Three factors increase the risk of VTE: the Virchow’s triad
Virchow R. 1856; Frankfurt: Staatsdruckerei
Rosendaal FR. Lancet 1999;353:1167-73
Some combinations of risk factors have synergistic effects: the cumulative risk is not simply additive, but exceeds the sum of the risks associated with each individual factor.
Cases of DVT per 10,000 person-years according to the use of oral contraceptives and the presence of factor V Leiden
Vandenbroucke, et al. N Engl J Med 2001;344:1527-35
| Inherited risk factors | Acquired risk factors | ||
|---|---|---|---|
| Inherent risk factors | Risk factors related to clinical condition | ||
| Deficit in antithrombin | Advanced age | Recent surgery | Respiratory failure |
| Deficit in protein C |
Obesity |
Immobilisation |
Ischaemic stroke |
| Deficit in protein S | Personal or family history of VTE | Trauma | Venous insufficiency,varicose veins |
| Factor V Leiden | Hormonal treatment | Cancer | Infection |
| Factor II gene mutation | Congestive heart failure |
Inflammatory disease | |
| Myocardial infarction | Pregnancy | ||
| Antiphospholipid syndrome | |||