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2/13/2014
Valvular Heart Disease Session
Aortic Regurgitation: How Do I Quantify!
SHA 25
5 February 2014
Dr. Maie S. Shahid
King Faisal Specialist Hospital & RC
Heart Center
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Aortic Regurgitation
Etiology
 Valve Leaflet Disease
Rheumatic heart disease
Congenital: Bicuspid AV / VSD
Degenerative Valve disease
Infective endocarditis
 Aortic Disease
Aortic root dilatation
Aortic dissection
Aortic Regurgitation
Role of Echocardiography
 Diagnose presence of regurgitation
 Asses aortic valve: Aorta anatomy and function
 Understand etiology and mechanism
 Quantification of severity of regurgitation
 Assess impact of regurgitation
Assessment of ventricular performance
Assessment of cardiac chamber size
Ventricle
Atria
PA systolic pressure
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Aortic Regurgitation
M-Mode Assessment
 Premature closure of MV
before onset of QRS.
Usually associated with:
Acute AR
Markedly raised LVEDP
 Premature diastolic opening
of aortic valve on or before
QRS complex. Usually
associated with acute aortic
regurgitation
Aortic Regurgitation
2-D Assessment
 Assess aortic valve morphology:
Bicuspid / Unicuspid aortic valve
Rheumatic valve
Flail / prolapsed valve
Endocarditis: Vegetation on the aortic valve
 Assess aortic morphology
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Rheumatic Aortic Regurgitation
Rheumatic Aortic Regurgitation
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Endocarditis of Bicuspid AV
Aortic Dissection
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Aortic Dissection
Aortic Aneurysm with AR
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Aortic Regurgitation
2-D Echocardiographic Assessment
 Assess hemodynamic
status of the left
ventricle: Usually
dilated
Size of left ventricle
Function of left
ventricle
Left ventricular
hypertrophy
(eccentric)
Severe AR: Normal LV Function
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Severe AR: LV Systolic Dysfunction
Aortic Regurgitation
Color Flow Imaging
 Color jet area & length are
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weakly correlated with
degree of AR, thus Not
recommended
Limitations:
Optimal gain / filter setting
Optimal angle of incidence
Blood pressure
Left ventricular function
LA compliance and size
Loading conditions
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Aortic Regurgitation
Assessment by Color Flow Imaging
 Three components to
the AR jet
Flow convergence
region in the aorta
= PISA
Vena contracta
through regurgitant
orifice
Jet turbulence and
size in the LV
Diastolic Flow Reversal In Descending
Aorta by PWD
 Velocity at early diastole is
equal or more than 0.6 m/s, and
persists till end diastole with
velocity of equal or more than
20 cm/s.
 TVI of diastolic reversal > 15 cm
 Holodiastolic reversal with
diastolic TVI similar to systolic
TVI
 Reduced aortic compliance with
aging may prolong normal
diastolic reversal
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Diastolic Flow Reversal In Abdominal
Aorta by PWD
 May be recorded in the
abdominal aorta
 Diastolic reversal in
abdominal aorta, especially
if holodiastolic, is
associated with severe AR
Aortic Regurgitation
Assessment by CWD
 Intensity of signal gives idea about severity:
Compare the diastolic signal to the systolic
aortic flow signal
 Density does not play a major role
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Aortic Regurgitation
Assessment by CWD
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Slope of AR signal by CWD
is a measure of the severity
of aortic regurgitation.
It measures the rate with
which aortic and LV
pressure equates in
diastole.
In general, the steeper the
slope, the more severe the
aortic regurgitation.
Should have a full envelope
Aortic Regurgitation
Assessment by CWD
 What is determined is
pressure half-time
(PHT) of aortic
regurgitation signal
 It is the time in msec
required for the initial
pressure to drop to half
of its value, or for the
velocity to drop by V
max / 1.4 (71%)
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Severe = Pressure half- Mild = Pressure half-time of
time of < 200 msec
> 500 msec
Pressure Half-Time Method
Limitations
 Affected by aortic pressure.
 Affected by compliance of LV.
 Requires parallel alignment
 Affected by LVEDP
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Aortic Regurgitation
Assessment by Color Flow Imaging
 Three components to
the AR jet
Flow convergence
region in the aorta
= PISA
Vena contracta
through regurgitant
orifice
Jet turbulence and
size in the LV
Aortic Regurgitation
Quantitative Assessment
Regurgitant Volume (RV) and Regurgitant
Fraction (RF)
 Effective Regurgitant Orifice (ERO)
 Proximal Isovelocity Surface Area (PISA)
 Concept of Vena Contracta
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Vena Contracta for AR
Vena Contracta For AR
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Narrowest portion of the
jet at the level of AV or
just below it before it
expands in the LVOT
Simple measurement
Requires visualization of
all 3 componenets of
regurgitant jet
Direct imaging of
regurgitant orifice area
by CFD
Use
zoom mode
Use narrowest
sector scan
possible
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Vena Contracta For AR
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Not affected by loading
conditions or driving
pressure
Can be obtained in
eccentric jets
Mild AR = < 0.3 cm
Severe AR = > 0.6 cm
at a Niquist limit of 5060 cm/sec
Vena Contracta For AR
Limitations
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Multiple jets: Not additive respective widths
Cannot be used in jets with irregular shapes
Assumes that the regurgitant orifice is
almost circular
With elleptical orifices: Looks of different
sizes in different views
3D color will be a helpful tool
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Proximal Isovelocity Surface Area
(PISA)
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Based on
conservation of flow
As blood in the aorta
converges towards
the regurgitant aortic
orifice, velocity
increases
A series of
hemispheres are
formed.
