American Society of Echocardiography: Recommendations for Evaluation of the Severity of Native...

Eur J Echocardiography (2003) 4, 237e261doi:10.1016/j.euje.2003.07.001

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GUIDELINES

American Society of Echocardiography:

Recommendations for Evaluation of the Severity

of Native Valvular Regurgitation with

Two-dimensional and Doppler Echocardiography

A Report from the American Society of Echocardiography’sNomenclature and Standards Committee and The Task Forceon Valvular Regurgitation, Developed in Conjunction with theAmerican College of Cardiology Echocardiography Committee,The Cardiac Imaging Committee, Council on Clinical Cardiology,The American Heart Association, and the European Society of

Cardiology Working Group on Echocardiography, Represented by:

W. A. Zoghbi, M. Enriquez-Sarano, E. Foster, P. A. Grayburn, C. D. Kraft,R. A. Levine, P. Nihoyannopoulos, C. M. Otto, M. A. Quinones, H. Rakowski,

W. J. Stewart, A. Waggoner and N. J. Weissman

American Society of Echocardiography, 1500 Sunday Drive, Suite 102, Raleigh, NC 27607, USA

8, 2016

Introduction

Valvular regurgitation has long been recognized as animportant cause of morbidity and mortality. Al-though the physical examination can alert theclinician to the presence of significant regurgitation,diagnostic methods are often needed to assess theseverity of valvular regurgitation and remodeling ofthe cardiac chambers in response to the volume

Reprinted from the Journal of the American Society of Echo-cardiography, July 2003, Vol. 16, No. 7, pp. 777e802.

These recommendations are endorsed by the American College ofCardiology (ACC), the American Heart Association (AHA), andthe European Society of Cardiology (ESC). Representative fromthe ACC Echocardiography Committee: Elyse Foster, MD;representative from the Cardiac Imaging Committee, Council onClinical Cardiology, AHA: Miguel A. Quinones, MD; representa-tive from the ESC Working Group on Echocardiography: PetrosNihoyannopoulos, MD.

Address document reprint requests to the American Society ofEchocardiography, 1500 Sunday Drive, Suite 102, Raleigh, NC27607, USA. Tel: +1 919 787-5181.

Received 17 June 2003; accepted 24 July 2003.

1525-2167/03/ $30.00/0 � 2003 The American Society o

overload state. Echocardiography with Doppler hasrecently emerged as the method of choice for thenoninvasive detection and evaluation of the severityand etiology of valvular regurgitation. This articleoffers a critical review of echocardiographic andDoppler techniques used in the evaluation of valvularregurgitation in the adult patient, and providesrecommendations for the assessment of severity ofvalvular regurgitation based on the scientific litera-ture and a consensus of a panel of experts. Issues ofmedical management and timing of surgical inter-vention will not be addressed in this article, as thesehave been recently published[1].

Two-dimensional and DopplerEchocardiography in Valvular

Regurgitation: General Considerations

Valvular regurgitation or incompetence results fromvarious etiologies including valvular degeneration,calcification, fibrosis or infection, alteration of thevalvular support apparatus or dilatation of the valveannulus. These conditions cause poor apposition ofthe valvular leaflets or cusps, and may lead to

f Echocardiography. Published by Elsevier Ltd. All rights reserved.

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prolapse, flail, restricted leaflet motion or valvularperforation. With the advent of Doppler techniquesthat are sensitive to detection of regurgitation, trivialand physiologic valvular regurgitation, even ina structurally normal valve, is now well recognizedand is noted to occur frequently in right-sided valves.The following sections describe general considera-tions of the role of echocardiographic and Dopplertechniques in the evaluation of regurgitant lesions.

Role of Two-DimensionalEchocardiography

Two-dimensional (2D) echocardiography allows anevaluation of the valvular structure as well as theimpact of the volume overload on the cardiacchambers. Calcifications, tethering, flail motion orvegetations can be readily assessed, which can giveindirect clues as to the severity of regurgitation.While prolapse, vegetations or calcifications are notnecessarily associated with significant regurgitation,a flail leaflet almost always is. In the cases of non-diagnostic transthoracic studies, transesophagealechocardiography (TEE) improves the visualizationof the valvular structure and delineates the mecha-nism and severity of regurgitation.The duration (acute or chronic) and severity of

valvular regurgitation are among the most importantdeterminants of the adaptive changes that occur in thecardiac chambers in response to the regurgitantvolume. Thus, a chronic significant regurgitation isusually accompanied by an increase in size and hyper-trophy of the involved cardiac chambers whereassignificant regurgitation of acute onset from a condi-tion such as endocarditis may not result acutely in this

Eur J Echocardiography, Vol. 4, issue 4, December 2003

remodeling. While cardiac chamber remodeling is notspecific for the degree of regurgitation (i.e. occurs incoronary artery disease, congestive cardiomyopathyetc.), its absence in the face of chronic regurgitationshould imply a milder degree of valvular insufficiency.Once a diagnosis of significant regurgitation is

established, serial 2D echocardiography is currentlythe method of choice for assessing the progression ofthe mechanical impact of regurgitation on cardiacchamber structure and function. Recommendationsfor determination of ventricular volumes and ejectionfraction have been previously published[2]. These,along with clinical evaluation are needed for ade-quate timing of surgical intervention.

Doppler Methods for Evaluation ofValvular Regurgitation

Doppler echocardiography is the most commontechnique used for the detection and evaluation ofseverity of valvular regurgitation. Several indices havebeen developed to assess the severity of regurgitationusing color Doppler, pulsed wave (PW) and contin-uous wave (CW) Doppler. Details of the Dopplertechniques and the methods involved in obtainingthese parameters are described in a recently publishedarticle from the American Society of Echocardiogra-phy on quantification of Doppler Echocardiogra-phy[3]. The following sections summarize the salientfeatures of these techniques for the purposes ofevaluation and quantitation of valvular regurgitation.

Color Doppler

Color flow Doppler is widely used for the detection ofregurgitant valve lesions. This technique provides

Figure 1. Color flow recording of a mitral regurgitation jet obtained from a zoomed view in the parasternal long axisdepicting the three components of the regurgitant jet: flow convergence, vena contracta (VC), and jet area in the leftatrium. Measurement of the vena contracta is shown between the red arrows.

Recommendations for Assessing Valvular Regurgitation 239


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visualization of the origin of the regurgitation jet andits width (vena contracta), the spatial orientation ofthe regurgitant jet area in the receiving chamber and,in cases of significant regurgitation, flow convergenceinto the regurgitant orifice (Fig. 1). Experience hasshown that attention to these three componentsof the regurgitation lesion by color Doppler d asopposed to the traditional regurgitant jet areaalone d significantly improves the overall accuracyof estimation and quantitation of the severity ofregurgitation with color Doppler techniques. The sizeof the regurgitation jet by color Doppler and itstemporal resolution, however, are significantly affect-ed by transducer frequency and instrument settingssuch as gain, output power, Nyquist limit, size anddepth of the image sector[4]. Thus, full knowledge bythe sonographer and interpreting echocardiographerof these issues is necessary for optimal imageacquisition and accuracy of interpretation.

Jet area Visualization of the regurgitant jet area inthe receiving chamber can provide a rapid screeningof the presence and direction of the regurgitant jetand a semi-quantitative assessment of its severity. In-general, a larger area may translate into a moresignificant regurgitation. However, the sole relianceon this parameter can be quite misleading. Numeroustechnical, physiologic and anatomic factors affect thesize of the regurgitant area and therefore alter itsaccuracy as an index of regurgitation severity[4]. Jetsize is affected by instrument factors, especially pulserepetition frequency (PRF) and color gain. Standardtechnique is to use a Nyquist limit (aliasing velocity)of 50e60 cm/s, and a color gain that just eliminatesrandom color speckle from non-moving regions. Jetarea is inversely proportional to PRF, and substantialerror can be introduced with the use of higher orlower settings than the nominal settings to whichechocardiographers have become accustomed. Re-garding hemodynamic factors, eccentric, wall-im-pinging jets appear significantly smaller thancentrally directed jets of similar hemodynamicseverity, mainly because they flatten out on the wallof the receiving chamber. Their presence, however,should also alert to the possibility of structuralabnormalities of the valve (e.g. prolapse, flail, orperforation), frequently in the leaflet or cusp oppositeto the direction of the jet. Lastly, color flow area isalso influenced by flow momentum d the product offlow rate and velocity. Thus a jet may appear largerby increasing the driving pressure across the valve;hence the importance of measuring blood pressurefor left heart lesions at the time of the echocardio-graphic examination, particularly in the intraoper-ative setting.

Vena contracta The vena contracta is the narrowestportion of a jet that occurs at or just downstreamfrom the orifice (Fig. 1). It is characterized by high

velocity, laminar flow and is slightly smaller than theanatomic regurgitant orifice due to boundary effects.Thus, the cross-sectional area of the vena contractarepresents a measure of the effective regurgitantorifice area (EROA), which is the narrowest area ofactual flow. The size of the vena contracta isindependent of flow rate and driving pressure fora fixed orifice[5]. However, if the regurgitant orifice isdynamic, the vena contracta may change with hemo-dynamics or during the cardiac cycle[6]. Comprised ofhigh velocities, the vena contracta is considerably lesssensitive to technical factors such as PRF comparedto the jet in the receiving chamber. To specificallyimage the vena contracta, it is often necessary toangulate the transducer out of the normal echocar-diographic imaging planes such that the area ofproximal flow acceleration, the vena contracta, andthe downstream expansion of the jet can be distin-guished. It is preferable to use a zoom mode tooptimize visualization of the vena contracta andfacilitate its measurement. The color flow sectorshould also be as narrow as possible, with the leastdepth, to maximize lateral and temporal resolution.Because of the small values of the width of the venacontracta (usually !1 cm), small errors in itsmeasurement may lead to a large percent error andmisclassification of the severity of regurgitation,hence the importance of accurate acquisition of theprimary data and measurement.

