Qualitative vs Quantitative

Question 1

What are the qualitative CFI parameters for assessing MR?

Answer 1

1. Vena contracta width
2. Flow convergence (PISA radius)
3. MR colour jet area

Question 2

What is the technique to measure VC-W?

Answer 2

• Zoom PLAX view (MV)
• Colour velocity scale (Nyquist limit) 50-70cm/s
• Measure narrowest neck of MR jet immediately below flow convergence region

Question 3

What is the significance of VCW with regards to MR severity?

Answer 3

• Mild MR = VCW < 0.3cm

- Severe MR = VCW ≥ 0.7cm

Question 4

Vena contracta area in primary vs secondary MR?

Answer 4

• Primary MR = circular

- Secondary MR = elliptical (underestimation of MR)

Question 5

What is the technique for measuring flow convergence (PISA radius)?

Answer 5

1. Zoomed view of MV
2. Colour baseline shift in direction of jet (30-40cm/s)
3. Measure radius on LV side from colour aliasing to valve level

Question 6

What is the significance of flow convergence radius (FCR) with regards to MR severity?

Answer 6

• Mild MR = FCR ≤ 0.3cm

- Severe MR = FCR ≥ 1.0cm

Question 7

Limitation of FCR: What is flow constraint?

Answer 7

• Eccentric MR jets often non-hemispherical
• Proximal flow convergence region encroaches on surrounding structures
• Flow constraint pushes the contours outwards from the regurgitant orifice

Question 8

Significance of colour jet area in assessment of MR severity?

Answer 8

• Mild MR: small, narrow, non-eccentric jet

- Severe MR: large central jet (>50% of LA) and wide VCW

Question 9

Limitation of CFI: What is the billiard ball effect?

Answer 9

Overestimation of severity by jet area due to displacement of RBCs detected that are already in the LA

Question 10

Limitation of CFI: Effect of blood pressure on jet area?

Answer 10

• Low BP = smaller jet areas when actually severe

- High BP = larger jet areas when only mild

Question 11

What is the significance of PWD Mitral Inflow in MR?

Answer 11

• E > A: impaired relaxation profile virtually excludes severe MR
• E ≥ 1.2m/s: E dominance (≥1.2m/s in primary MR) consistent with severe MR
• Most valid in patients > 50yrs; influenced by other causes of ↑ LAP

Question 12

What is the significance of PWD Pulmonary Venous Flow in MR?

Answer 12

• Mild MR: S dominant, S > D
• Moderate MR: S blunting, S < D
• Severe MR: S reversal
• Influenced by many other factors (LV diastolic function, atrial fibrillation, other causes for ↑ LAP)

Question 13

What is the significance of CWD MR jet duration in MR?

Answer 13

• MR is typically pan-systolic
• Late-systolic MR may occur with MVP
• CFI variables assume the MR jet is pan-systolic therefore CFI alone can overestimate severity

Question 14

What is the significance of CWD MR jet contour in MR?

Answer 14

• Typically, MR is parabolic

- V cut-off shape of MR due to increased LAP is frequently seen with acute severe MR

Question 15

What is the significance of CWD MR jet velocity in MR?

Answer 15

• When normal LAP and LVSP, MR Vmax > 5m/s
• Low vmax = reduced pressure gradient between LV and LA in systole
• This can occur when LAP is very high e.g. acute severe MR
• Can occur when LVSP very low (low SBP) e.g. systemic HTN
• Or, you can have a combination of both which reduce Vmax

Question 16

What is the definition of regurgitant volume?

Answer 16

Volume leaking through valve; measure of volume overload severity

Question 17

What is the definition of regurgitant fraction?

Answer 17

Ratio of RVol to total stroke volume

Question 18

What is the definition of regurgitant orifice area?

Answer 18

Size of the ‘hole’; fundamental measure of lesion severity

Question 19

MR: Formula for RVol via Stroke Volume Method

Answer 19

• RVol = SV mitral – SV LVOT
• SV mitral = 0.785 x D2 x Mitral Annulus VTI
• SV LVOT = 0.785 x D2 x LVOT VTI

Question 20

MR: Formula for RF via Stroke Volume Method

Answer 20

RF = RVol / SV mitral

Question 21

MR: Formula for ROA via Stroke Volume Method

Answer 21

ROA = RVol / MR VTI

Question 22

MR: Formula for RVol via LV Stroke Volume Method

Answer 22

• SV LV = LVEDV – LVESV
• SV LVOT = 0.785 x D2 x LVOT VTI
• RVol = SV LV – SV LVOT

Caution using LV SV; tends to underestimate LV volumes therefore underestimated mitral RVol so it is not recommended

Question 23

MR: Formula for RF via LV Stroke Volume Method

Answer 23

RF RVol / SV LV

Question 24

MR: Formula for ROA via LV Stroke Volume Method

Answer 24

ROA = RVol / MR VTI

Question 25

MR: Formula for ROA via PISA Method

Answer 25

ROA=(2πr^2×VN) / V MR

V MR = Vmax of MR jet

Question 26

MR: Formula for RVol via PISA Method

Answer 26

RVol = ROA x MR VTI

Question 27

MR: Formula for RF via PISA Method

Answer 27

RF = RVol / SV LV

LV SV tends to underestimate LV volumes and therefore underestimates mitral RF, so it is not recommended

(Not really PISA method - PISA can only calculate RVol & EROA)

Question 28

Best method for quantification of MR?

Answer 28

• PISA

- Fewer measurements = less room for error = more accurate

Question 29

EROA and RVol in primary MR

Answer 29

EROA and RVol are the strongest predictors of clinical outcomes and excess mortality in primary MR

Question 30

ROA in Functional MR

Answer 30

• ROA in functional MR is usually crescentic leading to underestimation of EROA
• 3D echo is able to overcome this limitation

Question 31

MR Duration for PISA Calculations (ROA vs RVol)

Answer 31

• ROA overestimates MR severity in non-holosystolic MR (eg. MVP)
• RVol accounts for short MR duration and is a better assessment in this setting