Thrombosis Knowledge Centre

Venous Thromboembolism

What is DVT?

Deep-vein thrombosis or deep venous thrombosis (DVT) is a thrombus in a deep vein. It commonly affects the leg veins (e.g. the femoral or the popliteal vein) or the deep veins of the pelvis. However, occasionally, the veins of the arm may be affected.

DVT can occur as a complication of a disease but may also be encountered in the absence of precipitating disorders. It may also recur.

Proximal and distal DVT

Proximal DVT: involves the popliteal, femoral (including the superficial femoral), or iliac veins
Distal DVT: involves the calf veins

Most DVT starts in the calf and proximal DVT are the more prone to embolise.

Clinical symptoms and signs of DVT are unreliable

DVT may present with pain, erythema, tenderness, and swelling of the affected limb. Furthermore, on examination, a palpable cord (reflecting a thrombosedvein), warmth, ipsilateral oedema, or superficial venous dilation may be observed. However, in most instances, DVT is clinically silent (or asymptomatic):

Almost 80% of DVT are clinically silent^1,2
More than 50% of proximal DVT are clinically silent³

Conversely, only about half the patients suspected of having DVT actually have the disease^4,5

Deep veins

References:
1. Girard, et al. Chest 1999;116:903–8;
2. Lethen, et al. Am J Cardiol 1997;80:1066-9;
3. McLachlin, et al. Arch Surg 1962;85:738-44;
4. Haeger, et al. Angiology 1969;20:219-23;
5. Lensing, et al. Lancet 1999;353:479–85