Haem: Haemostasis and thrombosis

Question 1

What is virchow’s triad

Answer 1

Blood composition
Vessel wall
Blood flow

Question 2

What is the coagulation cascade essentially about?

Answer 2

Activating thrombin which turns fibrinogen to fibrin

Question 3

What are the procoagulant factors?

Answer 3

Factors 5,8,11,9,10,2, fibrinogen and platelets

Question 4

What are the anticoagulant factors?

Answer 4

TFPI, Proteins C and S, Thrombomodulin, EPCR and anthithrombin

Question 5

What is factor 5 leiden

Answer 5

Mutation in factor 5 that makes it more active

Question 6

How does the vessel wall come into play with coagulation

Answer 6

It is largely anticoagulant:

Makes thrombomodulin, EPCR, heparan - All these help the anticoagulants

Also secretes antiplatelet - Prostacyclin and NO

Question 7

What happens to the vessel walls in inflammation

Answer 7

Expresses tissue factor, downregulates anticoagulants

Produces von willebrand factor which captures neutrophils and platelets

Question 8

Which factor confers the highest risk of thrombosis?

Answer 8

Antithrombin deficiency

Question 9

What types of anticoagulant therapies are available

Answer 9

Immediate and delayed

Question 10

What are the immediate anticoagulant therapies and how do they work?

Answer 10

Heparin - Increases anticoagulant therapy and potentiates anti thrombin
Anti factor 10a (Apixaban, rivaroxiban)
Anti factor 2a (Dabigatran)

Question 11

What are the problems with heparin

Answer 11

Long term disadvantage

Renal dependance

Question 12

How do the delayed anticoagulants work?

Answer 12

Warfarin - Inhibits synthesis of Vit K dependant protein - so Factors 2,7,9 and 10 all fall

Question 13

What else reduced with warfarin

Answer 13

Proteins C and S

Question 14

How can you counteract warfarin?

Answer 14

Give vitamin K for 12 hours or directly give factors 2,7,9,10

Question 15

Who should not be given warfarin

Answer 15

Pregnant women

Question 16

How do you reverse heparin activity

Answer 16

Protamine

Question 17

How is INR calculated

Answer 17

From Prothrombin time

Question 18

What are some examples of LMWH

Answer 18

Tinzaparin and enoxaparin

Question 19

Which anticoagulant produces less bleeding?

Answer 19

Direct acting ones (apixaban) as compared to warfarin

Question 20

What is the treatment protocol for DVT/PE?

Answer 20

LMWH + warfarin OR DOAC

If LMWH + warfarin given - stop LMWH when INR > 2 for 2 days

Continue warfarin or DOAC for 3 months

Question 21

Is there a need for anticoagulation due to increased risk of recurrent VTE after surgery?

Answer 21

No

Question 22

Is there a need for anticoagulation due to increased risk of recurrent VTE after idiopathic VTE?

Answer 22

Yes - try long term anticoagulation with DOAC

Question 23

Is there a need for anticoagulation due to increased risk of recurrent VTE after minor precipitants (COCP, long flight, trauma)?

Answer 23

For 3 months