REVIEW – October 2007

Venous thromboembolism


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Venous thromboembolism (VTE) affects 1-2 persons per 1000 in general population each year, usually as deep venous thrombosis of the leg, or pulmonary embolism. The incidence increases in older individuals – among persons older than 60 years the incidence rate is 1 per 100. Reduction of the burden of VTE requires effecitve primary prevention, prompt diagnosis, appropriate treatment of acute thrombosis and effective long term secondary prevention.
The risk factors for VTE can be classified as either acute provoking or chronic predisposing factors. Major risk factors include recent trauma (incl vertebral fractures), recent major surgery and thrombofilia. VTE is often the final common pathway in cardiovascular disease, cancer and disease of connective tissue. Usually, the diagnosis of VT based on clinical signs is unreliable and must be confirmed by ultrasonography, CT, MRT venography or contrast venography. A low clinical pretest probability of VTE and a negative D-dimer  result reliably exclude the diagnosis and the need for diagnostic imaging.
The aims of treatment are to relieve symptoms, to reduce the risk of pulmonary embolism or deep venous thrombosis, and to prevent post-thrombotic syndrome and recurrent VT. Anticoagulation is the mainstay of treatment and prevention for VT. Initial treatment of acute VT is with unfractionated heparin (UFH) or low-molecular weight heparin (LMWH). LMWH has become the standard of care because it is as effective and safe as UFH but is more convenient to use and has a more favourable side-effect profile. Initial treatment lasting at least 5-7 days is followed by warfarin for at least 3 months. Recent investigations have demonstrated the effectiveness and safety of LMWH for long term treatment and prevention of VT. Decisions regarding the optimal duration of anticoagulation should be individualised and balance the risk of recurrence. Treatment agents and duration depend on the cause.