Do tricuspid prosthetic valves require lifelong anticoagulation?

Anticoagulation Requirements for Tricuspid Prosthetic Valves

Mechanical tricuspid valve prostheses require lifelong anticoagulation with vitamin K antagonists (VKAs), while bioprosthetic tricuspid valves require anticoagulation for only the first 3 months after implantation unless other indications for anticoagulation exist. 1

Mechanical Tricuspid Valve Prostheses

Anticoagulation Requirements

• Lifelong oral anticoagulation with VKAs is mandatory for all mechanical valve prostheses, including those in the tricuspid position 1
• Target INR:
  • Although specific INR targets for tricuspid mechanical valves are not definitively established in guidelines, the recommended range is generally 2.0-3.0 1
  • Higher INR targets (3.0-4.5) may be needed for mechanical valves on the right side based on limited evidence 1

Rationale for Lifelong Anticoagulation

• Mechanical valves impose abnormal flow conditions with zones of low flow and high-shear stress that activate platelets, leading to valve thrombosis and embolic events 1
• Right-sided mechanical valves may have higher thrombosis risk than left-sided valves
• Studies have shown early valve failure is common (7 of 13 patients within 1 year) when mechanical pulmonary valves were managed with antiplatelet therapy alone without VKAs 1

Thrombotic Risk

• Mechanical tricuspid valves carry the highest risk of thrombosis of any cardiac valve position 2
• Thrombosis of mechanical tricuspid valves can present insidiously, with delayed diagnosis 3
• Tilting disc valves have shown higher thrombosis rates (20%) compared to Starr-Edwards valves (4%) in some studies 3

Bioprosthetic Tricuspid Valve Prostheses

Anticoagulation Requirements

• Oral anticoagulation with VKAs should be considered for the first 3 months after implantation of a tricuspid bioprosthesis (Class IIa recommendation) 1
• Target INR for initial anticoagulation: 2.0-3.0 1
• After 3 months, anticoagulation can be discontinued unless other indications exist 1
• Addition of aspirin is recommended during the initial anticoagulation period 1

Other Indications for Lifelong Anticoagulation

Lifelong anticoagulation is recommended for patients with bioprosthetic valves who have:

• Atrial fibrillation
• Venous thromboembolism
• Hypercoagulable states
• Severely impaired left ventricular function (ejection fraction <35%) 1

Comparing Mechanical vs. Bioprosthetic Tricuspid Valves

When a patient requires lifelong anticoagulation for other reasons (e.g., left-sided mechanical valve or atrial fibrillation), the choice between mechanical and bioprosthetic tricuspid valves should consider:

• Bioprosthetic valves may be preferable even in younger patients who need anticoagulation irrespective of TVR, as mechanical TVR has shown increased occurrence of valve-related events, especially thrombosis, embolism, and bleeding 4
• Freedom from composite endpoint of thrombosis, embolism, and bleeding was lower in mechanical TVR group (76.3% at 5 years) compared to bioprosthetic TVR group (97.6% at 5 years) 4

Clinical Pitfalls and Caveats

1. Monitoring challenges: Right-sided prosthetic valves may not be evaluated as precisely with echocardiography as left-sided valves. Fluoroscopy can be a valuable alternative for assessing leaflet motion in suspected tricuspid valve thrombosis 2

2. Thrombosis presentation: Symptoms of tricuspid valve thrombosis are often insidious, and diagnosis may be delayed. There is a continuing risk of this complication even years after the original operation 3

3. INR variability: High variability of INR is a strong independent predictor of reduced survival after valve replacement. Self-management of anticoagulation can reduce INR variability and should be considered for capable patients 1

4. Contraindicated medications: Direct oral anticoagulants (NOACs) are contraindicated in patients with mechanical valves, including tricuspid position 1

5. Special considerations: When managing anticoagulation for tricuspid valve prostheses, consider right ventricular function, as decreased function increases thrombotic risk 1