DVT

Question 1

Name 6 differentials for unilateral limb swelling

Answer 1

• Dvt
• cellulitis
• ruptured baker’s cyst
• ruptured popliteal aneurysm
• arterial occlusion
• lymphoedema

Question 2

Name 4 differentials for bilateral limb swelling

Answer 2

• Congestive cardiac failure
• DVT
• liver failure
• nephrotic syndrome
• fluid overload

Question 3

Name the 3 factors that contribute to thrombosis

Answer 3

Virchow’s triad
• stasis of blood flow
• endothetial injury
• hypercoagulability

Question 4

Name 3 complications DVT

Answer 4

• Pulmonary emboli
• phlegmasia caerulae dolens (“painfull blue inflammation”) : complete thrombosis of the deep venous system, including the collateral circulation. This results in significant venous congestion, fluid sequestration, and worsening edema. Untreated, it will progress to venous gangrene and cause massive tissue death.
• post thrombotic syndrome: chronic venous insufficiency with leg pain, leg heaviness, vein dilation, edema, skin pigmentation, and venous ulcers

Question 5

Name 5 modifiable risk factors DVT

Answer 5

Lifestyle
• Obesity
• immobilization

Drugs
• oral contraceptives
• hormone replacement therapy
• drugs: chemotherapy, tamoxifen

Question 6

Name 10 non modifiable risk factors DVT

Answer 6

Medical and surgical
•Previous DVT
• cancer
• surgery
• fractures
• paralysis
• acute medical illness
• varicose veins
• pregnancy
• hyper coagulable states:antiphospholipid antibodies, antithrombin deficiency, protein c and S deficiency, factor v Leiden, hyperhomocysteinaemia, prothrombin 20210a, high factor viii IX or xi

Host
• advanced age

Iatrogenic
• central venous line

Question 7

Name and describe wells criteria for clinical probability of DVT

Answer 7

ACCEPTS BS

• Active cancer, treatment ongoing or within previous 6 months or palliative (1)
• paralysis, paresis, recent plaster immobilization of lower extremities (1)
• recently bedridden >3 days or major surgery within 4 weeks (1)
• localized tenderness along distribution of deep venous system (1)
• entire leg swollen (1)
• calf swelling by > 3cm compared with asymptomatic leg (measured 10 cm below tibial tuberosity) (1)
. Pitting Edema (1)
• collateral superficial veins non varicose (1)
• alternative diagnosis as likely or more likely than that of DVT (-2)

0-low probability 5%
1-2= intermediate probability 33%
≥3 = high probability 85%

Question 8

Which investigations should be done for a patient with a low probability of DVT according to the wells score?

Answer 8

Controversial.
Some clinicians say always do duplex because D dimer can be falsely elevated.
Others say do D dimer. If low, 100% excludes DVT. If high, do duplex.

Question 9

Which investigations should be done for a patient with a intermediate probability of DVT according to the wells score?

Answer 9

Duplex ultrasound
If positive, treat.
If negative, repeat after 5-7 days (duplex has low sensitivity and specitivity for calf veins. Only 2% will extend proximally within 2 weeks for which it is very sensitive)

Question 10

Which investigations should be done for a patient with a high probability of DVT according to the wells score?

Answer 10

Duplex Ultrasound

Question 11

What is D dimer?

Answer 11

Product of fibrin degeneration

Question 12

Name 5 scenarios in which D dimer may be elevated

Answer 12

• DVT
• infection
• trauma
• surgery
• malignancy

Question 13

Name 3 imaging options for DVT

Answer 13

• Venography: most sensitive and accurate, gold standard. But invasive, need contrast, time consuming. Only used therapeutically for thrombolysis
• venous duplex ultrasound: first line.
• CT v and MRI

Question 14

Mechanical therapy for DVT?

Answer 14

• elevate leg
• compressive stocking
• Physiotherapy

Question 15

Medical treatment of DVT? (7)

Answer 15

• Low molecular weight heparin eg enoxaparin (clexane) subcutaneous 1 mg/kg bd
• warfarin oral initially 5 mg daily for 2 days then titrate according to INR. Maintenance dose usually 2,5-10 mg daily.

Start both at the same time due to initial pro-coagulant effect of warfarin for the first 3 days.
Stop heparin once INR reaches therapeutic range of 2-3 for 2 consecutive days
Continue warfarin for
-6 months If first episode of idiopathic DVT
-3 months if reversible cause
-12 months if thrombophilic disorders or antiphospholipid antibodies
- indefinitely for patients above and recurrent DVT

Question 16

Mechanism of action heparin?

