Aortic Regurgitation Ali Mahajerin Echo Conference September 17, 2008.

Aortic Aortic RegurgitationRegurgitation

Ali MahajerinAli Mahajerin

Echo ConferenceEcho Conference

September 17, 2008September 17, 2008

IntroductionIntroduction Aortic regurgitation (AR) is characterized by Aortic regurgitation (AR) is characterized by

diastolic reflux of blood from the aorta to the diastolic reflux of blood from the aorta to the LV.LV.

AR may be caused by malfunction of the aortic AR may be caused by malfunction of the aortic valve leaflets themselves, by dilation of the valve leaflets themselves, by dilation of the aortic root and annulus, or a combination of aortic root and annulus, or a combination of these factors.these factors. Aortic root disease now accounts for >50% of all Aortic root disease now accounts for >50% of all

AVRsAVRs Clinical presentation is highly variable and Clinical presentation is highly variable and

depends on multiple factors, including acuity of depends on multiple factors, including acuity of onset, aortic and LV compliance, hemodynamic onset, aortic and LV compliance, hemodynamic conditions, and severity of the lesion.conditions, and severity of the lesion.

EpidemiologyEpidemiology Incidence of clinically significant AR increases Incidence of clinically significant AR increases

with agewith age Typical peak in 4Typical peak in 4thth to 6 to 6thth decade of life decade of life More common in men than womenMore common in men than women

Overall prevalence of AR was 4.9% in Framingham Overall prevalence of AR was 4.9% in Framingham Heart Study and 10% in Strong Heart StudyHeart Study and 10% in Strong Heart Study Prevalence of moderate or greater severity was 0.5% Prevalence of moderate or greater severity was 0.5%

and 2.7%, respectivelyand 2.7%, respectively Most common cause of AR in developing countries Most common cause of AR in developing countries

is RHDis RHD In developed countries the leading cause of AR is In developed countries the leading cause of AR is

either either congenitalcongenital (particularly due to bicuspid (particularly due to bicuspid leaflets) or leaflets) or degenerativedegenerative disease (including disease (including annuloaortic ectasia).annuloaortic ectasia).

Valve-Related Causes of Valve-Related Causes of ARAR

Rheumatic diseaseRheumatic disease Cusps become fibrotic and retract (usually Cusps become fibrotic and retract (usually

also stenotic); MV involved as wellalso stenotic); MV involved as well Atherosclerotic degenerationAtherosclerotic degeneration Infective endocarditisInfective endocarditis

Leaflet perforationLeaflet perforation Vegetation interferes with coaptationVegetation interferes with coaptation

Trauma (chest wall or deceleration Trauma (chest wall or deceleration injury)injury)

Bicuspid aortic valve (can be associated Bicuspid aortic valve (can be associated with aortic root dilation as well)with aortic root dilation as well)

Other Valve-Related Causes Other Valve-Related Causes of ARof AR

Myxomatous degenerationMyxomatous degeneration Structural deterioration of Structural deterioration of

bioprosthesisbioprosthesis Other less common causes:Other less common causes:

Ankylosing spondylitis (can cause disease Ankylosing spondylitis (can cause disease of both the leaflets and the aortic root) of both the leaflets and the aortic root)

SLE, RASLE, RA Takayasu diseaseTakayasu disease Anorectic drugsAnorectic drugs Membranous subaortic stenosisMembranous subaortic stenosis

Aortic Root DiseaseAortic Root Disease

Dilation here is rare

As little as 2mm of

dilation here can cause AR

Dilation here is common; especially in AS; does not lead to AR

Between the Between the annulus and the annulus and the ascending aorta is ascending aorta is a collagenous a collagenous segment that segment that forms the sinuses forms the sinuses of valsalva.of valsalva.

Aortic Root DiseaseAortic Root Disease

Dilation of the Dilation of the aortic ridge aortic ridge eliminates the eliminates the normal overlap of normal overlap of the valvesthe valves

Aortic Root-Related Aortic Root-Related Causes of ARCauses of AR

Idiopathic aortic root dilationIdiopathic aortic root dilation Aortoannular ectasiaAortoannular ectasia Marfan syndromeMarfan syndrome Ehlers-Danlos syndromeEhlers-Danlos syndrome Osteogenesis imperfectaOsteogenesis imperfecta Aortic dissectionAortic dissection Syphilitic aortitisSyphilitic aortitis TraumaTrauma Ankylosing spondylitisAnkylosing spondylitis Bicuspid aortic valve with dilated aortic Bicuspid aortic valve with dilated aortic

rootroot

Acute Aortic Acute Aortic RegurgitationRegurgitation

Most commonly caused by bacterial Most commonly caused by bacterial endocarditis, aortic dissection, or blunt chest endocarditis, aortic dissection, or blunt chest traumatrauma

Sudden large regurgitant volume is imposed Sudden large regurgitant volume is imposed on an LV of normal size that has not had time on an LV of normal size that has not had time to accommodate the volume overload.to accommodate the volume overload.

Abrupt increase in LVEDV leads to rapid and Abrupt increase in LVEDV leads to rapid and dramatic increase in LVEDP and LA pressuresdramatic increase in LVEDP and LA pressures

Inability of ventricle to develop compensatory Inability of ventricle to develop compensatory chamber dilatation acutely results in a chamber dilatation acutely results in a decrease in forward stroke volume.decrease in forward stroke volume. Tachycardia may develop as a compensatory Tachycardia may develop as a compensatory

mechanism to maintain cardiac output, but often mechanism to maintain cardiac output, but often insufficient.insufficient.

