Aortic stenosis - valvular

Question 1

What are the leaflets of the aortic valve called?

Answer 1

• left
• right
• posterior

Question 2

What is aortic stenosis?

Answer 2

• obstruction of blood flow across the aortic valve due to pathological narrowing.

It is a progressive disease that presents after a long subclinical period with symptoms of:

decreased exercise capacity

exertional chest pain (angina)

syncope

heart failure.

Question 3

What is the cause of aortic stenosis?

Answer 3

• aortic calcification –> bloodflow obstruction (accounts for 80% of cases)
  
  • Calcific aortic disease represents a spectrum ranging from:
    • aortic sclerosis –> severe AS
• Congenitally bicuspid valves
  • biggest causes are coarctation of aorta & Turner’s syndrome
• Rheumatic heart disease

rare causes:

• connective tissue diseases
• radiotherapy
• hyperlipoproteinaemia syndromes

Question 4

What is aortic sclerosis?

Answer 4

leaflet thickening without obstruction

Question 5

In which condition does aortic stenosis progress faster?

Answer 5

CKD (due to abnormal calcium homeostasis)

Question 6

What are the risk factors for aortic stenosis?

Answer 6

• age >60 years
• congenitally bicuspid aortic valve
  
  • abnormal shear and mechanical stresses from birth
• rheumatic heart disease
  
  • prior Streptococcus infection –> autoimmune inflammatory reaction that targets valvular endothelium –> inflammation –> calcification
• chronic kidney disease

weak:

• radiotherapy
  
  • ​rare complication of mediastinal radiotherapy
  • presents 20yrs post-Tx
• high LDL cholesterol
• hyperlipoproteinaemia
  
  • e.g. due to Familial hypercholesterolaemia

Question 7

Summarise the epidemiology of aortic stenosis

Answer 7

• most common valvular disease
• 2nd most frequent cause for cardiac surgery
• Those with bicuspid aortic valve present earlier
• age: 70s, 80s
• prevalence is 0.2% in adults 50 - 59 yrs
• prevalence 1.3% in pts 60 - 69 yrs
• prevalence 9.8% in pts 80 - 89 yrs

Question 8

Which pathological change precedes aortic stenosis?

Answer 8

aortic sclerosis

suspected by presence of:

• an early-peaking, systolic ejection murmur

confirmed by:

• echocardiography

Question 9

What is the average time for aortic sclerosis to develop into aortic stenosis?

Answer 9

diagnosis of aortic sclerosis to development of

• moderate AS is 6yrs
• severe AS is 8yrs

Question 10

What is the epidemiology of congenital biscuspid valve?

Answer 10

• 0.9% to 1.36% of the general population
• 2:1 male:female ratio

Question 11

What proportion of aortic valve replacements are on congenital biscuspid valve pts?

Answer 11

1/2 of all aortic valve replacements are performed for congenitally malformed valves

Question 12

What are the presenting symptoms of aortic stenosis?

Answer 12

May be ASYMPTOMATIC initially

• Angina
  
  • (due to increased oxygen demand of the hypertrophied left ventricle)
• Syncope / dizziness on exertion
  
  • (due to outflow obstruction)
• Symptoms of heart failure
  
  • (e.g. dyspnoea, orthopnoea)

Question 13

What are thes signs of aortic stenosis O/E?

Answer 13

• Narrow pulse pressure
• Slow-rising pulse
• Thrill in aortic area (only if severe)
• Forceful, sustained, thrusting undisplaced apex beat
• Ejection systolic murmur at the aortic area
• • radiating to carotid artery
• S2 may be softened / absent
  
  • (due to calcification)

Question 14

What extra sign may be produced by a biscuspid aortic valve?

Answer 14

bicuspid valve ~ produce an ejection click

Question 15

What are some uncommon signs seen in aortic stenosis?

Answer 15

• carotid parvus et tardus
  
  • carotid upstroke delayed and diminished
• paradoxically split S2
  
  • ​severe stenosis
  • aortic valve closure ~ become so delayed that it follows pulmonic valve closure during expiration
• Gallavardin’s phenomenon
  
  • musical-quality, holosytolic murmur is present at apex of heart that occurs in older patients with calcific AS
  • ~ mimic mitral regurgitation.
• bleeding
  
  • acquired von Willebrand deficiency
  • caused by turbulent flow across stenotic valve

Question 16

What are the primary investigations for ?aortic stenosis?

Answer 16

• transthoracic echocardiogram
  
  • ~ left ventricular hypertrophy
  • thickened and immobile aortic valve
  • dilated aortic root
• Doppler echocardiogram​
  
  • elevated aortic pressure gradient
  • measurement of valve area and left ventricular ejection function
• ECG
  
  • LVH
  • absent Q waves
    
    • _​_the combination of the above 2 –> rules out aortic sclerosis & ischaemic heart disease
  • AV block OR
  • hemiblock OR
  • bundle branch block

Question 17

Which symptoms related to AS indicate a transthoracic echocardiogram?

Answer 17

• unexplained systolic murmur
• a single S2
• Hx of bicuspid aortic valve
• symptoms that might be due to AS

Question 18

What are some possible secondary investigations to consider in ?aortic stenosis>

Answer 18

• MRI (cardiac)
  
  • stenotic aortic valve
• cardiac catheterisation
  
  • direct aortic pressure gradient (elevated)
• ECG exercise stress testing
  
  • useful in asymptomatic patients
• dobutamine stress echo
  
  • identify pseudostenosis and the –> hence prevents referral for valve replacement surgery
  • presence of contractile reserve –> better prognosis and lower surgical risk with surgical valve replacement.