Quantification of mitral regurgitation by PISA

1. Quantification of Mitral
Regurgitation
PISA :Proximal Isovelocity Surface Area

2. Carpentier’ classification of MR
1. Type I
Mitral leaflet motion is normal
MR results from annular dilation
2. Type II
Excessive leaflet motion
Prolapse or flail leaflet
3. Type III is from restricted leaflet motion
Type IIIa:Leaflets have restricted motion in both systole and diastole
- Rheumatic MR
Type IIIb: Restricted motion during systole
-Ischemic MR/ functional MR

3. Normal
 LV minor axis: ≤2.8 cm/m2
 LV end-diastolic volume: ≤82 mL/m2
Maximal LA anteroposterior diameter : ≤2 cm/m2
Maximal LA volume: ≤36 mL/m2

4. Eye balling parameters
Parameters Mild MR Moderate MR Severe MR
LA size Normal Normal or
dilated
dilated
LV size Normal Normal or
dilated
dilated
Mitral leaflets Normal or
abnormal
Normal or
abnormal
Abnormal/flail
leaflet/ruptured
papillary muscle

5. Supportive parameters ( Doppler )
Parameter Mild MR Mod MR Severe MR
Colour flow jet
area
Small central
jet (usually <4
cm2 or <20% of
LA area)
Variable Large central jet (usually >10 cm2 or >40% of LA area) or
variable size wall-impinging jet swirling in LA
Mitral inflow,
pulsed wave
A wave
dominant|
Variable E wave dominant (E usually 1.2 m/s)
Jet density, CW Incomplete or
faint
Dense Dense
Jet contour, CW Parabolic Usually
parabolic
Early peaking, triangular
Pulmonary vein
flow
Systolic
dominance
Systolic
blunting
Systolic flow reversal

6. Definitive(Hard) Parameters
Quantitative
Parameters
Mild MR Mod MR Severe MR
Vena contracta
width (cm)
<0.3 0.3-0.69 ≥0.7
Regurgitant volume
(mL/beat)
<30 30-44 To 45-59 ≥60
Regurgitant fraction
(%)
<30 30-39 to 40-49 ≥50
EROA (cm2) <0.20 0.20-0.29 to 0.30-
0.39
≥0.40

7. What does these measurement mean ?

8. PISA is in LV and ERO is in LA

9. Proximal isovelocity surface area=PISA
• Fluid dynamic theory predicts that
as flow approaches a circular finite
orifice, it forms a series of
concentric hemispheric shells with
gradually decreasing area and
increasing velocity. Arrows refer to
direction of flow as it approaches
the proximal isovelocity surface
area region. R is the radius of a
hemispherical shell.With principle
of conservation of mass, flow
through the regurgitant orifice =
flow through the isovelocity
surface = 2πr2 × aliasing velocity

10. conservation of mass
• Flow through the regurgitant orifice = flow through the isovelocity
surface = 2πr2 × aliasing velocity=Regurgitant orifice X MR jet velocity
• Regurgitant orifice =2πr2 × aliasing velocity/MR jet velocity
• Regurgitant volume=Regurgitant orifice X MR jet VTI
• Regurgitant fraction=Regurgitant volume/TSV
• TSV=Regurgitant volume+LVOT VTI X LVOT area=Stroke volume can be
calculated as: (end-diastolic volume—end-systolic volume)/end-
diastolic volume .

11. • Effective orifice area=Vena
contracta area

12. Still need clues !
• Flow A=MR regurgitation volume
+B flow(LVOT flow)

13. Adjusting Nyquist limit to perfect PISA
• Baseline shifting of the Nyquist
limit toward the direction of the
regurgitant flow results in a
larger proximal isovelocity
surface area zone for optimal
measurement of the proximal
isovelocity surface area region
radius (right panel).

14. Angle correction(α)
• It is required in eccentric MR like flail anterior or posterior leaflet
• Angle correction is performed by multiplying the surface area
calculation by α/180, where α is the angle between the mitral leaflet
and the end of the PISA region confined by the LA wall
• This correction does introduce new error
• Angle correction is for bench discussion but not used clinically

15. • Radius (r) of PISA
• Convergence angle(α)
• Proximal convergence field for
central (left) and eccentric (right)
convergence
• The convergence angle is
obtained by projecting the most
distal point of the isovelocity
contour onto the constraining
wall.

16. Aliasing velocity Nyquist limit =19cm/sec

17. Effect of PISA radius on PISA shape and flow
calculation
• Isovelocity hemispheres
proximal to a mitral regurgitant
orifice (left) at three different
distances from the orifice and
corresponding plots of
calculated flow rates (Qc) as a
function of distance from the
orifice. The dashed line
represents the actual regurgitant
flow rate

18. Validity

19. Yes and No
Disadvantage
• If the valve orifice is not flat or
circular, the flow convergence zone
will not be hemispheric, thus PISA
radius cannot be used for the
calculation of the regurgitant flow.
• Systolic changes of regurgitant flow
are not taken into account.
• In assessment of regurgitant
flow/volume, errors in calculation
of PISA radius are squared.
Advantage
• Independent of hemodynamic
factors, aetiology of the disease
and presence of multiple valve
alterations.
• It can be used in central as well as
in eccentric jets (although less
accurate)
• It is a quantitative estimation of
lesion severity and volume
overload with an acceptable
reproducibility

20. Calculation

21. One page

22. Bench to Bedside
• Severe primary MR, class I indications for surgical intervention
• Symptomatic
• LV decompensation
• LV ejection fraction of 0.6 or less
• LV end-systolic diameter of 40 mm or more

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