Thromboembolic disease: DVT (R1)

Question 1

Pathophysiology
- What is Virchow’s triad?
- What is the breakdown product of blood clots/fibrin?

Answer 1

Stasis
Endothelial damage
Hypercoagulation

D-dimers

Question 2

Complications
- 2 complications of DVT?

Answer 2

Pulmonary embolism
If atrial septal defect, embolisations elsewhere (eg. brain –> stroke)

Question 3

Risk factors for DVT?

Answer 3

Past + personal history: have you or anyone in your family ever had blood clots in your legs or your lungs?

STASIS
Recent travel (in previous month)
Immobilisation (recent surgeries/hospitalisations in the previous month)
Obesity
Pregnancy

INFLAMMATION
Smoking
Autoimmune diseases eg. lupus
Recent COVID (vaccine)

HYPERCOAGULATION
Cancer
OCP/HRT
Blood clotting disorders

Question 4

Exam
- What findings on the legs?
- Palpation technique?

Answer 4

Inflammed leg: painful, swollen, red, warm
Prominent superficial veins

Use both hands to palpate to the back of the popliteal fossa.

Question 5

Investigation
- What are the criteria for Well’s score?

Answer 5

3 points: Clinical signs and symptoms of DVT
3 points: PE is the most likely diagnosis
1.5 points: Previous DVT or PE
1.5 points: Immobilisation for at least 3 days, or surgery in the previous 4 weeks
1.5 points: Heart rate >100
1 point: Haemoptysis
1 point: Malignancy treatment within 6 months or palliative

Question 6

Investigation
- Scores for low, moderate, high risk?

Answer 6

<2: low risk of PE
2-6: moderate risk of PE
>6: high risk of PE

Question 7

Investigation: labs
- What studies are you going to do to figure out baselines before treatment?
- Which additional study?

Answer 7

FBC, UEC, LFT; coagulation studies (PT, APTT, INR)

D dimer

Question 8

Investigations: labs
- When would you order a D dimer?
- D dimers have a ____ sensitivity and a ____ specificity. So they are good at ruling ___ DVT/PE.
- If you get back an elevated D dimer, what must you do?

Answer 8

• When there is a low probability of DVT/PE (ie: Well’s score <2).
• High sensitivity, low specificity .Ruling out.
• Move onto imaging

Question 9

Investigations: imaging
- What is the first line imaging for DVT?
- If the above modality is inconclusive, what should be used instead?

Answer 9

Ultrasound

CT/MRI venography

Question 10

Investigations: imaging
- For DVTs, what 2 findings will there be on ultrasound?

Answer 10

• Vein is non compressible
• Doppler shows abnormalities in blood flow.

Question 11

Treatment
- What is the mainstay of treatment?
- Timing of these treatments?

Answer 11

Anticoagulation
- LMWH: enoxaparin (Clexane)
- DOACs: apixaban + rivaroxiban (factor Xa inhibitors), dabigatran (direct thrombin inhibitor)
- Warfarin

Generally 3 months; however if unprovoked or the cause cannot be removed, permanent

Question 12

Treatment
- What if anticoagulation is contraindicated, or there is recurrent DVT despite adequate anticoagulation therapy?
- When should IVC filter be removed?

Answer 12

IVC filter
Remove if the contraindication to anticoagulation becomes resolved

Question 13

Treatment
- What if DVT is complicated? Eg. limb ischemia

Answer 13

Admit to hospital
Anticoagulants
Thrombolysis
Mechanical thrombectomy

Question 14

Treatment
- Overview?

Answer 14

Question 15

Prevention
- 2 for stasis?
- 2 for endothelial damage?
- 1 for hypercoagulability?

Answer 15