What is the management approach for mitral stenosis?

Management of Mitral Stenosis

The management of mitral stenosis requires a structured approach combining medical therapy for symptom control with timely intervention—percutaneous mitral balloon commissurotomy (PMBC) for favorable rheumatic disease or surgical options for unfavorable anatomy—guided by severity assessment, symptom status, and high-risk features such as pulmonary hypertension or atrial fibrillation. 1, 2

Diagnostic Assessment

Initial Evaluation

• Transthoracic echocardiography (TTE) is the preferred initial imaging modality for diagnosis and severity assessment 3
• Severity classification based on mitral valve area (MVA): severe ≤1.0 cm², moderate 1.0-1.5 cm², mild >1.5 cm² 2, 4
• Mean transmitral gradient >5-10 mmHg and pressure half-time ≥150 ms indicate severe stenosis 2

Additional Diagnostic Testing

• Transesophageal echocardiography (TOE) is indicated to exclude left atrial thrombus before PMBC, evaluate concurrent mitral regurgitation severity, clarify valve anatomy for intervention planning, and assess after embolic episodes 3
• 3D echocardiography provides superior accuracy for mitral valve area measurement 3
• Exercise stress echocardiography is reasonable when symptoms are discordant with resting hemodynamics, measuring changes in mitral gradient and pulmonary artery systolic pressure (PASP) 3, 4
• Right heart catheterization clarifies severity when echocardiographic data are inconclusive 3

Medical Management

Symptom Control

• Diuretics are recommended for pulmonary congestion or peripheral edema 1, 2, 4
• Beta-blockers or rate-limiting calcium channel blockers control heart rate, particularly critical in atrial fibrillation to prolong diastolic filling time 1, 2, 4
• Digoxin is specifically recommended for heart rate control in atrial fibrillation 1, 2, 4
• Ivabradine may provide superior exercise capacity compared to metoprolol and should be considered when beta-blockers are contraindicated (e.g., reactive airway disease) 5

Anticoagulation Strategy

• Vitamin K antagonists (target INR 2-3) are indicated for:
  • Atrial fibrillation (paroxysmal or permanent) 1, 2, 4
  • History of systemic embolism 1, 2
  • Dense spontaneous contrast in the left atrium 1, 2
  • Enlarged left atrium (M-mode diameter >60 mL/m²) 1, 2
• NOACs are contraindicated in mitral stenosis patients with atrial fibrillation—only vitamin K antagonists should be used 1, 4

Critical Caveat

Medical therapy is purely palliative and does not prevent disease progression; regular monitoring for intervention indications is essential 1, 4

Indications for Intervention

Symptomatic Severe Mitral Stenosis

• PMBC is the first-line intervention for symptomatic severe rheumatic mitral stenosis (NYHA class II-IV, MVA ≤1.5 cm²) with favorable valve morphology (minimal calcification, no significant mitral regurgitation, minimal subvalvular fusion) 1, 2, 6

Asymptomatic Severe Mitral Stenosis

Intervention should be considered when any of the following high-risk features develop:

• Pulmonary artery systolic pressure >50 mmHg 1, 2
• New-onset atrial fibrillation 1, 2
• High thromboembolic risk (history of embolism or dense spontaneous contrast) 1, 2

Moderate Mitral Stenosis

• PMBC may be considered in symptomatic patients with MVA >1.5 cm² if symptoms cannot be explained by another cause and valve anatomy is favorable 4
• Asymptomatic patients with moderate stenosis and favorable anatomy may be considered for PMBC if high thromboembolic risk or high risk of hemodynamic decompensation exists 4

Intervention Options

Percutaneous Approach

• PMBC is preferred over surgery for patients with favorable valve morphology, offering similar mortality benefit with less invasiveness 6, 7
• Favorable anatomy includes: pliable leaflets, minimal calcification, no significant mitral regurgitation, minimal subvalvular disease 2, 6

Surgical Options

• Open mitral commissurotomy for patients with favorable valve anatomy but unsuitable for PMBC (e.g., left atrial thrombus despite anticoagulation) 2, 7
• Mitral valve replacement for unfavorable valve anatomy (heavy calcification, significant subvalvular fusion, moderate-to-severe mitral regurgitation) 2, 7
• Preservation of subvalvular apparatus during surgery maintains left ventricular geometry 7

Degenerative Mitral Stenosis

• PMBC is contraindicated in degenerative mitral stenosis (secondary to mitral annular calcification) due to lack of commissural fusion 4, 8, 9
• These elderly, high-risk patients require medical management until symptoms are severely limiting, then surgical valve replacement if feasible 8, 9
• Transcatheter mitral valve replacement is emerging as a future option for inoperable degenerative cases 9

Surveillance Protocol

Asymptomatic Severe Mitral Stenosis (MVA ≤1.0 cm²)

• Follow-up every 2-3 years with clinical evaluation and echocardiography 1, 2
• More frequent monitoring (yearly) for very severe stenosis or borderline hemodynamics 2

Moderate Mitral Stenosis (MVA 1.0-1.5 cm²)

• Clinical and echocardiographic follow-up every 2-3 years 4
• Yearly monitoring if approaching severe stenosis or high-risk features develop 4

Monitoring Targets

• Development of symptoms, atrial fibrillation, or pulmonary hypertension 2
• Progression of valve area and hemodynamic parameters 1, 2

Special Populations

Pregnancy

• Severe emphasis on intervention before or during pregnancy, even for moderate stenosis, due to increased heart rate and stroke volume 4
• PMBC should be evaluated in pregnant patients with symptomatic moderate-to-severe stenosis 4
• Multidisciplinary cardio-obstetric team management is essential 4

High-Risk Populations

• Screening may be appropriate for high-risk populations and pregnant women at risk of rheumatic heart disease (RHD), typically school-aged cohorts 5-15 years old 3
• Population-based screening for RHD is not currently recommended 3

Common Pitfalls to Avoid

• Delaying anticoagulation in patients with enlarged left atrium or dense spontaneous contrast—these patients have significant embolic risk even without atrial fibrillation 4
• Using NOACs instead of warfarin in mitral stenosis with atrial fibrillation—this is contraindicated 1, 4
• Assuming medical therapy prevents progression—it only provides symptom relief; regular monitoring for intervention indications is mandatory 1, 4
• Overlooking stress testing when symptoms seem discordant with resting hemodynamics—this can lead to underdiagnosis of significant stenosis 4
• Attempting PMBC in degenerative mitral stenosis—it will fail and may cause harm due to lack of commissural fusion 4, 9