What is the initial management approach for a patient with mitral stenosis?

Initial Management of Mitral Stenosis

Begin with transthoracic echocardiography (TTE) to establish severity, followed by medical therapy for symptom control, anticoagulation when indicated, and structured surveillance with intervention reserved for symptomatic patients or high-risk asymptomatic patients based on valve anatomy. 1

Diagnostic Evaluation

Transthoracic echocardiography is the preferred initial imaging modality to diagnose mitral stenosis and assess severity, with valve area by planimetry serving as the reference measurement. 1

• Measure mitral valve area (MVA) using planimetry at the leaflet tips as the gold standard, supplemented by pressure half-time method, continuity equation, or PISA method when needed. 2
• Classify severity: severe (MVA ≤1.0 cm²), moderate (MVA 1.0-1.5 cm²), mild (MVA >1.5 cm²). 3, 4
• Assess valve morphology for commissural fusion (rheumatic) versus annular calcification without fusion (degenerative), as this fundamentally determines intervention options. 4, 5

Transesophageal echocardiography (TOE) is reserved for specific indications, not routine initial assessment:

• Exclude left atrial thrombus before percutaneous mitral commissurotomy (PMC). 1
• After embolic episodes. 1
• When TTE images are technically limited. 1

Exercise stress testing should be performed when symptoms are absent, equivocal, or discordant with resting echocardiographic severity to unmask exercise-induced symptoms or hemodynamic changes. 1, 3

Medical Management

Medical therapy provides symptom relief but does not prevent disease progression; regular monitoring for intervention indications remains essential. 3

Heart Rate Control

Beta-blockers or rate-limiting calcium channel blockers are the foundation of medical therapy to control heart rate and prolong diastolic filling time, particularly crucial in atrial fibrillation. 3, 4

• Digoxin is specifically recommended for heart rate control in atrial fibrillation. 3, 4
• Avoid medications causing tachycardia (high-dose dopamine, dobutamine), as shortened diastolic filling dramatically reduces cardiac output in fixed stenosis. 6

Volume Management

Diuretics are indicated for pulmonary congestion or peripheral edema to relieve congestive symptoms. 3, 4

• Fluid management requires careful titration: maintain preload adequate for left ventricular filling while avoiding pulmonary edema from excessive left atrial pressure. 6
• In hypotensive patients, establish invasive hemodynamic monitoring (right-heart catheterization or TEE) rather than relying on clinical assessment alone. 6

Anticoagulation

Vitamin K antagonists (target INR 2-3) are mandatory in the following situations—never use NOACs in mitral stenosis with atrial fibrillation: 1, 3, 4

• New-onset or paroxysmal atrial fibrillation. 3, 4
• History of systemic embolism. 3, 4
• Left atrial thrombus on imaging. 3
• Dense spontaneous echocardiographic contrast. 3, 4
• Enlarged left atrium (even without atrial fibrillation). 3, 4

Low-intensity anticoagulation (INR target 2) is as effective as moderate-intensity (INR target 3) with lower bleeding risk in patients with mitral stenosis and atrial fibrillation. 7

Surveillance Protocol

Asymptomatic patients with moderate mitral stenosis (MVA 1.0-1.5 cm²) require clinical and echocardiographic follow-up every 2-3 years. 1, 3

Asymptomatic patients with severe mitral stenosis (MVA ≤1.0 cm²) require yearly follow-up with more frequent monitoring if high-risk features develop. 1, 3

Indications for Intervention

Symptomatic Patients

Percutaneous mitral commissurotomy (PMC) is indicated for all symptomatic patients with clinically significant mitral stenosis (MVA <1.5 cm²) and favorable valve anatomy. 1

• Favorable anatomy includes rheumatic etiology with commissural fusion, minimal calcification (echocardiographic score ≤8), and absence of severe mitral regurgitation (≥2/4 grade). 1, 2
• PMC should be considered as initial treatment even with suboptimal anatomy (mild-moderate calcification or impaired subvalvular apparatus) if clinical characteristics are otherwise favorable. 1
• Surgery (mostly valve replacement) is indicated when PMC is unsuitable due to unfavorable anatomy, left atrial thrombus that persists despite anticoagulation, or severe mitral regurgitation. 1

Asymptomatic Patients

PMC should be considered in asymptomatic patients with favorable anatomy and any of the following high-risk features: 1

• Systolic pulmonary artery pressure >50 mmHg at rest. 1
• History of systemic embolism or high thromboembolic risk (dense spontaneous contrast, new-onset atrial fibrillation). 1
• Need for major non-cardiac surgery. 1
• Desire for pregnancy. 1

Surgery in asymptomatic patients is limited to rare cases at high risk of cardiac complications with contraindications to PMC and low surgical risk. 1

Critical Contraindications and Pitfalls

Left atrial thrombus is the most important contraindication to PMC. 1

• If thrombus is in the left atrial appendage only, PMC may be reconsidered after 1-3 months of anticoagulation if repeat TOE shows resolution. 1
• Surgery is indicated if thrombus persists. 1

Common pitfalls to avoid:

• Delaying anticoagulation in patients with enlarged left atrium or dense spontaneous contrast is dangerous, as embolic risk is significant even without atrial fibrillation. 3
• Using NOACs instead of warfarin is contraindicated in mitral stenosis with atrial fibrillation. 1, 3
• Attempting PMC in degenerative mitral stenosis will fail due to lack of commissural fusion and may cause harm. 3, 4, 5
• Never use vasodilators in hypotensive mitral stenosis patients, as these worsen hypotension by decreasing systemic vascular resistance. 6
• Cardioversion before intervention in severe mitral stenosis with persistent atrial fibrillation is not indicated, as sinus rhythm will not be durably restored until after successful intervention. 1

Special Populations

Pregnant patients with symptomatic moderate-to-severe mitral stenosis should be evaluated for PMC, which can be performed relatively safely even in NYHA class III-IV. 1, 4

Elderly patients with rheumatic mitral stenosis and high surgical risk can undergo PMC as a useful option, even if only palliative. 1

Degenerative mitral stenosis in elderly patients with severely calcified mitral annulus carries very high surgical risk and is not amenable to PMC; transcatheter valve implantation is investigational. 1, 5