Valve stenosis is a narrowing of one of the heart’s four valves (aortic, mitral, pulmonary or tricuspid) that restricts blood flow through it. The narrowed opening forces the heart to work harder to push blood forward, increasing pressure in the upstream chamber and, over time, causing the muscle to thicken or dilate. Stenosis can be congenital (present from birth due to abnormal valve development) or acquired through age-related calcification, rheumatic fever or inflammatory disease.
Aortic stenosis is by far the most common form in adults. Calcific aortic stenosis typically develops after the age of 65 as calcium deposits accumulate on the valve leaflets and progressively reduce the opening. Severe aortic stenosis classically produces three warning symptoms: angina (chest pain on exertion), breathlessness and exertional syncope (fainting). It carries a significant risk of sudden cardiac arrest, particularly during physical activity, because the fixed obstruction prevents cardiac output from meeting demand. Mitral stenosis, now relatively rare in the UK, is most often a late consequence of rheumatic heart disease and causes breathlessness, atrial fibrillation and, in severe cases, pulmonary oedema.
Diagnosis is made by echocardiography, which measures the valve opening area, the pressure gradient across the valve and the function of the heart chambers. Cardiac MRI and CT calcium scoring are used in selected cases. The severity of stenosis is graded as mild, moderate or severe based on standardised echocardiographic criteria. Regular surveillance echocardiograms allow the cardiology team to time intervention before irreversible heart muscle damage occurs.
Treatment of significant stenosis is valve replacement or repair. For aortic stenosis, transcatheter aortic valve implantation (TAVI) has become the preferred option for most patients, including many who are fit for surgery, because it avoids open-chest surgery and has excellent outcomes. Surgical aortic valve replacement remains standard for younger patients or those requiring concurrent bypass surgery. Following valve replacement, cardiac rehabilitation supports recovery, and survivors of sudden cardiac arrest caused by severe stenosis will also require review of their arrhythmia risk and, where appropriate, consideration of an ICD.
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