Aortic Stenosis Flashcards
What are the causes of aortic stenosis?
- Post inflammatory scarring (rheumatic heart disease)
- Senile calcific aortic stenosis
- Calcification of congenitally deformed heart valve
What can cause sudden death in Aortic stenosis?
MI
Aortic dissection
How does aortic stenosis occur?
Lipid accumulation, inflammation, calcification leads to valve thickening and stenosis
What is the pathophysiology of Aortic Stenosis?
As aortic valve progresses from sclerosis to stenosis, the left ventricle encounters chronic resistance to systolic ejection (increasing afterload) - this leads to thickening of the left ventricular wall
Effects of high LV afterload include decreased left ventricular myocardial elasticity and coronary blood flow and increase myocardial workload, O2 consumption and mortality
Late manifestations of LVH include smaller LV chamber size, which decreases preload and worsens systolic dysfunction. This results in insufficient stroke volume, CO and ejection fraction. Finally backward transmission of increase LV pressure to the lungs may cause pulmonary venous hypertension and reactive vasoconstriction of the pulmonary vasculature
Why might someone develop arm weakness with aortic valve endocarditis?
Thromboembolism which lead to stroke
Which coagulation system will not be affected by warfarin?
Intrinsic pathway
Define thrombus
Solid material formed from the constituents of blood in flowing blood
What are the surgical options for valve replacement
Mechanical valve - long lasting valve made of durable material
Tissue valve
Ross procedure - borrowing healthy valve and moving it into position of the damaged aortic valve
TAVI/TAVR procedure - transcatheter aortic valve replacement
Alternative option include aortic valve balloon valvuloplasty - widening of the valve with a balloon
If a patient with metallic valve develops IE why should the valve be removed?
The valve is a septic focus and can dehiss
What is the cause of branching hyphae on a removed metallic valve?
Fungal infection
- candida
- aspergillus
- microsporum
- trichophyton
- epidermophyton
What are the pros and cons of a metallic heart valve?
Pros
- excellent durability and low rate of re-operation
- easy to insert
Requires warfarin therapy
higher thromboembolism rate 1-2%/patient/year
higher bleeding risk 2%/patient/year
What are the pros and cons of tissue valve replacements?
Noiseless
Do not need warfarin
low risk of thromboembolism 0-1%
lower risk of bleeding 0-1%
Insertion can be more difficult
less durable
