Haematology 2 - venous thrombosis

Question 1

Consequences of thromboembolism

Answer 1

Death
Recurrence (20% in firsrt 2 years, 4% per annuum thereafter)
Thrombophlebitis syndrome
Pulmonary HTN

Question 2

Virchow’s triad

Answer 2

Vessel wall
Blood flow
Blood

Question 3

What is TFPI? What does it stand for and what does it do?

Answer 3

Tissue factor pathway inhibitor

Inhibits tissue factor 10a and factor 7a

Question 4

What does antithrombin inhibit?

Answer 4

Thrombin and factor 10a

Question 5

What property does the vessel wall normally have?

Answer 5

Normally antithrombotic

Question 6

What factors determine the viscocity of the blood?

Answer 6

Platelet count, haematocrit, protein/paraprotein, coagulation system, coagulation system

Question 7

Which anticoagulant molecules does the vessel wall express?

Answer 7

Endothelial Protein C receptor
Thrombomodulin
Heparans
TFPI

Question 8

Where is tissue factor found?

Answer 8

It is found in the subendothelial space, NOT expressed by the vessel wall

Question 9

What does the vessel wall secrete?

Answer 9

Prostacyclin (PGI2) from vessel wall, Nitric Oxide (NO)

Question 10

What does inflammation/injury do to the vessel wall?

Answer 10

Makes it prothrombotic

Question 11

Which factor confers the highest risk of thrombosis?

Answer 11

Antithrombin III deficiency

Question 12

Immediate anticoagulant therapy

Answer 12

heparin and DOACs

Question 13

Delayed anticoagulant therapy

Answer 13

Warfarin

Question 14

How does heparin work?

Answer 14

Potentiates antithrombin

Question 15

Disadvantages of heparin/DOACs

Answer 15

Osteoporosis, injections, variable renal dependence

Question 16

Examples of DOACs

Answer 16

Directly acting anti-10a e.g. rivaroxaban, apixaban, anti-2a/anti-thrombin e.g. dabigatran

Question 17

How do you monitor LMWH therapy?

Answer 17

Factor Xa assay (only required in some patients)

Question 18

Which patients require LMWH monitoring?

Answer 18

Extremes of weight or renal failure

Question 19

How do you monitor unfractionated heparin ?

Answer 19

APTT or factor Xa assay (ALWAYS monitor)

Question 20

Do DOACs require monitoring?

Answer 20

No

Question 21

Which factor has the shortest half life?

Answer 21

Factor 7

Question 22

When a patient is started on warfarin, what is the first factor to be depleted?

Answer 22

Factor 7

Question 23

Warfarin MOA

Answer 23

Vitamin K epoxide reductase inhibitor

Question 24

Which factors does warfarin inhibit?

Answer 24

Factors 2,7,9,10 and protein C and S

Question 25

How to reverse excess warfarin

Answer 25

Give vitamin K (Takes 12 hours) or give factors 2,7,9,10 (immediate)

Question 26

Monitoring of warfarin

Answer 26

It is ESSENTIAL
Measure INR (derived from PT/EXTRINSIC pathway)

Question 27

Which anticoagulant really only given if have prosthetic heart valve?

Answer 27

warfarin

Question 28

Reversal of heparin with…

Answer 28

protamine

Question 29

Treatment of DVT/PE

Answer 29

Immediately start on LMWH + warfarin, stop LMWH when INR >2 for >2 days, continue for 3-6 months OR just give DOAC from start

Question 30

Which type of patient is most likely to benefit from long term anticoagulation after DVT?

Answer 30

Patients with an unprovoked DVT

Question 31

Options for thromboprophylaxis

Answer 31

LMWH, TEDS, Flowtron (intermittent compression), sometimes DOAC+aspirin

Question 32

Which population of pts would you treat their thrombosis?

Answer 32

Life threatening PE or limb threatening DVT

Question 33

Why do we often not treat thrombosis/PE?

Answer 33

High risk of intraventricular haemorrhage