Acute AR - Acute AR - PathophysiologyPathophysiology

Patients often present with pulmonary Patients often present with pulmonary edema or cardiogenic shock.edema or cardiogenic shock.

May present with myocardial ischemia: May present with myocardial ischemia: As LVEDP approaches diastolic aortic As LVEDP approaches diastolic aortic and coronary pressures, myocardial and coronary pressures, myocardial perfusion pressure in the perfusion pressure in the subendocardium is diminished.subendocardium is diminished. LV dilation and thinning of LV wall result in LV dilation and thinning of LV wall result in

increased afterload, and combined with increased afterload, and combined with tachycardia leads to increased myocardial tachycardia leads to increased myocardial O2 demandO2 demand

Ischemia and its consequences, including Ischemia and its consequences, including sudden death, occur commonly in acute AR.sudden death, occur commonly in acute AR.

Chronic Aortic Chronic Aortic RegurgitationRegurgitation

Chronic AR imposes both volume and Chronic AR imposes both volume and pressure overload on the LV.pressure overload on the LV.

Increased regurgitant volume Increased regurgitant volume increased increased LVEDV and increased wall stressLVEDV and increased wall stress

Increased chamber compliance Increased chamber compliance accommodates increased volume w/o accommodates increased volume w/o increasing filling pressuresincreasing filling pressures

Compensatory eccentric hypertrophy also Compensatory eccentric hypertrophy also occurs, helping to maintain normal stroke occurs, helping to maintain normal stroke volume with the chamber enlargementvolume with the chamber enlargement

LVEDV increases but LV wall compliance LVEDV increases but LV wall compliance prevents increase in LVEDPprevents increase in LVEDP

Chronic AR - Chronic AR - PathophysiologyPathophysiology

Early CompensatedEarly Compensated Enlarged chamber size Enlarged chamber size

↑ afterload ↑ afterload hypertrophy of LV which hypertrophy of LV which preserves compliance preserves compliance normal filling pressuresnormal filling pressures

LVH LVH ↑ LV mass ↑ LV mass normal LV vol/mass ratio normal LV vol/mass ratio & EF& EF

Progressive LV dilation Progressive LV dilation and systolic HTN and systolic HTN ↑ wall ↑ wall stress and vol/mass ratiostress and vol/mass ratio

↑ ↑ wall stress eventually wall stress eventually leads to overt LV leads to overt LV dysfunction.dysfunction.

DecompensatedDecompensated LV systolic dysfunction LV systolic dysfunction

accompanied by accompanied by decreased LV diastolic decreased LV diastolic compliance due to compliance due to hypertrophy and fibrosishypertrophy and fibrosis

Leads to high filling Leads to high filling pressures and CHF pressures and CHF symptomssymptoms

Exertional dyspnea Exertional dyspnea common; angina can common; angina can occur due to reduced occur due to reduced coronary flow reserve coronary flow reserve with predominantly with predominantly systolic coronary flowsystolic coronary flow

Different Stages of ARDifferent Stages of AR

Bekerdjian R, et al. Circulation 2005; 112: 125-134.

Physical Exam - Physical Exam - AuscultationAuscultation

A2 often soft/absent, P2 normalA2 often soft/absent, P2 normal S3 if LV function severely depressedS3 if LV function severely depressed High frequency decrescendo diastolic High frequency decrescendo diastolic

murmur over the 3murmur over the 3rdrd or 4 or 4thth intercostal space intercostal space at left sternal borderat left sternal border Best heard sitting up, leaning forward at end Best heard sitting up, leaning forward at end

expirationexpiration Austin Flint murmur: mid-to-late diastolic Austin Flint murmur: mid-to-late diastolic

apical rumble, possibly due to vibration of apical rumble, possibly due to vibration of anterior mitral leaflet as it is struck by a anterior mitral leaflet as it is struck by a posteriorly directed AR jet.posteriorly directed AR jet.

Physical Exam – Peripheral Physical Exam – Peripheral FindingsFindings

Corrigan’s pulseCorrigan’s pulse – bounding “waterhammer” carotid – bounding “waterhammer” carotid pulsepulse

deMusset’s signdeMusset’s sign – head bob with each heart beat – head bob with each heart beat Mueller’s signMueller’s sign – systolic pulsation of uvula – systolic pulsation of uvula Traube’s signTraube’s sign – pistol shot pulse over the femoral – pistol shot pulse over the femoral

arteryartery Duroziez’s signDuroziez’s sign – systolic and diastolic bruits heard – systolic and diastolic bruits heard

when femoral artery partially compressedwhen femoral artery partially compressed Becker’s signBecker’s sign – visible pulsations of retinal arteries – visible pulsations of retinal arteries

and pupilsand pupils Hill’s signHill’s sign – popliteal cuff systolic pressure exceeding – popliteal cuff systolic pressure exceeding

brachial pressure by more than 60 mmHgbrachial pressure by more than 60 mmHg Mayne’s signMayne’s sign – more than 15 mmHg decrease in – more than 15 mmHg decrease in

diastolic blood pressure with arm elevationdiastolic blood pressure with arm elevation Rosenbach’s signRosenbach’s sign – systolic pulsations of the liver – systolic pulsations of the liver Gerhard’s signGerhard’s sign – systolic pulsations of the spleen – systolic pulsations of the spleen

