Venous thromboembolism
Venous thromboembolism (VTE) refers to a thrombus which originates in a vein. The most important types are deep vein thrombosis and pulmonary embolism.
VTE is a major source of mortality and morbidity, and its incidence is increasing. In the US alone it causes > 200 000 deaths annually, more than HIV, motor vehicle accidents, and breast cancer combined. VTE is preventable, and a major cause of preventable death. Many patients with VTE develop recurrent VTE later.
Etiology
VTE occurs due to Virchow’s triad, three categories of factors which contribute to thrombosis:
- Stasis (alteration in normal blood flow)
- Hypercoagulability (alteration in the constitution of blood predisposing to thrombosis)
- Endothelial injury
There are many risk factors for VTE, which we can categorise according to Virchow’s triad:
- Stasis
- Old age
- Recent immobility (especially after surgery or trauma)
- Heart failure
- Paralysis
- Obesity
- Varicose veins
- Hypercoagulability
- Cancer
- Smoking
- High oestrogen state
- Pregnancy
- Thrombophilia
- Sepsis
- Endothelial damage
- Surgery
- Previous VTE
- Trauma