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Flashcards in Thrombosis management Deck (21)
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1
Q

What is the anticoagulant effects of heparin?

A

Binds to antithrombin and catalyses the inactivation of thrombin, IIa, Xa, IXa, XIa and XIIa

BInds to HCH and inactivates IIz

Binds factor IXa which inhibits factor X activiation

2
Q

Mechanism of action of warfarin?

A

Vitamin K reductase inhibitor

–> Stops the reduction of Vitamin K –> stops carboxylation of factors II, VII, IX, X and XI

3
Q

Oral anti-Xa inhibitors?

A

Rivaroxaban and Apixaban

4
Q

Direct thrombin inhibitors?

A

Dabigatran

5
Q

Evidence for NOACs?

A

Non inferior to warfarin

NOACs have better safety profile - less major bleeding

6
Q

Highest risk of recurrence of VTE?

A

Unprovoked VTE

7
Q

Long term anticoagulation after VTE?

A

For unprovoked VTE only

Long term warfarin or NOACs

If doesn’t want warfarin or NOAC = aspirin
Aspirin decreases risk of recurrent VTE by 30%

8
Q

Thrombophilia testing after unprovoked VTE?

A

Most thrombophilias increase risk of a primary VTE but not recurrent VTEs

= Don’t test

9
Q

What about lupus anticoagulant?

A

Increases risk of venous and arterial thrombosis

10
Q

How to test for lupus anticoagulant?

A

Prolonged ApTT and DRVVT

ApTT not corrected with mixing test

Confirm test with dilute russel venom viper test - adding phospholipid will correct antibody

Also check for the presence of anti-cardiolipin antibody and Anti-beta2 GPI antibody

11
Q

What should be checked for if patient diagnosed with splanchic vein thrombosis?

A

Prevalence of JAK2

12
Q

What about IVC filters for preventing recurrence?

A

Nil mortality benefit

Increased mortality after 1 yr

Only for patients who can’t be anticoagulated safely

13
Q

How do you measure the presence of Dabigatran?

A

ApTT and Thrombin clotting time very sensitive to the presence of dabigatran

If normal ApTT and thrombin clotting time = minimal or no drug
If normal ApTT and prolonged thrmbin clotting time = low drug levels
If both prolonged = significant drug levels

14
Q

How do you measure the levels of dabigatran?

A

Haemaclot assay

15
Q

How do you measure the presence of anti-Xa drugs

A

Modified Anti-Xa assay

Need to know what drug the patient is taking

16
Q

How do you reverse Dabigatran

A

Idaracizimab
2.5gm bolus and repeated at 15 minutes
Works within 1 minute

Monoclonal antibody which has a greater binding affinity for dabigatran than thrombin –> neutralizes activity

17
Q

How to reverse rivaroxaban and apixaban?

A

Adexenate

Decoy Xa without anticoagulant activity
BInds drugs –> neutralizes activity

18
Q

Can NOACs be used for prosthetic heart valve prophylaxis?

A

NO

19
Q

Which side is a pregnant woman more likely to get a DVT?

A

Left side

Due to anatomy of the vessels

20
Q

Does screening for cancer in unprovoked VVTE improve outcomes?

A

10% of patients with unprovoked VTE have cancer at 12-24 months

SOME study = no difference in time to diagnosis, mortality from cancer or reduction in recurrent VTEs with extensive screening - targeted hx and ex and ix same outcomes

21
Q

Do males or females have a higher risk of recurrence of VTE?

A

Males