Natural History of ARNatural History of AR Depends on AR severity, aortic root Depends on AR severity, aortic root

pathology, and adaptive response of LV.pathology, and adaptive response of LV. Bonow et al:Bonow et al:

104 asymptomatic patients with severe AR 104 asymptomatic patients with severe AR and normal LVEFand normal LVEF

Death, symptoms, or asymptomatic LV Death, symptoms, or asymptomatic LV dysfunction was < 5%/year over 11-year dysfunction was < 5%/year over 11-year follow-upfollow-up

Rate of sudden death was only 0.4%/yearRate of sudden death was only 0.4%/year At 11 years, 58% remained asymptomatic and At 11 years, 58% remained asymptomatic and

had normal LV systolic function.had normal LV systolic function. Further strengthened serial changes in LV Further strengthened serial changes in LV

systolic function and/or LV dilatation as systolic function and/or LV dilatation as important to clinical outcome in AR and important to clinical outcome in AR and potential reasons for AVR.potential reasons for AVR.

Bonow RO, et al. Circulation 1991; 84: 1625-1635.

Natural History of ARNatural History of AR

Dujardin et al:Dujardin et al: 246 patients with moderate-severe AR, 246 patients with moderate-severe AR,

mean follow-up 7 yearsmean follow-up 7 years Not all asymptomatic with normal LV Not all asymptomatic with normal LV

systolic functionsystolic function Ten-year mortality rate 34%Ten-year mortality rate 34% Independent predictors of survival were Independent predictors of survival were

age, functional class, comorbidity index, age, functional class, comorbidity index, atrial fibrillation, LVESD, and LVEFatrial fibrillation, LVESD, and LVEF

Dujardin KS, et al. Circulation 1999; 99: 1851-1857.

Dujardin KS, et al. Circulation 1999; 99: 1851-1857.

Asymptomatic patients Asymptomatic patients with normal LV with normal LV function generally function generally have a favorable have a favorable prognosisprognosis

Decline in LVEF with Decline in LVEF with exercise or serial exercise or serial follow-up identifies follow-up identifies patients who will likely patients who will likely require surgical require surgical intervention.intervention.

Even moderate Even moderate symptoms or evidence symptoms or evidence of LV dilatation are at of LV dilatation are at higher risk and should higher risk and should be considered for early be considered for early intervention.intervention.

Natural History of Natural History of Chronic ARChronic AR

Diagnostic Tools: ECGDiagnostic Tools: ECG LVH with or without strain pattern, LAD, LAELVH with or without strain pattern, LAD, LAE One study suggests that in asymptomatic or One study suggests that in asymptomatic or

mildly symptomatic patients with pure AR, the mildly symptomatic patients with pure AR, the absence of ECG changes predicts LV systolic absence of ECG changes predicts LV systolic dimension < 55mm, and LVEF >45% and dimension < 55mm, and LVEF >45% and >40% with exercise.>40% with exercise. Up to 83% of patients with rest or exercise ST Up to 83% of patients with rest or exercise ST

segment abnormalities had an enlarged LV segment abnormalities had an enlarged LV (>55mm) or reduced LVEF < 45%.(>55mm) or reduced LVEF < 45%.

Conduction abnormalities rare except in late Conduction abnormalities rare except in late disease with severe LV dysfunction; sustained disease with severe LV dysfunction; sustained SVT or VT unusual in absence of significant LV SVT or VT unusual in absence of significant LV dysfunction.dysfunction.

Chest X-RayChest X-Ray CardiomegalyCardiomegaly Prominent Left Prominent Left

VentricleVentricle Ascending Ascending

Aortic dilatationAortic dilatation LAE only if LAE only if

severe LV severe LV dysfunctiondysfunction

Chest X-RayChest X-Ray

EchocardiographyEchocardiography

Most important diagnostic test for Most important diagnostic test for evaluation of AR as well as for serial evaluation of AR as well as for serial follow-upfollow-up

Allows for:Allows for: Assessment of the anatomy of the aortic Assessment of the anatomy of the aortic

leaflets and the aortic rootleaflets and the aortic root Detection of the presence and severity Detection of the presence and severity

of ARof AR Characterization of LV size and functionCharacterization of LV size and function

M-Mode M-Mode EchocardiographyEchocardiography

The aortic regurgitation jet can cascade The aortic regurgitation jet can cascade across the anterior mitral leafletacross the anterior mitral leaflet Creates a high-frequency fluttering of the Creates a high-frequency fluttering of the

anterior mitral leafletanterior mitral leaflet Increased duration between E and A peaksIncreased duration between E and A peaks Increased distance between the maximal Increased distance between the maximal

anterior motion of the mitral valve in early anterior motion of the mitral valve in early diastole (E point) and the most posterior diastole (E point) and the most posterior motion of the interventricular septum (e.g., motion of the interventricular septum (e.g., increased E-point septal separation [EPSS])increased E-point septal separation [EPSS])

In acute AR, premature closure of the MV In acute AR, premature closure of the MV can also be seen by M-modecan also be seen by M-mode Due to rapidly increasing LV pressureDue to rapidly increasing LV pressure

AR by 2D EchoAR by 2D Echo

2D Echo will give you a detailed 2D Echo will give you a detailed evaluation of the aortic valve and rootevaluation of the aortic valve and root

Detailed evaluation of LV size and functionDetailed evaluation of LV size and function Many important causes of AR easily seen Many important causes of AR easily seen

on 2D imagingon 2D imaging Even when AR is severe, sometimes 2D Even when AR is severe, sometimes 2D

imaging is surprisingly normalimaging is surprisingly normal Indirect signs of AR:Indirect signs of AR:

Diastolic curving of anterior mitral leaflet with Diastolic curving of anterior mitral leaflet with concavity towards ventricular septum due to concavity towards ventricular septum due to the direct effect of the regurgitant jetthe direct effect of the regurgitant jet

Dilated aortic root due to aortoannular ectasia

Large, mobile vegetation

Bicuspid aortic valve with characteristic elliptical opening

Acute AR due to aortic dissection

Bekerdjian R, et al. Circulation 2005; 112: 125-134.

