How do you manage anticoagulation in a patient with new onset atrial fibrillation when mitral stenosis is suspected but not confirmed?

Management of Anticoagulation in New Onset Atrial Fibrillation with Suspected Mitral Stenosis

In patients with new onset atrial fibrillation where mitral stenosis is suspected but not confirmed, warfarin anticoagulation should be initiated immediately with a target INR of 2.0-3.0 while pursuing definitive diagnosis of mitral stenosis. 1

Initial Approach to Suspected Mitral Stenosis in AF

• When mitral stenosis is suspected but not confirmed in a patient with new onset AF, the safest approach is to treat as if mitral stenosis is present until proven otherwise 1
• Echocardiography should be urgently arranged to confirm or rule out mitral stenosis 1
• While awaiting definitive diagnosis, anticoagulation should not be delayed 1

Anticoagulation Recommendations Based on Mitral Stenosis Status

If Mitral Stenosis is Suspected:

• Initiate warfarin with a target INR of 2.0-3.0 1, 2
• Do NOT use direct oral anticoagulants (DOACs) as they are specifically contraindicated in moderate-to-severe mitral stenosis 1
• For patients with rheumatic heart disease (mitral stenosis), a higher target INR of 2.5-3.5 may be appropriate 1
• Continue warfarin therapy indefinitely if mitral stenosis is confirmed 1

If Mitral Stenosis is Subsequently Ruled Out:

• Assess stroke risk using the CHA2DS2-VASc score 1
• For patients with CHA2DS2-VASc score ≥2 in men or ≥3 in women, continue anticoagulation 1
• Consider switching from warfarin to a DOAC (apixaban, dabigatran, edoxaban, or rivaroxaban) as DOACs are preferred over vitamin K antagonists in non-valvular AF 1
• For patients with CHA2DS2-VASc score of 0 in men or 1 in women, it is reasonable to omit anticoagulation 1

Special Considerations

• Patients with mechanical heart valves must remain on warfarin even if mitral stenosis is ruled out 1
• For patients requiring cardioversion, anticoagulation is mandatory regardless of mitral stenosis status 1
• If AF duration is >48 hours or unknown, anticoagulate for at least 3-4 weeks before and after cardioversion 1
• For immediate cardioversion in hemodynamically unstable patients, administer heparin concurrently and then transition to oral anticoagulation 1

Monitoring Recommendations

• Check INR at least weekly during initiation of warfarin therapy 1
• Once stable, monitor INR at least monthly 1
• Reevaluate the need for and choice of anticoagulant therapy at periodic intervals 1
• Assess renal and hepatic function before initiation of anticoagulation and at least annually 1

Common Pitfalls to Avoid

• Delaying anticoagulation while awaiting confirmation of mitral stenosis diagnosis 1
• Inappropriately prescribing DOACs for patients with confirmed moderate-to-severe mitral stenosis 1
• Using aspirin alone for stroke prevention in AF with suspected mitral stenosis 1, 2
• Failing to transition from parenteral to oral anticoagulation after emergency cardioversion 1
• Discontinuing anticoagulation if the patient spontaneously converts to sinus rhythm (anticoagulation should be continued based on risk factors) 1