2020A06Describe how the effects of warfarin can be reversed when URGENT surgery is indicated (40%).
For each option discuss the advantages and disadvantages (60%).

 

 

Intro:

Mechanism

·           Vitamin K epoxide reductase inhibitor

Factors affected

(half life)

·           Procoagulants: II (60h), VII (6h), IX (24h), X (36h)

·           Anticoagulants: protein C (8h), protein S (30h)

 

Reversal options:

Expectant

·           Offset in 5 days

·           Allows elimination of drug + production of coagulation factors

·           Can operate immediately if a) low risk of bleeding b) benign consequences of bleeding c) easily compressible site

·           Pro: ↓risk thrombotic events, less disruptive to patient

·           Con: ↑risk surgical bleeding

Vitamin K

·           2mg IV (6-12 hours), or 5-10mg PO (12-24 hours)

·           Promotes production of new factors

·           Pro: fairly rapid reversal, obviates risks of blood products

·           Con: insufficient if very high INR or if active bleeding, difficult to restart warfarin after a big dose of Vitamin K

FFP

·           Contains all clotting factors

·           IV 15-30mL/kg (or 2-4mL/kg if with prothrombinex)

·           Pro: immediate

·           Con: risk of TACO, risks of allogeneic transfusion

Prothrombinex

·           Contains factors 2, 9, 10

·           IV 25-50 units/kg

·           Preferred over FFP in Australia

·           Pro: immediate, universally compatible

·           Con: factor 7 absent

FEIBA

·           Contains factor 7a > 2,9,10

·           IV 50-100 units/kg

·           Pro: contains all deficient coag factors

·           Con: less data for warfarin reversal

Novoseven

·           Factor 7a

·           IV 50mcg/kg

·           Only if persistent uncontrollable haemorrhage despite all other physiological, pharmacological and surgical efforts

·           Pro: immediate

·           Con: very expensive, short half life, high risk of thrombotic complications

 

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