Aortic stenosis

Question 1

DEFINE Aortic stenosis

Answer 1

A narrowing of the left ventricular outflow tract at the level of the aortic valve

Question 2

Explain the aetiology and risk factors of aortic stenosis

Answer 2

Stenosis can be secondary to rheumatic heart disease (MOST COMMON WORLDWIDE)

Calcification of a congenital bicuspid aortic valve

Calcification/degeneration of a tricuspid aortic valve in the elderly

Question 3

Summarise the epidemiology of aortic stenosis

Answer 3

Present in 3% of 75 yr olds

More common in males

Those with bicuspid aortic valve present earlier

Question 4

Recognise the presenting symptoms of aortic stenosis

Answer 4

ASYMPTOMATIC initially in mild disease. Symptoms suggest that severe disease is present.

Classic triad:

1. Angina
   (due to decreased blood supply to myocardium)
2. Syncope (classically dizziness on exercise)
   (due to outflow obstruction - reduced blood supply to brain)
3. Dyspnoea/SOB

can also be orthopnoea
fatigue
signs of CHF if progressed

Question 5

Recognise the signs of aortic stenosis on examination

Answer 5

Narrow pulse pressure

Slow-rising pulse

Thrill in the aortic area (only if severe)

Forceful sustained thrusting undisplaced apex beat (may be slightly displaced)

Ejection systolic murmur at the aortic area, radiating to the carotid artery (say all this together)

May get early systolic click if no calcification - A bicuspid valve may produce an ejection click

Second heart sound may be softened or absent (due to calcification)

Heave - due to left ventricular hypertrophy

JVP normal

Question 6

Why can there be left ventricular hypertrophy in aortic stenosis?

Answer 6

the left ventricle has to work harder to push blood out of the stenotic valve

Question 7

What is the reason for the slow rising pulse in aortic stenosis?

Answer 7

Due to decreased flow across the narrow valve

Question 8

Identify appropriate investigations for aortic stenosis

Answer 8

ECG
CXR
Echocardiogram
Cardiac angiogram

Question 9

What would you see on investigations for aortic stenosis?

Answer 9

1. ECG;
A. Signs of left ventricular hypertrophy;  
   Deep S in V1/2 
   Tall R in V5/6 
   Inverted T waves in I, aVL and V5/6 
   Left axis deviation 

B. LBBB

2. CXR
   Post-stenotic enlargement of ascending aorta
   Calcification of aortic valve
3. Echocardiogram
   - Visualises 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
   - Assess left ventricular function
4. Cardiac angiography
   Allows differentiation from other causes of angina (e.g. MI)
   Allows assessment of concomitant coronary artery disease

NOTE: 50% of patients with severe aortic stenosis have significant coronary artery disease

Question 10

Mx?

Answer 10

No good medical therapy

Asymptomatic:
Do nothing

Sympotmatic; SOB
A. Surgery - Replace aortic valves whilst on bypass;
-> Mechanical vs tissue (pig) valves
- prefered if low surgical risk

B. Percutaneous - TAVI (Transcatheter aortic valve implantation)
- prefered if higher surgical risk

Question 11

what is the principle problem with mechanical valves?

Answer 11

thombus formation - have to keep on WARFARIN lifelong (nothing else suitable even in pregnant women!)

Question 12

what is the principle problem with tissue valves?

Answer 12

Deterioration - do not last fforever like mechanical valves, will need 2nd operation in future

deterioration faster in young people

Question 13

What must individuals receiving mechanical aortic valve have lifelong?

Answer 13

WARFARIN lifelong (nothing else suitable eg lmwh even in pregnant women!)