Prosthetic Valves and Anticoagulation — SAQ

Stem

A candidate is asked to manage a classic presentation of Prosthetic Valves and Anticoagulation in an exam setting. Use precise definitions, scores, doses, and decision thresholds.^[1]

Core knowledge (model answer backbone)

Prosthetic heart valves are mechanical (lifelong warfarin; ACC/AHA INR of 3.0 after a mechanical mitral prosthesis, INR of 2.5 after bileaflet aortic replacement without thromboembolic risk factors, plus aspirin 81 mg in the PROACT trials) or bioprosthetic (no lifelong VKA for the valve itself; ACC/AHA Class 2b VKA to INR 2.5 for 3 to 6 months after surgical replacement; if AF, rivaroxaban 20 mg daily was non-inferior to warfarin INR 2.0 to 3.0 in RIVER). DOACs are contraindicated in any mechanical valve (RE-ALIGN stopped after 252 patients; PROACT-Xa stopped after 863 patients for excess thromboembolism with apixaban 4.2 versus 1.3 percent per patient-year). After TAVI without another anticoagulation indication, rivaroxaban 10 mg caused harm versus an antiplatelet strategy (GALILEO). Acute prosthetic valve thrombosis: anticoagulation was inadequate in 82 percent of a TEE-diagnosed series; thrombolysis was completely successful in 86 percent of treated episodes.^{[1][3][6][7][10][11][13][20]}

Red flags

• Acute prosthetic valve thrombosis with shock or pulmonary oedema — TEE to confirm restricted occluder motion; anticoagulation inadequate in 82 percent; lysis completely successful in 86 percent of treated episodes.
• Mechanical mitral valve with INR under 2.5 — high thrombosis risk (ACC/AHA target INR of 3.0); recheck INR; image with TEE if symptomatic.
• Dabigatran or any DOAC in a mechanical valve — contraindicated (RE-ALIGN; PROACT-Xa excess TE).
• Fever plus a new murmur — prosthetic valve endocarditis until proven otherwise; cultures and TEE.^{[1][3][13][20]}

High-yield structure examiners expect

Cover: valve type and position, INR target, DOAC ban, pregnancy (ROPAC III), bridging (PERIOP2 plus ACC Class 2a high-risk ladder), GALILEO/RIVER.^[1][12][14]

Key doses / thresholds (from verified trials) ^{[1][11][10][6][7]}

• Mechanical mitral: ACC/AHA INR of 3.0 (PROACT Mitral restates guideline range 2.5 to 3.5).
• Mechanical bileaflet AVR, no TE risk: ACC/AHA INR of 2.5; PROACT On-X control used 2.0 to 3.0 plus aspirin 81 mg.
• Mechanical AVR with TE risk or older-generation prosthesis: ACC/AHA INR of 3.0.
• On-X aortic selected: INR 1.5 to 2.0 from 3 months plus aspirin 75 to 100 mg (Class 2b); PROACT used 81 mg.
• Rivaroxaban 20 mg daily after bioprosthetic mitral plus AF (RIVER).
• GALILEO antiplatelet arm: aspirin 75 to 100 mg plus clopidogrel 75 mg for 3 months.
• PCC in combination with vitamin K for VKA-associated major bleeding (no IU/kg dose reprinted here). ^[15]

Questions

a) Define the condition and give the most important classification or severity framework used in exams. (3 marks)^[1]

• Clear one-line definition matching standard teaching.
• Named classification / stages / types with discriminating features.
• One sentence on why classification changes management.

b) Outline pathophysiology in a mechanism chain that explains the main clinical features. (3 marks)^[1]

• Initiating insult → intermediate pathway → end-organ effect.
• Link at least two symptoms/signs to mechanism.
• Mention one complication pathway (e.g. shock, perforation, herniation, arrhythmia).

c) List discriminating clinical features and bedside assessment. (3 marks)^[1]

• Classic presentation plus one atypical group (elderly, pregnancy, child, immunocompromised).
• Named signs/manoeuvres if relevant.
• What must never be missed on exam/bedside (pregnancy test, airway, glucose, etc.).

d) Investigations with thresholds and one named score if applicable. (3 marks)^[18]

• First-line tests and what positive findings mean.
• Gold-standard or definitive investigation when needed.
• Score components reproduced exactly if a named score is standard for this topic.

e) Immediate resuscitation and definitive management with doses where standard. (3 marks)^[13][1]

• ABC / time-critical steps first.
• First-line drug(s) with agent + dose + route (or procedure steps).
• Escalation triggers (theatre, ICU, thrombolysis window, antidote, etc.).
• Disposition and safety-netting.

