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Mechanical Valve ACS Antithrombotic — RACP Adult Medicine MCQ

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HardCardiologyMechanical Valve ACS AntithromboticRACP Adult Medicine

A 55-year-old man with a mechanical aortic valve on warfarin develops acute STEMI. His INR is 2.8. He undergoes primary PCI with drug-eluting stent placement. What antithrombotic regimen should be used?

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Correct answer: C — Triple therapy: warfarin + aspirin + clopidogrel

For patients with a mechanical valve (where DOACs are contraindicated) requiring PCI/stent, triple therapy (warfarin + aspirin + clopidogrel) is needed initially but should be minimised in duration due to high bleeding risk. The 2025 Australian ACS guideline recommends the shortest period of triple therapy feasible (typically 1 week to 1 month depending on bleeding risk), then step-down to warfarin + clopidogrel (dropping aspirin). A PPI is mandatory with triple therapy. The INR target may be reduced to 2.0–2.5 during triple therapy to reduce bleeding risk.

Reference: NHF/CSANZ – 2025 – Australian ACS Guideline