How to Diagnose and Assess Severity of Mitral Regurgitation by Echo

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How to Diagnose and Assess Severity of Mitral
Regurgitation by Echo

• Noel Black
• Chief Cardiac Physiologist
• South Eastern Trust

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Calculating (PISA)

• Apical 4Ch view
• Narrow sector width
• Minimise depth
• Zoom
• Adjust Colour Doppler alaising velocity (20-40
  cm/s)

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PISA

• Measure the radius of the hemisphere. (red/blue
  interface)
• PISA radius 2pr2 (cm2)
• Mild MR lt0.4
• Severe MRgt1.0

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Consideration

• Non-circular orifice

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Colour Doppler Indicators of Mitral Regurgitation
Severity
Mild Moderate Severe
Colour Doppler
Jet area (cm2) Nyquist 50-60cm/s lt4 gt10
Ratio of jet area to left atrial area () lt20 gt40
Vena contracta width (cm) lt0.3 gt0.7
PISA radius (cm) at Nyquist 40cm/s lt0.4 gt1.0
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Continuous wave and Pulse wave Doppler

• Continuous wave spectral Strength
• Apical 4Ch view CW of regurgitant jet
• Faint in mild mitral regurgitation
• Denser in moderate and severe regurgitation.

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Chronic vs Acute MR

• Chronic
• Velocity remains high throughout systole.
• Acute
• Jet velocity starts to fall towards end systole.
• Pressure gradient between LV and LA equalises
  more rapidly

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Peak Mitral Valve E velocity

• Increased mitral valve E velocity (gt1.2m/s) may
  indicate significant regurgitation.
• Assumes ejection fraction isgt40)
• Decreased mitral valve DT (lt150msec) may indicate
  significant regurgitation.
• Assumes normal diastolic LV function.

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Pulmonary Vein Systolic Flow Reversal

• PW doppler 1cm into the pulmonary veins
• Systolic S (systolic) wave is normally larger
  than the D (diastolic) wave.
• If D wave is larger there is blunting of forward
  flow.
• S wave inversion demonstrates systolic flow
  reversal (indicative of severe MR).

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Limitation

• Eccentric jets may affect pulmonary vein flow

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Determination of Pulmonary Artery Pressures at
Rest and Exercise
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Multimodality Indicators of Mitral Regurgitation
Severity
Mild Moderate Severe
Multimodality
Regurgitant volume (mL/beat) lt30 30-59 gt60
Regurgitant fraction () lt30 30-49 gt50
Effective regurgitant orifice area (cm2) lt0.20 0.20-0.39 gt0.40
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Regurgitant Volume, Regurgitant Fraction and ERO

• Regurgitant volume
• Step 1
• A4ch view measure diameter of the mitral annulus.
• CSAMV 0.785 X (mitral annulus diameter)2

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Regurgitant volume

• Step 2
• Apical 4Ch view measure the VTI of the mitral
  inflow (using PWD)
• Commonly at valve tip level.
• VTIMV in cm
• Step 3. Stroke Volume
• SVMV (mL/beat) CSAMV X VTIMV

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Regurgitant volume

• Step 4
• In PLAx measure the diameter of the LVOT (cm).
• Calculate CSA of the LVOT (cm2)
• CSALVOT 0.785 x (LVOT diameter)2

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Regurgitant volume

• Step 5
• In the Ap5 Ch view measure the VTI of the LVOT
  outflow (using PWD)
• VTILVOT (cm)
• Step 6. Stroke volume
• SVLVOT CSALVOT x VTILVOT

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Regurgitant Volume/Fraction

• Step 6
• Mitral regurgitant volume (RV)(mL)
• RV SVMV SVLVOT
• Mild MRlt30 Mod MR31-59
• Severe MRgt60
• Step 7
• Mitral regurgitant Fraction (MF)(cm2)
• RF RV / SVMV (x100)
• Mild MRlt30 Mod MR31-49
• Severe MRgt50

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Regurgitant orifice area

• Step 8
• Measure the VTI of the mitral regurgitation VTIMR
  (cm) (using CWD)
• Calculate Regurgitant Orifice Area (ROA) in cm2
• ROA RV / VTIMR
• Mild MRlt0.20
• Mod MR0.21-0.39
• Severe MRgt0.40

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Regurgitant Orifice Area PISA method

• Step 1. Measure the radius of the hemisphere.
  (red/blue interface)
• PISA 2pr2 (cm2)
• Calculate regurgitant flow rate
• RFR mL/s PISA X aliasing velocity

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Regurgitant orifice area

• Step 2. CWD of the mitral regurgitation. Measure
  peak velocity (VMR) in cm/s.
• Calculate Regurgitant Orifice Area in cm2.
• ROA Regurgitant flow rate / VMR

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Common pitfalls

• Measuring regurgitant jet area or VC width on
  colour doppler with inappropriate colour gain
  settings
• Underestimating severity of eccentric jets on
  CFD.
• Failure to align the doppler beam with
  regurgitant flow during CW doppler interrogation.
• Inaccurate measurement of mitral valve orifice
  area or LVOT diameter when calculating RV.
• Trying to calculate RV when there is coexistant
  aortic regurgitation.
• Failure to average several readings when the
  patient is in AF.

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TOE

• Superior 2D images of anatomic structures
• Chordal rupture/ruptured papillary muscle
• Assessment of the jet area
• eccentric jets
• Prosthetic heart valves
• reduced masking effect
• Pulmonary vein assessment

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Factors affecting operative decision on the
patient with MR
Symptoms
Severity of MR
Feasibility of surgical repair
Decision to operate
Haemodynamic effects of MR on LV, LA and RV
Operative risk to the patient