Aortic Stenosis Flashcards
Causes of aortic stenosis
Congenital bicuspid deformation > Aging calcification
Rheumatic fever
Risk factors for calcification with aortic stenosis
HTN
HLD
(Same as CAD)
Symptoms of aortic stenosis
Loud systolic murmur
Classic triad: angina, syncope, CHF
Sudden cardiac death
Why is CPR challenging with aortic stenosis?
Difficult to open aortic valve limits forward flow
The SV in aortic stenosis is described as?
Fixed
Mean pressure gradient higher than ____ is considered severe aortic stenosis
50 mmHg
Peak pressure gradient higher than ___ is considered severe aortic stenosis
80 mmHg
What is secondary compensation with aortic stenosis?
Increased blood volume
Increased LV systolic pressure
Concentric ventricular hypertrophy
Concentric vs Eccentric hypertrophy
Concentric: Increased wall thickness, chamber size is unchanged or smaller
Eccentric: Decrease in wall thickness, chamber size increased
What are the consequences of compensation with aortic stenosis?
Hypertrophy of the LV > low ventricular compliance
- ventricle is stiffer
- more difficult to fill
- pressures will increase without the usual increase in volume
Describe the relationship between PCWP and LVEDP with LVEDV in aortic stenosis
PCWP over estimates LVEDV
-pressure reading over estimates volume because low compliance = higher pressure without accompanying volume
What kind of preload is needed with aortic stenosis?
Needs more preload for adequate SV
-PCWP needs to be higher than expected in order to achieve SV
What is very important with aortic stenosis?
Atrial kick
How much does atrial kick supply with aortic stenosis?
40% instead of the normal 20%
Hypertrophy puts patient at risk for ischemia why?
Hypertrophic muscle increases myocardial oxygen demand
Describe the situation of O2 supply and demand with aortic stenosis
Hypertrophic muscle increases demand
Higher ventricular systolic pressure increases demand
Supply is decreased due to higher LVEDP decreasing CPP
What is the rhythm and HR anesthesia goal for aortic stenosis?
Maintain SR -loss of atrial kick impacts SV and BP Keep HR between 70 and 80 -SV is fixed low HR decreases CO -High HR risks ischemia
What is the goal with SVR and aortic stenosis
Maintain SVR
- decreases in SVR > low DBP and CPP
- increased SVR > decreases in SV and CO
What is the goal with preload in aortic stenosis?
Maintain or increase preload
- noncompliant ventricle requires higher filling volume
- LVEDP will look height than actual LVEDV
What is the #1 anesthetic goal with aortic stenosis?
Maintain SVR
Describe the use of regional anesthesia with aortic stenosis
Spinal are relatively contraindicated because it will drop SVR
Epidurals less so
What is the AHA guideline for preop ABX with valve disease for endocarditis?
Dental procedures
Infected respiratory tract, skin, musculoskeletal, GI, GU
Cardiac surgery
What technique makes SVR more controllable with aortic stenosis?
General
Describe drug choice with aortic stenosis
Induce with any drug keeping HR and SVR stable
Muscle relaxant with CV stability