Proximal isovelocity surface area (PISA) or flowconvergence The PISA method is derived from thehydrodynamic principle stating that, as blood ap-proaches a regurgitant orifice, its velocity increasesforming concentric, roughly hemispheric shells ofincreasing velocity and decreasing surface area[7].Color flow mapping offers the ability to image one ofthese hemispheres that corresponds to the Nyquistlimit of the instrument. If a Nyquist limit can bechosen at which the flow convergence has a hemi-spheric shape, flow rate (ml/s) through the regurgi-tant orifice is calculated as the product of the surfacearea of the hemisphere (2pr2) and the aliasing velocity(Va) as 2pr2)Va (Fig. 2). Assuming that the maximalPISA radius occurs at the time of peak regurgitantflow and peak regurgitant velocity, the maximalEROA is derived as:

EROA ¼ ð6:28r2)VaÞ=PkVReg

where PkVReg is the peak velocity of the regurgitantjet by CW Doppler. The regurgitant volume can beestimated as EROA multiplied by the velocity timeintegral of the regurgitant jet. Since the PISAcalculation provides an instantaneous peak flow rate,EROA by this approach is the maximal EROA andmay be slightly larger than EROA calculated byother methods.Measurement of PISA by color flow mapping

requires adjustment of the aliasing velocity such thata well-defined hemisphere is shown. This is generally



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Figure 2. Schematic depiction of the flow convergence or proximal isovelocity surface area (PISA) method for quantitatingvalvular regurgitation. Va is the velocity at which aliasing occurs in the flow convergence towards the regurgitant orifice.PkVReg Z peak velocity of the regurgitant jet, determined by continuous wave Doppler. Reg flow Z regurgitant flow;EROA Z effective regurgitant orifice area; Reg jet Z regurgitation jet.


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done by shifting the baseline toward the direction offlow, or by lowering the Nyquist limit, or both (thelatter reduces the wall filter, whereas the former doesnot)[8]. If the base of the hemisphere is not a flatsurface (180(), then correction for wall constraintshould be performed, multiplying by the ratio of theangle formed by the walls adjacent to the regurgitantorifice and 180(. This has been shown to improve thereliability of the measurement[9].The limitations of PISA have been reviewed in

detail[10]. It is more accurate for central jets than foreccentric jets, and for regurgitation with a circularorifice. If the image resolution allows the flowconvergence to be seen well, and a Nyquist limitcan be chosen at which the flow convergence hasa hemispheric shape, it is easy to identify the aliasingline of the hemisphere. However, it can be difficult tojudge the precise location of the orifice and the flowconvergence shape. Any error introduced is thensquared, which can markedly affect the resulting flowrate and EROA. Recent modifications of the de-scribed PISA method use the distance between twoaliasing contours to circumvent the errors fromimprecise location of the orifice in the standard PISAformula, and automate localizing the most hemi-spheric shape[11]. Although promising, further expe-rience is needed with these methods.All the color Doppler parameters discussed above

provide instantaneous measures of regurgitation


severity. Criteria for these maximum instantaneousmeasurements corresponding to the severity of eachlesion assume a pan-systolic (or pan-diastolic) dura-tion. However, in some circumstances, such as mitralvalve prolapse, the duration of regurgitation may bebrief[12] and can be suspected from real-time, 2Dcolor Doppler. A time-based graphic, such as CWDoppler or color M mode, can better ascertain thisfinding. Although graphing the actual duration ofsuch flow patterns has not been systematicallystudied, a correction of color flow indices of regurgi-tation for the duration of regurgitation is advised.

Pulsed Doppler Quantitative Flow Methods

PW Doppler recordings of flow velocity can becombined with 2D measurements to derive flow ratesand stroke volume[13]. The technical details involvedin making these measurements and their sources oferror are described in the article on Quantitation ofDoppler Echocardiography[3]. This method is simplein theory but accurate results require individualtraining (e.g. practice in normal patients where thestroke volumes at different sites are equal). Briefly,stroke volume (SV) at any valve annulus d the leastvariable anatomic area of a valve apparatus d isderived as the product of cross-sectional area (CSA)and the velocity time integral (VTI) of flow at the



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annulus. Assumption of a circular geometry hasworked well clinically for most valves with theexception of the tricuspid annulus. Thus,

SV¼ CSA!VTI¼ pd2=4!VTI¼ 0:785d2!VTI

where d is the diameter of the annulus. Calculationsof stroke volume can be made at two or moredifferent sites d left ventricular outflow tract(LVOT), mitral annulus, and pulmonic annulus. Inthe absence of regurgitation, stroke volume determi-nations at these sites are equal. In the presence ofregurgitation of one valve, without any intracardiacshunt, the flow through the affected valve is largerthan through other competent valves. The differencebetween the two represents the regurgitant vol-ume[14,15]. Regurgitant fraction is then derived asthe regurgitant volume divided by the forward strokevolume through the regurgitant valve. Thus,

Regurgitant Volume¼ SVRegValv � SVCompValv

Regurgitant Fraction

¼ ðSVRegValv � SVCompValvÞ=SVRegValv

where SVRegValv is stroke volume derived at theannulus of the regurgitant valve and SVCompValv is thestroke volume at the competent valve. EROA can becalculated similar to the PISA method as regurgitantvolume divided by the velocity time integral of theregurgitant jet velocity (VTIRegJet) recorded by CWDoppler as:

EROA ¼Regurgitant Volume=VTIRegJet

The most common errors encountered in determiningthese parameters are (1) failure to measure the valveannulus properly (error is squared in the formula), (2)failure to trace the modal velocity (brightest signalrepresenting laminar flow) of the pulsed Dopplertracing and (3) failure to position the sample volumecorrectly, and with minimal angulation, at the level ofthe annulus. Furthermore, in the case of significantcalcifications of the mitral annulus and valve, quan-titation of flow at the mitral site is less accurate andmore prone to errors.In left sided regurgitant lesions, SVRegValv or total

stroke volume of the ventricle can also be measuredusing left ventricular volume calculations by 2Dechocardiography as end-diastolic volume minusend-systolic volume. Methods for calculation of leftventricular volumes have been previously detailed[2].Measurement of left ventricular volumes by echocar-diography has the potential pitfall of underestimatingtrue left ventricular volume and therefore under-estimating regurgitation severity. Recently, the use ofintravenous contrast agents that cross the pulmonarycirculation has shown promise in facilitating thetracing of the ventricular endocardium and improv-ing the accuracy and reproducibility of volume mea-surements[16,17]. Assessment of ventricular volumes

based on M-mode echocardiography has importantlimitations and is not recommended.

Other Pulsed and ContinuousWave Doppler Methods

There are several pulsed and CW Doppler methodsthat give indirect clues to the significance of valvularregurgitation. In general, the density of the spectraldisplay of a regurgitant jet is proportional to thenumber of red cells exhibiting regurgitation and is aqualitative index of severity. Other parameters resultfrom the hemodynamic consequences of the severityof regurgitation and are more valve specific (atrio-ventricular valve vs aortic or pulmonic valve). Foratrio-ventricular valves, these parameters include themagnitude of the early inflow velocity (E), thepulmonary or hepatic venous inflow pattern, andthe contour or shape of the regurgitant jet by CWDoppler. For aortic and pulmonic valve insufficiency,the parameter used is the rate of deceleration of theregurgitant jet velocity (pressure half-time), whichreflects the rapidity of equilibration of diastolicarterial and ventricular pressures. Another index ofseverity of aortic insufficiency is the magnitude ofdiastolic flow reversal in the aorta. Although helpfulin the overall evaluation of regurgitation, theseparameters are in general sensitive but less specificfor the severity of regurgitation, as they are in-fluenced by other hemodynamic and clinical condi-tions. These methods will be discussed in detail foreach valve (see below).

Doppler Methods in Acute vsChronic Regurgitation

Color Doppler measures are particularly deceptive inacute regurgitation, leading to the clinical paradox ofapparently small jet size in a critically ill patient,especially from the transthoracic echocardio-gram[18,19]. This is related in part to technical factors,particularly insufficient color Doppler temporalresolution in the tachycardic patient; practically,frame rate should therefore be maximized[20]. TEEhas been felt to provide a more sensitive view, and thedecreased depth also maximizes frame rate particu-larly for mitral regurgitation[18,19]. More fundamen-tally, however, the short duration of regurgitationand small receiving chambers limit the maximaldevelopment of jet area, and the rapid equalizationof pressures diminishes orifice velocity, jet momen-tum, and therefore jet area[21,22]. The proximal jet orvena contracta remains reliable in this setting, as doespulsed Doppler quantitation. Doppler hemodynamicsigns of elevated receiving chamber pressures, such asshort aortic insufficiency pressure half-time, earlytruncation of mitral regurgitant velocities, and pul-monary venous flow reversal, are particularly inform-ative in this setting, and may provide the only clues tosignificant regurgitation. In this clinical scenario of




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suspected acute valvular regurgitation, TEE is en-couraged for a more definite diagnosis and improvedpatient management[19,23].

