Isolated distal deep vein thrombosis (DVT) refers to thrombosis located below the popliteal vein at the knee:
- It cannot be detected by routine proximal vein compression ultrasonography.
- It can be identified by whole leg ultrasonography however this is technically difficult to perform and interpret. Many diagnostic imaging departments do not use it.
Patients with isolated distal DVT confined to intramuscular veins are at about half the risk of embolism compared to proximal DVT and in some cases distal DVTs resolve spontaneously. Therefore some centres advocate treating as follows:
- Use heparin if symptomatic and low risk of bleeding.
- Use serial ultrasound surveillance if asymptomatic and low VTE risk.
- Seek specialist advice in other situations.
Note: Confirm whether this is consistent with local treatment policies. For further details and recommendations on prevention and management of VTE consult the following guidelines:
SIGN Guideline 122 – Prevention and Management of Venous Thromboembolism
NICE Guidelines Embolism and Thrombosis