This document provides guidelines for the diagnosis and treatment of deep vein thrombosis (DVT). It recommends venous duplex scanning to diagnose DVT and further tests like venography if the scan is negative but clinical suspicion remains high. For treatment, it suggests anticoagulant drugs like low molecular weight heparin or warfarin depending on the patient's risk factors, pregnancy status, and whether they are hospitalized. It also provides recommendations for screening for thrombophilia and lengths of treatment with warfarin based on the type and risk factors associated with the DVT. Catheter-directed thrombolysis is considered for recent large DVT to help prevent post-thrombotic syndrome.

1. Deep vein thrombosis

2. Color duplex scan of DVT

3. Venogram
shows DVT

4. Patient with suspect symptomatic
Acute lower extremity DVT
Venous duplex scan negative Low clinical probability observe
High clinical probability
positive negative
Repeat scan /
Venography
Evaluate coagulogram /thrombophilia/ malignancy
Anticoagulant therapy
contraindication
yes IVC filter
No
pregnancy LMWH
OPD LMWH
hospitalisation UFH
+ warfarin
Compression treatment

5. Thrombophilia screening
Factor V leiden, Prot C/S deficiency
Antithrombin III deficiency
• Idiopathic DVT < 50 years
• Family history of DVT
• Thrombosis in an unusual site
• Recurrent DVT

6. Recommendation for
duration of warfarin
• 3-6 months first DVT with reversible risk
factors
• At least 6 months for first idiopathic DVT
• 12 months to lifelong for recurrent DVT or
first DVT with irreversible risk factors
malignancy or thrombophilic state

7. Diagram 6

9. Phlegmasia cerulea dolens
Venous gangrene

10. Catheter directed-thrombolysis
• Consider in: Acute< 10 days iliofemoral
DVT.
• Long-term benefit in preventing
post-phebitic syndrome is unknown.