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Flashcards in Thrombosis management Deck (21):
1

What is the anticoagulant effects of heparin?

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

Mechanism of action of warfarin?

Vitamin K reductase inhibitor

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

3

Oral anti-Xa inhibitors?

Rivaroxaban and Apixaban

4

Direct thrombin inhibitors?

Dabigatran

5

Evidence for NOACs?

Non inferior to warfarin
NOACs have better safety profile - less major bleeding

6

Highest risk of recurrence of VTE?

Unprovoked VTE

7

Long term anticoagulation after VTE?

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

Thrombophilia testing after unprovoked VTE?

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

= Don't test

9

What about lupus anticoagulant?

Increases risk of venous and arterial thrombosis

10

How to test for lupus anticoagulant?

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

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

Prevalence of JAK2

12

What about IVC filters for preventing recurrence?

Nil mortality benefit

Increased mortality after 1 yr

Only for patients who can't be anticoagulated safely

13

How do you measure the presence of Dabigatran?

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

How do you measure the levels of dabigatran?

Haemaclot assay

15

How do you measure the presence of anti-Xa drugs

Modified Anti-Xa assay
Need to know what drug the patient is taking

16

How do you reverse Dabigatran

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

How to reverse rivaroxaban and apixaban?

Adexenate

Decoy Xa without anticoagulant activity
BInds drugs --> neutralizes activity

18

Can NOACs be used for prosthetic heart valve prophylaxis?

NO

19

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

Left side

Due to anatomy of the vessels

20

Does screening for cancer in unprovoked VVTE improve outcomes?

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

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

Males