Mitral Stenosis (MS)

Risk factors

• Prior rheumatic fever after untreated group A strep pharyngitis
• Living in or migrating from areas with endemic rheumatic disease
• Mitral annular calcification (degenerative MS in elderly)
• Radiation therapy to the chest
• Carcinoid heart disease, SLE (Libman-Sacks), congenital MS

Pathophysiology

Rheumatic inflammation causes commissural fusion, leaflet thickening, and chordal shortening — producing a fish-mouth or funnel-shaped orifice. Obstruction raises left atrial pressure, leading to LA enlargement, pulmonary venous congestion, and eventually pulmonary arterial hypertension and right heart failure. The LV itself is typically protected.

Clinical presentation

Differential diagnosis

• Left atrial myxoma — Positional dyspnea, tumor plop instead of opening snap, embolic events; echo shows mobile LA mass
• Cor triatriatum — Congenital fibromuscular membrane dividing LA; presents in childhood with MS-like physiology
• Severe mitral annular calcification — Degenerative cause in elderly; echo shows annular Ca²⁺ without commissural fusion
• Mitral regurgitation — Holosystolic, not diastolic; volume-overload LV instead of pressure-loaded LA only
• Pulmonary hypertension of other cause — Right-sided signs without diastolic rumble or opening snap
• Austin Flint murmur of AR — Diastolic rumble at apex but with decrescendo diastolic AR murmur and wide pulse pressure; no opening snap

Diagnostic workup

Diagnostic algorithm

flowchart TD
  A[Symptomatic MS<br/>MVA ≤1.5 cm²] --> B[Transesophageal echo<br/>Wilkins score, LA thrombus?]
  B --> C{Favorable anatomy<br/>Wilkins ≤8?<br/>No thrombus, no MR?}
  C -->|Yes| D[Percutaneous mitral<br/>balloon valvuloplasty]
  C -->|No| E[Surgical mitral<br/>valve replacement]
  D --> F[Lifelong rheumatic<br/>prophylaxis if indicated]
  E --> F
  A --> G[Concurrent: diuretic,<br/>rate control,<br/>WARFARIN if Afib]

Treatment

Complications

• Atrial fibrillation and systemic embolism (especially stroke)
• Pulmonary hypertension and right heart failure
• Infective endocarditis
• Hemoptysis
• Recurrent rheumatic activity

PANCE pearls

• DOACs (apixaban, rivaroxaban, dabigatran) are NOT used in rheumatic MS — use warfarin only.
• Pregnancy unmasks MS: increased blood volume and HR shorten diastole, raising LA pressure dramatically.
• A shorter A2-OS interval suggests more severe stenosis (higher LA pressure opens the valve sooner).
• Ortner syndrome — hoarseness from giant LA compressing the recurrent laryngeal nerve.
• PMBV requires absence of LA thrombus on TEE and low Wilkins score; otherwise pursue surgery.

References

• ACC/AHA 2020 VHD — 2020 ACC/AHA Guideline for the Management of Patients with Valvular Heart Disease (Otto et al., Circulation 2021)
• ESC/EACTS 2021 — 2021 ESC/EACTS Guidelines for the Management of Valvular Heart Disease (Vahanian et al., Eur Heart J 2022)
• INVICTUS Trial — Rivaroxaban vs Vitamin K Antagonist in Rheumatic Atrial Fibrillation (Connolly et al., NEJM 2022)