Mitral stenosis

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

Carabello, B. Modern management of mitral stenosis. Circulation. 2005;112(3):432-437.

Masani, N. et al. Echocardiography: Guidelines for valve quantification. Available at: http://www.bhf.org.uk/publications/view-publication.aspx?ps=1001602

Vahanian, A. et al. Guidelines on the management of valvular heart disease. European Heart Journal. 2007; 28: 230–268.