Grading the Severity of Valvular Regurgitation

Characterization of the severity of regurgitant lesionsis among the most difficult problems in valvular heartdisease. Such a determination is important since mildregurgitation does not lead to remodeling of cardiacchambers and has a benign clinical course, whereassevere regurgitation is associated with significantremodeling, morbidity and mortality[1]. Contributingto the difficulty of assessment of regurgitation is thelack of a true gold standard, and the dependence ofregurgitation severity on the hemodynamic condi-tions at the time of evaluation. Although angiographyhas been used historically to define the degree of re-gurgitation based on opacification of the receivingchamber, it is also dependent on several technicalfactors and hemodynamics[24e27]. For example, an in-crease in blood pressure will increase all parameters ofaortic or mitral regurgitation, be it assessed as regur-gitant fraction or angiographic grade. Furthermore,the angiographic severity grades, which have rangedbetween 3 and 5, have only modest correlations withquantitative indices of regurgitation[14,24e28].Doppler methods for valvular regurgitation have

been validated in vitro and in animal models againstindependent flow parameters, and clinically, mostlyin adults, against the angiographic standard. Themajority of these validation studies have involved leftsided cardiac valves. As already discussed, there areseveral qualitative and quantitative echocardiographicparameters that can provide assessment of valvularregurgitation. The availability of these differentparameters provides an internal verification andcorroboration of the severity of the lesion, particu-larly when technical or physiologic conditions pre-clude the use of one or the other of these indices. Thismulti-faceted approach is essential. If there are signssuggesting that the regurgitation is significant and thequality of the data lends itself to quantitation, it isdesirable for echocardiographers with experience inquantitative methods to determine quantitatively thedegree of regurgitation, particularly for left sidedlesions. Ultimately, the interpreter must integrate theinformation and disregard ‘outlying’ data (because ofpoor quality or a physiologic condition that altersaccuracy of a certain parameter), making a bestestimate of regurgitation severity.The consensus of the Task Force is to classify

grading of severity of regurgitation into mild,moderate, and severe. In cases of overlap or in-termediate severity, the terms ‘mild-to-moderate’ or‘moderate-to-severe’ can be used. ‘Trace’ regurgita-tion is also used in the event that regurgitation isbarely detected. Usually this can be physiologic,particularly in right heart valves and mitral valve,and may not produce an audible murmur.


Finally, the echocardiographic and Doppler exam-ination in a patient with valvular regurgitation is bestinterpreted within the clinical context at the time ofthe examination. It has been clearly demonstratedthat the severity of regurgitation may be influencedby hemodynamic conditions. Therefore, it is essentialto record the patient’s blood pressure at the time ofthe study and note the patient’s medications when-ever possible. When following a patient with serialexaminations, these factors need to be considered incomparing the severity of regurgitation and itshemodynamic consequences.The following sections detail the use of 2D and

Doppler echocardiographic methods for the evalua-tion of each valvular lesion and provide suggestedcriteria and approach for the assessment of theseverity of regurgitation.

Mitral Regurgitation


Evaluation of the anatomy of the mitral valveapparatus by 2D echocardiography is critically impor-tant in the assessment of severity of mitral regurgita-tion (MR). The mitral apparatus includes the leaflets,chordae tendineae, annulus, and the papillary muscleswith their supporting left ventricular (LV) walls.Careful evaluation of these structures should be ableto define the mechanism of MR and yield clues to itsseverity. For example, a prominent flail leaflet isusually associated with severeMR. On the other hand,severe MR rarely occurs in the setting of an anatom-ically normal mitral valve and support apparatus.Defining the mechanism of MR may determinewhether valve repair is feasible instead of valvereplacement[29,30]. In patients with MR in the settingof LV dilatation and/or systolic dysfunction, it isimportant to determine whether MR is functional (i.e.due to LV dilatation) or primary (i.e. due to anabnormality of the valve apparatus). In functionalMR, the leaflets are usually tethered by outward dis-placement of the LV walls and papillary muscles, withorwithoutannulardilation[31].Underlyingwallmotionabnormalities in patients with coronary artery diseasemay also lead to functionalMR. Finally, evaluation ofleft atrial (LA) size and LV size and function providesclues to the severity ofMR, its acuteness or chronicity,and is important in determining the necessity andtiming of surgery[1,32]. Normal 2D-derived values forleft ventricular size and function have been previouslyreported[2]. Briefly, the end-diastolic minor axis di-mension of the LV obtained from the parasternalwindow by 2D is normally %2.8 cm/m2 while thenormal end-diastolic LV volume is !82 ml/m2

(reference [2]). For the left atrium, a normal antero-posterior diameter is %2 cm/m2 (reference [33]). Re-cent studies, however, have shown that determination



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of LA volumes with 2D echocardiography from theapical views is generally more accurate in assessingLA size than the traditional antero-posterior dimen-sion[34]. A normal maximal LA volume is %36 ml/m2

(reference [35]).

Doppler Methods

Color Flow Doppler

Color Doppler flow mapping is widely used to screenfor the presence of mitral regurgitation. Importantly,small color flow jets are seen in roughly 40% ofhealthy normal volunteers and therefore are consid-ered a normal variant[36]. The incidence of mildregurgitation tends to increase with age. The termstrace MR or MR closing volume have been applied tothese jets. There are three methods of quantifyingMR severity by color flow Doppler mapping: re-gurgitant jet area, vena contracta, and flow conver-gence (PISA). Although jet area was the first methodused for assessing MR severity, its sole use is lessaccurate than the latter two methods.

Regurgitant jet area As a general rule, large jets thatextend deep into the LA represent more MR thansmall thin jets that appear just beyond the mitralleaflets. However, the correlation between jet areaand MR severity is poor due to a variety of technicaland hemodynamic limitations as noted earlier[4].Patients with acute severe MR, in whom bloodpressure is low and LA pressure is elevated, may havea small eccentric color flow jet area, whereashypertensive patients with mild MR may have a largejet area. Furthermore, the same regurgitant flow willproduce larger or smaller jets depending on the size ofthe atrium, which has led to indexing for atrial

area[37]. Finally, color flow jets that are directedcentrally into the LA generally appear larger becausethey entrain red blood cells on all sides of the jet. Incontrast, eccentric jets that hug the LA wall cannotentrain blood on all sides and tend to appear smallerthan central jets of similar or lesser severity (Fig.3)[38e40]. Because of these considerations, deter-mination of the severity of MR by ‘eyeballing’ orplanimetry of the MR color flow jet area only, is notrecommended. Nevertheless, small, non-eccentric jetswith an area !4.0 cm2 or !20% of LA area areusually trace or mild MR (Table 1). Conversely, largejets that penetrate into the pulmonary veins are morelikely to be hemodynamically significant. However,the detection of eccentric, wall-impinging jets shouldalert the observer to avoid the use of jet area as anindex of severity and use other, more appropriatemethods described below.

Vena contracta The vena contracta should be ima-ged in high-resolution, zoom views for the largestobtainable proximal jet size for measurements. Theexaminer must search in multiple planes perpendic-ular to the commissural line (such as the parasternallong-axis view), whenever possible (Fig. 1). The widthof the neck or narrowest portion of the jet is thenmeasured. The regurgitant orifice in MR may not becircular, and is often elongated along the mitralcoaptation line. The two-chamber view, which isoriented parallel to the line of leaflet coaptation,generally shows a wide vena contracta even in mildMR, and should not be used to measure the venacontracta. Although the size of the vena contracta isindependent of flow rate and driving pressure fora fixed orifice[5], the regurgitant orifice in MR is oftendynamic and therefore the vena contracta maychange with hemodynamics or during systole[6].

Figure 3. Examples of color flow recordings of different mitral regurgitation (MR) lesions from the apical window. Thecase of mild regurgitation has no flow convergence and a small regurgitant jet area, in contrast to that of severe centralMR, which shows a prominent flow convergence and a large regurgitant jet area. The example with severe eccentric MRhas a small jet area impinging on the wall of the left atrium but a large flow convergence and a wide vena contracta.



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Table 1. Qualitative and quantitative parameters useful in grading mitral regurgitation severity.

Parameter Mild Moderate Severe

Structural parametersLA size Normal* Normal or dilated Usually dilatedyLV size Normal* Normal or dilated Usually dilatedyMitral leaflets or supportapparatus

Normal or abnormal Normal or abnormal Abnormal/flail leaflet/ruptured papillarymuscle

Doppler parametersColor flow jet areaz Small, central jet (usually

!4 cm2 or !20%of LA area)

Variable Large central jet (usually O10 cm2 orO40% of LA area) or variable sizewall-impinging jet swirling in LA

Mitral inflow d PW A-wave dominantx Variable E-wave dominantx (E usually R1.2 m/s)Jet density d CW Incomplete or faint Dense DenseJet contour d CW Parabolic Usually parabolic Early peaking d triangularPulmonary vein flow Systolic dominance{ Systolic blunting{ Systolic flow reversalk

Quantitative parameters**VC width (cm) !0.3 0.3e0.69 R0.7R Vol (ml/beat) !30 30e44 45e59 R60RF (%) !30 30e39 40e49 R50EROA (cm2) !0.20 0.20e0.29 0.30e0.39 R0.40

VCZ vena contracta; R Vol Z regurgitant volume; RF Z regurgitant fraction; EROAZ effective regurgitant orifice area; PWZ pulsedwave Doppler; CW Z continuous wave Doppler; LA Z left atrium; LV Z left ventricle.*Unless there are other reasons for LA or LV dilation. Normal 2D measurements: LV minor axis %2.8 cm/m2, LV end-diastolic volume%82 ml/m2, maximal LA antero-posterior diameter %2 cm/m2, maximal LA volume %36 ml/m2 (references [2,33,35]).yException: acute mitral regurgitation.zAt a Nyquist limit of 50e60 cm/s.xUsually above 50 years of age or in conditions of impaired relaxation, in the absence of mitral stenosis or other causes of elevated LApressure.{Unless other reasons for systolic blunting (e.g. atrial fibrillation, elevated left atrial pressure).kPulmonary venous systolic flow reversal is specific but not sensitive for severe MR.**Quantitative parameters can help sub-classify the moderate regurgitation group into mild-to-moderate and moderate-to-severe.

