Table 1.

Major risk factors for VTE [1–4]

Clinical factors	Surgical factors	Inherited factors
Advanced age Hospitalisation for acute medical illness Long-haul flights (duration > 4 h) Obesity Pregnancy, including the post-partum period	Central venous access Major surgery Orthopaedic surgery Trauma or fracture	Antithrombin deficiency Dysfibrinogenemia Factor V Leiden mutation Protein C deficiency Protein S deficiency Prothrombin 20210A mutation

Medical diseases	Drugs	Mixed or unknown factors
Antiphospholipid syndrome Congestive heart failure Inflammatory bowel disease Malignancy Myeloproliferative disorders Myocardial infarction Polycythemia vera Previous VTE Sepsis Stroke Varicose veins	Antiestrogens Antipsychotics Chemotherapy Heparin-induced thrombocytopenia High-dose therapy with progestogens Hormone replacement therapy Oral contraceptives Vaginal ring for contraception Strontium ranelate Thalidomide and lenalidomide	Activated protein C resistance in the absence of factor V Leiden mutation Family history of VTE High levels of factor VIII Hyperhomocysteinaemia Lupus anticoagulant

VTE venous thromboembolism