In which valvular heart diseases is anticoagulation indicated, and which anticoagulant should be used?

Anticoagulation in Valvular Heart Disease

All patients with mechanical heart valves require lifelong vitamin K antagonist (VKA) anticoagulation—this is non-negotiable. 1, 2

Mechanical Prosthetic Valves (Mandatory Anticoagulation)

Mechanical valves ALWAYS require VKA (warfarin):

• Mechanical aortic valve (AVR) without risk factors:

  • Target INR 2.5 (range 2.0-3.0) 1, 2

• Mechanical aortic valve WITH risk factors (atrial fibrillation, prior thromboembolism, LV dysfunction, hypercoagulable state) OR older-generation prosthesis (ball-in-cage):

  • Target INR 3.0 (range 2.5-3.5) 1, 2

• Mechanical mitral valve replacement:

  • Target INR 3.0 (range 2.5-3.5) 1, 2

Critical contraindications:

• Direct oral anticoagulants (DOACs) are CONTRAINDICATED with mechanical valves 1, 2, 1
• Dabigatran specifically caused increased thrombotic and bleeding events in the RE-ALIGN trial 1, 2
• Anti-Xa DOACs (rivaroxaban, apixaban, edoxaban) are not recommended—no safety data exists 1, 2

Bioprosthetic Valves (Selective Anticoagulation)

Surgical bioprosthetic valves (SAVR):

• First 3-6 months post-op: VKA with target INR 2.5 is reasonable if low bleeding risk 1, 2, 1
• After 3-6 months: Aspirin 75-100 mg daily (unless other indication for anticoagulation exists) 1, 2

Transcatheter aortic valve implantation (TAVI):

• Aspirin 75-100 mg daily is the standard approach 2, 1
• Dual antiplatelet therapy (aspirin + clopidogrel 75 mg) for 3-6 months may be reasonable if low bleeding risk 1, 2
• Rivaroxaban 10 mg + aspirin is CONTRAINDICATED (increased bleeding without benefit in GALILEO trial) 1, 2, 1

Native Valvular Disease (No Prosthesis)

Rheumatic mitral stenosis:

• With atrial fibrillation, prior embolism, OR left atrial thrombus: VKA with target INR 2.5 (range 2.0-3.0) 2, 3
• With left atrial diameter ≥55 mm in sinus rhythm: VKA with target INR 2.5 is reasonable 3
• Normal sinus rhythm + LA <55 mm: No anticoagulation needed 3

Other native valve disease (aortic stenosis, mitral regurgitation, etc.):

• No anticoagulation indicated unless concurrent atrial fibrillation or other thromboembolic indication exists 4, 5

Atrial Fibrillation + Valvular Disease

With mechanical valve:

• Continue VKA as above—DOACs contraindicated 2

With bioprosthetic valve >3 months post-op OR native valve disease (except moderate-severe rheumatic mitral stenosis):

• DOACs are acceptable alternatives to VKA based on CHA₂DS₂-VASc score 2
• Options: apixaban, rivaroxaban, edoxaban, dabigatran

With rheumatic mitral stenosis:

• VKA required—DOACs not validated in this population 2

New-onset AF ≤3 months after bioprosthetic valve:

• VKA with target INR 2.5 is reasonable 2

Common Pitfalls to Avoid

1. Never use DOACs with mechanical valves—this is associated with increased thrombosis and bleeding 1, 2

2. Don't forget risk factors when setting INR targets for mechanical aortic valves—presence of AF, prior embolism, LV dysfunction, or hypercoagulable state increases target from 2.5 to 3.0 1, 2

3. Mitral position is higher risk than aortic—mechanical mitral valves always require INR 3.0 regardless of risk factors 1, 2

4. Bioprosthetic valves need early anticoagulation—the first 3-6 months carry highest thrombotic risk before endothelialization completes 1, 2

5. Rheumatic mitral stenosis is different—even with AF, this remains a "valvular AF" indication where DOACs are not recommended 2

6. Don't use rivaroxaban + aspirin after TAVI—the GALILEO trial showed harm 1, 2, 1