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Several studies have shown that the width of thevena contracta is accurate in assessing the severity ofMR, either by transthoracic echocardiography orTEE[41e45]. The width of the vena contracta in long-axis views and its cross-sectional area in short-axisviews can be standardized from the parasternalviews[44]. A vena contracta !0.3 cm usually denotesmild MR whereas the cut-off for severe MR hasranged between 0.6 cm and 0.8 cm[43e45]. Althoughintermediate values tend to correlate well withmoderate MR, there is enough overlap that anothermethod should be used for confirmation. A particularstrength of the vena contracta method is that it worksequally well for central and eccentric jets. In fact, ineccentric jets of severe MR, the width of the venacontracta along with flow convergence alerts theechocardiographer to the severity of regurgitation bycolor Doppler (Fig. 3). In patients with multiple MRjets, the respective widths of the vena contracta arenot additive, but their cross-sectional areas can be[44].In the future, three-dimensional imaging of the venacontracta should improve the accuracy of measuringEROA by this technique.

Flow convergence or PISA Most of the experiencewith the PISA method for quantitation of regurgi-tation is with MR. Qualitatively, the presence ofPISA on a routine examination (at Nyquist limit of


50e60 cm/s) should alert to the presence of signifi-cant MR. Several clinical studies have validatedPISA measurements of regurgitant flow rate andEROA[12,46,47]. As mentioned earlier, there are manytechnical considerations related to optimal acquisi-tion of flow convergence images and to quantitationof mitral regurgitant orifice area by PISA. Thismethodology is more accurate for central regurgitantjets than eccentric jets, and for a circular orifice thana non-circular orifice. Flow convergence should beoptimized from the apical view, usually the four-chamber view, using a zoom mode. Combining datafrom two views through the major and minor axes ofa non-circular orifice (apical two- and four-chamberviews) provides greater accuracy, but adds morecomplexity[8,44,48]. The size of the PISA has meaningonly in terms of the aliasing velocity that defines thecolor surface. Results vary widely for calculations atdifferent aliasing velocities, and care must be taken touse the velocity at which the hemispheric formulaapplies best[49,50]. Furthermore, for determination ofEROA, it is essential that the CW Doppler signal bewell aligned with the regurgitant jet. Poor alignmentwith an eccentric jet will lead to an underestimationof velocity and an overestimation of the EROA.Generally, an EROA R0.4 cm2 is consistent withsevere MR, 0.20e0.39 cm2 with moderate, and!0.20cm2 with mild MR.


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Figure 4. Example of findings of continuous wave Doppler recordings and pulmonary vein flow by pulsed Doppler in a casewith mild and another with severe mitral regurgitation (MR). In mild MR, spectral recording of the jet has a soft densitywith a parabolic, rounded contour of the regurgitant velocity whereas in severe MR, the jet is dense with a triangular, earlypeaking of the velocity (arrow). Pulmonary vein flow is normal in mild MR with predominance of systolic flow (S). Incontrast, the case with severe MR displays systolic flow reversal. D Z diastolic flow velocity.


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Continuous Wave Doppler
In most patients, maximum MR velocity is 4e6 m/sdue to the high systolic pressure gradient between theLV and LA. The velocity itself does not provideuseful information about the severity of MR.However, the contour of the velocity profile and itsdensity are useful. A truncated, triangular jet contourwith early peaking of the maximal velocity indicateselevated LA pressure or a prominent regurgitantpressure wave in the LA (Fig. 4).The density of the CW Doppler signal is a qualita-

tive index of MR severity. A dense signal thatapproaches the density of antegrade flow suggestssignificantMR, whereas a faint signal, with or withoutan incomplete envelope represents mild or trace MR,presuming the recording is made through the venacontracta (Fig. 4). In eccentric significant MR, it maybe difficult to record the full envelope of the jetbecause of its eccentricity, while the signal intensityshows dense features. Recently, the returning power ofthe regurgitant velocity signal, which is proportionalto the area of the vena contracta, has been used toobtain instantaneous regurgitant orifice area and flowrate[51]. This method offers considerable promise.Using CW Doppler, the tricuspid regurgitation jet

should be interrogated in order to estimate pulmo-nary artery systolic pressure. The presence of pul-monary hypertension provides another indirect clueas to MR severity and compensation to the volumeoverload.

Pulsed Doppler

Pulsed Doppler tracings at the mitral leaflet tips arecommonly used to evaluate LV diastolic function.Patients with severe MR often demonstrate a mitralinflow pattern with a dominant early filling (increasedE velocity) due to increased diastolic flow across themitral valve, with or without an increase in LApressure[52]. In severe mitral regurgitation withoutstenosis, the mitral E velocity is higher than thevelocity during atrial contraction (A velocity), andusually greater than 1.2 m/s. For these reasons,a mitral inflow pattern with an A-wave dominancevirtually excludes severe MR. Because of the effect ofrelaxation on mitral inflow indices, these observa-tions are more applicable in individuals older than 50years of age or in conditions of impaired myocardialrelaxation.In contrast to ventricular filling dynamics, calcula-

tion of flow and stroke volume through the mitralvalve with pulsed Doppler is performed at the mitralannulus level. Several studies have shown the validityand clinical utility of quantitative Doppler measure-ments of MR severity[14,15,53e55]. The values forregurgitant volumes, regurgitant fraction and EROAby quantitative Doppler for various degrees of MRare shown in Table 1. It should be remembered,however, that in individual patients, these valuesmight vary. For example, a patient with severe MRand a small LV may have a low regurgitant volumebut a high regurgitant fraction and EROA. There are




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no data regarding indexing these measurements tobody surface area. Quantitative Doppler measure-ments may be more applicable to patients witha single regurgitant valve. For example, in thepresence of combined MR and significant aorticregurgitation, the calculated regurgitant volume willbe erroneous if the LV outflow site is used forcomparison. In this case, systemic flow could becalculated at the pulmonic annulus. Lastly, thequantitative PW Doppler method offers an advantagein the case of eccentric or multiple regurgitant MRjets, where PISA is not as accurate and venacontracta is not applicable in the latter situation.

Pulmonary Vein Flow

Pulsed Doppler evaluation of pulmonary venous flowis a useful adjunct to evaluating the hemodynamicconsequences of MR. Normal pulmonary venousflow is characterized by a velocity during ventricularsystole that is higher than during ventricular diastole.With increasing severity of MR, there is a diminutionof the systolic velocity. In many patients with severeMR, the flow in the pulmonary veins becomesreversed in systole (Fig. 4). Since the mitral regur-gitant jet may selectively enter one or the other of thepulmonary veins, sampling through all pulmonaryveins is recommended, especially during TEE. Onelimitation of pulmonary venous pattern in theassessment of severity of MR is that elevation inLA pressure of any etiology, and atrial fibrillationalso result in a blunted systolic forward flow[56]. Asa result, the use of pulmonary venous flow patternshould be used adjunctively with other parameters.Nevertheless, the finding of systolic flow reversal inmore than one pulmonary vein is specific but notsensitive for severe mitral regurgitation.

Role of TEE in Assessing MitralRegurgitation Severity

TEE is indicated to evaluate MR severity in patientsin whom transthoracic echocardiography is incon-clusive or technically difficult. In addition, TEE isparticularly well suited to identify the underlyingmechanism of MR and for planning mitral valvesurgery. All of the above methods of quantifying MRcan also be used during TEE. In particular, the higherresolution of TEE, multiplane capabilities, andproximity to the mitral valve make vena contractaimaging and PISA easier and probably more accu-rate. On the other hand, since jet size is affected bytransducer frequency, PRF, and signal strength, thesame jet may appear larger on TEE compared totransthoracic images. Quantitative pulsed Doppler byTEE works well provided that a deep transgastricview is obtained to properly align the PW Dopplerbeam to the LV outflow tract. The latter, however, ismore difficult than with the transthoracic approach.


Interrogation of all pulmonary veins is generallyfeasible with TEE.

