Aortic Regurgitation

2D and Doppler Assessment Dr.Sohail Abrar Khan MBBS,FCPS (Med), FCPS (Card) Diplomate of American certification Board of Echo Assistant Professor and Consultant Cardiologist Aga Khan University Hospital Karachi

Introduction     Aortic regurgitation is a common and serious health problem Echo is the most valuable tool in the diagnosis and management of AR Echo evaluation of AR requires a comprehensive evaluation by an experienced person Visual and qualitative assessment may be unreliable and misleading

Introduction

cont…    Patients are often asymptomatic until AR becomes significant AR murmur usually not heard until AR severity > mild Detection of AR may be the first clue that aortic root or aortic valve disease is present

Role of Echo in Assessment AR

 2D and Doppler echocardiography is indispensable in the diagnosis and management of patients with AR  This should be used to assess the severity of AR, the LV response to volume overload (systolic function, ejection fraction [EF] and end-systolic and diastolic dimensions).  Echocardiography may also identify the anatomic cause of AR, which is important for determining the surgical approach

Assessment of Regurgitation

2D Echo CFI Hemodynamics ERO/RV AR ERO/R Vol CW Doppler PW Doppler

Hemodynamics of AR

    

Chronic AR

Progressive ↑ AR Heart has time to compensate ↑ LV volume ↑ dilatation ↑ Stroke Volume     

Acute AR

Rapid onset of AR Insufficient time for heart to compensate Leads to ↑ LVEDP Pulmonary edema Decreased effective forward Stroke vol

Hemodynamics of AR cont… Acute AR Chronic AR Adapted From: Lilly L. Pathophysiology of Heart Disease

Aortic Regurgitation

2D Echo

    Assess valvular function Identification of functional anatomy Assess LV size and function Evidence of increased LVEDP

2D Echo

cont…    

Assessment of LV

Serial reproducible findings LV chamber enlargement LV function assessment Predictors of preserved LV function after AVR  LVESD < 55 mm  LV EF > 50%

Conservative Rx for Severe AR Survival vs Indexed LV Systolic Diameter

100

89 ±3% LVS/BSA <25

80

81 ±5%

60

50 ±9% LVS/BSA  25

40

34 ±10%

20 0 0 Dujardin KS: Circ,99 2 4

Years

6 8 10 CP993609-9

Aortic Regurgitation

2-D and M-Mode

Clues of AR

 Diastolic fluttering of anterior MV leaflet  Reverse “doming” of anterior MV leaflet  Diastolic flutter of aortic valve

Evidence for increased LVEDP

 Presystolic (premature) closure of MV  Presystolic (premature) opening of AV

Aortic Regurgitation Functional Anatomy     

Valvular

Congenital (bicuspid) Degenerative Rheumatic Endocarditis Cusp rupture

Functional Anat

omy

cont…

Aortic Root

Chronic Dilatation  Marfan syndrome  Senile/hypertensive  Chronic aortitis  Idiopathic Annuloaortic ectasia  Sinus of valsalva aneurysm Acute Disruption  Dissection  Chest trauma  Endocarditis  Post-procedure

Aortic Regurgitation

Color Flow Imaging Jet area



LVOT area Jet width



LVOT width

CP993609-12

Color Flow Imaging

cont… Jet Width/LVOT Width Perry et al. JACC 1987

Color Flow Imaging

cont… Jet area/LVOT area  AR jet area and LVOT area from parasternal short axis view  Correlates best with angiographic severity of AR  Assess AR at the level of the aortic annulus, just below the AV Oh, Seward,Tajik: The Echo Manual

Color Flow Imaging

cont… Jet area/LVOT area Grade I Grade II Grade III Grade IV < 5% 5 - 24% 25 - 59% > 60%

Vena Contracta

    Measure from PLAX (zoom) Use standard color scale  No baseline shift  Measure width of AR jet at the narrowest point  Measure just below flow convergence Vena contracta < 6 mm = severe AR Vena contracta < 3 mm = mild AR

Vena Contracta

cont… VC Width 5 mm

6 mm

7 mm ERO≥0.3 cm 2 RegVol≥60 ml Sn 100 96 Sp 73 81 Sn 95 81 Sp 90 94 Sn 84 65 Sp 95 96 Tribouilloy et al: Circulation, 2000

Vena Contracta Optimize the flow convergence zone

Vena Contracta Measure width of AR at narrowest point of emitting jet Vena contracta is usually smaller than LVOT jet height

Aortic Regurgitation CW Doppler Assessment  Density of CW signal reflects Reg Vol  Pressure half-time  Mild AR > 400 msec  Severe AR < 250 msec Oh,Seward, Tajik: The Echo Manual

Align Doppler parallel to flow

Move lateral or try a lower rib space

CW Doppler Assessment cont… Pressure Half Time PHT Otto and Pearlman: Textbook of Clinical Echocardiography Mild AR > 400 msec

