Mechanical mitral valve thrombosis after stopping warfarin — case discussion

Presentation

Practice case (not a real patient). A 59-year-old woman in a regional Australian hospital has had a bileaflet mechanical mitral valve for 6 years. She stopped warfarin 10 days ago because she ran out of tablets.^[1][3] She now has 2 days of worsening breathlessness and is in pulmonary oedema at rest (NYHA class IV). Her INR is 1.2.^[1] The ward team notes a stenotic murmur and muffled closing clicks.^[3]

Step 1 — What is happening?

Discussion:

• ESC/EACTS 2025 says obstructive valve thrombosis should be suspected in any patient with any type of prosthetic valve who presents with new-onset dyspnoea or HF symptoms, an embolic event, or an unexpected increase in transvalvular gradients.^[1]
• ACC/AHA 2020 says mechanical valve thrombosis is typically a subacute to acute event causing rapid valve dysfunction from abnormal or absent leaflet motion, often associated with inadequate VKA anticoagulation; physical examination may demonstrate a stenotic murmur and muffled closing clicks, and further urgent diagnostic evaluation is required.^[3]

Step 2 — Imaging

Transthoracic echocardiography shows a high transmitral gradient, but the left atrial side of the prosthesis is poorly seen.^[2]

• ACC/AHA 2020 says the left atrial side of a prosthetic mitral valve is obscured by acoustic shadowing on TTE, reducing sensitivity for prosthetic mitral thrombus, pannus or vegetation.^[2]
• ESC/EACTS 2025 recommends TOE and/or 4D-CT in suspected valve thrombosis to confirm the diagnosis (Class I, Level C), and says TOE and/or CCT should distinguish thrombus, pannus and degeneration if TTE findings are uncertain.^[1]
• ACC/AHA 2020 says urgent evaluation with TTE, TEE, fluoroscopy and/or multidetector CT is indicated in suspected mechanical valve thrombosis to assess valve function, leaflet motion, and the presence and extent of thrombus (COR 1, LOE B-NR).^[3]

Step 3 — Anticoagulation and transfer

TOE confirms thrombus on the mitral prosthesis with restricted leaflet motion.^[1]

• ESC/EACTS 2025 says adequate anticoagulation must be promptly restored in all patients with MHV thrombosis and a subtherapeutic INR.^[1]
• It recommends Heart Team evaluation in acute HF (NYHA class III or IV) due to obstructive MHV thrombosis, to determine appropriate management (repeat valve replacement or low-dose slow-infusion fibrinolysis) (Class I, Level B).^[1]

Step 4 — Surgery or fibrinolysis

Discussion:

• ESC/EACTS 2025 says surgery remains the first-line option in critically ill patients, although emergency valve replacement carries increased risk, while fibrinolysis increases bleeding and systemic embolism; slow, low-dose infusion appears to lower complication rates while preserving thrombolytic success rates.^[1]
• ACC/AHA 2020 Table 23 lists features favouring surgery (for example readily available surgical expertise, low surgical risk, NYHA class IV, a large clot over 0.8 cm², LA thrombus) and features favouring fibrinolysis (for example no surgical expertise available, high surgical risk, a first-time episode, NYHA class I, II or III, a small clot of 0.8 cm² or less).^[3]
• For surgery in mechanical valve thrombosis, ACC/AHA 2020 gives an overall 30-day mortality of 10% to 15%, under 5% with NYHA class I or II symptoms.^[3]

Step 5 — After the crisis

She undergoes repeat valve replacement and recovers.^[1]

• If she again receives a mechanical mitral valve, ESC/EACTS 2025 recommends lifelong OAC with a VKA to prevent thromboembolic complications (Class I, Level A), with an INR target of 3 (2.5–3.5) for any mitral MHV without additional pro-thrombotic factors (Table 10).^[1]
• Patient education is recommended to improve the quality of OAC (Class I, Level A), and INR self-monitoring and self-management are recommended over standard monitoring in selected, trained patients to improve efficacy (Class I, Level A).^[1]
• Had she instead been treated non-surgically, ESC/EACTS 2025 says imaging should be repeated in the case of thrombolytic and antithrombotic treatment of MHV thrombosis (printed "MVH thrombosis" in the source), even if gradients are normalised.^[1]

Learning points

• Suspect obstructive valve thrombosis with new-onset dyspnoea or HF symptoms, an embolic event, or an unexpected rise in transvalvular gradients in any patient with a prosthetic valve (ESC/EACTS 2025).^[1]
• TOE and/or 4D-CT are recommended to confirm suspected valve thrombosis (ESC/EACTS 2025, Class I, Level C); TTE may miss the left atrial side of a mitral prosthesis (ACC/AHA 2020).^[1][2]
• Obstructive MHV thrombosis with acute HF (NYHA class III or IV): Heart Team evaluation is recommended to determine appropriate management (repeat valve replacement or low-dose slow-infusion fibrinolysis) (ESC/EACTS 2025, Class I, Level B).^[1]
• DOACs and/or DAPT are not recommended to prevent thrombosis with an MHV (ESC/EACTS 2025, Class III, Level A).^[1]