Integrative Approach to Assessment ofMitral Regurgitation Severity

The approach to the evaluation of MR severityideally integrates multiple parameters rather thandepending on a single measurement. This helpsminimize the effects of technical or measurementerrors that are inherent to each method previouslydiscussed. It is also important to distinguish betweenthe amount of MR and its hemodynamic consequen-ces. For example, a modest regurgitant volume thatdevelops acutely into a small, noncompliant LA maycause severe pulmonary congestion and systemichypotension. Conversely, some patients with chronicsevere MR remain asymptomatic due to compensa-tory mechanisms and a dilated, compliant LA.Parameters that describe the amount of MR

include vena contracta width, regurgitant volumeand fraction, and EROA calculated either by PISA orquantitative pulsed Doppler. Because regurgitantflows may be holosystolic or brief, as in valve pro-lapse[12], color Doppler techniques should be adjustedfor duration of MR: for example, a wide venacontracta occurring briefly conveys only mild MR.On the other hand, the hemodynamic consequencesof MR are reflected in several parameters includingLA and LV volumes, the contour of the CW Dopplerprofile, and pulmonary venous flow pattern. Advan-tages and limitations of the various echo/Dopplerparameters used in assessing severity of MR aredetailed in Table 2. An MR index has been devisedthat assigns different weights to six different indica-tors of MR[57], using a score of 0e3 for jetpenetration into the LA, PISA radius, CW jetintensity, pulmonary artery pressure, pulmonaryvenous flow pattern, and LA size. A score of 1.7 orless reliably separated mild MR from severe MR;a considerable overlap, however, was observed be-tween moderate and severe MR. Although it may beimpractical for routine clinical use, this scoring sys-tem emphasizes the need to evaluate multiple echo-cardiographic parameters.Based on data in the literature and a consensus of

the committee members, the Task Force proposesa scheme of specific signs (R90% specificity), alongwith supportive signs and quantitative parameters tohelp grade the severity of MR (Table 3). In applyingthis scheme, the Task Force also wishes to recognizethe following. The specific signs have inherently a highpositive predictive value for the severity of regurgi-tation. On the other hand, the supportive signs orclues may be helpful in consolidating the impressionof the degree of MR, although their predictive valueis more modest, since they are influenced by severalfactors (Table 2). It is the consensus of the committeemembers that the process of grading MR should be


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Table 2. Echocardiographic and Doppler parameters used in the evaluation of mitral regurgitation severity:utility, advantages and limitations.

Parameter Utility/advantages Limitations

Structural parametersLA and LV size Enlargement sensitive for chronic significant MR,

important for outcomes. Normal size virtuallyexcludes significant chronic MR

Enlargement seen in other conditions. May benormal in acute significant MR

MV leaflet/supportapparatus

Flail valve and ruptured papillary muscle specific forsignificant MR

Other abnormalities do not imply significant MR

Doppler parametersJet area d color flow Simple, quick screen for mild or severe central MR;

evaluates spatial orientation of jetSubject to technical, hemodynamic variation;significantly underestimates severity in wall-impinging jets

Vena contracta width Simple, quantitative, good at identifying mild orsevere MR

Not useful for multiple MR jets; intermediate valuesrequire confirmation. Small values; thus small errorleads to large % error

PISA method Quantitative; presence of flow convergence atNyquist limit of 50e60 cm/s alerts to significant MR.Provides both, lesion severity (EROA) and volumeoverload (R Vol)

Less accurate in eccentric jets; not valid in multiplejets. Provides peak flow and maximal EROA

Flow quantitation d PW Quantitative, valid in multiple jets and eccentric jets.Provides both lesion severity (EROA, RF) andvolume overload (R Vol)

Measurement of flow at MV annulus less reliable incalcific MV and/or annulus. Not valid withconcomitant significant aortic regurgitation unlesspulmonic site is used

Jet profile d CW Simple, readily available Qualitative; complementary dataPeak mitral E velocity Simple, readily available. A-wave dominance

excludes severe MRInfluenced by LA pressure, LV relaxation, MV area,and atrial fibrillation. Complementary data only, donot quantify MR severity

Pulmonary vein flow Simple. Systolic flow reversal is specific for severeMR

Influenced by LA pressure, atrial fibrillation. Notaccurate if MR jet directed into the sampled vein

CW Z continuous wave Doppler; EROA Z effective orifice regurgitant area; LA Z left atrium; PISA Z proximal isovelocity surfacearea; LV Z left ventricle; PW Z pulsed wave Doppler; MV Z mitral valve; MR Z mitral regurgitation; R Vol Z regurgitant volume.

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comprehensive, using a combination of clues, signsand measurements obtained by Doppler echocardi-ography. If the MR is definitely determined as mildor less using these signs, no further measurement isrequired. If there are signs suggesting that the MR ismore than mild and the quality of the data lends itselfto quantitation, it is desirable for echocardiographerswith experience in quantitative methods to determinequantitatively the degree of MR, including theregurgitant volume and fraction as descriptors ofvolume overload and the effective regurgitant orificeas a descriptor of the lesion severity. It is also theconsensus of the Task Force that the wording chosenfor expressing the degree ofMR, which is a continuumbest defined by quantitative measurements, caninclude qualifiers such as mild-to-moderate to des-cribe the lowest end of the moderate range andmoderate-to-severe to describe the upper end of themoderate range. Finally, it is important to stress thatwhen the evidence from the different parameters iscongruent, it is easy to grade MR severity with con-fidence. When different parameters are contradictory,one must look carefully for technical and physiologicreasons to explain any discrepancies and rely on thecomponents that have the best inherent quality of theprimary data and are the most accurate consideringthe underlying physiologic condition.

Aortic Regurgitation

The assessment of aortic regurgitation (AR) is basedon a comprehensive utilization of 2D echocardiogra-phy, color-flow imaging, pulsed and CW Dopplertechniques and is essential in the clinical evaluation ofaortic valvular disease[1]. The echocardiographic andDoppler evaluation of AR uses qualitative andquantitative measures that can be derived in a singleexamination. While qualitative or semi-quantitativemeasures are used uniformly, quantitative measuresare often more time consuming and are used moreselectively.


2D echocardiography provides important informa-tion regarding valve anatomy and structural deform-ities, presence and severity of aortic root dilatationand adaptation of the LV to the volume overloadstate. While mild degrees of AR are associated ingeneral with mild pathology of the valve and aorticroot and do not result in LV remodeling, severechronic AR is usually observed in the setting ofsignificant structural abnormalities of the valve or



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Table 3. Application of specific and supportive signs, and quantitative parameters in the grading of mitralregurgitation severity.

Mild Moderate Severe

Specific signsof severity

� Small central jet !4 cm2 or!20% of LA area*

Signs of MR Omild present,but no criteria for severe MR

�Vena contracta width R0.7 cm withlarge central MR jet (area O40% ofLA) or with a wall-impinging jet ofany size, swirling in LA*

�Vena contracta width !0.3 cm �Large flow convergencey�No or minimal flow convergencey �Systolic reversal in pulmonary veins

�Prominent flail MV leaflet orruptured papillary muscle

Supportive signs � Systolic dominant flow inpulmonary veins

Intermediate signs/findings �Dense, triangular CW Doppler MRjet

�A-wave dominant mitral inflowz �E-wave dominant mitral inflow(EO1:2 m=s)z

� Soft density, parabolic CW DopplerMR signal

�Enlarged LV and LA sizex(particularly when normal LVfunction is present)

�Normal LV size{Quantitative parameterskR Vol (ml/beat) !30 30e44 45e59 R60RF (%) !30 30e39 40e49 R50EROA (cm2) !0.20 0.20e0.29 0.30e0.39 R0.40

CW Z continuous wave; EROA Z effective regurgitant orifice area; LA Z left atrium; LV Z left ventricle; MV Z mitral valve; MR Zmitral regurgitation; R Vol Z regurgitant volume; RF Z regurgitant fraction.*At a Nyquist limit of 50e60 cm/s.yMinimal and large flow convergence defined as a flow convergence radius !0.4 cm and R0.9 cm for central jets, respectively, witha baseline shift at a Nyquist of 40 cm/s; cut-offs for eccentric jets are higher, and should be angle corrected (see text).zUsually above 50 years of age or in conditions of impaired relaxation, in the absence of mitral stenosis or other causes of elevated LApressure.xIn the absence of other etiologies of LV and LA dilatation and acute MR.{LV size applied only to chronic lesions. Normal 2D measurements: LV minor axis %2.8 cm/m2, LV end-diastolic volume %82 ml/m2,maximal LA antero-posterior diameter %2 cm/m2, maximal LA volume %36 ml/m2 (references [2,33,35]).kQuantitative parameters can help sub-classify the moderate regurgitation group into mild-to-moderate and moderate-to-severe as shown.

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aortic root, and results in LV enlargement in the
chronic state. Importantly, evaluation of LV size andfunction in significant AR provides clues as to theacuteness or chronicity of the regurgitation and helpsdetermine management strategies and timing of sur-gical intervention.

Doppler Methods

Color Flow Doppler

Color-flow imaging directly shows the regurgitantflow through the aortic valve during diastole. Theregurgitant flow has three components that can bevisualized: the flow convergence region in the aorta,the vena contracta through the regurgitant orifice, andthe jet direction and size in the left ventricle (Fig. 5).

