DVT

Question 1

What is a DVT?

Answer 1

Formation of a thrombus within the deep veins (most commonly calf or thigh)

Question 2

What are the 2 types of DVT?

Answer 2

Provoked: a/w a transient RF e.g. immobility, surgery, trauma, + pregnancy/ puerperium, COCP + HRT. These RFs can be removed, thereby reducing risk of recurrence.

Unprovoked: occurs in absence of a transient RF. The person may have no identifiable RF or a RF that is persistent + not easily correctable (e.g. active cancer or thrombophilia). Because these RFs cannot be removed, the person is at increased risk of recurrence.

Question 3

What describes the 3 broad factors leading to thrombus formation?

Answer 3

Virchows triad:
Venous stasis
Vessel wall injury
Blood hypercoagulability.

Question 4

Based on Virchows triad, list risk factors for DVT

Answer 4

Venous stasis: Prolonged immobility
Vessel wall injury: Trauma, Surgery
Blood hypercoagulability: Cancer, APLS

Question 5

Describe the epidemiology of DVT

Answer 5

1-2 per 1000

Question 6

Describe the symptoms in DVT

Answer 6

Asymptomatic
OR
Unilateral lower limb swelling + throbbing pain

Question 7

What signs may a DVT present with?

Answer 7

Swelling, erythema, warmth
Calf tenderness
Severe leg oedema + cyanosis
Signs of PE on resp exam (fever, tachycardia, pleuritic chest pain)

Question 8

What scoring system is used to asses risk of DVT?

Answer 8

Wells
>,2 = Likely DVT

Question 9

What are the parameters of the two-level Wells score?

Answer 9

Cancer
Calf Swelling (>3cm larger than other)
Collateral Superficial veins

Swelling of entire leg
Oedema (Pitting) of symptomatic leg
Bed rest >3 days/ major surgery in past 12w

Localised pain along distribution of deep venous system
Immobilisation/ paralysis of LL
Previous DVT/ PE

Alt dx at least as likely (-2)

Question 10

What baseline bloods should be performed in suspected DVT?

Answer 10

FBC
U+Es
LFTs
PT + APTT

Question 11

For those with a Wells score >,2, what should be offered?

Answer 11

Proximal vein US with results available within 4h:
If +ve: start anticoagulant
If -ve: perform D-dimer. If both -ve consider ddx.

If US not possible within 4h: D-dimer test + interim therapeutic anticoagulation whilst awaiting US (within 24h)
If scan -ve, D dimer +ve: stop interim anticoagulation + repeat US in 6-8 days

Question 12

Describe management of those with a Wells score <2

Answer 12

Perform D-dimer within 4h (if not possible, give anticoagulant until result available)
If -ve: consider ddx
If +ve: proximal leg US within 4h (if not possible give anticoagulation whilst waiting)

Question 13

What anticoagulant should be used in the interim if required in suspected DVT?

Answer 13

DOACs:
Apixaban
or
Rixaroxaban
Continue if dx is confirmed

Question 14

Describe DVT management if DOACs are unsuitable

Answer 14

LMWH followed by dabigatran or edoxaban
OR
LMWH followed by a vitamin K antagonist (VKA, i.e. warfarin)

Question 15

Describe DVT management in active cancer

Answer 15

DOAC (unless CI)

Question 16

Describe management of DVT if severe renal impairment (<15/min)

Answer 16

LMWH, unfractionated heparin or LMWH followed by a VKA

Question 17

Describe management of DVT in antiphospholipid syndrome

Answer 17

LMWH followed by a VKA

Question 18

Describe duration of anticoagulation therapy following DVT

Answer 18

All: min. 3 months
If provoked: stop after 3 months
(3-6 months if active cancer)
If unprovoked: continue for further 3 months (6 months total)

Question 19

Which tool can assess patient risk of bleeding?

Answer 19

ORBIT score

Question 20

Describe sensitivity of proximal vein leg US for suspected DVT

Answer 20

Good sensitivity for femoral veins; less sensitive for calf veins

Question 21

Name 2 complications of DVT

Answer 21

PE (+/- death)
Post-thrombotic syndrome

Question 22

What is post-thrombotic syndrome?

Answer 22

Chronic venous HTN causing limb pain, swelling, hyperpigmentation, dermatitis, ulcers, venous gangrene, + lipodermatosclerosis.
Affects up to 50% within 2y of DVT

Question 23

List 2 complications of the treatment of DVT

Answer 23

Bleeding: mostly a/w previously unknown lesion e.g. duodenal ulcer
Heparin-induced thrombocytopaenia (usually 5-7 days post exposure)

Question 24

Post-anticoagulation, which further investigations may be performed following unprovoked DVT?

Answer 24

Ix for Cancer: review PMH + bloods. No further Ix unless relevant clinical Sx
Ix for Thrombophilia: if planning to stop anticoagulant test APL abs / Hereditary Thrombophilia if VTE in 1st degree relative

Question 25

List 9 risk factors for hypercoagulability

Answer 25

COCP/ HRT
Obesity
Pregnancy
Trauma
Smoking
Polycythaemia
Anti-phospholipid syndrome
Thrombophilia disorders (e.g. protein C deficiency)
Active malignancy.

Question 26

What is the investigation of choice in patients with suspected PE and renal impairment?

Answer 26

V/Q scan
(to avoid use of contrast)