Aortic Stenosis

Question 1

Define aortic stenosis and summarise its aetiology and epidemiology.

Answer 1

Definition: Narrowing of the left ventricular outflow at the level of the aortic valve.

Aetiology:
1- Stenosis secondary to rheumatic heart disease (commonest worldwide);
2- calcification of a congenital bicuspid aortic valve;
3- calcification/degeneration of a tricuspid aortic valve in the elderly.

Epidemiology:
- Prevalence in approx. 3% of 75-year-olds.
- Female > Male.
- Those with bicuspid aortic
valve may present earlier (as young adults).

Question 2

Describe the history/presenting symptoms of aortic stenosis

Answer 2

• May be asymptomatic initially.
• Angina (because of increased oxygen demand of the hypertrophied ventricles).
• Syncope or dizziness on exercise.
• Symptoms of heart failure (e.g. dyspnoea).

Question 3

What are the signs of aortic stenosis upon physical examination?

Answer 3

• BP: Narrow pulse pressure.
• Pulse: Slow-rising.
• Palpation: Thrill in the aortic area (if severe).
• Forceful sustained thrusting undisplaced apex
  beat.
• Auscultation:
  • Harsh ejection systolic murmur at aortic area, radiating to the carotid artery and apex.
  • Second heart sound (A2 component) may be softened or absent (because of calcification).
  • A bicuspid valve may produce an ejection click.
• Distinguish from aortic sclerosis and hypertrophic obstructive cardiomyopathy
  (HOCM)

Question 4

What investigations are used to identify aortic stenosis?

Answer 4

- ECG: Signs of left ventricular hypertrophy:    
    •  Deep S wave in V1–2    
    • Tall R wave in V5–6   
    •  Inverted T waves in I, aVL, V5–6 
    •  left-axis deviation, 
LBBB

• CXR:
  • Post-stenotic enlargement of the ascending aorta.
  • calcification of aortic valve.
• Echocardiogram:
  • Visualizes structural changes of the valves and level of stenosis (valvar,
  supravalvar or subvalvar).
  • Estimation of aortic valve area and pressure gradient across the valve in systole and left ventricular function may be assessed.
• Cardiac angiography:
  • Allows differentiation from other causes of angina, and to assess for
  concomitant coronary artery disease

(50% of patients with severe aortic stenosis have significant coronary artery disease).