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Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.

Prosthetic heart valves and anticoagulation

Cardiology · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

RapidFull
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Escalate

Acute dyspnoea, shock, embolism or a new/muffled prosthetic click suggests obstructive thrombosis; major bleeding on warfarin requires immediate reversal and specialist input. Neither should wait for routine clinic review.

Synopsis

Select and monitor antithrombotic therapy, recognise prosthetic dysfunction and act safely on thrombosis or bleeding.

  • Every mechanical valve requires lifelong vitamin K antagonist therapy; a DOAC is not an acceptable substitute.
  • The INR target is valve- and patient-specific: a modern bileaflet mechanical aortic valve commonly targets 2.5, while a mechanical mitral valve or added thromboembolic risk commonly targets 3.0; older high-thrombogenicity valves need higher targets.
  • A low INR risks valve thrombosis and embolism; a high INR risks bleeding. Use the implant record, valve position/type and risk factors to document one target explicitly.
  • After TAVI without another anticoagulation indication, NICE advises single antiplatelet therapy with aspirin, or clopidogrel if aspirin is not tolerated; do not add routine oral anticoagulation.
  • Early antithrombotic therapy after a surgical bioprosthesis differs by position; mitral/tricuspid valves have greater early thrombosis risk than aortic valves.
  • New symptoms or a changed click, gradient or regurgitation demand prompt TTE, then TOE/CT/fluoroscopy as needed; do not assume anticoagulation failure before defining obstruction.
  • Periprocedural interruption and bridging are determined by both bleeding risk and valve-thrombosis risk; a mechanical mitral valve is not equivalent to a low-risk bileaflet aortic valve.
  • Stable warfarin control still requires interaction, illness, alcohol, diet and adherence review; check INR 3-5 days after starting an interacting medicine.

Key red flags

Obstructive valve thrombosis

Acute dyspnoea, pulmonary oedema, shock, embolus, new murmur or a softer/absent mechanical click is an emergency.

Prosthetic endocarditis

Fever, rigors, embolic features, new regurgitation or conduction delay needs urgent cultures and endocarditis-team imaging.

Anticoagulant harm

Melaena, haematemesis, haematuria, severe headache, collapse or rapid haemoglobin fall on warfarin demands urgent severity and INR assessment.

Investigation priorities

01
INR with anticoagulation recordFirst step

Measure current VKA effect and time in therapeutic range.

Management branches

RoutineSelect antithrombotic therapy

After valve replacement or when reviewing an established prosthesis.

  1. Identify valve type, manufacturer, position, implant date and separate indications for anticoagulation.
  2. For any mechanical valve, use lifelong warfarin with a written target INR; do not use a DOAC.
  3. For a surgical bioprosthesis, decide early aspirin versus VKA by valve position and bleeding risk; after the initial phase continue anticoagulation only for another indication unless the valve team specifies otherwise.
  4. After TAVI without another anticoagulation indication, use single antiplatelet therapy; if AF/VTE requires anticoagulation, use anticoagulation alone unless a separate recent coronary indication requires antiplatelet therapy.

Key medicines

WarfarinSmPC typical induction 10 mg once daily for 2 days and usual maintenance 3-9 mg once daily, but prosthetic-valve dosing must be individualised to INR; common targets are 2.5 for a modern bileaflet aortic valve and 3.0 for a mechanical mitral valve or added risk.Narrow therapeutic index, major interactions, teratogenicity and bleeding. Do not copy a loading schedule without specialist assessment; record target and monitoring plan.
Aspirin75 mg by mouth once daily.GI/other bleeding, aspirin hypersensitivity and additive bleeding with anticoagulants; do not add routinely to therapeutic warfarin.
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Sources and review status6 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • NICE NG208: Heart valve disease presenting in adultsUK antithrombotic recommendations after mechanical, surgical biological and transcatheter valves.
  • 2025 ESC/EACTS valvular heart disease guidelineCurrent specialist prosthetic-valve, thrombosis and peri-intervention framework.
  • Warfarin 0.5 mg tablets SmPCLicensed dosing, monitoring and safety information.
  • NHS SPS: Warfarin monitoringCurrent UK monitoring frequency, poor-control and interaction checks.
  • Phytomenadione injection SmPCLicensed severe-haemorrhage reversal dosing.
  • Beriplex P/N 1000 IU SmPCProduct-specific four-factor PCC dosing, monitoring and thrombosis precautions for urgent VKA reversal.

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateRapid draftClinical stateAwaiting reviewJurisdictionUnited Kingdom