Patients suffering from deep venous thrombosis are exposed to a more serious risk of pulmonary embolism when the thrombosis is above the knee rather than below. Deep venous thrombosis sometimes causes local after-effects such as leg pains, varicose veins, oedema, and sometimes skin ulcers.
In the initial phase, an anticoagulant is justified, particularly for patients suffering from deep venous thrombosis of the leg above the knee, or from a pulmonary embolism. A low-molecular-weight heparin (LMWH) injected subcutaneously is the first-line anticoagulant for this condition.
For patients with renal failure, or at a high risk of haemorrhage, unfractionated heparin is preferable, administered intravenously or subcutaneously, the dose to be adjusted according to coagulation tests.
Thrombolytic or "clot-busting" drugs may perhaps reduce mortality in patients suffering from a massive pulmonary embolism.
Heparins expose patients to a risk of sometimes severe thrombocytopenia. All anticoagulants carry a risk of haemorrhage.
©Prescrire 1 April 2013
"Deep venous thrombosis and pulmonary embolism. Part 1. Initial treatment: usually a low-molecular-weight heparin" Prescrire Int 2013; 22 (137): 99-104. (Pdf, subscribers only).