Table 1

Risk factors for venous thromboembolic disease

Venous stasis or injury, secondary hypercoagulable states:
Immobilisation or other cause of venous stasis—for example, stroke
Major trauma or surgery within 4 weeks
Active cancer (treatment within previous 6 months or palliative therapy)
Prior history of thromboembolism
Reduced cardiac output (congestive heart failure)
Obesity, advanced age
Pregnancy, early puerperium, contraceptive pill with high oestrogen content
Indwelling catheters and electrodes in great veins and right heart
Acquired thrombotic disorders—for example, antiphospholipid antibodies, heparin induced thrombocytopenia, thrombocytosis, post-splenectomy
Primary hypercoagulable states (thrombophilia):
Deficiency of antithrombin III, protein C or S
Resistance to activated protein C (factor V Leiden)
Elevated plasminogen activator inhibitor
High plasma concentration of factor VIII
Prothrombin gene mutation (G20210A polymorphism)