Mitral stenosis is a valvulopathy due to the mitral valve obstructing blood flow from the left atrium to the left ventricle, presenting with heart failure symptoms and pulmonary hypertension. It is diagnosed with echocardiography and treated with diuretics, beta-blockers, anticoagulants, comissurotomy, or valve replacement.
Pathophysiology
- Scarring and narrowing of mitral valve due to immune-mediated damage after rheumatic fever
- Obstructs flow from left atrium to left ventricle
- Increased left atrial pressure and size -> atrial fibrillation
- Increased pulmonary venous pressure -> pulmonary congestion -> pulmonary hypertension
- Longstanding pulmonary hyptension results in right ventricular pressure
Contextual Factors
- Rheumatic fever
- Female
Clinical Manifestation
- Hemoptysis due to bronchial vein rupture
Cardiac
- Heart palpitations
- Chest pain
Auscultation
- Loud S1
- S2 followed by early diastolic opening snap
- Closer snap is to S2 = more severe disease
- Early diastolic opening snap followed by low-pitched decrescendo-crescendo rumbling
- Increases with Valsalva maneuver
- Signs of right ventricular failure: right ventricular heave, jugular vein distension, hepatomegaly, ascites
Pulmonary
- Exertional dyspnea
- Orthopnea
- Paroxysmal nocturnal dyspnea
- Loud P2 due to pulmonary hypertension
Complications
- Mitral regurgitation
- Atrial fibrillation
- Thromboembolism
Diagnosis
- Echocardiography
- Left atrial enlargement
- Thick calcified mitral valve
- Narrow “fish-mouth” mitral valve orifice
| Severity | Valve Area (cm^2) | Diastolic Pressure Half-Time (ms) |
|---|---|---|
| Moderate | > 1.5 - 2.5 | < 150 |
| Severe | <= 1.5 | >= 150 |
- ECG: P wave > 0.12 due to left atrial enlargement, notched P wave
- Chest x-ray: straightening of left cardiac border, widening carina
Treatment
Medication
- Diuretics: relieves pulmonary congestion and edema
- Beta blockers or calcium channel blockers: decreases heart rate to increase diastolic time -> improved LV filling/ LA emptying
Surgery
- Percutaneous balloon commissurotomy: indicated for younger patients without severe signs of disease progression
- Surgical commissurotomy: indicated for patients with severe subvalvular disease
- Mitral valve replacement: indicated for patients with severe changes that would make commissurotomy difficult
- Mechanical valve: requires lifetime warfarin
- Bioprosthetic valve: 3-6 months of warfarin