Overview

Aortic stenosis (AS) is the narrowing of the aortic valve. It may happen at the aortic valve as well as above and below it. It can lead to the obstruction of blood flow and can be due to aortic valve fibrosis and calcification.

Aortic sclerosis is usually considered to be the precursor of aortic stenosis and describes the calcification and degeneration of the aortic valve.

Epidemiology

  • Aortic stenosis is the most common type of valvular heart disease in people >65 years
  • Congenital bicuspid valves are the second most common
  • Rheumatic heart disease is less common in developed countries

Causes

  • Degenerative calcification and fibrosis – most common
  • Congenital bicuspid valves
    • More common in people with coarctation of the aorta or Turner’s syndrome
  • Rheumatic heart disease

Risk Factors

Presentation

Signs on examination

  • Ejection systolic murmur that is:
    • Loudest in the right upper sternal border that radiates to the carotid arteries
    • Louder on expiration
    • Crescendo-decrescendo in volume that starts at S1 and ends right before S2
  • S2 changes:
    • Soft in aortic stenosis
    • Normal/loud in aortic sclerosis
  • In severe aortic stenosis:
    • S4 – suggests left ventricular hypertrophy
    • Narrow pulse pressure
    • Slow rising pressure
  • Thrills if the murmur grade is high

Differential Diagnoses

Aortic sclerosis

  • S2 is normal/loud
  • Non-radiating
  • Difficult to distinguish clinically

Hypertrophic obstructive cardiomyopathy

  • Standing up after sitting or the Valsalva manoeuvre increases the murmur
  • The murmur softens with squatting

Investigations

All patients

  • Transthoracic echocardiogram:
    • Identifies aortic stenosis
    • Shows elevated aortic pressure gradient
  • ECG:
    • May show left ventricular hypertrophy
    • May show absent Q waves
  • Chest x-ray:
    • To look for pulmonary congestion or other lung pathology

Management

Asymptomatic patients

  • If no cardiac dysfunction:
    • Watch and wait
  • If valvular gradient >40mmHg or left ventricular ejection fraction (LVEF) <50%:
    • Valve surgery e.g. replacement

Symptomatic patients

  • Valve surgery e.g. replacement

Unfit for surgery

  • Balloon valvuloplasty

Monitoring

  • Asymptomatic patients are followed-up very closely
  • Some patients need follow-up transthoracic echocardiography. In general, this is done in the following manner:
    • Mild stenosis: every 3-5 years
    • Moderate stenosis: every 1-2 years
    • Severe stenosis: 6-12 months

Patient Advice

  • Patients who are currently asymptomatic should seek immediate help if they develop symptoms
  • Patients should adopt a healthier lifestyle through a balanced diet, exercise, and smoking cessation even after surgery.

Complications

Prognosis

  • Cardiac arrest is a common cause of death
  • Women have a higher mortality than men due to late diagnoses and less frequent and delayed referrals for surgery
  • Factors associated with a worse prognosis are:
    • Older age
    • Atherosclerosis and its risk factors
    • Reduced left ventricular ejection fraction
    • Exertional symptoms and syncope

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