Warfarin is the definitive treatment to reduce stroke risk in patients with severe rheumatic mitral regurgitation and atrial fibrillation
For a patient with severe rheumatic mitral regurgitation and atrial fibrillation, warfarin (target INR 2.0-3.0) is the recommended anticoagulant to prevent stroke. This recommendation applies regardless of whether the patient has had a prior embolic event, because rheumatic valvular disease represents a distinct high-risk category that requires vitamin K antagonist therapy 1, 2.
Why Warfarin is the Correct Answer
Rheumatic mitral regurgitation, even without stenosis, represents rheumatic valvular disease and mandates warfarin therapy rather than direct oral anticoagulants (DOACs) like apixaban. 2
- DOACs including apixaban are contraindicated in rheumatic valvular heart disease because all major DOAC trials specifically excluded patients with moderate-to-severe mitral stenosis or rheumatic valvular disease 2
- The combination of rheumatic valvular disease plus atrial fibrillation creates an extremely high stroke risk—up to 17-fold increased compared to non-valvular AF 2
- Long-term warfarin therapy with target INR of 2.5 (range 2.0-3.0) is reasonable for patients with rheumatic mitral valve disease, whether or not AF is present 1
Why the Other Options Are Inadequate
Aspirin (Option B) provides grossly inadequate protection in this high-risk population:
- Aspirin reduces stroke risk by only 19% compared to placebo in AF patients, while warfarin reduces stroke by 60-68% 1, 2
- In a comparative study of rheumatic mitral stenosis with AF, coumadin prevented all strokes while aspirin failed to prevent cardioembolic events 3
- Aspirin should not be routinely added to warfarin to avoid additional bleeding risk without meaningful benefit 1
Apixaban (Option C) is contraindicated:
- All DOAC trials excluded patients with rheumatic valvular disease, leaving no safety or efficacy data for this population 2
- Even if the patient has difficulty maintaining therapeutic INR with warfarin, switching to a DOAC is not appropriate 2
Digoxin (Option D) has no role in stroke prevention:
- Digoxin may help with rate control in AF but provides zero protection against thromboembolism 1
Practical Implementation
Target INR and monitoring schedule:
- Target INR: 2.5 (acceptable range 2.0-3.0) 1, 4
- Monitor INR at least weekly during initiation, then monthly when stable 1, 4
- Indefinite anticoagulation is required as long as AF persists and rheumatic valvular disease remains 2
Management of recurrent embolism on warfarin:
- If stroke occurs despite therapeutic warfarin, consider adding aspirin 81 mg daily rather than abandoning anticoagulation 1
- Recurrent embolism occurs in 30-65% of patients with rheumatic mitral valve disease who have a prior embolic event, with 60-65% of recurrences within the first year 1
Critical Pitfalls to Avoid
Do not discontinue anticoagulation after successful rhythm control—the stroke risk persists even if sinus rhythm is restored 2
Do not use aspirin monotherapy in this population—it provides inadequate protection compared to the extremely high baseline stroke risk 2, 3
Do not substitute a DOAC for warfarin even if INR management is challenging, as there is no evidence supporting DOAC use in rheumatic valvular disease 2
Do not delay anticoagulation in patients with rheumatic mitral regurgitation and new-onset AF—the annual embolic risk ranges from 1.5-4.7% even without prior stroke 1, 5