Regurgitant jet size Imaging of the regurgitant jetis used in all patients with AR because of its simpli-city and real-time availability[58]. The length of jetpenetration into the left ventricle is an unsatisfactoryindicator of AR severity[59]. The preferred assessmentis based on the proximal jet width or cross-sectionalarea immediately below the aortic valve, within 1 cmofthe valve[59,60]. The parasternal views are preferred to


apical views because of better axial resolution. Therecommended measurements are those of maximalproximal jet width obtained from the long-axis viewsand its ratio to the LV outflow tract diameter[59].Similarly, the cross-sectional area of the jet from theparasternal short-axis view and its ratio to the LVoutflow tract area can also be used[59]. The criteria todefine severe AR are ratios of R65% for jet widthand R60% for jet area (Table 4) (Fig. 6). Althoughsmall jets reliably reflect small degrees of AR, thereare important limitations to color-flow imaging of re-gurgitant jet, similar to mitral regurgitation[38,40]. Jetshape may affect the measurements. If the proximaljet does not have a shape with parallel borders in theLV outflow, it is difficult to know where to measureit. Jet direction is also a confounding variable.Eccentric jets that are directed predominantly to theanterior leaflet of the mitral valve (Fig. 5) or theseptum tend to occupy a small portion of theproximal outflow tract and may thus appear narrowand underestimate the severity of regurgitation[38].Conversely, central jets tend to expand fully in theoutflow tract and may be overestimated. Further-more, the severity of AR in diffuse jets arising fromthe entire coaptation line is also poorly evaluated bycolor-flow imaging. This can be suspected from short


Figure 5. Examples of central and eccentric aortic regurgitation (AR) jets recorded by TEE. The components of AR bycolor Doppler are highlighted by arrows in the example of central AR: flow convergence, vena contracta (VC) and jetwidth in the left ventricular outflow tract. Note the smaller size and location of the vena contracta compared to the jetwidth in the LV outflow tract. The eccentric AR jet is directed towards the mitral valve (arrow) with a prominent flowconvergence. Jet width in the left ventricular outflow in this eccentric jet cannot be used for evaluation of AR severity.LA Z left atrium; LV Z left ventricle.

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axis imaging at the aortic valve. In practice, theassessment of AR based on jet size in the LV outflowis most often based on visual estimation rather thandirect quantitative measurement and is used as a grossindicator of the degree of AR.

Vena contracta The vena contracta is defined as thesmallest neck of the flow region at the level of theaortic valve, immediately below the flow convergenceregion. It is different from the jet width discussedabove, which is measured in the LVOT, below the


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Table 4. Qualitative and quantitative parameters useful in grading aortic regurgitation severity.


Structural parametersLV size Normal* Normal or dilated Usually dilatedyAortic leaflets Normal or abnormal Normal or abnormal Abnormal/flail, or wide

coaptation defect

Doppler parametersJet width in LVOT d color flowz Small in central jets Intermediate Large in central jets; variable in

eccentric jetsJet density d CW Incomplete or faint Dense DenseJet deceleration rate d CW (PHT, ms)x Slow O500 Medium 500e200 Steep !200Diastolic flow reversal indescending aorta d PW

Brief, early diastolicreversal

Intermediate Prominent holodiastolic reversal

Quantitative parameters{VC width, cmz !0.3 0.3e0.60 O0.6Jet width/LVOT width, %z !25 25e45 46e64 R65Jet CSA/LVOT CSA, %z !5 5e20 21e59 R60R Vol, ml/beat !30 30e44 45e59 R60RF, % !30 30e39 40e49 R50EROA, cm2 !0.10 0.10e0.19 0.20e0.29 R0.30

AR Z aortic regurgitation; CSA Z cross-sectional area; CW Z continuous wave Doppler; EROA Z effective regurgitant orifice area;LVZ left ventricle; LVOTZ left ventricular outflow tract; PHTZ pressure half-time; PWZ pulsed wave Doppler; R VolZ regurgitantvolume; RF Z regurgitant fraction; VC Z vena contracta.*Unless there are other reasons for LV dilation. Normal 2D measurements: LV minor axis%2.8 cm/m2, LV end-diastolic volume%82 ml/m2 (reference [2]).yException would be acute AR, in which chambers have not had time to dilate.zAt a Nyquist limit of 50e60 cm/s.xPHT is shortened with increasing LV diastolic pressure and vasodilator therapy, and may be lengthened in chronic adaptation to severeAR.{Quantitative parameters can sub-classify the moderate regurgitation group into mild-to-moderate and moderate-to-severe regurgitationas shown.



Figure 6. Color Doppler and continuous wave (CW) Doppler recordings of the regurgitant jet as well as pulsed wave (PW)Doppler recording of flow in the descending thoracic aorta in examples of mild and severe aortic regurgitation (AR).Compared to the mild AR, the case of severe AR has a large jet width in the left ventricular outflow, a steep decelerationrate of the AR velocity by CW Doppler, and a holodiastolic flow reversal in the descending (desc) aorta (arrows).


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aortic valve (Fig. 5). The measurement of venacontracta width is significantly smaller than that ofjet width in the LVOT because the jet expandsimmediately after the vena contracta. Imaging of thevena contracta is obtained similarly from parasternallong-axis views[61]. The vena contracta provides anestimate of the size of the EROA. To appropriatelyvisualize the vena contracta, it is essential to see allthree components of the regurgitant flow, i.e. the flowconvergence, the vena contracta and the jet[61]. Mea-surement of vena contracta is simple and has a highfeasibility both by transthoracic echocardiographyand TEE. Furthermore, it appears to be more robustthan jet width and area in the LVOT for theassessment of AR severity[61]. Limitations of thisparameter occur in the presence of multiple jets orjets with irregular shapes, where one diameter maynot be reflective of the severity of the AR; a short-axisview, however, will provide a better appreciation ofthe regurgitation[62]. The thresholds of vena contractawidth associated with severe AR are 0.5 cm asa highly sensitive threshold, 0.7 cm as a highly specificthreshold and 0.6 cm as the threshold with the bestcombination of specificity and sensitivity[61].

Flow convergence or PISA Considerably less expe-rience exists with PISA for the assessment of ARcompared to MR. Imaging of the proximal flowconvergence region by transthoracic echocardiogra-phy is performed from the apical, para-apical views,or the upper right-sternal border, with images zoomedon the valvular and supra-valvular region. TheNyquist limit is adjusted to obtain a rounded and


measurable flow convergence zone and the aliasingradius is measured from the stop frame with thelargest observable PISA. CW Doppler recording ofthe regurgitant peak velocity and velocity timeintegral allows calculation of the EROA and regur-gitant volume. This method has been shown toprovide accurate quantitation of AR[63]. However, itis feasible in a lower percentage of patients comparedto MR due to interposition of valve tissue (apicalviews) and difficulty in obtaining high quality imagesof the flow convergence region. Another pitfall isrelated to the timing of measurement of the flowconvergence radius, which should be in early diastole,closest to the peak regurgitant velocity. Furthermore,ascending aortic aneurysms, which deform the valvu-lar plane, may lead to underestimation of AR by thismethod[63]. The thresholds for severe AR are anEROA R0.30 cm2 and a regurgitant volume R60 ml.

Pulsed Wave Doppler

Aortic diastolic flow reversal It is normal to observea brief diastolic flow reversal in the aorta. The flowreversal is best recorded in the upper descendingaorta at the aortic isthmus level using a suprasternalview, or in the lower descending aorta using a longi-tudinal subcostal view. With increasing aortic re-gurgitation both the duration and the velocity of thereversal increase[64]. Therefore, a holodiastolic re-versal is usually a sign of at least moderate aorticregurgitation (Fig. 6) and appears to be more specificif recorded from the thoraco-abdominal aorta. Thevelocity of flow reversal at end-diastole, the velocitytime integral of the reversal, and the ratio of reversal



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to forward velocity time integrals in the descendingaorta have all been proposed as semi-quantitative in-dices of AR severity[64,65]. A prominent holodiastolic reversal with a diastolic time integral similar to thesystolic time integral is a reliable qualitative sign ofsevere AR. However, reduced compliance of the aortaseen with advancing age may also prolong the normaldiastolic reversal in the absence of significant AR.

Flow calculations Quantitation of flow with pulsedDoppler for the assessment of AR is based oncomparison of measurement of aortic stroke volumeat the LVOT with mitral or pulmonic strokevolume[14,15]. Total stroke volume (aortic strokevolume) can also be derived from quantitative 2Dmeasurements of LV end-diastolic and end-systolicvolumes. EROA can be calculated from the regurgi-tant stroke volume and the regurgitant jet velo-city time integral by CW Doppler [15,53]. As with thePISA method, a regurgitant volume R60 ml andEROAR0.30 cm2 are consistent with severe AR. Thequantitative Doppler method cannot be used if thereis more than mild mitral regurgitation, unless thepulmonic site is used for systemic flow calculation.


Signal density The density of the CWDoppler spec-tral display of the AR jet reflects the volume of re-gurgitation, especially in comparison to the antegradespectral density. However, the AR jet density is alsodetermined by the respective directions of initial anddistal jet within the beam of ultrasound and alsopossibly by the ability of the jet to expand andmobilizeadjoining red blood cells.While a faint spectral displayis compatible with trace or mild AR, significant over-lap between moderate and severe regurgitation existsin more dense jet recordings. Therefore, CW Dopplerjet density is an imperfect indicator of severity of AR.

Diastolic jet deceleration The rate of decelerationof the diastolic regurgitant jet and the derivedpressure half-time reflect the rate of equalization ofaortic and LV diastolic pressures. With increasingseverity of AR, aortic diastolic pressure decreasesmore rapidly. The late diastolic jet velocity is lowerand hence pressure half-time is shorter[66]. Pressurehalf-time is easily measured if the peak diastolicvelocity is appropriately recorded. A pressure half-time O500 ms is usually compatible with mild ARwhereas a value !200 ms is considered consistentwith severe AR (Fig. 6). However, the diastolic ARvelocity is also determined by LV diastolic compli-ance and pressure. For a given severity of AR,pressure half-time can be further shortened by anelevated LV diastolic pressure or by vasodilatortherapy that reduces AR[66,67]. On the other hand,pressure half-time can be lengthened or normalizedwith chronic LV adaptation to severe AR[68].

