deep vein thrombosis

Last edited 05/2020 and last reviewed 01/2021

Deep vein thrombosis, a subset of venous thromboembolism (VTE), occurs in normal veins, usually the deep calf veins of the leg and propagates more proximally (1).

  • it may also affect other sites such as the upper limbs, intracranial and splanchnic veins (2)
  • anatomically, it can be divided as
    • proximal DVT
      • involves popliteal vein and proximal veins
      • around 80% of DVTs
    • distal DVT
      • involves  calf vein and distal veins (3)
  • the disease is often asymptomatic, but 1 per 1,000 people/year in the general population presents with clinical symptoms (2)

It is generally thought of as a complication of surgery or illness.

  • surveillance data have revealed that the absolute risk of DVT in general medical patients is 10%-20% while it increases to 40%-80% in patients having hip surgery, knee surgery, or major trauma (4)

However, a number of situations predispose an individual to a deep vein thrombosis, and are encapsulated in Virchow's Triad (blood hypercoagulability, endothelial damage and venous stasis) (4).

The natural history is one of gradual breakdown of the thrombus with recanalisation. Damage to the valves may produce deep venous incompetence.

DVT is a usual precursor of both fatal PE and post-thrombotic syndrome (PTS) (4).