Qualitative vs Quantitative Flashcards
What are the qualitative CFI parameters for assessing MR?
- Vena contracta width
- Flow convergence (PISA radius)
- MR colour jet area
What is the technique to measure VC-W?
- Zoom PLAX view (MV)
- Colour velocity scale (Nyquist limit) 50-70cm/s
- Measure narrowest neck of MR jet immediately below flow convergence region
What is the significance of VCW with regards to MR severity?
- Mild MR = VCW < 0.3cm
- Severe MR = VCW ≥ 0.7cm
Vena contracta area in primary vs secondary MR?
- Primary MR = circular
- Secondary MR = elliptical (underestimation of MR)
What is the technique for measuring flow convergence (PISA radius)?
- Zoomed view of MV
- Colour baseline shift in direction of jet (30-40cm/s)
- Measure radius on LV side from colour aliasing to valve level
What is the significance of flow convergence radius (FCR) with regards to MR severity?
- Mild MR = FCR ≤ 0.3cm
- Severe MR = FCR ≥ 1.0cm
Limitation of FCR: What is flow constraint?
- Eccentric MR jets often non-hemispherical
- Proximal flow convergence region encroaches on surrounding structures
- Flow constraint pushes the contours outwards from the regurgitant orifice
Significance of colour jet area in assessment of MR severity?
- Mild MR: small, narrow, non-eccentric jet
- Severe MR: large central jet (>50% of LA) and wide VCW
Limitation of CFI: What is the billiard ball effect?
Overestimation of severity by jet area due to displacement of RBCs detected that are already in the LA
Limitation of CFI: Effect of blood pressure on jet area?
- Low BP = smaller jet areas when actually severe
- High BP = larger jet areas when only mild
What is the significance of PWD Mitral Inflow in MR?
- 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
What is the significance of PWD Pulmonary Venous Flow in MR?
- 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)
What is the significance of CWD MR jet duration in MR?
- 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
What is the significance of CWD MR jet contour in MR?
- Typically, MR is parabolic
- V cut-off shape of MR due to increased LAP is frequently seen with acute severe MR
What is the significance of CWD MR jet velocity in MR?
- 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
What is the definition of regurgitant volume?
Volume leaking through valve; measure of volume overload severity
What is the definition of regurgitant fraction?
Ratio of RVol to total stroke volume
What is the definition of regurgitant orifice area?
Size of the ‘hole’; fundamental measure of lesion severity
MR: Formula for RVol via Stroke Volume Method
- RVol = SV mitral – SV LVOT
- SV mitral = 0.785 x D2 x Mitral Annulus VTI
- SV LVOT = 0.785 x D2 x LVOT VTI
MR: Formula for RF via Stroke Volume Method
RF = RVol / SV mitral
MR: Formula for ROA via Stroke Volume Method
ROA = RVol / MR VTI
MR: Formula for RVol via LV Stroke Volume Method
- 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
MR: Formula for RF via LV Stroke Volume Method
RF RVol / SV LV
MR: Formula for ROA via LV Stroke Volume Method
ROA = RVol / MR VTI
MR: Formula for ROA via PISA Method
ROA=(2πr^2×VN) / V MR
V MR = Vmax of MR jet
MR: Formula for RVol via PISA Method
RVol = ROA x MR VTI
MR: Formula for RF via PISA Method
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)
Best method for quantification of MR?
- PISA
- Fewer measurements = less room for error = more accurate
EROA and RVol in primary MR
EROA and RVol are the strongest predictors of clinical outcomes and excess mortality in primary MR
ROA in Functional MR
- ROA in functional MR is usually crescentic leading to underestimation of EROA
- 3D echo is able to overcome this limitation
MR Duration for PISA Calculations (ROA vs RVol)
- ROA overestimates MR severity in non-holosystolic MR (eg. MVP)
- RVol accounts for short MR duration and is a better assessment in this setting
