Anticoagulation in Mitral Regurgitation
Anticoagulation is NOT routinely indicated for isolated mitral regurgitation in patients who remain in sinus rhythm, regardless of severity. 1
Primary Mitral Regurgitation Without Atrial Fibrillation
No anticoagulation is recommended for patients with primary (organic) mitral regurgitation who maintain normal sinus rhythm, even when severe. 1 This represents a critical distinction from mitral stenosis, where anticoagulation considerations differ substantially.
Key Clinical Scenarios:
- Sinus rhythm with severe MR: No anticoagulation indicated unless other risk factors present 1
- No proven benefit: Prospective trials are lacking to determine whether antithrombotic therapy reduces stroke risk in mitral regurgitation patients without atrial fibrillation 1
Mitral Regurgitation WITH Atrial Fibrillation
Anticoagulation is mandatory when atrial fibrillation develops, following standard atrial fibrillation anticoagulation guidelines rather than valvular-specific protocols. 1
Anticoagulation Regimen:
- Target INR 2.0-3.0 with warfarin (vitamin K antagonist) 1
- Direct oral anticoagulants (DOACs) may be used in mitral regurgitation with atrial fibrillation, as this is considered "nonvalvular AF" 2
- DOACs (dabigatran, rivaroxaban, apixaban) have demonstrated safety and efficacy comparable to warfarin in patients with mitral regurgitation and AF 2
Mechanical Prosthetic Valve Replacement for MR
If mitral valve replacement with a mechanical prosthesis is performed, anticoagulation requirements change dramatically:
- Mechanical mitral valve: Target INR 3.0 (range 2.5-3.5) 1
- Add aspirin 80-100 mg/day to warfarin therapy 1
- Higher intensity than aortic position due to increased thrombotic risk in mitral location 1
Bioprosthetic Valve Replacement for MR
Following bioprosthetic mitral valve replacement:
- Warfarin for first 3 months post-implantation (INR target 2.5, range 2.0-3.0) 1
- Continue indefinitely if atrial fibrillation present 1
- Aspirin 80 mg/day after initial 3-month period if in sinus rhythm 1
Critical Distinctions: Mitral Regurgitation vs. Mitral Stenosis
This is a common pitfall: Mitral stenosis has entirely different anticoagulation recommendations than mitral regurgitation. 1
Mitral Stenosis (for comparison):
- Anticoagulation indicated with history of systemic embolism OR atrial fibrillation (Class I) 1
- Consider anticoagulation in sinus rhythm if left atrial diameter ≥55 mm 1
- Rheumatic mitral stenosis carries higher embolic risk than mitral regurgitation 1
Perioperative Anticoagulation Management
For patients with mechanical valves undergoing noncardiac surgery:
- High thrombotic risk patients (mechanical mitral valve, recent thrombosis, or ≥3 risk factors): Bridge with unfractionated heparin 1
- Risk factors include: atrial fibrillation, previous embolus, hypercoagulable condition, mechanical prosthesis, LVEF <30% 1
- Minimally invasive procedures: Briefly reduce INR to low/subtherapeutic range, resume normal dose immediately after 1
Important Clinical Caveats
Common errors to avoid:
- Do not anticoagulate isolated MR in sinus rhythm based on severity alone—this differs fundamentally from mitral stenosis 1
- Do not use DOACs for mechanical valves—warfarin remains mandatory 1, 2
- Recognize mixed pathology: Patients may have both MR and MS; anticoagulation decisions follow the more restrictive indication 1
- Atrial fibrillation changes everything: Once AF develops, anticoagulation becomes indicated regardless of valve pathology 1
Secondary (Functional) Mitral Regurgitation
No specific anticoagulation recommendations exist for secondary MR beyond standard heart failure and atrial fibrillation guidelines. 1 The decision is driven by: