Aortic stenosis

Question 1

Aetiology

Answer 1

Most common = age-related ‘senile’ calcification of aortic valve (typically older Px)
- congenital bicuspid aortic valve (should normally have 3 cusps)
- rhuematic fever = rare as incidence is low in developed countries

Question 2

Defintion

Answer 2

Narrowing of aortic valve resulting in obstruction to left ventricular outflow during systole

Question 3

Symptoms

Answer 3

SAD!
- Syncope on exertion
- Angina on exertion
- Dyspnoea on exertion

Question 4

Signs

Answer 4

• Ejection systolic crescendo-decrescendo murmur (gets louder then quieter) at right sternal border, 2nd IC radiating to carotids
• Pulsus tardus et parvus (slow-rising pulse = carotid pulse felt after S2 (closure of aortic & pulmonary valves), should be silmutaneous normally)
• Narrow pulse pressure (due to obstruction in LV outflow, systolic aortic pressure decreases & gets closer to diastolic pressure)
• Pathological S4 gallop (in late diastole 01.s before S1, due to atria contracting 7 forcing blood into hypertrophied non-compliant left ventricle)

Question 5

Pathophysiology + how aortic stenosis causes heart failure?

Answer 5

Narrowing of aortic valve leads to obstruction of lV outflow during systole→ pressure gradient develops across aortic valve causing left ventricular hypertrophy
- Hypertrophied left ventricle is non-compliant & stiff→ pathological S4 gallop sound (occurs in late diastole 0.1s before S1 due to atria contracting to pump blood into non-compliant ventricle)
- Hypertrophied left ventricle has greater myocardial O2 demand → angina (chest pain radiating to left arm or jaw/teeth, induced by exertion & relieved by 5 mins rest or GTN spray )
- Exertional syncope due to reduction in LV outflow & CO, CO can’t increase to meet O2 demands during exercise.

Reduction in LV outflow causes HFrEF (systolic dysfunction, ejection fraction <40%). Left ventricular hypertrophy makes LV non-compliant which impairs diastolic filling, exacerbating heart failure.

Question 6

Diagnosis

Answer 6

GS = Echocardiogram - assesses 2 measurements: aortic valve area & Doppler-derived gradient AND LV size
CXR- shows LVH
ECG- shows left ventricular hypertrophy

Question 7

Treatment

Answer 7

Surgery is indicated if patient is SYMPTOMATIC or evidence of heart failure. 2 options:
Surgical aortical valve replacement OR TAVI (Transcutaneous Aortic Valve implantation)
- TAVI is less invasive as done percutaneously via radial or femoral artery, so better for older & high-risk Px
- TAVI just stents the aortic valve open whereas open surgical repair = definitive Tx

Question 8

What is TAVI?

Answer 8

TAVI =Transcutaneous Aortic Valve implantation
- TAVI is less invasive as done percutaneously, so better for older & high-risk Px
- Catheter inserted via femoral or radial artery, balloon inflated across aortic valve to crack calcification (senile calcification = MOST COMMON cause), then new aortic valve implanted