Marking tips

Full marks require specificity (numbers, names, doses) not generic "give antibiotics/fluids." Regional practice (ICMR / NICE / AHA) may be cited as alternative where relevant.^[1]

References20ShowHide

1. [1]Otto CM, Nishimura RA, Bonow RO, et al. 2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines Circulation, 2021.PMID 33332150
2. [2]Vahanian A, Beyersdorf F, Praz F, et al. 2021 ESC/EACTS Guidelines for the management of valvular heart disease Eur Heart J, 2022.PMID 34453165
3. [3]Eikelboom JW, Connolly SJ, Brueckmann M, et al. Dabigatran versus warfarin in patients with mechanical heart valves N Engl J Med, 2013.PMID 23991661
4. [4]Capodanno D, Petronio AS, Prendergast B, et al. Standardized definitions of structural deterioration and valve failure in assessing long-term durability of transcatheter and surgical aortic bioprosthetic valves: a consensus statement from the European Association of Percutaneous Cardiovascular Interventions (EAPCI) endorsed by the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS) Eur Heart J, 2017.PMID 29020344
5. [5]Adams DH, Popma JJ, Reardon MJ, et al. Transcatheter aortic-valve replacement with a self-expanding prosthesis N Engl J Med, 2014.PMID 24678937
6. [6]Guimarães HP, Lopes RD, de Barros E Silva PGM, et al. Rivaroxaban in Patients with Atrial Fibrillation and a Bioprosthetic Mitral Valve N Engl J Med, 2020.PMID 33196155
7. [7]Dangas GD, Tijssen JGP, Wöhrle J, et al. A Controlled Trial of Rivaroxaban after Transcatheter Aortic-Valve Replacement N Engl J Med, 2020.PMID 31733180
8. [8]Habib G, Lancellotti P, Antunes MJ, et al. 2015 ESC Guidelines for the management of infective endocarditis: The Task Force for the Management of Infective Endocarditis of the European Society of Cardiology (ESC). Endorsed by: European Association for Cardio-Thoracic Surgery (EACTS), the European Association of Nuclear Medicine (EANM) Eur Heart J, 2015.PMID 26320109
9. [9]Jawitz OK, Wang TY, Lopes RD, et al. Rationale and design of PROACT Xa: A randomized, multicenter, open-label, clinical trial to evaluate the efficacy and safety of apixaban versus warfarin in patients with a mechanical On-X Aortic Heart Valve Am Heart J, 2020.PMID 32693197
10. [10]Puskas JD, Gerdisch M, Nichols D, et al. Reduced anticoagulation after mechanical aortic valve replacement: interim results from the prospective randomized on-X valve anticoagulation clinical trial randomized Food and Drug Administration investigational device exemption trial J Thorac Cardiovasc Surg, 2014.PMID 24512654
11. [11]Chu MWA, Ruel M, Graeve A, et al. Low-Dose vs Standard Warfarin After Mechanical Mitral Valve Replacement: A Randomized Trial Ann Thorac Surg, 2023.PMID 36610532
12. [12]Kovacs MJ, Wells PS, Anderson DR, et al. Postoperative low molecular weight heparin bridging treatment for patients at high risk of arterial thromboembolism (PERIOP2): double blind randomised controlled trial BMJ, 2021.PMID 34108229
13. [13]Lengyel M, Vandor L The role of thrombolysis in the management of left-sided prosthetic valve thrombosis: a study of 85 cases diagnosed by transesophageal echocardiography J Heart Valve Dis, 2001.PMID 11603604
14. [14]van der Zande JA, Ramlakhan KP, Sliwa K, et al. Pregnancy with a prosthetic heart valve, thrombosis, and bleeding: the ESC EORP Registry of Pregnancy and Cardiac disease III Eur Heart J, 2026.PMID 40237423
15. [15]Ostermann H, von Heymann C Prothrombin complex concentrate for vitamin K antagonist reversal in acute bleeding settings: efficacy and safety Expert Rev Hematol, 2019.PMID 31159607
16. [16]Jeong SI, Kim HR, Song JY, et al. Inappropriate antibiotic prophylaxis before dental procedures in congenital heart disease: Insights from a nationwide Korean cohort J Infect Public Health, 2026.PMID 41270450
17. [17]Pradhan A, Mahalawat S, Perrone MA From the INVICTUS Trial to Current Considerations: It's Not Time to Retire Vitamin K Inhibitors Yet! Pharmaceuticals (Basel), 2024.PMID 39598370
18. [18]Habets J, Tanis W, Reitsma JB, et al. Are novel non-invasive imaging techniques needed in patients with suspected prosthetic heart valve endocarditis? A systematic review and meta-analysis. Eur Radiol, 2015.PMID 25680715
19. [19]Lengyel M Management of prosthetic valve thrombosis. J Heart Valve Dis, 2004.PMID 15222276
20. [20]Wang TY, Svensson LG, Wen J, et al. Apixaban or Warfarin in Patients with an On-X Mechanical Aortic Valve NEJM Evid, 2023.PMID 38320162