Valvular disease - Aortic Stenosis Flashcards
What is Aortic stenosis?
https://www.youtube.com/watch?v=JorBOLNzfUY
Narrowing of the exit of the left ventricle of the heart (where the aorta begins), such that problems result.
What are causes of Aortic Stenosis?
- Age-related Degeneration - atherosclerosis of the valve
- Acute Rheumatic Fever
- Bicuspid calcificaiton
- Williams Syndrome
What are symptoms of Aortic Stenosis?
Long asymptomatic phase
Cardinal Symptoms
- Chest pain - angina
- Syncope/Dizziness - exertional pre-syncope
- Breathlessness on exertion
- Dizziness
Why would you get exertional chest pain in AS?
When exertion increases, cardiac ouput cannot compensate due to obstruction, thus resulting in decreased coronary perfusion relative to demand, resulting in ischaemia
Why does exertional syncope occur in AS?
Cardiac ouput can’t meet increased requirements of the body, and cannot perfuse the brain properly
What signs are seen in someone with Aortic stenosis?
- Slow rising, low volume pulse - pulsus parvus et tardus
- Narrow pulse pressure
- Heaving, non-displaced Apex
- LV heave
- Aortic Thrill
- Sounds - Ejection click, soft A2, S4
- Murmur - Systolic, low pitched ESM - RADIATES TO CAROTIDS
- Signs of HF
What is an ejection systolic murmur?
Mid to late peaking Crescendo decrescendo murmur. Often heard in stenotic valvular disease (Aortic or pulmonary). Blood flowing over the stenotic valve in systole causes the murmur
What maneuovres could increase the volume of murmur in Aortic stenosis?
Manoeuvres which increase venous return - such as squatting increase venous return, stroke volume, flow across the valve and thus the murmur
What manoevres can decrease the volume of murmurs in Aortic stenosis?
Manoeuvres which decrease venous return - The strain of Valsalva, which decreases venous return, has the opposite effect on the intensity of the murmur
Why do you get an ejection click in aortic stenosis?
Systolic ejection clicks occur in early systole and may result from either the abrupt opening of the semilunar valves or the rapid distention of the proximal aorta or pulmonary artery at the onset of ejection
Why would you get LV heave and a heaving non-diplaced apex beat in Aortic Stenosis?
In order to compensate for the increased pressure load on the left ventricle, the ventricle enlarges in size, making it more likely to be palpable - causing heave and more easily palpable apex
Why is pulse pressure narrow in Aortic Stenosis?
LV outflow obstruction leads to decreased SV, which causes sympathetic activation resulting in the body trying to maintain diastolic BP by increasing vascular resistance. Therefore, the cause of narrow PP = Decreased Systolic BP + Maintained Diastolic BP
Why do individuals with AS have a slow rising pulse?
Aortic stenosis causes a decrease in the rate of ejection of blood from the left ventricle, while at the same time the duration of ejection is prolonged. Consequently, amplitude is decreased resulting in a smaller pulsation.
The delayed nature of the pulse is thought to be caused by the combined effects of:
- Flow stenosis
- Compliance of the vessel distal to the stenosis
- Venturi effect - sucks in the arterial wall, narrowing the arterial lumen and further delaying the arterial pulse.
What is Pulsus parvus et tardus?
Refers to a carotid pulse that is of small volume (parvus) on palpation and delayed (tardus) in its peak (i.e. the peak is closer to the second heart sound).
What is the mechanism behind reverse splitting of the heart sounds?
In aortic stenosis, the valve becomes so stiffened and closes so slowly that it is heard after the pulmonary valve.
What is the mechanism behind a soft A2 heard in Aortic Stenosis?
Occurs due to rigid calcific valve, therefore closure of the valve doesn’t happen as smoothly
Why might you hear an S4 heart sound sound in AS?
An S4 is typically found in conditions that cause a decrease in compliance of the left ventricle or diastolic dysfunction. Any condition causing stiffening of the left ventricle may cause an S4.
What type of ventricular hypertrophy occurs in Aortic stenosis?
Concentric hypertrophy, in which the walls of the LV are (approximately) equally thickened
If you suspected Aortic Stenosis, what investigations might you perform?
- ECG
- CXR
- Echo
- Cardiac MRI
What might you see on an ECG in someone with Aortic Stenosis?
- P-mitrale - Bifid P wave lead II, total P-wave > 110ms
- Signs of LVH - Left axis deviation, R wave in V4, V5 or V6 > 26 mm, R wave in V5 or V6 plus S wave in V1 > 35 mm, Largest R wave plus largest S wave in precordial leads > 45 mm
- Left anterior hemiblock
- LBBB
- Complete heart block
What might you see on CXR in someone with Aortic Stenosis?
- LVH
- Calcified Aortic Valve
- Post-stenotic Dilatation of the Aorta
What is the differential diagnosis for someone displaying symptoms similar to Aortic Stenosis?
Hypertrophic cardiomyopathy
What would indicate severe aortic stenosis on ECHO?
Peak gradient > 50 mmHg and area < 1cm2
If someone is symptomatic, what is the average prognosis?
2-3 years without surgical intervention
What is the management for aortic stenosis?
Treatment for HF
Definitive treatment is Valve replacement
- Open valve replacement
- Percutaneous Valvuloplasty
- TAVI
What might you see on ECHO in someone with AS?
Calcified AV
LV hypertrophy
What are surgical criteria for surgery in asymptomatic patients?
- Symptoms during an exercise test or with a drop in blood pressure
- A left ventricular EF of <50%
- Moderate–severe stenosis undergoing CABG, surgery of the ascending aorta or other cardiac valve.
What is Aortic Sclerosis?
Senile degeneration of the valve - is thickening of the leaflets, without narrowing of the valve itself.
What are causes of pressure overload to the left ventricle?
All causes lead to concentric hypertrophy - non-displaced apex
- Hypertension
- Aortic Stenosis
- Coarctation of the Aorta
- Hypertrophic cardiomyopathy
How does aortic sclerosis differ in terms of presentation to aortic stenosis?
- Normal Apex
- Normal pulse
- ESM over Aortic area, which does not radiate