Color Flow DopplerColor Flow Doppler Color flow jet composed of 3 distinct segments:Color flow jet composed of 3 distinct segments:

Proximal flow convergence zone = area of flow Proximal flow convergence zone = area of flow acceleration into the orificeacceleration into the orifice

Vena contracta = narrowest and highest velocity region Vena contracta = narrowest and highest velocity region of the jet at or just downstream from the orificeof the jet at or just downstream from the orifice

The jet itself occurs distal to the orifice in the LV cavityThe jet itself occurs distal to the orifice in the LV cavity Measurement of the jet area or penetration into Measurement of the jet area or penetration into

the LV cavity is not accurate in assessing AR the LV cavity is not accurate in assessing AR severity, though:severity, though: If jet width/LVOT width < 25% If jet width/LVOT width < 25% specific for mild AR specific for mild AR If jet width/LVOT width > 65% If jet width/LVOT width > 65% specific for severe AR specific for severe AR This works best when regurgitant orifice is relatively This works best when regurgitant orifice is relatively

round in shape.round in shape.

Color Flow DopplerColor Flow Doppler

Color flow Doppler is the most common Color flow Doppler is the most common technique to visualize ARtechnique to visualize AR

Sensitivity > 95%Sensitivity > 95% False negatives can occur in tachycardia with mild False negatives can occur in tachycardia with mild

ARAR Frame rate allows only a few diastolic frames to Frame rate allows only a few diastolic frames to

be displayedbe displayed Can be overcome by using CW -- has a higher Can be overcome by using CW -- has a higher

sampling ratesampling rate Specificity ~100%Specificity ~100% Detects even trivial ARDetects even trivial AR

1% of subjects under age 401% of subjects under age 40 10-20% of patients greater than age 6010-20% of patients greater than age 60

Eccentric AR jetEccentric AR jet Width measured at Width measured at

origin of jet origin of jet adjacent to leafletsadjacent to leaflets

Jet width/LVOT Jet width/LVOT width is <25%width is <25%

Case of mild ARCase of mild AR

Jet width/LVOT Jet width/LVOT width > 65%width > 65%

Case of severe ARCase of severe AR

Bekerdjian R, et al. Circulation 2005; 112: 125-134.

(Same patient – aortic valve endocarditis as cause of AR)

AR jet directed toward anterior mitral leaflet

Vena ContractaVena Contracta The narrowest diameter of flow streamThe narrowest diameter of flow stream Independent of volume flow rate and driving Independent of volume flow rate and driving

pressure, relatively unaffected by instrument pressure, relatively unaffected by instrument settingssettings

Narrow range of values though, so care needed Narrow range of values though, so care needed to obtain optimal images. Ideal sample is:to obtain optimal images. Ideal sample is: Perpendicular to jet widthPerpendicular to jet width In zoom modeIn zoom mode Narrow sectorNarrow sector Minimum depthMinimum depth

For AR, vena contracta can be measured in For AR, vena contracta can be measured in parasternal long-axis view preferably in zoom parasternal long-axis view preferably in zoom mode.mode.

Vena ContractaVena Contracta

Vena contracta Vena contracta width of ≥ 6 mm width of ≥ 6 mm correlates well correlates well with severe AR with severe AR (sensitivity 95%, (sensitivity 95%, specificity 90%)specificity 90%)

Vena contracta Vena contracta width of < 3 mm width of < 3 mm specific for mild specific for mild AR.AR.

Enriquez-Sarano M, et al. NEJM 2004; 351: 1539-1546.

Proximal Isovelocity Proximal Isovelocity Surface AreaSurface Area

Acceleration of flow occurs proximal to the Acceleration of flow occurs proximal to the valve plane with a series of isovelocity valve plane with a series of isovelocity “surfaces” leading to the high-velocity jet in “surfaces” leading to the high-velocity jet in the regurgitant orifice.the regurgitant orifice. Velocity for a PISA can be determined as the Velocity for a PISA can be determined as the

aliasing velocity where a distinct red-blue interface aliasing velocity where a distinct red-blue interface seen (at this interface, velocity is equivalent to seen (at this interface, velocity is equivalent to Nyquist limit). Nyquist limit).

Assuming a hemispherical shape, the surface Assuming a hemispherical shape, the surface area of the PISA region is 2area of the PISA region is 2ππrr22

Peak regurgitant flow obtained by multiplying Peak regurgitant flow obtained by multiplying surface area by aliasing velocity, and effective surface area by aliasing velocity, and effective regurgitant orifice area (EROA) is peak regurgitant orifice area (EROA) is peak regurgitant flow divided by peak velocity regurgitant flow divided by peak velocity obtained by CW Doppler.obtained by CW Doppler.

