What is the recommended management for symptomatic severe mitral stenosis in adults?

Management of Symptomatic Severe Mitral Stenosis

Percutaneous mitral commissurotomy (PMC) is the treatment of choice for symptomatic patients with severe mitral stenosis (MVA ≤1.5 cm²) who have favorable valve morphology, no left atrial thrombus, and less than moderate mitral regurgitation. 1

Initial Assessment and Severity Confirmation

Before determining the intervention approach, confirm severity using echocardiography:

• Measure mitral valve area by planimetry (the reference standard), which should be ≤1.5 cm² for severe stenosis 1, 2
• Document mean transmitral gradient (typically >10 mmHg in severe disease) and pulmonary artery systolic pressure (>50 mmHg indicates severe hemodynamic consequences) 1, 2
• Perform transesophageal echocardiography (TEE) to exclude left atrial thrombus before any intervention, as thrombus is an absolute contraindication to PMC 1

Determining Suitability for PMC vs. Surgery

PMC is Indicated When:

• Favorable valve anatomy (Wilkins score <8): pliable, non-calcified leaflets with minimal subvalvular disease 1, 3
• No or mild mitral regurgitation (less than moderate/2+ grade) 1
• No left atrial thrombus on TEE 1
• Patient is symptomatic (NYHA class II-IV) 1

PMC provides excellent results in this setting, with >100% increase in valve area and procedural mortality of 0.5-4% 2

Surgery (Usually Valve Replacement) is Indicated When:

• Unfavorable valve anatomy: heavily calcified leaflets, Wilkins score >10, or extensive subvalvular fusion 1, 3
• Moderate or severe mitral regurgitation present 1
• Left atrial thrombus detected 1
• Concomitant cardiac surgery needed (e.g., coronary artery disease requiring bypass, other valve disease) 1
• Failed prior PMC 1

Special Consideration: Suboptimal Anatomy

For patients with suboptimal valve anatomy (mild-moderate calcification, some subvalvular disease) but favorable clinical characteristics (young age, no severe comorbidities), PMC should still be considered as initial treatment 1. This is particularly important when surgical risk is high or the patient is not a surgical candidate 1.

Medical Therapy as Adjunct (Not Primary Treatment)

While intervention is the definitive treatment, medical therapy provides symptom relief:

• Diuretics for pulmonary congestion or edema 1
• Beta-blockers or calcium channel blockers for heart rate control, especially in atrial fibrillation 1
• Anticoagulation with vitamin K antagonist (INR 2-3) if atrial fibrillation present or if history of systemic embolism 1

Critical Pitfalls to Avoid

• Do not delay intervention until pulmonary hypertension becomes severe (near-systemic pressures), as this leads to irreversible right ventricular dysfunction and persistent pulmonary hypertension even after successful intervention 2
• Do not rely solely on mean gradient to determine severity, as it varies with heart rate and cardiac output; always use valve area by planimetry as the primary criterion 1, 4
• Do not perform PMC without first obtaining TEE to exclude left atrial thrombus, as this can lead to catastrophic embolic complications 1
• Do not assume degenerative/calcific mitral stenosis in elderly patients is amenable to PMC—these patients typically require surgical valve replacement as there is no commissural fusion to dilate 5

Timing of Intervention

Intervention should be performed promptly once symptoms develop in the setting of severe stenosis (MVA ≤1.5 cm²), as untreated symptomatic patients have poor prognosis with 10-year survival of only 0-15% 2. The goal is to intervene before development of irreversible pulmonary vascular disease and right heart failure 1, 2.