Aortic Stenosis

Question 1

what is the definition of aortic stenosis?

Answer 1

• Narrowing of the aortic valve resulting in obstruction to the left ventricular stroke volume, leading to symptoms of chest pain, breathlessness, syncope and fatigue

Question 2

what is the epidemiology of aortic stenosis?

Answer 2

• The most common type of valvular disease in the western world
• Types:
  • Supravalvular (above valve) e.g congenital fibrous diaphragm above the aortic valve
  • Subvalvular (below valve) e.g congenital condition in which a fibrous ridge or diaphragm is situated immediately below the aortic valve
  • Valvular - most common

Question 3

what is the aetiology of aortic stenosis?

Answer 3

• Primarily a disease of ageing
• Congenital is the second most common cause
  3 main causes:
• Calcific aortic valvular disease (CAVD) - essentially calcification of the aortic valve resulting in stenosis, most commonly seen in elderly
• Calcification of a congenital bicuspid aortic valve (BAV) (valve has 2 leaflets instead of 3 due to genetic disease - this is the most common congenital heart disease) resulting in stenosis
• Rheumatic heart disease - rare now due to eradication

Question 4

what are the risk factors for aortic stenosis?

Answer 4

• over 60
• Congenital bicuspid aortic valve (BAV) predisposes to stenosis and regurgitation - bicuspid valves are more likely to develop stenosis, Congenital BAV is predominant in males
• rheumatic heart disease
• CKD

Question 5

what is the pathophysiology for aortic stenosis?

Answer 5

• Due to the narrowing there is obstructed left ventricular emptying and a pressure gradient develops between the left ventricle and the aorta resulting in an increased afterload
• This results in increased left ventricular pressure and compensatory left ventricular hypertrophy
• In turn, this results in relative ischaemia of the left ventricular myocardium (since hypertrophy results in increased blood demand), and consequent angina, arrhythmias and left ventricular failure
• The obstruction to left ventricular emptying is relatively more severe on exercise - since exercise causes a many-fold increase in cardiac output, however due to the severe narrowing of the aortic valve, the cardiac output can hardly increase - thus, the blood pressure falls, coronary ischaemia worsens, the myocardium fails and cardiac arrhythmias develop
• When this compensatory mechanism is exhausted left ventricular function decline rapidly

Question 6

what are the key presentations for aortic stenosis?

Answer 6

• Think aortic stenosis in ANY elderly person with chest pain, exertional dysponea or syncope (loss of consciousness due to lack of blood), fatigue, risk factor presence

Question 7

what are the signs of aortic stenosis?

Answer 7

Heart sounds:
• Soft or absent second heart sound (paradoxically split S2)
• Prominent 4th (S4) heart sound due to left ventricular hypertrophy
• Ejection systolic murmur-crescendo-decrescendo character
• Loudness does NOT tell you anything about severity
Slow rising carotid pulse (pulsus tardus) and decreased pulse amplitude (pulsus parvus)
Heart failure (usually after 60)

Question 8

what are the symptoms of aortic stenosis?

Answer 8

• Syncope - usually exertional
• Angina (increases myocardial oxygen demand; with resulting demand/ supply mismatch)
• Dysponea on exertion due to heart failure

Question 9

what are the first line and gold standard investigations for aortic stenosis?

Answer 9

• transthoracic echocardiogram: -GOLD S
  • Two measurement obtained are:
• Left ventricular size & function; left ventricular hypertrophy, dilation and ejection fraction
• Doppler derived gradient and valve area (AVA), allows for the assessment of the pressure gradient across the valve during systole
• ECG:
  • Left ventricular hypertrophy
  • Left atrial delay
  • Left ventricular ‘strain’ pattern due to ‘pressure overload’ - depressed ST segments and T-wave inversion in leads orientated towards left ventricle i.e. I, AVL, V5 & 6 when disease is severe
• CXR:
  • Left ventricular hypertrophy
  • Calcified aortic valve

Question 10

what are the differential diagnoses for aortic stenosis?

Answer 10

• Aortic regurgitation

- Subacute bacterial endocarditis

Question 11

how is aortic stenosis managed?

Answer 11

• rigorous dental hygiene
• surgical aortic valve replacement in any symptomatic patient or any patient with decreasing ejection fractions
• TAVI

Question 12

how is aortic stenosis monitored?

Answer 12

regular heart monitoring

Question 13

what are the complications of aortic stenosis?

Answer 13

Heart failure
Stroke
Blood clots
Bleeding
Heart rhythm problems (arrhythmias)
Infections that affect the heart, such as endocarditis
Death

Question 14

what is the prognosis for aortic stenosis?

Answer 14

mortality decreases as it become symptomatic. 2-3 years survival in symptomatic patients