PISA - LimitationsPISA - Limitations

Isovelocity contour flattens as it approaches the orifice, Isovelocity contour flattens as it approaches the orifice, underestimating flowunderestimating flow

Proximal structures can distort the isovelocity contourProximal structures can distort the isovelocity contour Sensitive to errors in radius measurementSensitive to errors in radius measurement

10% error in radius leads to 21% error in flow10% error in radius leads to 21% error in flow

Continuous Wave Continuous Wave DopplerDoppler

Because AR jet is high velocity, CW Doppler Because AR jet is high velocity, CW Doppler necessary to record envelope of jet.necessary to record envelope of jet.

Several types of info can be derived:Several types of info can be derived: AntegradeAntegrade flowflow velocityvelocity Signal intensitySignal intensity relative to antegrade flow relative to antegrade flow Time courseTime course (shape) of velocity curve (shape) of velocity curve

AR results in increased antegrade volume AR results in increased antegrade volume flow rate across AV, which is reflected in an flow rate across AV, which is reflected in an increase in the antegrade velocity across increase in the antegrade velocity across the valve.the valve. The greater the severity of AR, the higher the The greater the severity of AR, the higher the

antegrade velocity across the AVantegrade velocity across the AV Must also consider possibility of coexisting ASMust also consider possibility of coexisting AS

AR

Antegrade

Signal intensity is proportional to # RBCs contributing Signal intensity is proportional to # RBCs contributing to regurgitant signal.to regurgitant signal.

Can compare intensity of regurgitant signal to Can compare intensity of regurgitant signal to antegrade flow as a qualitative estimate of regurgitant antegrade flow as a qualitative estimate of regurgitant severity.severity.

Weak signal reflects mild severity; signal nearly equal Weak signal reflects mild severity; signal nearly equal to antegrade flow reflects severe regurgitation.to antegrade flow reflects severe regurgitation.

CW Doppler: Pressure CW Doppler: Pressure Half-TimeHalf-Time

Shape of AR velocity curve depends on time Shape of AR velocity curve depends on time course of diastolic pressure difference across course of diastolic pressure difference across AVAV

Chronic severe AR results in increased aortic Chronic severe AR results in increased aortic pulse pressure with low aortic EDP. Rapid pulse pressure with low aortic EDP. Rapid rate of decline in aortic pressure is reflected rate of decline in aortic pressure is reflected in steeper diastolic deceleration slope (even if in steeper diastolic deceleration slope (even if LVEDP remains low).LVEDP remains low). Thus, diastolic deceleration slope provides a Thus, diastolic deceleration slope provides a

semiquantitative measure of AR severity.semiquantitative measure of AR severity. A flat slope (PA flat slope (P1/21/2 > 500 msec) is consistent > 500 msec) is consistent

with mild AR, and a steep slope (Pwith mild AR, and a steep slope (P1/21/2 < 200 < 200 msec) indicates severe AR.msec) indicates severe AR.

For a given severity of AR, PFor a given severity of AR, P1/21/2 will be will be shortened by elevated LVEDP or vasodilator shortened by elevated LVEDP or vasodilator therapy that reduces AR.therapy that reduces AR.

Pressure Half-TimePressure Half-Time

With acute AR, LV compliance has not yet With acute AR, LV compliance has not yet adapted leading to significant increase in adapted leading to significant increase in LVEDP. In extreme cases, aortic and LV EDP LVEDP. In extreme cases, aortic and LV EDP may equalize at end-distole, resulting in a may equalize at end-distole, resulting in a triangular-shaped CW-Doppler with linear triangular-shaped CW-Doppler with linear deceleration slope from maximum velocity to deceleration slope from maximum velocity to baseline.baseline.

Limitations of pressure half-time assessment:Limitations of pressure half-time assessment: Pressure half-time sensitive to chronicity of ARPressure half-time sensitive to chronicity of AR

Acute AR leads to much shorter values than chronic AR Acute AR leads to much shorter values than chronic AR when LV is dilated with increased compliancewhen LV is dilated with increased compliance

Pressure half-time varies with SVRPressure half-time varies with SVR Vasodilators may shorten the pressure half-time even as Vasodilators may shorten the pressure half-time even as

the aortic regurgitant fraction improves.the aortic regurgitant fraction improves.

Pressure Half-TimePressure Half-Time

Regurgitant Volume or Regurgitant Volume or FractionFraction

Can compare flow through AV versus MV or Can compare flow through AV versus MV or PVPV

Stroke volume at any valve annulus is derived Stroke volume at any valve annulus is derived as the product of CSA and VTI of flow at the as the product of CSA and VTI of flow at the annulusannulus

In the absence of regurgitation, SV In the absence of regurgitation, SV determinations at different sites (LVOT, mitral determinations at different sites (LVOT, mitral annulus, pulmonic annulus) should be equalannulus, pulmonic annulus) should be equal

In the presence of regurgitation of one valve, In the presence of regurgitation of one valve, without any intracardiac shunt the flow without any intracardiac shunt the flow through the affected valve is larger than the through the affected valve is larger than the other valvesother valves RV is the difference between the two flowsRV is the difference between the two flows RF is the RV divided by forward stroke volume RF is the RV divided by forward stroke volume

through the regurgitant valve.through the regurgitant valve.