Role of TEE

TEE is seldom needed to evaluate severity of AR dueto the proximity of the aortic valve to the chest fromthe parasternal window. However, TEE may beneeded in patients with poor acoustic windows, inwhom transthoracic echocardiography cannot pro-vide adequate delineation of anatomy or accurateDoppler recordings. Color Doppler criteria on jetwidth and the size of the vena contracta apply equallyto TEE and may show improved image quality insome patients. However, due to more difficulty withTEE in obtaining views where the jet direction isparallel to the ultrasound beam, measurements ofregurgitant fraction by PW Doppler and recording ofthe AR velocity with CW Doppler are more difficultto obtain reliably. With proper angulation, themagnitude of the proximal flow convergence can bemeasured. In addition, one can record the diastolicflow reversal in the ascending aorta with PW Dopplerfrom the upper esophageal views, which also showthe aortic arch.

Integrative Approach to Assessmentof AR

The assessment of AR by Doppler echocardiographyis an integrative and comprehensive process based onall information collected during the examination. Theadvantages and limitations of the 2D and Dopplerparameters in evaluating AR severity are shown inTable 5. In all cases one should routinely perform anevaluation of the aortic valve, LV size and function,an assessment by color-flow imaging of the proximaljet width and, if possible, the vena contracta. The LVoutflow velocity and the velocity in the proximaldescending aorta and/or abdominal aorta should berecorded by pulsed Doppler. CW Doppler of the ARjet should also be routinely recorded but only utilizedif a complete signal is obtained.Based on data in the literature and a consensus of

the committee members, the Task Force proposesa scheme of specific signs (R90% specificity), alongwith supportive signs in which predictive accuracy ismore modest, and quantitative parameters for ARseverity (Table 6). In applying this scheme, it is theconsensus of the committee members that the processof grading AR should be comprehensive usinga combination of these signs, clues and measurementsobtained by Doppler echocardiography. If the AR isdefinitely determined as mild or less using these signs,no further measurement is required. If there areparameters suggestive of more than mild AR and thequality of the primary data lends itself to quantita-tion, it is desirable for echocardiographers withexperience in quantitative methods to measure quan-titatively the degree of AR, including the regurgitantvolume and fraction as descriptors of volume over-load and the effective regurgitant orifice as a descriptor



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Table 5. Echocardiographic and Doppler parameters used in the evaluation of aortic regurgitation severity:utility, advantages and limitations.


Structural parametersLV size Enlargement sensitive for chronic significant

AR, important for outcomes. Normal sizevirtually excludes significant chronic AR

Enlargement seen in other conditions. Maybe normal in acute significant AR

Aortic leaflets alterations Simple, usually abnormal in severe AR; flailvalve denotes severe AR

Poor accuracy, may grossly underestimate oroverestimate the defect

Doppler parametersJet width or jet cross-sectional

area in LVOT d color flowSimple, very sensitive, quick screen for AR Expands unpredictably below the orifice.

Inaccurate for eccentric jetsVena contracta width Simple, quantitative, good at identifying mild

or severe ARNot useful for multiple AR jets. Small values;thus small error leads to large % error

PISA method Quantitative. Provides both lesion severity(EROA) and volume overload (R Vol)

Feasibility is limited by aortic valvecalcifications. Not valid for multiple jets, lessaccurate in eccentric jets. Provides peak flowand maximal EROA. Underestimation ispossible with aortic aneurysms. Limitedexperience

Flow quantitation d PW Quantitative, valid with multiple jets andeccentric jets. Provides both lesion severity(EROA, RF) and volume overload (R Vol)

Not valid for combined MR and AR, unlesspulmonic site is used

Jet density d CW Simple. Faint or incomplete jet compatiblewith mild AR

Qualitative. Overlap between moderate andsevere AR. Complementary data only

Jet deceleration rate (PHT) d CW Simple Qualitative; affected by changes in LV andaortic diastolic pressures

Diastolic flow reversal in descendingaorta d PW

Simple Depends on rigidity of aorta. Brief velocityreversal is normal

AR Z aortic regurgitation; CW Z continuous wave Doppler; EROA Z effective regurgitant orifice area; LV Z left ventricle; LVOT Zleft ventricular outflow tract; MR Z mitral regurgitation; PHT Z pressure half-time; PW Z pulsed wave Doppler; R Vol Z regurgitantvolume; RF Z regurgitant fraction; VC Z vena contracta width.

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Table 6. Application of specific and supportive signs, and quantitative parameters in the grading of aorticregurgitation severity.

Mild Moderate Severe

Specific signs forAR severity

� Central jet, width !25% of LVOT* Signs of AR Omild presentbut no criteria for severe AR

�Central jet, width R65% of LVOT*

� Vena contracta !0.3 cm* �Vena contracta O0.6 cm*� No or brief early diastolic flow

reversal in descending aorta

Supportive signs � Pressure half-time O500 ms Intermediate values �Pressure half-time !200 ms� Normal LV sizey �Holodiastolic aortic flow reversal in

descending aorta�Moderate or greater LVenlargementz

Quantitative parametersxR Vol, ml/beat !30 30e44 45e59 R60RF, % !30 30e39 40e49 R50EROA, cm2 !0.10 0.10e0.19 0.20e0.29 R0.30

AR Z aortic regurgitation; EROA Z effective regurgitant orifice area; LV Z left ventricle; LVOT Z left ventricular outflow tract;R Vol Z regurgitant volume; RF Z regurgitant fraction.*At a Nyquist limit of 50e60 cm/s.yLV size applied only to chronic lesions. Normal 2D measurements: LV minor axis %2.8 cm/m2, LV end-diastolic volume %82 ml/m2

(reference [2]).zIn the absence of other etiologies of LV dilatation.xQuantitative parameters can help sub-classify the moderate regurgitation group into mild-to-moderate and moderate-to-severeregurgitation as shown.




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of the lesion severity. The wording chosen forexpressing the degree of AR, which is a continuumbest defined by quantitative measurements, can in-clude qualifiers such as mild-to-moderate to describethe lowest end of the moderate range and moderate-to-severe to describe the upper end of the moderaterange. Similar to MR, when the evidence from thedifferent parameters is congruent, it is easy to gradeAR severity. When different parameters are contra-dictory, one must look carefully for technical andphysiologic reasons to explain these discrepancies andrely on the components that have the best quality ofthe primary data and that are the most accurateconsidering the underlying clinical condition.

Tricuspid Regurgitation

A small degree of tricuspid regurgitation (TR) ispresent in about 70% of normal individuals[69e71].Pathologic regurgitation is often due to right ven-tricular (RV) and tricuspid annular dilation second-ary to pulmonary hypertension or RV dysfunction.Primary causes of TR include endocarditis, carcinoidheart disease, Ebstein’s anomaly, and rheumaticdisease[72e74].Evaluation of TR severity has been hampered by

the lack of a quantitative standard for severity.Furthermore, in contrast to left sided lesions, surgicalintervention for severe TR alone is uncommon. Moreoften, tricuspid annuloplasty is performed as anadjunct to other cardiac surgery when TR issignificant. The echocardiographic examinationtherefore seeks to determine the etiology of re-gurgitation and provides a semi-quantitative estimate

of severity. The various parameters used in thisevaluation are detailed in Table 7. More quantitativemeasures of TR severity are rarely needed. Duringthe examination, it is important to measure the TRvelocity with CW Doppler, which provides anestimation of RV systolic pressure.


Evaluation of the tricuspid valve apparatus with 2Dechocardiography is important in determining theetiology of TR. Secondary findings like right atrialand RV enlargement often accompany significantchronic TR. Such an evaluation is usually qualitative.Although enlargement of right-sided chambers is notspecific for significant regurgitation, its absencesuggests milder degree of TR. Paradoxical ventricularseptal motion may occur with the RV volumeoverload due to severe TR. However, this sign isnot specific for TR, as it is affected by manyfactors[75e77]. Lastly, imaging of the inferior venacava in the subcostal view for size and respiratoryvariation provides an evaluation of right atrialpressure[78e80].

Doppler Methods

Color Flow Doppler

The simplest approach to evaluate TR severity iscolor-flow imaging in several views to establish thecharacteristics, direction and the size of the regur-gitant jet. Since the RV is situated in the anterior

Table 7. Echocardiographic and Doppler parameters used in the evaluation of tricuspid regurgitation severity:utility, advantages and limitations.


