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Haemophilia with Mechanical Valve — RACP Adult Medicine MCQ

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HardHaematologyHaemophilia with Mechanical ValveRACP Adult Medicine

A 55-year-old man with known haemophilia B (factor IX deficiency) requires anticoagulation for a new mechanical aortic valve. What is the recommended anticoagulant approach?

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Correct answer: B — Factor IX replacement + warfarin at standard INR

Patients with haemophilia and mechanical valves require anticoagulation despite their bleeding disorder. Factor IX replacement is given to maintain adequate trough levels (typically >15–20% for factor IX in this setting), and warfarin is commenced at standard INR target for the valve type. This requires close collaboration between haematology and cardiology. DOACs are contraindicated for mechanical valves. The factor replacement provides haemostatic coverage for the warfarin-induced anticoagulation. Regular factor level monitoring is essential.

Reference: National Blood Authority – 2024 – Haemophilia Management; eTG – 2025 – Haematology