Regurgitant Volume or Regurgitant Volume or FractionFraction

Regurgitant Volume or Regurgitant Volume or FractionFraction

Regurgitant Volume (fraction):Regurgitant Volume (fraction): Mild: < 30 cc (< 30%)Mild: < 30 cc (< 30%) Mild-moderate: 30-44 cc (30-39%)Mild-moderate: 30-44 cc (30-39%) Moderately severe: 45-59 cc (40-49%)Moderately severe: 45-59 cc (40-49%) Severe: ≥60 cc (≥50%)Severe: ≥60 cc (≥50%)

Limitations:Limitations: Assumes normal flow through comparison Assumes normal flow through comparison

valvevalve Cannot be used in presence of shuntsCannot be used in presence of shunts Sensitive to small measurement errors Sensitive to small measurement errors

(measurement errors of the radius and (measurement errors of the radius and tracing the VTI)tracing the VTI)

RF by CW Doppler of RF by CW Doppler of Distal ArchDistal Arch

Aortic regurgitant fraction can be Aortic regurgitant fraction can be estimated by ratio of reversed flow VTI / estimated by ratio of reversed flow VTI / forward flow VTI in the distal aortic arch.forward flow VTI in the distal aortic arch.

Antegrade

Retrograde

Aortic Flow ReversalAortic Flow Reversal

An important supportive sign of severe AR is An important supportive sign of severe AR is diastolic flow reversal in the descending diastolic flow reversal in the descending aorta.aorta.

Holodiastolic flow reversal usually indicates Holodiastolic flow reversal usually indicates at least moderate AR at least moderate AR

Best measured with PW Doppler from a Best measured with PW Doppler from a suprasternal probe position.suprasternal probe position.

If observed in the proximal abdominal aorta If observed in the proximal abdominal aorta (from the subcostal position), is even more (from the subcostal position), is even more sensitive (100%) and specific (97%) for sensitive (100%) and specific (97%) for severe AR.severe AR.

False positives may occur if a PDA is present.False positives may occur if a PDA is present.

Zoghbi WA, et al. JASE 2003; 16: 777-802.

Zoghbi WA, et al. JASE 2003; 16: 777-802.

Cardiac CatheterizationCardiac Catheterization May be needed to evaluate coronary anatomy in May be needed to evaluate coronary anatomy in

patients requiring surgical intervention.patients requiring surgical intervention. Men age > 35 years, pre-menopausal women age > 35 Men age > 35 years, pre-menopausal women age > 35

years with risk factors for CAD, or postmenopausal womenyears with risk factors for CAD, or postmenopausal women Supravalvular aortography = semiquantitative way to Supravalvular aortography = semiquantitative way to

grade AR, based on amount of contrast in LV after grade AR, based on amount of contrast in LV after aortographyaortography Mild AR (1+): contrast appears in LV but clears after each Mild AR (1+): contrast appears in LV but clears after each

beat.beat. Moderate AR (2+): faint opacification of entire LV over Moderate AR (2+): faint opacification of entire LV over

several cardiac cycles.several cardiac cycles. Mod-severe AR (3+): opacification of entire LV with same Mod-severe AR (3+): opacification of entire LV with same

intensity as aortaintensity as aorta Severe AR (4+): opacification of entire LV on first heart Severe AR (4+): opacification of entire LV on first heart

beat with intensity higher than aorta.beat with intensity higher than aorta. Subjective, depends on amount of contrast injected Subjective, depends on amount of contrast injected

and the size of the LV, and correlates poorly with and the size of the LV, and correlates poorly with regurgitant volume particularly in patients with regurgitant volume particularly in patients with dilated LVs.dilated LVs.

Cardiac MRCardiac MR CMR is widely recognized as the non-invasive gold CMR is widely recognized as the non-invasive gold

standard for quantification of LV volumes and standard for quantification of LV volumes and ejection fraction.ejection fraction. Can overcome the limitations of echo, such as studies Can overcome the limitations of echo, such as studies

limited by body habitus or cases with eccentric limited by body habitus or cases with eccentric regurgitant jets.regurgitant jets.

Phase velocity encoding is used to calculate Phase velocity encoding is used to calculate forward stroke volume through the AV; total LV forward stroke volume through the AV; total LV stroke volume is determined from LVEDV and stroke volume is determined from LVEDV and LVESV, and the difference between aortic and LV LVESV, and the difference between aortic and LV stroke volumes is the regurgitant volume.stroke volumes is the regurgitant volume.

Volumetric CMR assessment of AR has been shown Volumetric CMR assessment of AR has been shown to be accurate and reproducible.to be accurate and reproducible.

CMR has the potential to be a very useful tool for CMR has the potential to be a very useful tool for serial evaluations, though referring physicians are serial evaluations, though referring physicians are often more comfortable with qualitative often more comfortable with qualitative interpretations of regurgitation severity such as interpretations of regurgitation severity such as those provided by echo assessment.those provided by echo assessment.

Cardiac MRCardiac MR Gelfand et al. addressed the issue of Gelfand et al. addressed the issue of

concordance between quantitative CMR and concordance between quantitative CMR and qualitative echocardiographic determinations qualitative echocardiographic determinations of regurgitant severity.of regurgitant severity.

Compared echo and CMR findings in 141 Compared echo and CMR findings in 141 consecutive patients with varying degrees of consecutive patients with varying degrees of MR and/or AR, to identify CMR regurgitant MR and/or AR, to identify CMR regurgitant fractions that correlated with qualitative mild, fractions that correlated with qualitative mild, moderate, and severe regurgitaion by echo.moderate, and severe regurgitaion by echo.

Average age 53 ± 15 yr, 43% female. 24 with Average age 53 ± 15 yr, 43% female. 24 with AR, 83 with MR, 35 with no MR/AR. Median AR, 83 with MR, 35 with no MR/AR. Median interval 31 days between CMR and Echo.interval 31 days between CMR and Echo.

