Aortic Valve Disease Flashcards
1
Q
Aortic Valve Disease
- Aortic stenosis
- Aortic regurgitation or insufficiency
- Combined valvular disease
A
- Aortic stenosis
- Abnormal thickening & restriction in aortic valve leaflet motion
- Aortic regurgitation or insufficiency
- Abnormal retrograde flow across the valve
- Combined valvular disease
- Aortic stenosis + aortic regurgitation
2
Q
Obstruction to LV Outflow
- Normal aortic valve
- Subvalvular obstruction
- Valvular stenosis
- Supravalvular stenosis
A
- Normal aortic valve
- 3 leaflets: right, left, & non-coronary cusps
- Leaflets are attached to the aortic wall in the sinuses of Valsava
- Commissure: region where the leaflet edges coapt
- Cross-sectional area: 3-4 cm2
- Subvalvular obstruction
- Abnormal thickening of the intraventricular septum (ex. hypertrophic cardiomyopathy)
- Congenital subaortic membranes in the left ventricular outflow tract
- Valvular stenosis
- Narrowing, stiffening, thickening, fusion or blockage of one or more valves
- Supravalvular stenosis
- Muscular ridge or hypoplasia of the ascending thoracic aorta
3
Q
Hemodynamics of Valvular Aortic Stenosis
- Normal aortic valve
- Opens when…
- Closes when…
- Pressure gradient
- Congenital valvular disease
- General
- Unicuspid aortic valves
- Bicuspid aortic valves
- Acquired valvular disease
- Rheumatic valve disease
- Calcific degenerative valve disease
- Systemic disease
A
- Normal aortic valve
- Opens when LV systolic pressure > central aortic pressure
- Closes when LV pressure < central aortic pressure
- Normally: no significant gradient across the aortic valve during systolic ejection
- Congenital valvular disease
- Congenitally malformed aortic valves
- Unicuspid aortic valves: present during infancy & childhood
- Bicuspid aortic valves: present later in life (3rd - 5th decades)
- Acquired valvular disease
- Rheumatic valve disease
- Thickening of the valve leaflet margins w/ commissural fusion & restriction in leaflet motion
- Long-term sequelae of the valvulitis associated w/ acute rheumatic fever
- Rarely occurs in the absence of concomitant mitral valve disease, esp in women
- Calcific degenerative valve disease
- Abnormal thickening & calcification of valve leaflets w/ age
- Chornic inflammation + upregulation of neurohormonal mediators
- Ex. renin-angiotensin system, lipid accumulation, & lymphocytic infiltration of valve surfaces leading to leaflet calcification
- Systemic disease (uncommon)
- Rheumatoid arthritis, ankylosing spondylitis, Paget’s disease, & onchronosis
- Rheumatic valve disease
4
Q
Changes Following Aortic Valve Area Decrease
A
- LV systolic pressure increases
- Aortic transvalvular pressure gradient presents throughout systolic ejection
- Contour of the centrla aortic pressure tracing becomes blunted
- LV hypertrophy
- Response to chronic elevation in LV end systolic pressure
- Increase LV systolic pressure –> increase LV wall tension
- Replication fo myofibrils –> compensatory thickening of LV wall (hypertrophy)
- Tries to maintain normal wall tension in the presence of chronically elevated afterload
- Cencentric LV hypertrophy
- With little change in LV cavity size
5
Q
LV Compliance
- Hypertrophy vs. compliance
- LV pressure-volume relationship
A
- Hypertrophy vs. compliance
- Increase ventricular hypertrophy –> decrease LV compliance
- LV pressure-volume relationship
- Upward & leftward shift
- For any given LV volume, there’s a higher corresponding LVEDP
- Increase LVEDP –> prominent a-waves on the LA pressure tracing during late diastole w/ atrial contraction (atrial “kick”)
6
Q
Aortic Stenosis Physical Findings
- PMI
- Carotid pulse contour
A
- PMI
- Inferolaterally displaced
- Sustained
- Prolonged LV systolic ejection –> prolonged apical impulse
- Presystolic heave
- LV end diastolic pressure increases –> prominent atrial “kick” during late diastolic atrial contraction
- Carotid pulse contour: pulsus parvus et tardus
- Decreases in amplitude
- Delay of carotid upstroke
7
Q
Aortic Stenosis Cardiac Auscultation
A
- Turbulent flow across a stenotic valve –> rhomboid shaped SEM
- Heard at the caridac base
- Can radiate to the suprasternal notch & LV apex
- Restricted but pliable valves (ex. bicuspid aortic valves) –> early systolic ejection sound (“click”)
- Heard in the suprasternal notch or apex
8
Q
Severe Aortic Stenosis Auscultatory Findings
- SEM peaking
- S2 splitting
- S2 splitting (other)
- SEM intensity
- Extra heart sounds
A
- Late peaking SEM
- Narrowing aortic valve –> delay in time to peak systolic ejection
- Narrowed S2 splitting
- May –> paradoxical splitting
- Normally: A2 closes before P2
- Inspiration: negative pressure –> increased venous return –> increased pulmonary vascular bed capacitance –> prolonged RV systolic ejection time –> widened separation b/n A2 & P2 –> widened S2 split
- Expiration: narrowed separation b/n A2 & P2 –> narrowed S2 split
- Worsening aortic stenosis: LV ejection time increases –> delayed A2 closure –> A2 moves closer to P2 –> diminished / more singular S2
- Reversed splitting of S2 w/ paradoxical movement w/ respiration
