Valve diseases - Aortic Stenosis

Question 1

Stenosis definition

Answer 1

Increased upstream pressure + proximal chamber DILATION + HYPERTROPHY (Stenotic = narrowed valve lumen)
- Heart becomes huge and rigid, poorly compliant

Question 2

Murmurs rule (RILE)

Answer 2

Right sided defects = best heard on Inspiration
Left sided defects = best heard on Expiration

Question 3

Epidemiology

Answer 3

MOST COMMON HEART VALVE DEFECT
Male (2:1)
Older (60+)
Patients with bicuspid valves + AS present two weeks earlier on average than ones with tricuspid valves

Question 4

Risk factors

Answer 4

Age (60+)
Congenitally bicuspid aortic valve
Rheumatic valve
Chronic kidney disease

Question 5

Aetiology

Answer 5

Senile calcification of aortic valve = MC
Bicuspid valve
Rheumatic fever

Question 6

Pathophysiology

Answer 6

Normal area = 3-4cm2 - Sx when 1/4 lumen size = LV dilation + hypertrophy
Can be:
Supraventricular above aortic valve
Sub-ventricular
Valvular
- Narrowing -> obstructed left ventricular emptying -> pressure gradient develops between left ventricle + aorta - increased afterload
left ventricular hypertrophy
Relative ischemia of left ventricular myocardium -> angina, arrhythmias, left ventricular failure
The obstruction to left ventricular emptying = more severe on exercise
When this compensatory mechanism is exhausted left ventricular functions decline rapidly.

Question 7

Signs and symptoms

Answer 7

SAD:
- Syncope (exertion)
- Angina
- Dyspnoea (related to heart failure)
Dizziness,
Faints,
Systemic emboli (if IE)
Signs:
- MURUMUR: EJECTION SYSTOLIC CRESCRENDO DECRESCENO MURMUR - radiating to carotids and apex, 2nd IC space
- Prominent S4 sound - LVH
- Narrow pulse pressure + slow rising pulse (NOT collapsing Corrigan pulse)

Question 8

Diagnosis

Answer 8

ECG - LVH
- Deep S waves in V1 + V2,
- Poor R wave progression, in V5, V6,
- Left ventricular strain in severe disease, LBBB or AV block
CXR - post stenotic dilating ascending aorta + left ventricular hypertrophy + cardiomegaly if HF develops
GOLD STANDARD = ECHO = LV size + function, aortic valve area (Doppler derived)

Question 9

Treatment

Answer 9

Healthy patient:
Open repair/valve replaced (DEFINITVE)
More at risk (e.g. 75+) - TAVI (transcutaneous aortic valve implant) - less invasive, just stents valve open

Question 10

Differential

Answer 10

Hypertrophic cardiomyopathy
Aortic sclerosis