What is the recommended medical and interventional management for mitral stenosis?

Treatment of Mitral Stenosis

For symptomatic patients with clinically significant mitral stenosis (valve area ≤1.5 cm²), percutaneous mitral commissurotomy (PMC) is the treatment of choice when valve morphology is favorable, while mitral valve surgery is indicated for those unsuitable for PMC. 1

Medical Management

Medical therapy serves as supportive treatment but does not alter disease progression:

• Diuretics are useful for managing heart failure symptoms and pulmonary congestion 1
• Beta-blockers are reasonable for rate control, particularly in patients with atrial fibrillation 1
• Anticoagulation with vitamin K antagonists (VKA) remains the standard of care for patients with moderate to severe rheumatic mitral stenosis who have atrial fibrillation 2
  • NOACs are contraindicated in rheumatic mitral stenosis with AF, as the INVICTUS trial demonstrated superior outcomes with VKA compared to rivaroxaban 2
• ACE inhibitors and ARBs should not be given to pregnant patients with valve stenosis 1

Interventional Management: Decision Algorithm

Step 1: Assess Severity and Symptoms

Intervention is indicated for clinically significant mitral stenosis defined as valve area ≤1.5 cm² (or ≤1.7-1.8 cm²) 1

Step 2: Symptomatic Patients (NYHA Class II-IV)

For symptomatic patients, determine suitability for PMC based on valve morphology:

PMC is Indicated (Class I-B) when: 1

• Favorable valve characteristics are present (absence of: extensive calcification, echo score ≤8, Cormier score <3, severe subvalvular disease) 1
• No left atrial thrombus on transesophageal echocardiography 1

PMC provides excellent results: typically achieves >100% increase in valve area, with good initial results defined as valve area >1.5 cm² without significant mitral regurgitation 1

Surgery is Indicated (Class I-C) when: 1

• Unfavorable valve morphology for PMC (extensive calcification, severe subvalvular deformity, echo score >8) 1
• Contraindication to PMC (left atrial thrombus, more than mild mitral regurgitation) 1
• High surgical risk patients with contraindication to surgery should still receive PMC as initial treatment 1

Step 3: Asymptomatic Patients with Severe MS

PMC should be considered (Class IIa-C) in asymptomatic patients with favorable characteristics AND high-risk features: 1

High-risk features include:

• Previous history of embolism 1
• Dense spontaneous contrast in left atrium 1
• Recent or paroxysmal atrial fibrillation 1
• Systolic pulmonary pressure >50 mmHg at rest 1
• Need for major non-cardiac surgery 1
• Desire for pregnancy 1

Truly asymptomatic patients without these high-risk features should undergo surveillance every 6-24 months rather than intervention 1

Special Populations

Pregnancy

• Valve intervention is recommended before pregnancy for symptomatic patients with severe MS 1
• PMC is recommended before pregnancy for asymptomatic patients with severe MS who have favorable valve morphology 1
• PMC is reasonable during pregnancy (Class IIa-B) for patients with severe MS and NYHA class III-IV symptoms despite medical therapy 1
• All pregnant patients with severe MS should be monitored in a tertiary care center with a dedicated multidisciplinary Heart Valve Team 1

Degenerative/Calcific Mitral Stenosis

• PMC has no role in degenerative MS due to absence of commissural fusion and extensive annular calcification 3
• Surgical valve replacement is the conventional therapy, though transcatheter mitral valve replacement is emerging as a potential option 3, 4

Surgical Techniques

When surgery is required:

• Open-heart mitral commissurotomy using cardiopulmonary bypass corrects both commissural fusion and subvalvular deformity 1
• In selected young patients from experienced centers, 15-year survival is 96% with 92% freedom from valve-related complications 1
• Mitral valve replacement is performed when repair is not feasible due to unfavorable anatomy 1

Procedural Risks and Outcomes

PMC complications: 1

• Procedural mortality: 0.5-4%
• Hemopericardium: 0.5-10%
• Embolism: 0.5-5%
• Severe regurgitation: 2-10%
• Emergency surgery needed: <1%

Long-term outcomes after PMC: 7-year event-free survival (without mitral valve replacement or repeat PMC) is 65%, with the best outcomes in patients achieving post-procedure valve area ≥1.5 cm² and mean pulmonary artery wedge pressure ≤18 mmHg 5

Critical Pitfalls to Avoid

• Do not use NOACs in rheumatic mitral stenosis with atrial fibrillation—VKA is mandatory 2
• Do not perform valve intervention in pregnancy unless there are severe heart failure symptoms (NYHA class IV) or risk to mother's life 1
• Do not overlook left atrial thrombus—transesophageal echocardiography is mandatory before PMC 1
• Do not attempt PMC in degenerative/calcific mitral stenosis without commissural fusion 3