Prosthetic Heart Valves

Key points

• Mechanical valves need lifelong warfarin (VKA). Target INR depends on valve thrombogenicity and patient risk factors: a current bileaflet aortic valve with no risk factors targets INR 2.5 (range 2.0-3.0); mitral/tricuspid valves, higher-thrombogenicity designs, or added prothrombotic factors target INR 3.0 (range 2.5-3.5). DOACs are contraindicated with mechanical valves.
• Add low-dose aspirin to the VKA only if there is another indication (e.g. established atherosclerotic disease) or if thromboembolism occurs despite a therapeutic INR (ESC 2021).
• Bioprosthetic valves usually need no long-term anticoagulation; a short period (about 3 months) of VKA or aspirin may be used depending on position and risk. For a bioprosthesis with AF, a DOAC (from 3 months, aortic) or VKA is used. Bioprostheses suit older patients (roughly over 65 aortic, over 70 mitral) to avoid lifelong anticoagulation.
• Mechanical valves: bileaflet is now the commonest type (ball-and-cage obsolete) — durable but thrombogenic, hence lifelong anticoagulation.
• Summary: bioprosthetic → aspirin (VKA/DOAC if AF); mechanical → warfarin (+ aspirin only if indicated). Endocarditis prophylaxis (NICE CG64, amended 2016) is not recommended routinely for procedures such as dental work.

Decision points in this pathway

• Which type of valve is implanted?

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