The normal area of the mitral valve is 4-6cm ^2
Mild mitral stenosis: area 1.6-2cm^2 with a mean pressure drop of <5mmHg
Severe mitral stenosis: area <1cm^2 with a mean pressure drop of >10mmHg
Aetiology
- Most commonly rheumatic fever
- Rarely:
- Carcinoid syndrome
- Weight loss medications
Presentation
- Exertional dyspnoea
- Orthopnoea
- Paroxysmal nocturnal dyspnoea
- Haemoptysis – due to pulmonary hypertension causing rupture of anastomoses of bronchial veins
- Rarely –horseness due to compression of left recurrent laryngeal nerve
On examination
- Mitral facies
- AF – 40%
- Loud S1 (or absent S1 in severe disease)
- Opening snap
- Rumbling mid-diastolic murmur
- Occasionally – high-pitched blowing murmur at cardiac base = Graham Steell murmur
- If pulmonary hypertension has developed:
- Hepatomegaly
- Ascites
- Oedema
Diagnosis is usually by echocardiography
Management
- Medications
- Diuretics/long-acting nitrates to improve dyspnoea
- Beta-blockers/calcium channel blockers may improve exercise tolerance
- Anticoagulate if AF
- Percutaneous mitral commissurotomy (=balloon dilation)
- Indicated if valve area <1.5cm^2 AND
- symptomatic OR
- asymptomatic but at high risk of embolism OR
- haemodynamic decompensation
- Risks:
- Mortality 0.5-4%
- Haemopericardium 0.5-10%
- Embolism 0.5-5%
- Severe MR 2-10%
- Surgery
References