Gelfand EV, et al. Journal of CMR 2006; 8: 503-507.

Cardiac MRCardiac MR The mean CMR aortic The mean CMR aortic

regurgitant fractions regurgitant fractions for each for each echocardiographic echocardiographic grade was significantly grade was significantly different (p < 0.001 for different (p < 0.001 for trend, p<0.05 for each trend, p<0.05 for each pairwise comparison)pairwise comparison)

The CMR-RF thresholds The CMR-RF thresholds with maximal with maximal agreement for aortic agreement for aortic regurgitation:regurgitation: Mild ≤ 15%Mild ≤ 15% Moderate 16-27%Moderate 16-27% Mod-sev or severe > Mod-sev or severe >

27%27%

These thresholds yielded These thresholds yielded 100% concordance within 100% concordance within 1 regurgitation grade.1 regurgitation grade.

For patients without AR on For patients without AR on echo, the CMR aortic echo, the CMR aortic regurgitant fraction was 2 regurgitant fraction was 2 ± 2%.± 2%.

Gelfand EV, et al. Journal of CMR 2006; 8: 503-507.

Serial Testing with EchoSerial Testing with Echo If chronic nature of lesion uncertain and no If chronic nature of lesion uncertain and no

initial surgical indication, should repeat exam initial surgical indication, should repeat exam and echo within 2-3 months after initial and echo within 2-3 months after initial evaluation.evaluation.

Asx, mild AR, little/no LV dilation, normal LV Asx, mild AR, little/no LV dilation, normal LV systolic function: see yearly, echo q2-3 yearssystolic function: see yearly, echo q2-3 years

Asx, severe AR, significant LV dilation (LVEDD Asx, severe AR, significant LV dilation (LVEDD > 60 mm), normal LV fx: echo q6-12 months> 60 mm), normal LV fx: echo q6-12 months

Asx, severe AR, severe LV dilation (LVEDD > Asx, severe AR, severe LV dilation (LVEDD > 70 mm), normal LV fx: echo q4-6 months.70 mm), normal LV fx: echo q4-6 months.

Repeat echo for onset of symptoms, equivocal Repeat echo for onset of symptoms, equivocal history of changing symptoms or exercise history of changing symptoms or exercise tolerance, or clinical findings to suggest tolerance, or clinical findings to suggest worsening regurgitation or progressive LV worsening regurgitation or progressive LV dilatation.dilatation.

Bonow RO, et al. Circulation 2006; 114: e84-e231.

Chronic AR Management - Chronic AR Management - SurgerySurgery

AR is a surgical disease. The timing of AR is a surgical disease. The timing of surgery is clinically dependent.surgery is clinically dependent.

In patients with pure, chronic AR, AVR In patients with pure, chronic AR, AVR should be considered only if AR is severe.should be considered only if AR is severe. Operative mortality for AVR ~4%, higher with Operative mortality for AVR ~4%, higher with

concomitant aortic root replacement or CABG concomitant aortic root replacement or CABG or if comorbidities such as advanced age. or if comorbidities such as advanced age.

Death rate for Asx with normal LV Death rate for Asx with normal LV <0.2%/year.<0.2%/year.

Symptomatic pts with chronic severe AR: Symptomatic pts with chronic severe AR: >10%/yr>10%/yr

Bonow RO, et al. Circulation 2006; 114: e84-e231.

ACC/AHA 2006 ACC/AHA 2006 GuidelinesGuidelines

Class I indications for AVR in chronic, Class I indications for AVR in chronic, severe AR:severe AR: Symptomatic patientsSymptomatic patients Asymptomatic with LVEF ≤ 50% at restAsymptomatic with LVEF ≤ 50% at rest Undergoing CABG or other heart/aorta Undergoing CABG or other heart/aorta

surgerysurgery Class IIa for AVR in chronic, severe AR:Class IIa for AVR in chronic, severe AR:

Asymptomatic, normal LV systolic function Asymptomatic, normal LV systolic function (LVEF ≥ 50%) but with severe LV dilatation (LVEF ≥ 50%) but with severe LV dilatation (LVEDD > 75 mm or LVESD > 55 mm)(LVEDD > 75 mm or LVESD > 55 mm)

Bonow RO, et al. Circulation 2006; 114: e84-e231.

Surgical OutcomesSurgical Outcomes 450 patients with 450 patients with

severe AR:severe AR: Operative mortality Operative mortality

14%, 6.7%, and 3.7% 14%, 6.7%, and 3.7% for those with LVEF for those with LVEF <35%, 36-49%, and ≥ <35%, 36-49%, and ≥ 50%, respectively.50%, respectively.

Post-op outcome for Post-op outcome for pts with reduced LVEF pts with reduced LVEF pre-op depends on pre-op depends on magnitude of magnitude of reduction.reduction. Pre-op LVEF < 35%, Pre-op LVEF < 35%,

10-year post-op 10-year post-op survival rate is 41%survival rate is 41%

Pre-op LVEF 35-49%, Pre-op LVEF 35-49%, survival 56%.survival 56%.

Pre-op LVEF ≥ 50%, Pre-op LVEF ≥ 50%, survival 70% at 10 survival 70% at 10 years post-op.years post-op.

Chaliki HP, et al. Circulation 2002; 106: 2687-2693.

