AE 1.6 - Aortic Valve/AS/AI & Mitral Valve/MS/MR

Common causes of aortic stenosis across different age groups

younger = bicuspid aortic valve / congenital defects, rhematic disease

older = senile calcification/degenerative disease

Secondary cardiac changes associated with chronic aortic stenosis

- SOB, angina, syncope, CHF

- LVH

- LV becomes less compliant —> LVEDP (end diastolic pressure) increases —> LV dilates

- LA enlargement

- aortic dilation

Hemodynamic consequences of pressure overload

increased afterload (more resistance through the AV)

Echocardiographic appearance of a bicuspid aortic valve

- possible eccentric closure line in m-mode

- PLAX view “doming” into the aorta when open

- fusion/seam of 2 cusps

- 2 equal sized cusps & “football” shape

Best imaging view and timing for evaluating a bicuspid aortic valve

PSAX

systole (when valve is open)

Parameters used to grade aortic stenosis severity

- Peak velocity (A5C, A3C) 

- Mean pressure gradient 

- Aortic valve area (AVA) 

- Indexed aortic valve area

- Dimensionless severity index (velocity ratio) (velocity before & after valve) 

Pressure gradients involved in aortic stenosis

Peak pressure gradient (Δ P_^max)

- is calculated from max aortic jet velocity

- Bernoulli equation ΔPmax = 4V2 max

Mean pressure gradient (ΔP_mean)

- is calculated by digitally tracing the aortic jet velocity curve & averaging the instantaneous gradients over the systolic ejection period

- ΔP_mean = 4V₁²+V₂²+V₃²+... / n

- only comparable gradient between cath & echo 

Continuity Equation

- AS

- based on the assumption that the SV proximal to the narrowing is = the SV across the narrowing

PW_LVOT = CW_AV

AVA = VTI_LVOT x 0.785 x D² / VTI_{AS jet}

Why multiple acoustic windows are used during Doppler evaluation

Importance of obtaining the highest transaortic velocity

Common sources of error when calculating aortic valve area

Causes of aortic regurgitation

Hemodynamic effects of chronic aortic regurgitation

Secondary cardiac changes associated with chronic volume overload

Parameters used to assess severity

Purpose of serial echocardiograms in patients with chronic AI

Most common cause of mitral stenosis

Typical echocardiographic appearance of rheumatic mitral stenosis

Secondary cardiac changes associated with mitral stenosis

Hemodynamic effects of mitral stenosis

Methods used to calculate mitral valve area

Advantages of 3D planimetry

Primary vs. secondary mechanisms of mitral regurgitation

Common causes of mitral valve prolapse and flail leaflets

Expected direction of a regurgitant jet based on leaflet pathology

Parameters used to determine MR severity

Common clinical findings associated with mitral valve prolapse

Pressure gradients associated with aortic stenosis and mitral stenosis

Pressure waveform changes associated with common valvular diseases

Timing of systolic and diastolic Doppler waveforms

Selection of the appropriate Doppler modality for valve assessment

Basic principles behind continuity equation calculations