DVT Flashcards
Clinical presentation
Unilateral leg pain and/or swelling
May be warm to touch
May be provoked by clear temporary risk factor (e.g surgery) or unprovoked
score used to assess possible DVT
wells score
name 3 checkpoints from the wells score
- active cancer in last 6 months
- tender along deep vein
- prior DVT
- unil;ayteral pitting oedema
- entire leg swollen
- calf swelling 3cm more than other side
- paralysis / immobilisation of lower leg
- Bedridden >3 days or major surgery <12 weeks ago
- Collateral superficial veins
outcome of wells score
Wells score = 0 – 5% prevalence of DVT
Wells score 1/2 – 17% prevalence DVT
Wells score 3+ - 17-53% prevalence DVT
US doppler detects DVT by assessing the compressibility of the leg veins and is a highly reliable and practical method for diagnosing DVT
if you suspect DVT but the scan and result will be in more than 4 hours, what should you do?
anticoagulate while awaiting results
how long should you administer anticoagulation for dvt?
Clear provoking factor which has resolved – 3 months
Cancer – continue until 6 months after cancer treatment is complete and in remission
Unprovoked – continue long term
Persistent provoking factor – continue whilst provoking factor persists
management if dvt is limb threateneing
consider additional catheter directed thrombolysis
management if contra-indications to anticoagulation
Temporary IVC filter to prevent distant embolization
– must be removed as can itself be prothrombotic!
aetiology
Immobilisation
Surgery
Long hall flights
investigations
1st line:
D-dimer - high sensitivity but low specificity (positive result doesn’t mean diagnosis)
A D-dimer test is a blood test that checks for blood-clotting problems
>0.50mg/L= Likely clot
<0.50mg/L = Clot unlikely
Gold standard:
Doppler Ultrasound - very reliable (veins should be able to compress - thrombosis will
other:
CT/MRI
venography
wells results to decide upon D-dimer
DVT Likely (≥2) wells :
Straight to proximal leg vein ultrasound within 4 hours. Alternatively, request D-dimer, give interim anticoagulation and arrange ultrasound within 24 hours
DVT Unlikely (≤1) wells :
Prevalence of DVT ~5%. Proceed to d-dimer testing. If test is positive proceed to proximal leg vein ultrasound testing
management
- First line – DOAC (apixaban or rivaroxaban)
- Thrombolysis in some cases
- Compression stockings + Calf Exercises
- Long term anti-coagulation: DOAC, warfarin or LMWH
- Anti - Platelets: Low dose Aspirin
Provoked DVT - 3 Months on Apixaban
Unprovoked DVT - 6 Months on Apixaban
complications
Heparin induced thrombosis - more common after unfractionated heparin
Bleeding
PE
Ischaemia
Limb loss - rare
mechanical prevention
Often used if a contra-indication to anticoagulation
Aim to prevent stasis
Compression stockings for most
Intermittent pneumatic compression
Special groups e.g stroke patients
Pharmacological intervention
Low weight molecular heparin
Dosed based on weight
Duration based on period of risk
whats catheter directed thrombolysis?
a catheter is inserted into neck or groin and directed using imaging techniques to the thrmobus - then streptokinase is released to break down the clot
how many criteria on wells
10
score of 1-9