CW Doppler Assessment

cont… Pressure Half Time PHT Otto and Pearlman: Textbook of Clinical Echocardiography Severe AR < 250 msec

CW Doppler Ass

essment cont…   AR PHT may be shortened due to other causes of elevated LVEDP i.e LV systolic and diastolic dysfunction and Mitral Regurgitation It can be increased due to Mitral Stenosis

Aortic Regurgitation PW Doppler Assessment  LV stroke volume  Mitral inflow  Descending thoracic aorta  Abdominal aorta

PW Doppler

cont…

Mitral Inflow

 High LA Pressure & LVEDP  Restrictive mitral inflow  Mitral pattern dependent on compliance of ventricle Oh,Seward, Tajik: The Echo Manual

PW Doppler cont… Premature Cessation of Mitral Flow in Acute Severe AR Pre-op Post-op

PW Doppler

cont…

CP993609-21

PW Doppler

cont…

Descending Aorta

 Diastolic flow reversal  Retrograde flow TVI Severe AR TVI > 14 cm

PW Doppler

cont…

Abdominal Aorta

 Place PW sample volume in abdominal aorta  Diastolic flow reversal consistent with significant aortic regurgitation Otto and Pearlman: Textbook of Clinical Echocardiography

Indications for Quantitative Doppler    When regurgitation appears moderate or more by CFI/qualitative assessment Serial assessment  Assess LV size & function  Assess regurgitation Assist clinician/surgeon  Clinical management  Timing of surgery

Quantitative Doppler Methods CSA TVI

Continuity Equation PISA Method

Continuity Equation  Stroke volume  Valve area  Shunt lesions  Regurgitant volume  Regurgitant fraction

Continuity Equation

cont…

What goes in

(the ventricle)

must go out!!

Regurgitant Volume  Volume of blood that regurgitates through an incompetent valve with each heart beat

Continuity Equation Calculation

Stroke volume = A Area X TVI TVI CP944143- 6

Continuity Method

cont…  

“What goes in must go out”

Measurements required  LVOT diameter & TVI  MV annulus diameter & TVI Limitation of continuity method Unable to use with multiple regurgitant lesions > mild and shunt lesions

Continuity Method

cont… 

Calculate SV LVOT

Measure LVOT diameter Obtain PW Doppler signal in LVOT  Trace LVOT TVI  SV LVOT = CSA LVOT x TVI LVOT

Continuity Method cont…

Calculate SV MV

 Measure diameter of mitral annulus  Obtain PW Doppler signal at level of mitral annulus  Trace MV annulus TVI  SV MV = CSA MV x TVI MV

Regurgitant Volume and Fraction SV LVOT = CSA LVOT x TVI LVOT SV MV = CSA MV x TVI MV RV AR = SV LVOT - SV MV RF AR = RV AR / SV LVOT

Pitfalls of Continuity Method       Learning curve of the operator Incorrect placement of sample volume Incorrect annulus measurement Requires 4 separate measurements Introduces 4 possible errors Diameters are squared in the equation so any small error will be magnified and spoil the result Invalid with multivalvular regurgitation or intracardiac shunts

PISA

P

roximal

I

sovelocity

S

urface

A

rea

Advantages of PISA Method    Can be used in the presence of other valvular regurgitation or shunts Can be used in the presence of valve stenosis or prosthetic valves Uses fewer variables (2 measurements)

PISA Method  Shift color baseline in the direction of flow  Alias velocity varies (range of 20-40 cm)  Note alias velocity Adapted from Oh, et. al.

AR Peak Velocity and VTI  Using CW Doppler, obtain optimal regurgitant jet  Use alternate windows to be parallel to flow  Measure peak regurgitant velocity  Trace regurgitant TVI

PISA Calculations



Flow (cc/sec)

= 6.28 x [r (cm)] 2 x V a (cm/sec) 

ERO (cm 2 )

= Flow (cc/sec) V (cm/sec) 

RV (cc)

= ERO (cm 2 ) x TVI (cm)

E ffective R egurgitant O rifice   Size of orifice through which regurgitation passes Also referred to as ROA (regurgitant orifice area)

Pitfalls of PISA Method

    Learning curve of operator Assumption of hemispherical flow convergence area Inability to accurately measure radius Inability to obtain complete MR jet by CW Doppler

Jet/LVOT area Jet/LVOT Width Vena Contracta CW Doppler AR PHT Descending Aorta Reversal TVI

Severity of AR

Mild

<2 5%

Severe

> 60% < 25% > 60% < 3 mm > 6 mm faint > 400 msec early diastolic > 14 cm dense < 250 msec holodiastolic

Summary       Aortic regurgitation is a common and serious health problem Echo is the most valuable tool in the diagnosis and management of AR Echo evaluation of AR is complex and often suboptimal Visual and qualitative assessment is is often misleading It is now very reliable by the use of quantitative methods An organized and comprehensive approach by using all the available qualitative and quantitative methods is required for proper assessment of AR

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