Venous thromboembolic disease

1. What is the most common first clinical sign of DVT?
2. What are factors associated with DVT?
3. What is Virchow's triad?
4. What are common prophylactic agents for DVT?
5. What are diagnostic tests for DVT?
6. How long is anticoagulation given in case of DVT?

Answers:
1. Sudden death (due to PE) in 70-80%.
2. Immobility, paresis, fracture, soft-tissue injury, age >40.
3. Venous stasis, vessel-wall damage, hypercoagulable state.
4. Low dose unfractionated heparin, LMWH, intermittent pneumatic compression, warfarin, IVC filter.
5. Doppler ultrasound, impedance plethysmography, I-fibrinogen scanning, contrast venography (gold standard).
6. 3-6 months.