Proximal Isovelocity Surface Area
(PISA)
 The flow at each of them is
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the same
Color flow imaging can
identify a PISA on the aorta
side of the AV because of
blue-red aliasing
Flow velocity at the blue-red
aliasing equals the aliasing
velocity
Flow rate at PISA =
Hemispheric Area x Aliasing
velocity
Area of a hemisphere =
2  R2
VR
R
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PISA
How to Measure
 Measure the radius
after optimization of
flow. Note VR
 Measure peak
velocity of regurgitant
CWD signal
 Convert to cm / sec
 Measure TVI of aortic
regurgitant CWD
signal by tracing it: In
cm
VR
R
PISA: For Aortic ERO and RV
How to Measure
Start by measuring flow at any hemisphere
 Need R of hemisphere
 Need VR of hemisphere
 Convert all measurements obtained to cms
 Flow AR = Area Shell x V Shell
(cm3/sec)
(cm2)
(cm/s)
= 2 x 22/7 x R2 x VR
= 6.28 x R2 x VR

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Proximal Isovelocity Surface Area
Measurement
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Regurgitant Flow (Flow AR) at any
hemisphere = Instantaneous flow rate in cm3/s
Effective Regurgitant Orifice (ERO)
ERO (cm2) = Flow (cm3 / sec) / VAR (cm/sec)
Regurgitant Volume (RV)
RV (cm3) = ERO (cm2) x TVIAR (cm)
Proximal Isovelocity Surface Area
 Grade I (Mild)
ERO (cm2)
< 0.10
RV (cc)
<30
 Grade IV (Severe)
 0.30
60
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Aortic Regurgitation
Diastole
MV
Flow
RV
RV = Aortic Regurgitant Volume
Aortic Regurgitation
Systole
AV
Flow
RV
+
MV
Flow
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Aortic Regurgitant Volume
It is the difference between aortic flow and
mitral (or RVOT) flow
Regurgitant
+
Volume
Forward Flow
Through MV
Flow Through Regurgitant
Aortic Valve = Aortic Flow
Aortic Regurgitant Volume
Calculation
1. Measure mitral annular diameter
2. Calculate cross sectional area (CSA) of
mitral annulus
CSA Mitral = 0.785 x D2 Mitral
3. Measure TVI of mitral annulus:
Trace modal velocity
4. Calculate MV stroke volume = Inflow Volume
SV MV = CSA Mitral x TVI Mitral
cm3
cm2
cm
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Aortic Regurgitant Volume
Calculation
5. Measure LVOT diameter
6. Calculate cross sectional area (CSA) of
LVOT
CSA LVOT = 0.785 x D2 LVOT
7. Measure TVI of LVOT
8. Calculate AV stroke volume = Outflow Volume
SV AV = CSA LVOT x TVI LVOT
(cm3)
(cm2)
(cm)
Aortic Regurgitant Volume / Fraction
Calculation
9. Calculate regurgitant Volume (RV)
RV (cm3) = AV outflow Volume – MV Inflow
Volume
10. Calculate Regurgitant Fraction (RF)
RF (%) = RV / AV Outflow Volume
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MV Annulus= 2.6 cm
MV SV = 74 cc
LVOT SV = 50 cc
RV = 74–50
= 24 cc
RF = 24 / 74 x 100
= 32%
LVOT Diameter = 2 cm
MV TVI = 14 cm
LVOT TVI = 16 cm
Effective Regurgitant Orifice (ERO)
Definition
Size of hole through
which the aortic
regurgitation passes.
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Effective Regurgitant Orifice of AR
Measurement Required
Effective Regurgitant Orifice of AR
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Calculate aortic regurgitant Volume (RV)
RV (cm3) = AV outflow Volume - MV
Inflow Volume
Optimize AR CWD velocity signal
Trace AR signal to get TVI of AR
ERO (cm2) = RV (cm3) / TVI AR (cm)
> 0.3 cm2 = Moderate severe AR
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Aortic Regurgitant Volume
Pitfalls of Measurement
 Learning curve of operator
 Proper Doppler angle < 200 : If high will lead to
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underestimation of velocities and TVI’s
Incorrect placement of sample volume
Incorrect measurement of annulus diameter: Error
will be squared
Not averaging enough measurement:
3-5 beats in SR
Arrhythmias: Average 10 beats.
Should have no multi-valve regurgitant lesions and
no shunts
Diastolic MR caused by Severe AR
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Aortic Regurgitation
Role of TEE
 Seldom needed to assess severity
 Needed in patients with poor acoustic window and
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inadequate transthoracic study
Color Doppler criteria and vena contracta apply as
for TTE
Alignment with flow is difficult. Therefore cannot
measure saitsfactorly VTI and velocity for RV
With manipulation, may get a good proximal flow
convergence
Can get reversal in ascending aorta by PWD
Aortic Regurgitation
Role of Exercise
 Development of symptoms during exercise predict
outcome
 Absence of contractile reserve (Decrease in LV EF
by 4%) at exercise predicts LV decompensation
after surgery
 Note: Change in EF / SV affected by:
Myocardial contractile function
Severity of volume overload
Exercise induced changes in pre=load and
peripheral resistance
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Aortic regurgitation
PWD Assessment: Mitral Inflow
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High LVEDP
Restrictive mitral
inflow
Dependent on LV
compliance
3-D in AV Surgery
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