Deep vein thrombosis (CV)

Question 1

Define DVT.

Answer 1

Development of a blood clot in a major deep vein in the leg, thigh, pelvis or abdomen

Question 2

Why are clots more likely to form in the deep veins of the leg?

Answer 2

More prone to blood stasis (Virchow’s triad)

Question 3

What are the clinical features of DVT? (5)

Answer 3

• calf swelling (asymmetric)
• warmth and erythema
• dull pain (may also be painless)
• asymmetric oedema
• prominent superficial veins

Question 4

What is seen on examination of DVT? (8)

Answer 4

• red, hot, swollen, tender calf
• measure leg circumference
• varicosities (swollen, tortuous vessels)
• skin colour changes
• Homan’s sign
• pitting oedema
• mild fever
• examine for PE (RR, pulse ox, pulse rate)

Question 5

What is Homan’s sign in DVT?

Answer 5

Deep calf pain on forced passive dorsiflexion of the foot

Question 6

What are some risk factors for DVT? (12)

Answer 6

• age
• COCP
• post-surgery / hospitalisation
• prolonged immobility
• pregnancy
• malignancy / active cancer
• smoking
• polycythaemia / thrombophilia
• recent long-haul travel
• obesity
• past DVT
• medication e.g. raloxifene, tamoxifen, olanzapine, other antidepressants

Question 7

What criteria is used for assessing DVT risk?

Answer 7

Well’s criteria (criteria low yield)

• active cancer
• paralysis, paresis or recent plaster immobilisation of lower extremities
• recently bedridden for 3+ days / major surgery within 12 seeks requiring general or regional anaesthesia
• localised tenderness along distribution of deep venous system
• entire leg swollen
• calf swelling at least 3cm larger than asymptomatic side
• pitting oedema confined to symptomatic leg
• collateral superficial veins (non-varicose)
• previously documented DVT
• (alternative diagnosis at least as likely as DVT = subtract 2 points)

Question 8

How do we use Well’s criteria in DVT?

Answer 8

• score of 2 or more –> DVT likely, proceed to duplex USS
• score of 1 or less –> DVT unlikely, proceed to D dimer
  
  • D-dimer normal: DVT excluded
  • D-dimer elevated: do duplex USS

Question 9

What is the 1st line investigation for DVT?

Answer 9

• Well’s score of 2 or more –> DVT likely, proceed to duplex USS (if -ve –> D-dimer)
• Well’s score of 1 or less –> DVT unlikely, proceed to D dimer
  
  • D-dimer normal: DVT excluded
  • D-dimer elevated: do duplex USS
• if pregnant: do duplex USS straight away
• in patients with headache: D-dimer (negative predictor)

Question 10

How do you investigate a pregnant patient with suspected DVT?

Answer 10

Duplex USS straight away

Question 11

How do you manage a suspected DVT with a headache?

Answer 11

D-dimer –> negative predictor

Question 12

What do you do if you cannot get either a scan (duplex USS) or D-dimer within 4 hours of suspected DVT?

Answer 12

Start a DOAC

Question 13

What is the gold standard investigation for suspected DVT?

Answer 13

Proximal leg doppler ultrasound

Question 14

What are some abnormal findings in doppler ultrasound in suspected DVT? (5)

Answer 14

• inability to fully compress lumen of vein using ultrasound transducer
• reduced or absent spontaneous flow
• lack of respiratory variation
• intraluminal echoes
• colour flow abnormalities

Question 15

What do we do in suspected DVT if imaging negative but D-dimer positive?

Answer 15

Stop interim therapeutic anticoagulation and repeat scan in 6/7 days

Serial ultrasounds until D-dimers drop or clot is shown

Question 16

What investigations do we do if PE is suspected instead of DVT? (3)

Answer 16

• ECG
• CXR
• ABG

Question 17

What are some differential diagnoses for DVT? (6)

Answer 17

• pulmonary embolism
• cellulitis
• Achille’s tendon tear
• calf muscle haematoma
• ruptured popliteal cyst
• pelvis mass/tumour compressing venous outflow from leg

Question 18

What is the initial management of DVT with phlegmasia cerulea dolens (severe swelling and cyanosis)?

Answer 18

• anticoagulation - heparin / enoxaparin / dalteparin
• referral to vascular surgeon (catheter-directed thrombolysis, pharmacomechanical-directed thrombolysis, and surgical thrombectomy)
• without phlegmasia cerulea dolens - consider anticoagulation, baseline blood tests

Question 19

What does the 1st line management of DVT include?

Answer 19

• anticoagulation (DOAC/LMWH)
• 1st line - apixaban or rivaroxaban (DOACs)
• if this not suitable then LMWH (e.g. enoxaparin) followed by dabigatran/edoxaban/vitamin K antagonist (warfarin)

Question 20

In what scenario is LMWH (e.g. enoxaparin) preferred to DOAC in DVT? (3)

Answer 20

• eGFR <15L/min
• pregnant
• antiphospholipid syndrome (LMWH followed by vitamin K antagonist)

Question 21

How long do patients need to be anticoagulated for PROVOKED DVTs (/ do not extend beyond knee)?

Answer 21

3 months

Question 22

How long do patients need to be anticoagulated for UNPROVOKED DVTs (/ extend beyond knee / active cancer)?

Answer 22

6 months

Question 23

What do you do if anticoagulation is contraindicated and there is risk of embolisation in DVT?

Answer 23

IVC filter

Question 24

How can you prevent DVT? (3)

Answer 24

• compression stockings
• mobilisation
• prophylactic heparin (high risk patients e.g. hospitalised)

Question 25

What are some complications of DVT? (6)

Answer 25

• pulmonary embolism
• venous infarction and gangrene
• thrombophlebitis (Hx of DVT and varicose veins)
• chronic venous insufficiency
• heparin-induced thrombocytopenia
• post-thrombotic syndrome

Question 26

What are the clinical features of post-thrombotic syndrome (DVT complication)? (4)

Answer 26

Calves:

• pruritus
• swelling
• varicose veins
• venous ulceration

Question 27

How do we relieve symptoms of post-thrombotic syndrome (DVT complication)?

Answer 27

Graduated compression stockings

Question 28

Describe the prognosis of DVTs. (2)

Answer 28

• below knee DVTs - good prognosis
• proximal DVTs - greater risk of embolisation