VTE risk The likelihood of developing a VTE is increased by well-recognised risk factors. However, there are few population-based studies on VTE risk in hospitalised patients, and estimates of the magnitude of risk are sometimes contradictory or outdated (for example, by changes in surgical techniques or patient characteristics). There are no evidence-based algorithms for assigning a patient to ‘low’ or ‘high’ risk categories, based on single risk factors or combinations of risk factors. Known risk factors are listed below, and their presence or absence should inform clinical decisions on the use of thromboprophylaxis. The risk factors are grouped into the following categories: individual patient risk factors; risks related to an acute medical illness; and risks related to an injury or a surgical procedure. Risks related to the individual may be either inherited or exogenous. Depending on their magnitude the risk factors related to an injury, a surgical procedure, or an acute medical illness often exert a dominating influence for their duration. 1. Individual patient risk factors • age (the annual incidence of VTE rises with each decade over the age of forty) • pregnancy and the puerperium • active or occult malignancy • previous VTE • varicose veins • marked obesity • prolonged severe immobility (prolonged bed rest, immobilisation in a plaster cast or brace or prolonged travel resulting in limited movement and subsequent venous stasis) • use of oestrogen-containing hormone replacement therapy or oral contraceptives in women • inherited or acquired thrombophilia (conditions that carry a high risk of VTE include inherited deficiency of antithrombin, protein C or protein S, homozygosity or double heterozygosity for factor V Leiden or the G20120A prothrombin gene mutation, the phospholipid antibody syndrome). 2. Risks related to an acute medical illness: • acute or acute on chronic chest infection • heart failure • myocardial infarction • stroke with immobility • some forms of cancer chemotherapy • acute inflammatory bowel disease. 3. Risks related to an injury or surgical procedure: • all surgical procedures but especially abdominal, pelvic, thoracic or orthopaedic surgical procedures – risk is determined by the type of surgery (major joint surgery carries a very high risk, as does curative surgery for cancer), the type of anaesthesia, the likely duration of immobility (including duration of surgery), and surgical complications • leg injury that requires surgery or prolonged immobilisation
Posted on: Mon, 19 Jan 2015 22:57:19 +0000
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