- S2 split narrows w/ inspiration & widens w/ expiration
- Worsening aortic stenosis –> prolonged systolic ejection time –> A2 occurs after P2
- Decreased SEM intensity
- LV fails –> decrease SV –> decrease SEM intensity
- S4
- Increase LV hypertrophy –> decrease ventricular compliance
9
Q
Natural History of Aortic Stenosis
- Symtpom development
- Cardinal symptoms
- Avg survival after developing a cardinal symptom
A
- Patients typically have a failry long latent period before developing symptomatic disease
- Cardinal symptoms
- Angina
- Syncope
- Dyspnea & congestive heart failure
- Avg survival after developing a cardinal symptom
- Angina: 5 years
- Syncope: 3 years
- Congestive heart failure: 2 years
10
Q
Angina
- Angina
- Severe aortic stenosis
- LVEDP vs. myocardial blood flow
A
- Angina
- Occurs when there’s a mismatch b/n myocardial oxygen supply & demand
- Severe aortic stenosis
- Chronic elevation in LV systolic pressure
- Myocardial oxygen demand increases in response to increased myocardial wall tension
- Chronic elevation in the LVEDP can compromise myocardial blood flow
- Coronary blood noramlly flows form the epicardial to endocardial surfaces of the myocardium
- Driven by the pressure gradient b/n the aorta & LV
- Aortic stenosis –> decrease MAP –> increase LVEDP –> decrease transmyocardila perfusion pressure gradient –> mismatched myocardial supply & demand –> angina
- Coronary blood noramlly flows form the epicardial to endocardial surfaces of the myocardium
11
Q
Syncope
A
- Results from cerebral hypoperfusion
- May be exacerbated by physical exertion, bradyarrhythmias, or tachyarrhythmias
12
Q
Congestive Heart Failure
- Mild aortic stenosis
- Worsening aortic stenosis
- Ongoing disease progression
A
- Mild aortic stenosis
- Increase LV systolic pressure & aortic transvalvular gradients
- Normal to mildly elevated LVEDP
- Normal CO & systemic BP
- Worsening aortic stenosis
- Increase LV outflow tract obstruction + decrease LV compliance –> increase LVEDP –> increase pressure in pulmonary vascular bed
- –> pulmonary hypertension, interstitial pulmonary edema, & congestive heart failure
- Ongoing disease progression
- LV systolic dysfunction –> decrease forward flow across aortic valve –> decrease transvalvular gradients –> increase pulmonary arterial pressure –> worsen CHF
13
Q
Evaluation of Aortic Stenosis
- Echocardiography (cardiac ultrasound)
- Cardiac catheterization lab
- EKG
- Chest X-ray
A
- Echocardiography (cardiac ultrasound)
- Noninvasive
- 2-D echo provides info about LV function & valvular anatomy
- Doppler interrogation of the aortic valve provides quantitative info about…
- Valve gradients
- Orifice area
- Valvular regurgitation
- Pulmonary arterial pressure
- Cardiac catheterization lab
- Invasive
- Calculate aortic valve area from CO, systolic ejection time, & aortic valve gradients
- Used to verify inconsistent data in hemodynamic info from noninvasive tests
- Coronary angiography: evaluates coronary anatomy prior to surgical aortic valve replacement
- Coronary artery bypass grafting (CABG): performed at the time fo aortic valve replacement if coronary artery disease is identified
- EKG
- LVH
- LA enlargement
- LAD
- Chest X-ray
- Cardiomegaly
- Aortic valve calcification
- Aortic dilation
14
Q
Medical Management of Aortic Stenosis
- Drugs
- What to avoid
A
- Diuretics
- Manage intravascular volume overload
- Digoxin
- Enhances myocardial contractility to treat congestive heart failure
- Intravenous inotropes
- DA & dobutamine are used for acute management of more criticall ill patients
- Avoid vasodilators in severe aortic stenosis
- Patients may not be able to adequately augment CO in response to peripheral vasodilation
15
Q
Surgical Management of Aortic Stenosis
- When to use surgery vs. medicine
- Aortic valve replacement
- Bioprosthetic or metallic valve prosthesis
- Percutaneous balloon valvuloplasty
- Limited use
- Peri-procedural complications
- Percutaneous transcatheter aortic valve replacement (TAVR)
A
- Symptomatic severe aortic stenosis is pirmarily a surgical disease
- Aortic valve replacement
- In symptomatic patients w/ moderate to severe aortic stenosis
- Bioprosthetic or metallic valve prosthesis
- Variety of variables taken into consideration when choosing the appropriate valve for a patient
- Percutaneous balloon valvuloplasty
- Limited use in long-term management of severe aortic stenosis
- Used primarily as a bridge to aortic valve replacement
- Exception: congential aortic stenosis in peds
- Peri-procedural complications
- Death
- Severe aortic regurgitation
- Myocardial perforation
- Infarction
- Recurrent aortic stenosis at 6 months
- Limited use in long-term management of severe aortic stenosis
- Percutaneous transcatheter aortic valve replacement (TAVR)
- For patients who arent’ candidates for traditional surgical valve replacement
- Femoral arterial catheters are advanced across the aortic valve in a retrograde fashion
- Aortic valve is pre-dilated w/ a balloon tipped catheter
- Catheter implantation of a bioprosthetic valve