What are the indications for oral anticoagulant therapy in a patient with Rheumatic Heart Disease (RHD)?

Indications for Oral Anticoagulation in Rheumatic Heart Disease

All patients with rheumatic mitral stenosis and atrial fibrillation require lifelong vitamin K antagonist (VKA) therapy with warfarin targeting an INR of 2.0-3.0, and this is a Class I recommendation regardless of CHA₂DS₂-VASc score. 1, 2

Primary Indications for Anticoagulation in RHD

Mandatory Anticoagulation (Class I)

Atrial Fibrillation (Paroxysmal or Chronic):

• VKA therapy is indicated for all patients with rheumatic mitral valve disease and AF, regardless of hemodynamic severity 1, 2
• Target INR: 2.5 (range 2.0-3.0) 1, 2
• Critical point: NOACs are contraindicated in rheumatic mitral stenosis even with AF 1, 2

History of Systemic Embolization:

• Prior thromboembolic events mandate lifelong anticoagulation with VKA 1, 2
• Target INR: 2.0-3.0 1

Left Atrial Thrombus:

• Documented thrombus on echocardiography requires immediate VKA therapy 2, 3
• If found pre-procedurally before percutaneous mitral balloon valvotomy, increase target INR to 3.0 (range 2.5-3.5) until thrombus resolution 2

Strong Indications (Class IIa)

Severe Left Atrial Enlargement:

• Left atrial diameter >5.5 cm in normal sinus rhythm warrants anticoagulation 1, 2
• Target INR: 2.0-3.0 1

Spontaneous Echo Contrast:

• Dense spontaneous echo contrast in the left atrium indicates high thromboembolic risk 1, 3
• Anticoagulation should be considered even in sinus rhythm 1

Heart Failure:

• Right- or left-sided heart failure in the setting of rheumatic valvular disease is an indication for warfarin 4
• This applies regardless of rhythm 4

Anticoagulation Algorithm by Clinical Scenario

Rheumatic Mitral Stenosis WITH Atrial Fibrillation:

1. Initiate warfarin immediately 1
2. Target INR 2.5 (range 2.0-3.0) 1, 2
3. Never use NOACs - they are Class III (harm) in this population 1, 2
4. Continue lifelong 2, 3

Rheumatic Mitral Stenosis WITHOUT Atrial Fibrillation:

Anticoagulate if ANY of the following:

• Left atrial diameter ≥55 mm 1, 2
• Spontaneous echo contrast on echocardiography 1, 2
• Left atrial thrombus 2, 3
• Previous systemic embolism 1, 2
• Heart failure 4

Target INR: 2.0-3.0 1, 2

Other Rheumatic Valve Disease (Non-Stenotic):

• Anticoagulation indicated if AF present, using CHA₂DS₂-VASc score ≥2 1
• VKA or NOAC acceptable for non-stenotic rheumatic valve disease with AF 1
• If history of embolism or AF present, use VKA with INR 2.0-3.0 1

Warfarin Initiation and Monitoring

Starting Dose:

• Begin with 2-5 mg daily 2
• Use lower doses (2 mg) in elderly patients 2

Monitoring Schedule:

• Daily INR until therapeutic range achieved 1
• Then 2-3 times weekly for 1-2 weeks 1
• Weekly for 1 month 1
• Monthly once stable (goal time in therapeutic range >65-70%) 2

Target INR:

• Standard: 2.5 (range 2.0-3.0) for most RHD indications 1, 2
• Higher: 3.0 (range 2.5-3.5) if left atrial thrombus present pre-intervention 2

Critical Pitfalls to Avoid

NOAC Use in Rheumatic Mitral Stenosis:

• Never use NOACs in patients with rheumatic mitral stenosis, even if they have AF 1, 2
• All landmark NOAC trials specifically excluded moderate-to-severe rheumatic mitral stenosis 5, 6
• One recent study suggests DOACs may be acceptable post-bioprosthetic MVR in RHD patients, but this requires validation 7

Antiplatelet Agents:

• Do not routinely add aspirin to warfarin in rheumatic valve disease - increases bleeding risk without clear benefit 1
• Exception: recurrent embolism despite adequate anticoagulation may warrant adding aspirin 81 mg daily 1

Inadequate Anticoagulation Intensity:

• Using INR target <2.0 provides insufficient protection 1
• Maintain INR 2.0-3.0 for standard indications 1, 2

Pregnancy Considerations:

• Warfarin is teratogenic in first trimester 1
• Women with severe RHD considering pregnancy need pre-pregnancy counseling and possible intervention 1
• Anticoagulation choice during pregnancy requires multidisciplinary discussion 1

Special Populations

Post-Bioprosthetic Valve Replacement:

• VKA recommended for first 3 months after bioprosthetic mitral valve replacement 1
• If AF persists or develops, continue indefinitely 1
• Recent data suggests DOACs may be acceptable post-bioprosthetic MVR in RHD patients, but warfarin remains standard 7

Mechanical Prosthetic Valves:

• All mechanical valves require lifelong VKA 1
• Target INR 2.5-3.5 for mechanical valves 1
• NOACs are contraindicated with mechanical valves 1

Pregnancy:

• Anticoagulation should be considered for women in AF 1
• Also consider in sinus rhythm with very severe LA dilatation, spontaneous echo contrast, or heart failure 1
• Choice of anticoagulant requires careful discussion given teratogenic risks 1