Mitral stenosis

Mitral stenosis describes the obstruction of blood flow across the mitral valve from the left atrium to the left ventricle. This leads to increases in pressure within the left atrium, pulmonary vasculature and right side of the heart.

It is said that the causes of mitral stenosis are rheumatic fever, rheumatic fever and rheumatic fever. Rarer causes that may be seen in the exam include mucopolysaccharidoses, carcinoid and endocardial fibroelastosis

Features

dyspnoea

↑left atrial pressure → pulmonary venous hypertension

haemoptysis

due to pulmonary pressures and vascular congestion

may range from pink frothy sputum to sudden haemorrhage secondary to rupture of thin-walled and dilated bronchial veins

mid-late diastolic murmur (best heard in expiration)

loud S1

opening snap indicates mitral valve leaflets are still mobile

low volume pulse malar flush

atrial fibrillation secondary to ↑ left atrial pressure → left atrial enlargement

Features of severe MS

length of murmur increases opening snap becomes closer to S2

Chest x-ray

left atrial enlargement may be seen

Echocardiography

the normal cross-sectional area of the mitral valve is 4-6 sq cm. A 'tight' mitral stenosis implies a cross-sectional area of < 1 sq cm

Management

patients with associated atrial fibrillation require anticoagulation

currently warfarin is still recommended for patients with moderate/severe MS

there is an emerging consensus that direct-acting anticoagulants (DOACs) may be suitable for patients with mild MS who develop atrial fibrillation

#asymptomatic patients

monitored with regular echocardiograms

percutaneous/surgical management is generally not recommended

#symptomatic patients

percutaneous mitral balloon valvotomy

mitral valve surgery (commissurotomy, or valve replacement)