Contemporary CardiologyEssential EchocardiographyA Practical Handboo - PDF document

Contemporary Cardiology:Essential Echocardiography:A Practical Handbook With DVDEdited by:S. D. Solomon ©Humana Press,Totowa,NJ 223 Echocardiographic Evaluation of Aortic RegurgitationSusan M. Sallach, and Sharon C. Reimold, NTRODUCTIONSSESSMENTIN / Aortic Regurgitation225Aortic regurgitant flow leads to rapid increase in leftventricular diastolic pressure. When this exceeds leftatrial pressure,the mitral valve closes. Premature closureof the mitral valve and other echocardiographic signs ofleft ventricular overload may be evident (Because aortic regurgitation hemodynamically over-loads the left ventricle,it leads to an absolute increase inleft ventricle ejection fraction. Patients whose ejectionfraction falls below 55% have depressed left ventricularsystolic function. This may be partly reversible if aorticvalve replacement is undertaken within 6 mo of the devel-opment of systolic dysfunction. For this reas

on assessmentechocardiographic examination in aortic regurgitation. DOPPLER ECHOCARDIOGRAPHICEVALUATION OF THE PATIENT WITH AORTIC REGURGITATIONColor flow Doppler imaging provides a semiquantita-tive method to evaluate the severity of aortic regurgita-tion. The regurgitant jet can be visualized by color flow Fig. 1. Anatomical relationships of aortic valve and leaflets on two-dimensional echocardiography. Fig. 2. Sketch illustrating various etiologies of aortic regurgitation. / Aortic Regurgitation227Fig. 5. Bicuspid aortic valves may have a visible raphe„the fusion ridge of two aortic leaflets. The aortic orifice often exhibits an ovoidor fish mouthŽappearance during systole. PSAX,parasternal short axis view. (Please companion DVD for corresponding video.) Fig. 6. (A)Left ventricle dimensions (parasternal long-axis [PLAX] measurements). / Aortic Regurgitation229 Fig. 9. Semi-quantitative assessment of aor

tic regurgitation severity by the vena contracta width. Note the three components of the aortic regurgitant flow:the flow convergence„above the orifice,the vena contracta„through the orifice,and the regurgitant jet„below the orifice. consistent with moderate aortic regurgitation,whereas avena contracta width greater than 0.6 cm indicates severeaortic regurgitation (Visualization of the color jet of aortic regurgita-tion on the parasternal short-axis view is anothermethod for quantitation of the severity of regurgita-). The regurgitant color jet area can bemeasured and compared to that of the left ventricularoutflow tract with the result expressed as a percent-). Using this simplified area ratiomethod,patients with mild aortic regurgitation haveratios of less than 5%. Severe aortic regurgitationoccurs when ratios exceed 60%,with a broad rangebetween 5 and 60% indicative of moderate aorticregurgitation.The col

or jet disturbance of aortic regurgitation is also easily visualized from the apical windows companion DVD for corre-sponding video). The color jet length and area,how-ever,are less proportional (in these views) to thedegree of regurgitation and are more influenced bythe aortic to left ventricular diastolic pressure gradi-ent as well as interactions between the regurgitantjet and the outflow tract walls (,please companion DVD for corresponding video). Theview but the parasternal projection provides betterQUANTITATIVE MEASURES OF AORTIC REGURGITATIONContinuous-wave Doppler of the aortic regurgitantjet reflects the pressure difference between the aortaand the left ventricle during diastole. The continuous-waveDoppler signal is best measured from the apicalwindows. For eccentric jets,better signals may beobtained from the second right intercostal window.The denser the spectral envelope,the more severe is thereg

urgitation (). The rate of deceleration of thecontinuous-wave Doppler signal is both a function ofthe degree of regurgitation and the ventricular end-). As the degree of regur-gitation increases,the aortic diastolic pressure decreasesand the left ventricular end-diastolic pressure increases.This leads to a rapid drop-off in pressure (as well asvelocity) across the valves„corresponding to the fami-liarclinical signs of a widened pulse pressure. A pres-severe aortic regurgitation. Moderate aortic regurgita-whereas mild regurgitation is indicated by a pressurehalf-time exceeding 500 ms (). Overall,pres-of aortic regurgitation than volumetric measures ofaortic regurgitation,as pressure-half time is influ- Sallach and Reimoldpressures. Accurate measurement of pressure half-signal from the regurgitant jet. Patients with smallvolumes of regurgitation or poor windows may haveurement difficult.Calculation of regurgit

ant volume and regurgitantfraction provides a better quantization of the severityof valve insufficiency (). The regurgitant vol-ume is equal to flow out the aortic valve (aortic strokevolume) minus flow through the mitral valve (mitralstroke volume). Calculation of regurgitant volumerequires measurement of the left ventricular outflowtract and mitral annular diameters,as well as velocitytime integrals (VTI) of flow through the left ventricu-lar outflow tract and the mitral annulus. Aortic flow isof the left ventricular outflow multiplied by the VTI ofaortic flow. Mitral flow is calculated as eter multiplied by the VTI of mitral flow. Mild aorticregurgitation is considered when the regurgitant frac-tion is less than 30mL/beat,moderate…between 30and 60 mL/beat,and severe regurgitation„in excessThe regurgitant fraction is equal to the regurgitantvolume divided by the total stroke volume. The totalstroke volume

