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Deep Vein Thrombosis (DVT)

The formation of a blood clot in a deep vein of the leg or lower pelvis. Symptoms may include pain, swelling, warmth, and redness in the affected area. Also called DVT.

PubMed Health Glossary
(Source: NIH - National Cancer Institute)

Deep Vein Thrombosis

Deep vein thrombosis (throm-BO-sis), or DVT, is a blood clot that forms in a vein deep in the body. Blood clots occur when blood thickens and clumps together.

Most deep vein blood clots occur in the lower leg or thigh. They also can occur in other parts of the body.

A blood clot in a deep vein can break off and travel through the bloodstream. The loose clot is called an embolus (EM-bo-lus). It can travel to an artery in the lungs and block blood flow. This condition is called pulmonary embolism (PULL-mun-ary EM-bo-lizm), or PE.

PE is a very serious condition. It can damage the lungs and other organs in the body and cause death.

Blood clots in the thighs are more likely to break off and cause PE than blood clots in the lower legs or other parts of the body. Blood clots also can form in veins closer to the skin's surface. However, these clots won't break off and cause PE.

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What works? Research summarized

Evidence reviews

The use of anticoagulants to prevent deep venous thrombosis and pulmonary embolism following surgery for abdominal aortic aneurysm

Deep vein thrombosis (DVT) is a preventable complication of surgery. The blood clot can break away and travel to the lungs to cause respiratory distress and death (pulmonary embolism). Deep vein thrombosis is believed to occur less often following aortic surgery than in general surgical operations because heparin used during most vascular operations may protect against intra‐operative DVT. Vascular patients are usually older, with more co‐morbidity (presence of other diseases or conditions), and are subject to prolonged immobility, which increase the likelihood of developing DVT. Bleeding (haemorrhagic) complications could however occur if further anticoagulants are used for DVT prophylaxis during recovery.

Physical methods for preventing deep vein thrombosis in stroke

After a stroke, blood clots can form in the veins of the legs (deep vein thrombosis, or DVT). These clots can break off and be carried in the blood stream to the heart and lungs (causing pulmonary embolism). This can be life threatening. Although anticoagulant drugs can reduce the risk of DVT they can also cause serious bleeding. A number of physical methods have been developed to prevent DVT forming. These include wearing graduated compression stockings, intermittent pneumatic compression and electrical stimulation of leg muscles. The physical methods are used to increase the blood flow in the leg veins and reduce the risk of clots forming. We aimed to evaluate the effects of these physical methods in patients with a recent stroke. We found two randomised trials of graduated compression stockings, involving 2615 participants, and two small trials of intermittent pneumatic compression involving 177 participants. Graduated compression stockings were no better than 'best medical treatment' in reducing the risk of DVT after stroke. Stockings caused more skin problems (for example ulcers and blisters) on the legs. Intermittent pneumatic compression appeared promising but was not proven to be definitely beneficial. The evidence does not support routine use of graduated compression stockings or intermittent pneumatic compression in patients with a recent stroke. The trials that are ongoing at present should provide reliable evidence on the benefits and harms of intermittent pneumatic compression.

New types of anticoagulants to prevent deep vein thrombosis and pulmonary embolism following total hip or knee replacement surgery

Venous thromboembolism is the presence of a blood clot that blocks a blood vessel within the venous system; it includes deep vein thrombosis (DVT) and pulmonary embolism (PE) which can be fatal. Venous thromboembolism occurs in 44% to 90% of those patients who undergo total hip or knee replacement and who do not receive anticoagulants (blood thinning drugs).

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Summaries for consumers

The use of anticoagulants to prevent deep venous thrombosis and pulmonary embolism following surgery for abdominal aortic aneurysm

Deep vein thrombosis (DVT) is a preventable complication of surgery. The blood clot can break away and travel to the lungs to cause respiratory distress and death (pulmonary embolism). Deep vein thrombosis is believed to occur less often following aortic surgery than in general surgical operations because heparin used during most vascular operations may protect against intra‐operative DVT. Vascular patients are usually older, with more co‐morbidity (presence of other diseases or conditions), and are subject to prolonged immobility, which increase the likelihood of developing DVT. Bleeding (haemorrhagic) complications could however occur if further anticoagulants are used for DVT prophylaxis during recovery.

Physical methods for preventing deep vein thrombosis in stroke

After a stroke, blood clots can form in the veins of the legs (deep vein thrombosis, or DVT). These clots can break off and be carried in the blood stream to the heart and lungs (causing pulmonary embolism). This can be life threatening. Although anticoagulant drugs can reduce the risk of DVT they can also cause serious bleeding. A number of physical methods have been developed to prevent DVT forming. These include wearing graduated compression stockings, intermittent pneumatic compression and electrical stimulation of leg muscles. The physical methods are used to increase the blood flow in the leg veins and reduce the risk of clots forming. We aimed to evaluate the effects of these physical methods in patients with a recent stroke. We found two randomised trials of graduated compression stockings, involving 2615 participants, and two small trials of intermittent pneumatic compression involving 177 participants. Graduated compression stockings were no better than 'best medical treatment' in reducing the risk of DVT after stroke. Stockings caused more skin problems (for example ulcers and blisters) on the legs. Intermittent pneumatic compression appeared promising but was not proven to be definitely beneficial. The evidence does not support routine use of graduated compression stockings or intermittent pneumatic compression in patients with a recent stroke. The trials that are ongoing at present should provide reliable evidence on the benefits and harms of intermittent pneumatic compression.

New types of anticoagulants to prevent deep vein thrombosis and pulmonary embolism following total hip or knee replacement surgery

Venous thromboembolism is the presence of a blood clot that blocks a blood vessel within the venous system; it includes deep vein thrombosis (DVT) and pulmonary embolism (PE) which can be fatal. Venous thromboembolism occurs in 44% to 90% of those patients who undergo total hip or knee replacement and who do not receive anticoagulants (blood thinning drugs).

See all (113)

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See Also: Pulmonary Embolism, Venous Thromboembolism

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