Post-Op OutcomesPost-Op Outcomes Surgery for symptomatic patients with severe Surgery for symptomatic patients with severe

AR reduces LV volumes, LV mass, wall stress AR reduces LV volumes, LV mass, wall stress and increases LVEF. and increases LVEF.

If asymptomatic, some say surgery is ideally If asymptomatic, some say surgery is ideally performed when LVEF 50-55%. performed when LVEF 50-55%.

Dilated LV or low LVEF pre-op can still benefit Dilated LV or low LVEF pre-op can still benefit from surgery.from surgery.

Patients with markedly decreased LVEF should Patients with markedly decreased LVEF should not be denied surgery – these patients generally not be denied surgery – these patients generally have an improvement in LVEF post-op as a have an improvement in LVEF post-op as a result of relief of high afterload, especially if LV result of relief of high afterload, especially if LV dysfunction has lasted less than one year. dysfunction has lasted less than one year. It is almost never “too late” to operate in chronic, It is almost never “too late” to operate in chronic,

severe AR.severe AR.

Vasodilators?Vasodilators? Short-term studies on the effects of Short-term studies on the effects of

vasodilators in acute severe AR have vasodilators in acute severe AR have suggested improvement in hemodynamic suggested improvement in hemodynamic and structural parameters.and structural parameters.

The long-term benefit of vasodilator therapy The long-term benefit of vasodilator therapy in chronic severe AR is unclear.in chronic severe AR is unclear.

A total of 10 studies of vasodilator therapy A total of 10 studies of vasodilator therapy in asymptomatic patients with chronic, in asymptomatic patients with chronic, severe AR have yielded conflicting and quite severe AR have yielded conflicting and quite inconsistent results. inconsistent results. Only two studies have assessed clinical outcomes Only two studies have assessed clinical outcomes

such as time to AVR (the remainder have only such as time to AVR (the remainder have only reported hemodynamic and/or structural reported hemodynamic and/or structural parameters).parameters).

Vasodilators – Clinical Vasodilators – Clinical OutcomesOutcomes

Scognamiglio et al. randomized 143 asymptomatic Scognamiglio et al. randomized 143 asymptomatic patients with chronic, severe AR to nifedipine or patients with chronic, severe AR to nifedipine or digoxin.digoxin.

Patients treated with nifedipine had a significantly Patients treated with nifedipine had a significantly lower rate of progression to AVR than digoxin lower rate of progression to AVR than digoxin patients.patients.

By 6 years, a mean of 34% ± 6% of digoxin patients By 6 years, a mean of 34% ± 6% of digoxin patients underwent AVR, while 15% ± 3% of nifedipine underwent AVR, while 15% ± 3% of nifedipine patients underwent AVR.patients underwent AVR.

Twenty digoxin pts. required AVR for reduced LV fx Twenty digoxin pts. required AVR for reduced LV fx and/or onset of symptoms, while all 6 nifedipine pts and/or onset of symptoms, while all 6 nifedipine pts who needed surgery were d/t reduced LVEF.who needed surgery were d/t reduced LVEF.

Post-op LVEF after AVR significantly higher in Post-op LVEF after AVR significantly higher in nifedipine versus digoxin (65% ± 4% vs. 58% ± 8%). nifedipine versus digoxin (65% ± 4% vs. 58% ± 8%).

Scognamiglio R, et al. NEJM 1994; 331: 689-694.

Scognamiglio R, et al. NEJM 1994; 331: 689-694.

Vasodilators – Clinical Vasodilators – Clinical OutcomesOutcomes

Evangelista et al. randomly assigned 95 patients Evangelista et al. randomly assigned 95 patients with chronic, severe AR to nifedipine, enalapril, or with chronic, severe AR to nifedipine, enalapril, or placebo.placebo.

Followed patients for ~7 years.Followed patients for ~7 years. Rates of AVR were not significant across the 3 Rates of AVR were not significant across the 3

groups: groups: 12/31 (39%) of control group12/31 (39%) of control group 16/32 (50%) of enalapril group16/32 (50%) of enalapril group 13/32 (41%) of nifedipine group13/32 (41%) of nifedipine group 11% of patients dropped out of study, though on-11% of patients dropped out of study, though on-

treatment analysis yielded similar rates of treatment analysis yielded similar rates of progressionprogression

No significant changes in SBP, DBP, or HR noted; No significant changes in SBP, DBP, or HR noted; furthermore saw no significant changes in LVEF, furthermore saw no significant changes in LVEF, LVESD, LVEDVILVESD, LVEDVI

Evangelista A, et al. NEJM 2005; 353: 1342-1349.

Evangelista A, et al. NEJM 2005; 353: 1342-1349.

Current Guidelines for Current Guidelines for VasodilatorsVasodilators

Class I:Class I: Chronic therapy in severe AR with symptoms Chronic therapy in severe AR with symptoms

or LV dysfunction when not a surgical or LV dysfunction when not a surgical candidate.candidate.

Class IIa:Class IIa: Short-term therapy to improve hemodynamics Short-term therapy to improve hemodynamics

in patients with severe CHF Sx and severe LV in patients with severe CHF Sx and severe LV dysfunction before proceeding with AVR.dysfunction before proceeding with AVR.

Class IIb:Class IIb: Long-term therapy in asymptomatic patients Long-term therapy in asymptomatic patients

with severe AR who have LV dilatation but with severe AR who have LV dilatation but normal systolic function (previously a class I normal systolic function (previously a class I indication before the Evangelista article).indication before the Evangelista article).

Bonow RO, et al. Circulation 2006; 114: e84-e231.

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