is equivalent to flow out the aortic valve Fig. 10. (A)The color jet area measured from the parasternal short-axis view (PSAX) is proportional to the regurgitation orifice area.In these images,color from the aortic regurgitation (blue) is seen centrally,but varies throughout diastole owing to a changingfice area (please Semi-quantitative assessment of aortic regurgitation severity by color flowDoppler assessment (simplified jet/left ventricular outflow tract [LVOT] area ratio) using PSAX. / Aortic Regurgitation231as previously defined. Regurgitant fractions of less than30% are consistent with mild regurgitation,30…50%with moderate regurgitation,and more than 50% withsevere regurgitation.The regurgitant orifice area may be calculated as theregurgitant volume multiplied by the VTI of the continuous-waveDoppler jet (). This parameter representsthe average size of the defect in the aortic valve duringFig. 11. )

From the apical windows,the aortic regurgitation jet appears as a diastolic color flow disturbance in the left ventricularoutflow tract. Jet length and jet area are influenced by the aortic driving pressure (aorta-to-left ventricular pressure) and aless reliable indicators of disease severity. Measuring jet width from the apical projections is possible,but generally less re) Continuous-wave (CW) Doppler assessment of flow across the aortic valve in a patient with aorticregurgitation. Many patients have mixed aortic valve disease. Increased transvalvular systolic velocities may represent stenosicompanion DVD for corresponding video.) Sallach and Reimold Fig. 12. Signal intensities in aortic regurgitation severity.Fig. 13. Deceleration rate. The rate of deceleration of the continuous-wave Doppler signal reflects both the degree of regurgitationand the ventricular end-diastolic pressure. Sallach and Reimoldbec

omes sustained throughout diastole at velocitiesexceeding 20 cm/s. Criteria for flow reversal have beenestablished in the distal aortic arch. Significant sustainedreversal in the abdominal aorta is also a sensitive signof severe aortic regurgitation.Individuals with severe aortic regurgitation may exhibitaltered mitral flow patterns. Because aortic regurgitationresults in elevated diastolic left ventricular pressures andmitral inflow ceases early in diastole,this can lead toshortened mitral deceleration times. For this reason,the Fig. 16. The regurgitant orifice area or EROA represents the average size of the defect in the aortic valve during diastole and is pro-portional to regurgitant severity. The regurgitant volume across the aortic valve may be calculated as the difference between the LVOTvolume and the transmitral volume,assuming there is no significant mitral regurgitation (Fig. 17. Aortic flow revers

al. Diastolic flow reversal can be seen in significant aortic regurgitation by Doppler interrogation of flowin the aortic arch and descending thoracic aorta. In this pulsed wave Doppler envelope,the regurgitant flow velocities almost ethose of systolic forward flow„a feature indicative of severe aortic regurgitation. / Aortic Regurgitation235Table 3AEchocardiographic Findings of Aortic Regurgitation and Relationship to Disease Severity Literature evidence for grading ParametersBest TTE viewwith selected references Two-dimensional/M-modeLA dilatationPLAX,A4C,A5C,A3CPremature MV closurePLAX/PSAXAMVL fluttering or reverse domingPLAX/PSAX M-modeIncreased E-point septal separation PLAX M-mode(between AMVL and septum)LVdilatation/functionA4C,A5C,A3CSensitive for chronicityAortic annular dilatationPLAX,PSAXDiastolic AV opening/saggingPLAX/PSAX Simple,if present,AI is usually severeM-mode,A5C,A3CFlow propagation ve

locityPLAXOnbasili 2002Aortic root dilatationA3C,R-PLAX, A4C,apical four-chamber; A3C,apical three-chamber; A5C,apical five-chamber; AI,aortic regurgitation; AMVL,anterior mitral valveleaflet; LA,left atrium; MV,mitral valve; PLAX,parasternal long-axis; PSAX,parasternal short-axis; TTE,transthoracic echocardiography.Table 2Assessment of Aortic Regurgitation Severity by Doppler Echocardiography: A Summary or Semi-Quantitative Methods Classification of aortic regurgitation severity Aortic regurgitation VariableMildMild-moderateModerate-severeSevereJet/LVOT width25…44%45…64%Vena contracta width (mm)3…5.93…5.9Regurgitant volume (mL/beat)30…4445…59Regurgitant fraction30…39%40…49%Effective regurgitant orifice area (mm) 10…1920…29Pressure half time (P 1/2 t) (ms)-7;ं.;瀀500350…500200…350 )22…32…3.5LVOT,left ventricular outflow tract.Table 3BEchocardiographic Findings of Aortic Regurgitation and Relations

