Andexanet Alfa for Xa Inhibitor Reversal — EECC MCQ
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Correct answer: C — Andexanet alfa — a modified recombinant factor Xa molecule that acts as a decoy, binding and sequestering rivaroxaban (and apixaban); for life-threatening bleeding with factor Xa inhibitors, andexanet alfa provides rapid and effective anticoagulation reversal
Specific DOAC reversal agents per the 2024 ESC AF Guidelines: (1) Andexanet alfa (Ondexxya): reversal agent for FACTOR Xa INHIBITORS (rivaroxaban, apixaban, edoxaban). Mechanism: modified recombinant factor Xa protein (catalytically inactive) that binds the factor Xa inhibitor as a decoy, restoring endogenous factor Xa activity. Dose: low-dose (400 mg bolus + 480 mg infusion) if >8h since last dose or apixaban/rivaroxaban at reduced dose; high-dose (800 mg bolus + 960 mg infusion) if ≤8h since rivaroxaban 20 mg or apixaban 5 mg. The ANNEXA-4 study showed effective haemostatic control in ~82% of cases. (2) Idarucizumab (Praxbind): reversal agent for DABIGATRAN only (anti-factor IIa) — 5 g IV, immediate and complete reversal (RE-VERSE AD trial). (3) Four-factor PCC (Beriplex/Octaplex): alternative when specific agents are unavailable — less targeted but partially effective for factor Xa inhibitors.
Reference: ESC (2024): AF Guidelines; ANNEXA-4/RE-VERSE AD