- Clinical science
Mitral stenosis (MS) is a valvular anomaly of the mitral valve that leads to obstruction of blood flow into the left ventricle. The most common cause of MS is rheumatic fever. The clinical manifestations depend on the extent of stenosis: reduced mitral opening leads to progressive congestion behind the stenotic valve. Initial dilation of the left atrium (complications: atrial fibrillations, emboli) is followed by progressive congestion of the lungs and subsequent cardiac asthma (coughing, dyspnea). Acute decompensation can cause pulmonary edema. Echocardiography is the main diagnostic tool for evaluating the mitral valve apparatus, left atrial size, and pulmonary pressure. In the event of high grade and/or symptomatic stenosis, percutaneous valvuloplasty or surgical valve replacement is often required.
- Mitral valve stenosis → obstruction of blood flow into the left ventricle (LV) → limited diastolic filling of the LV (↓ end-diastolic LV volume) → decreased stroke volume → decreased cardiac output (forward heart failure)
- Mitral valve stenosis → increase in left atrial pressure → backup of blood into lungs → increased pulmonary capillary pressure → cardiogenic pulmonary edema → pulmonary hypertension → backward heart failure and right ventricular hypertrophy
Auscultation (see )
Diastolic murmur typically heard best at the 5th left intercostal space at the mid-clavicular line (the apex)
- Heard loudest when the patient is lying on his/her left side.
- Loud first heart sound (S1)
- Opening snap of the mitral valve after S2: A high frequency, early-to-mid diastolic sound that occurs when leaflet motion suddenly stops during diastole after the stenosed valve has reached its maximum opening
- Shorter interval between S2 and opening snap is indicative of more severe disease; , because left atrial pressure is greater than left ventricular end-diastolic pressure (LVEDP).
- Diastolic murmur typically heard best at the 5th left intercostal space at the mid-clavicular line (the apex)
- X-ray chest
- Echocardiography: most important diagnostic method for detecting and assessing valvular abnormalities
- Coronary angiography may be conducted prior to surgical interventions to assess the risk of associated coronary artery disease
- Conservative treatment
- Indication: severe (MVA ≤ 1.5 cm2) and/or symptomatic mitral stenosis
First-line: percutaneous of the mitral valve (PMBC) if the following criteria are fulfilled:
- Favorable valve morphology e.g., no valvulvar calcifications
- No left atrial thrombus
- No or mild mitral regurgitation
- Alternatives: open commissurotomy and surgical valve replacement ( or )
- Atrial fibrillation → thromboembolic events
- Progressive congestion of the lungs, pulmonary edema, pulmonary hypertension
- Congestive heart failure
- Enlarged left atrium (rare) → esophageal compression; , recurrent laryngeal nerve palsy
We list the most important complications. The selection is not exhaustive.