Answer 16

Potentate inhibition of thrombin and activated factor Xa through antithrombin 3

Question 17

Name 4 complications and limitations unfractioned heparin

Answer 17

• Unpredictable coagulation response, must monitor with aptt (activated partial thromboplastin time) to maintain it at 1,5 times the mean of the control value
• bleeding
• heparin induced thrombocytopenia
• osteoporosis

Question 18

Name 6 advantages of using low molecular weight instead of unfractioned heparin

Answer 18

• Predictable coagulation response based on body weight so no need to monitor, cost effective.
• long half life and predictable clearance; can be given once (prophylaxis) or twice (treat) daily
• great bioavailability soon after subcutaneous injection
• fewer bleeding complications
• fewer complicating with heparin induced thrombocytopenia
• fewer complicating osteoporosis

Question 19

Mechanism of action warfarin? (2)

Answer 19

• Inhibit vitamin K dependent factors 2,7,9,10
• thrombogenic by inhibiting vitamin k dependant proteins c and s first 3 days

Question 20

Which 2 newer, expensive oral anticoag can be used instead of warfarin?

Answer 20

• Dabigatran
• rivaroxaban

Question 21

Which location DVT is most likely to develop post thrombotic syndrome?

Answer 21

Iliofemoral 80-90% who are developed with anticoagulacion alone will develop

Question 22

Name 3 methods of early clot removal in high risk. patients eg iliofemoral DVT to prevent post thrombotic syndrome and ulcers

Answer 22

• Catheter directed thrombolysis (CDT) (accelerate lysis thrombus and preserve valve function. Thrombolysis with tissue plasminogen activator tPA or urokinase)
• pharmacomechanical therapy
• surgical thrombectomy (for patients with venous gangrene with contraindications CDT)

Question 23

Name 5 contraindications thrombolysis

Answer 23

• Bleeding diathesis (tendency)
• high risk bleeding eg recent surgery, gi bleed, trauma
• renal or hepatic failure
• pregnancy
• malignancy

Question 24

Name 7 criteria for catheter directed thrombolysis

Answer 24

• Extensive acute iliofemoral DVT!
• symptoms < 14 days
• good life expectancy >1 year
• low risk bleeding
• angioplasty and stenting for underlying venous lesion
• pharmacomechanical therapy if expertise available (tPA, urokinase )
• still give normal anticoagulation therapy

Question 25

Name 4 indications inferior vena cava filter for DVT

Answer 25

To reduce incidence pe:
•DVT with contraindications to anticoagulation
• recurrent pe on full anticoagulation
• anticoagulation complications that require discontinuation
• debatable: polytrauma or cancer patients with increased risk VTE because of increased risk bleeding

Question 26

Which patients are at moderate risk of DVT following surgery? (3)

Answer 26

• Any surgery in patient age 40-60
• major surgery in <40
• minor surgery with 1 or more risk factors

Question 27

Which patients are at high risk of DVT following surgery? (2)

Answer 27

• Surgery in age > 60
• major surgery in age 40-60 with 1 or more risk factors

Question 28

Which patients are at very high risk of DVT following surgery? (8)

Answer 28

Major surgery in age >40 with
• previous DVT
• cancer
• hyper coagulability
• major orthopaedic surgery
• elective neurosurgery
• multiple trauma
• acute spinal cord injury

Question 29

Thromboprophylaxis for low risk patients (<40, uncomplicated surgery, no risk factors) (3)

Answer 29

•Early ambulating
• graduated compressive stockings
• intermittent pneumatic compression

Question 30

Thromboprophylaxis for moderate to high risk patients post op?

Answer 30

Mechanical methods plus anticoagulation.
0,5 mg/kg per day subcutaneous lmwh (some sources say 1 ) for 5-7 days or until mobilised
Can also use UFH, warfarin etc but need regular monitoring

Question 31

Name 5 factors associated with increased mortality from pe

Answer 31

• CCD
• CLD
• syncope
• hypotension
• right heart failure

Question 32

Name 5 symptoms pulmonary embolism

Answer 32

• Difficulty breathing
• tachycardia
• chest pain
• some may have haemoptysis
• May mimic acute mi or exacerbation of CLD

Question 33

Name 4 investigations and findings for pe

Answer 33

• ECG: may show right bundle branch block, t wave inversion in leads V1 to v4, S wave lead 1, q wave and inverted t wave lead 3.
• D dimer: good screening
Troponin (cardiac biomarker) for risk stratification : elevation = increased mortality
• cxr: exclude other lung pathology but may show cardiomegaly, pulmonary artery enlarge, oligaemia (watermark sign) or wedge shaped infarction
. VQ ventilation perfusion scan: not used any more
Best - spiral CT scan

Question 34

Treatment pulmonary embolism? (2)

Answer 34

• Low risk: anticoagulation alone (same as DVT)
• high risk with massive pe: thrombolysis or thrombectomy with anticoagulation.