hip to Disease Severity Literature evidence for grading ParametersBest TTE viewwith selected references Color flow imaging LVfilling/dilation/jet directionPLAX,A5C,A3C,A4CRJAPSAXc/w angiographic severity (Perry 1987, Spain 1989,Enrique-Sarano 1993) / Aortic Regurgitation237assessment of mitral valve area in a patient with mitralstenosis can be overestimated in patients with aorticinsufficiency.Common semi-quantitative methods using Dopplerchocardiography for grading aortic regurgitant severityare shown in Table 2. A summary of various echocar-diographic parameters used to assess aortic regurgita-Table 3A…DAscah KJ,Stewart WJ,Jiang L,et al. A Doppler-two-dimensionalechocardiographic method for quantitation of mitral regurgi-Boughner DR. Assessment of aortic insufficiency by transcutaneousCape EG,Skoufis EG,Weyman AE,Yoganathan AP,Levine RA. A new method for noninvasive quantification of valvular regur-based

on conservation of momentum. In vitro validation.Cape EG,Yoganathan AP,Weyman AE,Levine RA. Adjacent solidboundaries alter the size of regurgitant jets of Doppler colorflow maps. J Am Coll Cardiol 1991;17:1094…1102.Chen C,Koschyk D,Brockhoff C,et al. Noninvasive estimation ofregurgitant flow rate and volume in patients with mitralregurgitation by Doppler color mapping of accelerating flowfield. J Am Coll Cardiol 1993;21:374…383.Enriquez-Sarano M,Bailey KR,Seward JB,Tajik AJ,Krohn MJ,Mays JM. Quantitative Doppler assessment of valvular regur-gitation.CirEnriquez-Sarano M,Seward JB,Bailey KR,Tajik AF. Effectiveregurgitant orifice area:a noninvasive Doppler developmentof an old hemodynamic concept. J Am Coll Cardiol 1994;23:Giesler M,Grossmann G,Schmidt A,et al. Color Doppler echocar-diographic determination of mitral regurgitant flow from theproximal velocity profile of the flow convergence region. AmGrayburn

PA,Smith MD,Handshoe R,Friedman BJ,DeMaria AN.Detection of aortic insufficiency by standard echocardiogra-phy,pulsed Doppler echocardiography,and auscultation:acomparison of accuracies. Ann Intern Med 1986;104:599…605.Griffin BP,Flachskampf FA,Siu S,Weyman AE,Thomas JD. Theeffects of regurgitant orifice size,chamber compliance,and sys-temic vascular resistance on aortic regurgitant velocity slopeand pressure half-time. Am Heart J 1991;122:1049…1056. Jenni R,Ritter M,Eberli F,Grimm J,Krayenbuehl HP. Quantificationof mitral regurgitation with amplitude-weighted mean velocityfrom continuous wave Doppler spectra. Circulation 1989;79:Kitabatake A,Ito H,Inoue M,et al. A new approach to noninvasiveevaluation of aortic regurgitant fraction by two-dimensionalDoppler echocardiography. Circulation 1985;72:523…529.Masuyama T,Kodama K,Kitabatake A,et al. Noninvasive evaluationof aortic regurgitation by continuous wave D

oppler echocardio-graphy. Circulation 1986;73:460…466.Onbasili OA,Tekten T,Ceyhan C,Ercan E,Mutlu B. A new echocar-diographic method for the assessment of the severity of aorticregurgitation:color M-mode flow propagation velocity. J AmÖzkan M,Özdemir N,Kaymaz C,Kirma C,Deligönül U.Measurement of aortic valve anatomic regurgitant area usingtransesophageal echocardiography:implications for thequantitation of aortic regurgitation. J Am Soc Echo 2002;2:Padial LR,Oliver A,Vivaldi M,et al. Doppler echocardiographicassessment of progression of aortic regurgitation. Am JPai RG,Stoletniy LN. Rates of left ventricular isovolumic pressurerise and fall from the aortic regurgitation velocity signal:description of the method and validation in human beings. J Am Soc Echo 1998;11:631…637.Perry GJ,Helmcke F,Nanda NC,Byard C,Soto B. Evaluation ofaortic insufficiency by Doppler color flow mapping. J AmRecusani F,Bargiggia GS,Y

oganathan AP,et al. A new method forquantification of regurgitant flow rate using color Dopplerflow imaging of the flow convergence region proximal toTable 3DEchocardiographic Findings of Aortic Regurgitation and Relationship to Disease Severity Literature evidence for grading ParametersBest TTE viewwith selected references Jet width:LVOT widthPLAX,PSAXWillems 1997Jet CSA:LVOT CSAPLAX,PSAXWillems 1997Regurgitant volume and fractionPLAX and A3C,A5CAscah 1985 (AVMV),Kitabatake 1985 (AVPV),Rokey 1986 (AVEROA PLAX and A3C,A5CEnriquez-Sarano 1993,1994 Jet MomentumPLAX and A3C,A5CNot widely used,Cape 1989MV,mitral valve; PLAX,parasternal long-axis; PSAX,parasternal short-axis; AV,aortic valve; A5C,apical five-chamber view; A3C,apical three-chamber view; A4C,apical four-chamber view; LVOT,left ventricular outflow tract; TTE,transthoracic echocardiographCSA,cross-sectional area; EROA,effective regurgitant orifice a