Echocardiographic Assessment

Question 1

What are the echo characteristics of calcific AS?

Answer 1

1. Increased reflectivity
2. Diffuse thickening
3. Reduced systolic excursion
   Note: >70yrs unlikely congenital, no MV involvement unlikely rheumatic

Question 2

What are the echo characteristics of rheumatic AS?

Answer 2

1. Thickening of free edges
2. Variable commissural fusion; may be functionally bicuspid
   Note: almost always associated with mitral valve stenosis

Question 3

What are the echo characteristics of bicuspid AS?

Answer 3

1. 2 commissural attachments to aortic root
2. Elliptical systolic orifice
3. May be aortic root dilatation and/or effacement of aorta
   Note: likely BAV if younger patient (<60yrs) with significant AS

Question 4

At what stage of the cardiac cycle is the diagnosis of BAV made?

Answer 4

Diagnosis made in systole (when the valve is open), not diastole

Question 5

Characteristics of Stage 0 Aortic Stenosis (Impact of Aortic Stenosis)

Answer 5

No cardiac damage

Question 6

Characteristics of Stage 1 Aortic Stenosis (Impact of Aortic Stenosis)

Answer 6

LV damage

• Increased LV mass index
• Diastolic dysfunction
• Reduced LV systolic function

Question 7

Characteristics of Stage 2 Aortic Stenosis (Impact of Aortic Stenosis)

Answer 7

LA or Mitral Damage

• Dilated LA
• Moderate-severe MR
• Atrial fibrillation

Question 8

Characteristics of Stage 3 Aortic Stenosis (Impact of Aortic Stenosis)

Answer 8

Pulmonary vasculature or tricuspid damage

• PHTN
• Moderate-severe TR

Question 9

Characteristics of Stage 4 Aortic Stenosis (Impact of Aortic Stenosis)

Answer 9

RV damage

- Moderate-severe RV dysfunction

Question 10

What are the primary parameters used to determine AS severity?

Answer 10

1. AV Vmax (m/s)
2. Mean PG (mmHg)
3. AVA (cm2)

Question 11

What are the supportive parameters used to determine AS severity?

Answer 11

1. Indexed AVA

2. DVI/VR (velocity ratio)

Question 12

Formula to calculate AVA (continuity equation)?

Answer 12

AVA= (LVOT area × LVOT VTI)/(AV VTI)

LVOT area = 0.785 x D^2

Question 13

Formula to calculate AVA (Vmax method)?

Answer 13

AVA= (LVOT area × LVOT Vmax)/(AV Vmax)

Question 14

Limitations of AVA via Continuity Principle

Answer 14

1. LVOTd measurements
2. LVOT VTI measurements
3. Non-parallel alignment with AS jet (AV VTI)

Question 15

AVA consequence of LVOTd underestimation?

Answer 15

Underestimation of AVA

Question 16

AVA consequence of LVOTd overestimation?

Answer 16

Overestimation of AVA

Question 17

AVA consequence of LVOT VTI underestimation (sample volume placed too far into the LV)?

Answer 17

Underestimation of AVA

Question 18

AVA consequence of LVOT VTI overestimation (sample volume placed too close to AV in flow acceleration region)?

Answer 18

Overestimation of AVA

Question 19

AVA consequence of AV VTI non-parallel alignment with AS jet

Answer 19

• Underestimation of AV VTI

- Overestimation of AVA

Question 20

When is pressure gradient correction required?

Answer 20

Required when LVOT velocities are ≥ 1.2m/s

Question 21

Formula to correct peak AV pressure gradient?

Answer 21

Corrected PPG = PPG(AV) - PPG(LVOT)

Question 22

Formula to correct mean AV pressure gradient?

Answer 22

Corrected mPG = mPG(AV) - mPG(LVOT)

Question 23

Alternative AVA Methods: Formula for AVA using LV volumes?

Answer 23

AVA = (LVEDV-LVESV)/AV VTI

Question 24

Alternative AVA Methods: Limitations of AVA using LV volumes?

Answer 24

• Method tends to underestimate stroke volume and is not recommended

Question 25

Alternative AVA Methods: Formula for AVA using RVOT SV?

Answer 25

AVA = (RVOT area × RVOT VTI)/AV VTI

• RVOTd measured at PV opening in PSAX
• Used when LVOTOB or LVOT flow is not laminar

Question 26

Alternative AVA Methods: Limitations of AVA using RVOT SV?

Answer 26

• Can’t be used if significant AR, PR or intracardiac shunt

- Assumes SV AV = SV RVOT

Question 27

Alternative AVA Methods: How to measure AVA using planimetry?

Answer 27

• Measured in PSAX at maximal AV opening during systole

- Acceptable alternative when Doppler unreliable

Question 28

Alternative AVA Methods: Limitations of AVA using planimetry?

Answer 28

• Measures anatomical orifice area rather than effective orifice area (vena contracta)
• AOA > EOA

Question 29

Alternative AVA Methods: Formula for Velocity Ratio (VR)?

Answer 29

VR = LVOT VTI/AV VTI
or
VR = LVOT Vmax/AV Vmax

Question 30

Alternative AVA Methods: Significance of 0.25 Velocity Ratio (VR)?

Answer 30

VR of 0.25 corresponds to an AVA 25% of normal = severe AS

Question 31

When might we expect highest AS velocities from RSE?

Answer 31

Suspect highest AS velocities from RSE when LV-to-aorta angle is acute (<115°)

Question 32

AS vs MR: Signal Shape

Answer 32

• MR signal: parabolic, peaks in mid-late systole

- AV signal: V shaped, peaks in early systole

Question 33

AS vs MR: Duration

Answer 33

• MR incorporates IVCT and IVRT and is therefore longer in duration than AV/AS signal
• AV duration is shorter (excludes IVCT and IVRT)
• LVOT PWD has the same duration as AV CWD (clue to identifying AV signal)

Question 34

AS vs MR: Continuity

Answer 34

• AV is not continuous with mitral flow

- MR will be continuous with mitral flow

Question 35

AS vs MR: Velocity

Answer 35

MR gradient will always exceed AS gradient

Question 36

In the presence of a membranous VSD, AVA will be?

Answer 36

• Overestimated
• LVOT VTI will increase (blood passing through LVOT before exiting to RV)
• AV VTI will decrease (some blood bypassing AV through to RV)

Question 37

Can AVA via the continuity equation be accurately assessed in a patient with AS and AR?

Answer 37

• Yes
• LVOT SV and AV SV in systole will be the same
• If LVOT SV increased due to AR, AV SV will also be increased due to AR
• AR occurs in diastole