Aortic Stenosis

Definition/diagnostic criteria Aortic stenosis (AS) is characterised by the narrowing of the aortic valve opening, leading to obstructed blood flow from the left ventricle to the aorta. Diagnostic criteria include echocardiographic evidence of valve calcification, reduced valve area, and increased mean transvalvular gradient.

Epidemiology AS is the most common valvular heart disease in developed countries, particularly among the elderly. In the UK, it affects 3% of those over 75 years. Risk factors include age-related degenerative changes, congenital bicuspid aortic valve and, less commonly, rheumatic heart disease.

Diagnosis
Clinical features: Patients may present with the classic triad of symptoms: dyspnoea, angina and syncope. However, many remain asymptomatic until the disease is advanced. A late-peaking, harsh, crescendo-decrescendo systolic murmur, best heard at the right upper sternal border, is a key clinical sign.

Investigations:

• Echocardiography: The gold standard for diagnosis, assessing valve anatomy, severity of stenosis and left ventricular function.
• Chest X-ray: May show evidence of cardiac enlargement and calcification of the aortic valve.
• Electrocardiogram (ECG): Can reveal left ventricular hypertrophy or other associated changes.
• Cardiac catheterisation: Reserved for discrepancies between clinical assessment and echocardiography or to assess coronary artery disease in patients being considered for valve replacement.

Treatment Management strategies depend on the severity and symptomatology:
Asymptomatic patients:

• Regular follow-up with echocardiography is advised. Intervention is generally not recommended unless there is evidence of rapid disease progression or abnormal left ventricular function.

Symptomatic patients:

• Medication: While specific medications do not alter the progression of AS, they are used for associated conditions (e.g., hypertension, coronary artery disease).
• Surgical aortic valve replacement (SAVR): The standard treatment for symptomatic severe AS, especially in younger, healthier patients.
• Transcatheter aortic valve implantation (TAVI): Recommended for patients at high surgical risk or with comorbidities that preclude SAVR.

Prognosis The prognosis of AS largely depends on the stage at diagnosis and the timely initiation of appropriate treatment. Once symptoms develop, the average survival rate without intervention is two to three years. Interventional treatment can significantly improve symptoms and survival, but the presence of comorbid conditions can affect outcomes.