pill should be stop at least 6 weeks prior.