DVT

Protocol for investigation and management of possible DVT

Discuss with on-call physician if:

Acutely unwell
Suspected PE

Discuss with on-call obstetrician if patient pregnant

Primary care assessment

Complete pre-test probability using Wells score below or online calculator

Criterion	Score
Active cancer (treatment ongoing, within the last 6 months, or palliative).	+1
Paralysis, paresis, or recent plaster immobilization of the legs.	+1
Recently bedridden for 3 days or more, or major surgery within the last 12 weeks requiring general or regional anaesthesia.	+1
Localized tenderness along the distribution of the deep venous system (such as the back of the calf).	+1
Entire leg is swollen.	+1
Calf swelling by more than 3 cm compared with the asymptomatic leg.	+1
Pitting oedema confined to the symptomatic leg.	+1
Collateral superficial veins (non-varicose).	+1
Previously documented DVT.	+1
Subtract two points if an alternative cause (Baker's cyst, cellulitis) is considered at least as likely as DVT.	-2
Total

DVT is likely if the score is 2 or more

DVT is unlikely if the score is 0 or 1

DVT unlikely - Well's score 0 or 1

Check D-Dimer

D-Dimer positive

Refer for urgent USS leg via SCI Gateway. Ensure D-dimer and Well's score is included in clinical details.
Start Apixaban 10mg BD for 7 days then 5mg BD unless contra-indication.
Take blood for FBC, U&E, LFT, Clotting but no need to await results before starting Apixaban.

D-Dimer negative

DVT excluded
Consider alternative diagnosis

DVT likely - Well's score 2 or more

Do D-dimer but negative result does not rule out DVT in this group so also
Refer for urgent USS leg via SCI Gateway. Ensure Well's score is included in clinical details.
Start Apixaban 10mg BD for 7 days then 5mg BD unless contra-indication.
Take blood for FBC, U&E, LFT, Clotting but no need to await results before starting Apixaban.

Scan negative

Stop any anticoagulation that had been started
Advise patient on signs DVT
If D-dimer was positive, reassess in 7 days
Consider repeat USS if ongoing or worsening signs

Scan positive

Start Apixaban 10mg bd for a week then 5mg BD for 3 months.

Advise patients they should use grade 2 compression stockings lifelong.

For patients with significant ongoing swelling routine referral to vascular for review is reasonable.

If patient has active cancer, liaise with their cancer team about treatment as this can vary depending on the type of cancer. 6 months treatment may be recommended.

Consider causes for unprovoked DVT:

10% of patients with unprovoked DVT will have malignancy
Consider underlying malignancy if D-dimer very high (>4000)
May be presenting sign of prostate or pancreatic cancer
Review patient for physical examination
Review baseline bloods and symptoms
No indication for further investigations for cancer if no relevant symptoms or signs elicited

Ilio-femoral DVT

This may be suitable for thrombolysis or clot retrieval, particularly in otherwise well people ('good functional status, life expectancy of one year or more and low risk of bleeding' - NICE 2020).

It needs to be done within 14 days of symptom onset. If scan shows common femoral/iliac vein clot (or inferior vena cava or subclavian DVT and they have severe symptoms:

Severe pain, especially groin and calf pain
Severe swelling and tenderness
Inability to weight bear/use limb/walk
Any concern about venous ischaemia/compartment syndrome
Concerning imaging features (e.g. hanging IVC clot)

Phone vascular on-call at Hairmyres to discuss in relevant patients - 01355 585 260.

Last reviewed: 25/10/2023

Next review date: 24/10/2025

Author(s): Sian Finlay.

Version: 1.0

Co-Author(s): Jozef Lastik, Joseph Sathianathan.

Approved By: Interface group

Reviewer name(s): Fergus Donachie.