What is the management of severe mitral stenosis?

Management of Severe Mitral Stenosis

For severe mitral stenosis, percutaneous mitral balloon commissurotomy (PMBC) is the first-line intervention for symptomatic patients with favorable valve anatomy, while mitral valve surgery is indicated when PMBC is not feasible or appropriate. 1

Diagnosis and Assessment

• Severe mitral stenosis is defined as:

  • Mitral valve area (MVA) ≤1.0 cm²
  • Diastolic pressure half-time ≥150 ms
  • Mean transmitral pressure gradient ≥10 mmHg
  • Severe left atrial enlargement 1

• Critical distinction: Determine if the stenosis is:

  • Rheumatic mitral stenosis (RMS): Has commissural fusion, amenable to PMBC
  • Degenerative mitral stenosis (DMS): Lacks commissural fusion, not suitable for PMBC 1, 2

Initial Medical Management

1. Symptom relief:

   • Diuretics for pulmonary congestion and edema
   • Careful diuresis to avoid hypotension 1

2. Heart rate control:

   • For sinus rhythm: Beta-blockers (preferably beta-1 selective) are most effective 1, 3
   • For atrial fibrillation: Verapamil shows best results, followed by metoprolol 3
   • Digoxin is less effective but may be used for rate control in atrial fibrillation 1

3. Anticoagulation:

   • Vitamin K antagonists (VKAs) with target INR 2-3 for all patients with atrial fibrillation
   • NOACs should NOT be used in mitral stenosis with atrial fibrillation
   • For patients in sinus rhythm, oral anticoagulation is indicated with:
     • History of systemic embolism
     • Left atrial thrombus
     • Dense spontaneous echo contrast on TEE
     • Enlarged left atrium (>50 mm or >60 mL/m²) 4, 1

Interventional Management

Percutaneous Mitral Balloon Commissurotomy (PMBC)

Indications:

• First-line for symptomatic severe RMS with favorable valve anatomy
• Consider for asymptomatic severe RMS with:
  • High thromboembolic risk
  • High risk of hemodynamic decompensation
  • Pulmonary artery systolic pressure >50 mmHg at rest
  • Planning pregnancy 4, 1

Contraindications:

• Absence of commissural fusion (degenerative MS)
• Unfavorable valve morphology
• Left atrial thrombus
• More than mild mitral regurgitation 4

Surgical Intervention

Indications:

• Symptomatic severe MS when PMBC is not available or contraindicated
• Failed PMBC with persistent symptoms
• Concomitant need for other cardiac surgery
• Severe degenerative MS (as PMBC is ineffective) 4, 1

Options:

• Mitral valve repair (commissurotomy) if valve is suitable
• Mitral valve replacement when repair is not feasible 4

Special Populations and Scenarios

Pregnancy

• Medical therapy is first-line
• For symptomatic (NYHA III-IV) severe MS despite medical therapy, PMBC can be performed relatively safely
• Surgery carries significant risk to mother and fetus 4, 5

Elderly Patients

• PMBC is useful even if only palliative in elderly with rheumatic MS
• For degenerative MS with severely calcified annulus:
  • Surgery is very high risk
  • Transcatheter valve implantation may be considered in inoperable patients 4

Combined Valve Disease

• With severe aortic valve disease: Surgery is preferred if not contraindicated
• With moderate aortic valve disease: PMBC may postpone surgery for both valves
• With severe tricuspid regurgitation:
  • PMBC may be considered in selected patients with sinus rhythm and functional TR
  • Otherwise, surgery on both valves is preferred 4, 1

Follow-up and Monitoring

• Asymptomatic severe MS: Annual clinical and echocardiographic examinations
• Moderate MS: Follow-up every 2-3 years
• After successful PMBC: Similar to asymptomatic patients
• More frequent monitoring if asymptomatic restenosis occurs 4

Common Pitfalls to Avoid

1. Failing to distinguish between rheumatic and degenerative MS, as treatment approaches differ significantly 1

2. Delaying intervention in pregnancy, which can lead to maternal and fetal complications 1

3. Using NOACs instead of VKAs in mitral stenosis with atrial fibrillation 4

4. Attempting cardioversion before intervention in severe MS, as it does not durably restore sinus rhythm 4

5. Underestimating the importance of anticoagulation due to high risk of left atrial thrombus 1