Venous Thromboembolism

Question 1

What is Vichow’s triad of predisposing VTE conditions?

Answer 1

1. Altered thrombotic tendency
2. Altered blood flow
3. Alteration to vessel wall

Question 2

Where does VTE normally occur?

Answer 2

Most often in the legs of deep veins (DVT)

Question 3

What are the risk factors for DVT?

Answer 3

LEG IMMOBILISATION
-Medical hospitalisation
-Surgery
Low extremity trauma
-Pregnancy
-Recent long distance air travel
-Increasing Age

CLOTTING DISORDER

• Anti-clot deficiency (prothrombin/protein C or S/antithrombin)
• Factor V Leiden
• Antiphospholipid antibody syndrome (SLE)

MEDICAL HISTORY

• Active Cancer
• PHx DVT
• FHx DVT

DRUGS

• Tamoxifen
• HRT
• Combined oral contraceptive

Question 4

What are the clinical features of DVT?

Answer 4

• Asymptomatic
• Limb pain and tenderness
• Unilateral swelling of calf or thigh
• Increase skin temperature
• Distension of superficial veins
• Skin discolouration
• A palpable vein (hard/thickened)

Question 5

What is the ‘special test’ in examining for DVT?

Answer 5

1. Measure each calf 10cm below the tibial tuberosity

2. A difference >3cm is clinically significant

Question 6

What is the score system for assessing likeliness of DVT?

Answer 6

TWO LEVEL WELLS SCORE

• Active Cancer = 1
• Recent immobilisation of lower leg = 1
• Bedridden > 3d / major surgery in last 1y = 1
• Localised calf tenderness = 1
• Entire leg swollen = 1
• Calf swelling at least 3cm larger than asymptomatic = 1
• Pitting oedema in asymptomatic leg = 1
• Collateral superficial veins = 1
• Hx DVT = 1
• Another diagnosis more likely than DVT = -2

Question 7

How is Two Level Well scored?

Answer 7

2 points or more = DVT likely

1 point or less = DVT unlikely

Question 8

If DVT scored as unlikely what are the next investigative steps?

Answer 8

1. Perform D dimer ==> IF positive…
2. Proximal leg US scan

If have to wait >4h give LMWH

Question 9

If DVT scored as likely what are the next investigative steps?

Answer 9

1. Proximal leg US scan
2. IF US scan negative = D-Dimer
3. If US scan cannot be carried out = D-Dimer and LMWH

Question 10

What is the management if DVT diagnosed?

Answer 10

CONSERVATIVE
-TED stockings, lose weight, diet

ANTICOUGULATION THERAPY

1. LMWH OR fondaparinux
   - Continued for at least 5 days or until INR >2.0

AND

2. Warfarin/NOAC given within 24h
   - Given for at least 3 months (target INR = 2.5)