Quantification of AR Severity

Question 1

Definition of Regurgitant Volume (RV)

Answer 1

Volume of blood through the leaky valve

Question 2

Definition of Regurgitant Fraction (RF)

Answer 2

• Regurgitant volume divided by total volume

- % of stroke volume through the leaky valve

Question 3

Definition of Regurgitant Orifice Area (EROA)

Answer 3

Size of ‘hole’ in the leaky valve

Question 4

Which calculations can be derived via stroke volume method?

Answer 4

1. RV
2. RF
3. EROA
   (All can be derived via SV method)

Question 5

Which calculations can be derived via PISA?

Answer 5

1. RV

2. EROA

Question 6

Concept for stroke volume through the LVOT in the presence of AR?

Answer 6

• In diastole, regurgitant volume (RV) enters LV and combines with inflow stroke volume coming through MV
• Therefore, SV LVOT = SV MV + RV

Question 7

Stroke Volume Method: Formula to calculate AR Regurgitant Volume?

Answer 7

RV(AR) = SV LVOT - SV MV

Question 8

Stroke Volume Method: Formula to calculate SV LVOT

Answer 8

SV LVOT = LVOT area x LVOT VTI

Question 9

Stroke Volume Method: Formula to calculate mitral annular SV

Answer 9

SV MV = MV area x MV VTI

Question 10

Stroke Volume Method: How to measure mitral annular diameter?

Answer 10

• Zoomed view of A4V

- MV measured in early diastole (open valve leaflets) at leaflet insertion (inner edge to inner edge)

Question 11

Stroke Volume Method: How to measure MV VTI?

Answer 11

• Different to normal
• Cursor placed at MV annulus level with 1-2mm sample volume
• Trace modal velocity (dense part of signal) and avoid ‘fluffy’ bits

Question 12

Normal mitral annulus diameter

Answer 12

3.0 - 3.5cm

Question 13

Normal mitral annulus VTI

Answer 13

10 - 13cm

Question 14

Normal LVOTd

Answer 14

1.8 - 2.2cm

Question 15

Normal LVOT VTI

Answer 15

18 - 22cm

Question 16

Stroke Volume Method: RVol formula for AR

Answer 16

RV (mL) = SV LVOT – SV MV

Question 17

Stroke Volume Method: RF formula

Answer 17

RF (%) = (RV / SV regurgitant valve) x 100

Question 18

Stroke Volume Method: EROA formula

Answer 18

EROA (cm2) = RV / VTI regurgitant valve

Question 19

Limitations of Stroke Volume Methods

Answer 19

1. Diameter measurement errors
2. VTI measurement errors
3. Assumptions of calculation
4. Significant learning curve in performing calculation - especially mitral annular stroke volume

Question 20

Assumptions of Stroke Volume Method Calculations

Answer 20

1. Assumes flow occurs in a rigid, circular tube
2. Assumes uniform velocity across vessel
3. Assumes circular annulus areas

Question 21

PISA Method Principles/Assumptions

Answer 21

• Assumes flow proximal to a narrowed orifice must flow through the narrowed orifice (continuity principle)
• Assumes as flow converges towards narrowed orifice, it conforms concentric hemispheric shells
• Assumes flow rate proximal to narrowed opening (Q1) = flow rate through narrowed opening (Q2)

Question 22

PISA Method: Equation for EROA

Answer 22

EROA= (2πr^2×VN)/VRJ

VN = Nyquist limit
VRJ = peak velocity of regurgitant jet (CW Doppler)

Question 23

PISA Technique

Answer 23

1. Zoom in on AV
2. Move colour baseline in direction of AR jet
3. Cine to find optimal hemispheric PISA dome
4. Measure PISA dome radius from regurgitant orifice to 1st aliased zone (red-blue interface)

Question 24

Which Nyquist limit to note when performing PISA calculation?

Answer 24

1. If flow towards the Tx (red), note top of colour bar

2. If flow away from Tx (blue), note bottom of colour bar

Question 25

Which direction do you move colour baseline for PISA?

Answer 25

- Always move baseline in the direction of flow - If flow is towards from the Tx, move baseline upwards (regurgitant flow is red) - If flow is away from the Tx, move baseline down (regurgitant flow is blue)

Question 26

Equation for Regurgitant Volume via PISA?

Answer 26

RV = EROA x VTI AR

Question 27

Is RV or EROA more useful in the assessment of AR?

Answer 27

RV because AR occurs in diastole and flow varies over the diastolic period

Question 28

Assumptions of PISA Method (Limitations)

Answer 28

Assumes that: 1. Radius is consistent over flow period 2. Regurgitant orifice is circular 3. EROA is consistent over the flow period

Question 29

PISA Method Limitations

Answer 29

- Multiple jets (not additive) - Aortic valve calcification - Under-estimation possible with aortic root aneurysms

Question 30

SV vs PISA Method: Which is preferred and why?

Answer 30

- PISA method is preferred as there are less measurements | - The less measurements we have to do, the more reliable the method will be