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 | |
| Hyperhomocysteinaemia | |
| High plasma concentration of factor VIII | |
| Prothrombin gene mutation (G20210A polymorphism) | |