A 38-year-old woman with rheumatic mitral stenosis (mitral valve area 1.2 cm²) presents with progressive dyspnea on exertion and palpitations. On examination, she has an opening snap followed by a low-pitched diastolic murmur at the apex. Her heart rate is 92/min in sinus rhythm. Chest X-ray shows pulmonary congestion. Echocardiography confirms severe mitral stenosis with an ejection fraction of 58%. She has no prior history of atrial fibrillation. What is the most appropriate next step in management?

Explanation

## Pathophysiology of Mitral Stenosis and the Cardiac Cycle **Key Point:** In mitral stenosis, the narrowed mitral valve orifice obstructs blood flow from the left atrium to the left ventricle during diastole. This increases left atrial pressure, leading to pulmonary venous congestion and eventually pulmonary edema. The left ventricle remains underfilled and has reduced preload, which paradoxically preserves systolic function (EF remains normal or near-normal). ## Hemodynamic Consequences ```mermaid flowchart TD A["Mitral Valve Stenosis<br/>Narrowed orifice"]:::outcome --> B["Increased LA pressure<br/>during diastole"]:::outcome B --> C["Pulmonary venous congestion"]:::outcome C --> D{"Severity?"}:::decision D -->|Mild-Moderate| E["Medical management<br/>Diuretics, rate control"]:::action D -->|Severe + Symptoms| F["Percutaneous or surgical<br/>intervention indicated"]:::action E --> G["Monitor for progression"]:::action F --> H{"Suitable for<br/>valvuloplasty?"}:::decision H -->|Yes| I["Percutaneous mitral<br/>balloon valvuloplasty"]:::action H -->|No| J["Surgical mitral valve<br/>replacement"]:::action ``` ## Clinical Assessment of This Patient | Feature | Finding | Significance | |---------|---------|---------------| | Mitral valve area | 1.2 cm² | Severe stenosis (normal >4 cm²) | | Symptoms | Dyspnea on exertion, palpitations | Symptomatic severe MS | | Ejection fraction | 58% | Preserved (LV not primarily affected) | | Rhythm | Sinus rhythm | No atrial fibrillation yet | | Chest X-ray | Pulmonary congestion | Elevated LA pressure | ## Indications for Intervention in Mitral Stenosis **High-Yield:** Symptomatic patients with severe mitral stenosis (MVA <1.5 cm²) require intervention. The choice between percutaneous mitral balloon valvuloplasty (PMBV) and surgical mitral valve replacement depends on: 1. **Suitability for PMBV:** Requires: - No left atrial thrombus (must exclude with TEE) - Favorable valve morphology (Wilkins score <8) - No significant mitral regurgitation - No commissural calcification 2. **This patient is suitable for PMBV because:** - Severe symptomatic mitral stenosis - Sinus rhythm (lower thromboembolism risk) - Preserved LV function - No mention of unfavorable morphology **Clinical Pearl:** PMBV is the preferred initial intervention in suitable candidates because it: - Avoids surgery and cardiopulmonary bypass - Preserves the native valve - Has good long-term outcomes (70–80% remain symptom-free at 10 years) - Can be repeated if restenosis occurs - Is cost-effective ## Medical Management Bridge While awaiting PMBV: - **Diuretics** (furosemide): Reduce pulmonary congestion and improve dyspnea - **Beta-blockers or rate-limiting calcium channel blockers:** Slow ventricular rate, prolong diastole, and allow better LV filling across the stenotic mitral valve - **Anticoagulation:** Consider if atrial fibrillation develops or if there are other thromboembolic risk factors **Mnemonic: DRAB for Mitral Stenosis Management** - **D**iuretics (reduce congestion) - **R**ate control (beta-blockers, CCBs) - **A**nticoagulation (if AF develops) - **B**alloon valvuloplasty (definitive in suitable cases) [cite:Harrison 21e Ch 291; Robbins 10e Ch 12]