RV/RA/IVC size Enlargement sensitive for chronic significant TR.Normal size virtually excludes significantchronic TR

Enlargement seen in other conditions. May benormal in acute significant TR

TV leaflet alterations Flail valve specific for significant TR Other abnormalities do not imply significant TRParadoxical septal motion

(volume overload pattern)Simple sign of severe TR Not specific for TR

Jet area d color flow Simple, quick screen for TR Subject to technical and hemodynamic factors.Underestimates severity in eccentric jets

Vena contracta width Simple, quantitative, separates mild fromsevere TR

Intermediate values require further confirmation

PISA method Quantitative Validated in only a few studiesFlow quantitation d PW Quantitative Not validated for determining TR regurgitant

fractionJet profile d CW Simple, readily available Qualitative, complementary dataPeak tricuspid E velocity Simple, usually increased in severe TR Depends on RA pressure and RV relaxation,

TV area, and atrial fibrillation; complementarydata only

Hepatic vein flow Simple; systolic flow reversal is sensitive forsevere TR

Influenced by RA pressure, atrial fibrillation

CW Z continuous wave Doppler; EROA Z effective orifice regurgitant area; IVC Z inferior vena cava; PISA Z proximal isovelocitysurface area; PWZ pulsed wave Doppler; RAZ right atrium; RVZ right ventricle; TVZ tricuspid valve; TRZ tricuspid regurgitation.



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Figure 7. Examples of jet recordings by color Doppler, continuous wave Doppler, and hepatic vein flow by pulsed Dopplerin a case of mild tricuspid regurgitation (TR) and another with severe TR. The case of mild TR shows a small central colorjet with minimal flow convergence in contrast to the severe TR with a very large flow convergence and jet area in the rightatrium. CW Doppler recording shows a parabolic spectral display in mild TR whereas in severe TR, early peaking andtriangular shape of the velocity is seen (arrow). Hepatic vein flow pattern in mild TR is normal whereas in severe TR,hepatic venous flow reversal in systole (S) is seen. D Z diastolic hepatic venous flow.


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chest, transthoracic images usually are adequate and
should include the parasternal RV inflow view, theparasternal short-axis view, the apical four-chamberview and the subcostal four-chamber view. Asa general rule, jets that extend deep into the rightatrium represent more TR than small central jets thatappear just superior to the tricuspid leaflets (Fig. 7).Overall, color Doppler flow mapping of TR severityusing jet area correlates well with angiographicevaluation[81] and clinical measures of regurgitantseverity[82,83]. However, there can be considerableoverlap of jet areas in patients with mild vs moderateTR[83]. Furthermore, and similar to MR, flow jetsthat are directed centrally into the right atriumgenerally appear larger by color Doppler thaneccentric, wall-impinging jets with similar or worseseverity.Color-flow imaging also may be used to determine

TR severity by the PISA method. Visualization of ameasurable contour of the flow convergence zone ismore challenging than with MR. Quantitation of TRusing the PISA method has been validated in smallstudies but is rarely needed clinically[81,84]. Onthe other hand, visualization of the vena contractawidth is technically less demanding and can be uti-lized either quantitatively or qualitatively[82,85,86]. Ajet width O0.7 cm identifies severe TR with a sen-sitivity of 89% and a specificity of 93% and correlateswell with EROA[85,86]. Both the PISA and vena cont-racta methods are more accurate for determining TRseverity in central jets compared to eccentric jets, and


appear to be more accurate than jet area. However,there can be overlap in values of jet width betweenmild and moderate TR. Underestimation of severeTR can also occur in 20e30% of patients using jetarea or PISA[81].


Recording of TR jet velocity provides a usefulmethod for noninvasive measurement of RV orpulmonary artery systolic pressure. It is importantto note that TR jet velocity, similar to velocity ofother regurgitant lesions, is not related to the volumeof regurgitant flow. In fact, massive TR is oftenassociated with a low jet velocity (!2 m/s), as there isnear equalization of RV and right atrial pressures(Fig. 7). Conversely, mild regurgitation may havea very high jet velocity when pulmonary hypertensionis present.Similar to MR, the features of the TR jet by CW

Doppler that help in evaluating severity of regurgi-tation, are the signal intensity and the contour of thevelocity curve (Fig. 7). With severe TR, a densespectral recording is seen along with a triangular,early peaking of the velocity because of a prominentregurgitant pressure wave. With severe tricuspidregurgitation and normal RV pressures, the ante-grade and retrograde CW flow signals across thevalve are almost mirror images of each other, cor-responding to the ‘to-and-fro’ flow across the severelyincompetence valve orifice[87].



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Pulsed Doppler

The severity of TR will affect the early diastolic tri-cuspid E velocity, similar toMR. Values above 1.0 m/sare often recorded in patients with severe regurgi-tation even without valve stenosis. In theory, tricuspidregurgitant volume can be calculated by subtractingthe flow across a non-regurgitant valve from theantegrade flow across the tricuspid valve annulus. Incontrast to MR and AR, this approach is rarelyutilized for TR, partly because of errors in measuringthe tricuspid valve annulus.Similar to the use of pulmonary vein flow pattern

in MR, PW Doppler examination of the hepatic veinshelps corroborate the assessment of TR severity.With increasing severity of TR, the normallydominant systolic wave is blunted. With severetricuspid regurgitation, systolic flow reversal occurs(Fig. 7). However, hepatic vein flow patterns are alsoaffected by abnormalities in right atrial and RVrelaxation and compliance, the phase of the re-spiratory cycle, preload, and atrial fibrillation[88]. Thesensitivity of flow reversal for severe TR is 80%[83].While the specificity of systolic flow reversal is notwell defined, experience has shown that it is alsoa specific sign of severe TR, provided that themodulating conditions mentioned above are ac-counted for during interpretation.

Role of TEE

Most often, TR can be adequately evaluated ontransthoracic imaging. Even when parasternal andapical views are suboptimal, subcostal views allowcolor flow mapping, and recording of hepatic veinflow pattern. When transthoracic images are poor,TEE may be helpful. Color flow mapping can beperformed using the high esophageal four-chamberand short-axis views as well as the transgastric four-

chamber and RV inflow views. Similar to MR, jetarea may appear larger with TEE than with trans-thoracic imaging.CW Doppler signals can be recorded from high

esophageal or transgastric views. However, obtaininga parallel intercept angle can be problematic. Hepaticvein flow can be recorded by starting in a parasternallong-axis view of the right atrium and then followingthe inferior vena cava caudally until the hepatic veinsare visualized. The goals of the TEE examination areidentical to those of the surface examination so thatstandard image planes and multiple approaches toevaluation of regurgitant severity should be per-formed when pathologic tricuspid valve disease issuspected.

Integrative Approach to Assessmentof Tricuspid Regurgitation Severity

Similar to the assessment of other regurgitant lesions,an integrative approach is recommended for evalua-tion of TR (Table 8). This includes evaluation of thesize of right-sided chambers, septal motion andvarious Doppler parameters. Color Doppler flowmapping in at least two orthogonal planes should beperformed, with particular attention to the venacontracta, flow convergence and the direction andsize of the jet. CW Doppler recording of the TR jetshould be recorded to evaluate the signal intensityand contour of the jet, and estimate pulmonary arterysystolic pressure. Moreover, the size of the inferiorvena cava and response to respiration as well ashepatic vein flow pattern help evaluate right atrialpressure and adaptation to the volume overload.With the lack of extensive data on quantitation ofTR, the Task Force recommends integration ofinformation from all available parameters discussed(Table 8). The more congruent the findings are

Table 8. Echocardiographic and Doppler parameters useful in grading tricuspid regurgitation severity.


Tricuspid valve Usually normal Normal or abnormal Abnormal/flail leaflet/poor coaptationRV/RA/IVC size Normal* Normal or dilated Usually dilatedyJet area d central jets (cm2)z !5 5e10 O10VC width (cm)x Not defined Not defined, but !0.7 O0.7PISA radius (cm){ !0.5 0.6e0.9 O0.9Jet density and contour d CW Soft and parabolic Dense, variable contour Dense, triangular with early peakingHepatic vein flowk Systolic dominance Systolic blunting Systolic reversal

CW Z continuous wave Doppler; IVC Z inferior vena cava; RA Z right atrium; RV Z right ventricle; VC Z vena contracta.*Unless there are other reasons for RA or RV dilation. Normal 2D measurements from the apical four-chamber view: RV medio-lateralend-diastolic dimension %4.3 cm, RV end-diastolic area %35.5 cm2, maximal RA medio-lateral and supero-inferior dimensions %4.6 cmand 4.9 cm, respectively, and maximal RA volume %33 ml/m2 (references [35,89]).yException: acute TR.zAt a Nyquist limit of 50e60 cm/s. Not valid in eccentric jets. Jet area is not recommended as the sole parameter of TR severity due to itsdependence on hemodynamic and technical factors.xAt a Nyquist limit of 50e60 cm/s.{Baseline shift with Nyquist limit of 28 cm/s.kOther conditions may cause systolic blunting (e.g. atrial fibrillation, elevated RA pressure).




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regarding severity, the more confident the diagnosis.Inherent to this process is the particular attention tothe quality of the data obtained, and to thephysiologic conditions that can alter the accuracy ofthese parameters as indices of regurgitation severity.

Pulmonary Regurgitation

Minor degrees of pulmonary regurgitation (PR)have been reported in 40e78% of patients withmorphologically normal pulmonary valves and noother evidence of structural heart disease[90e92].Pathologic regurgitation is infrequent, and shouldbe diagnosed mainly in the presence of significantstructural abnormalities of the right heart. In theadult, acquired PR is most often seen in patients withpulmonary hypertension, which is often associatedwith dilatation of the pulmonary artery, rightventricle, right atrium and hepatic veins. PR in thiscondition, however, is rarely severe. Severe PR isusually observed in patients with anatomic abnor-malities of the valve or after valvotomy. Because ofthe difficulties in imaging the pulmonary valve andthe low prevalence of severe, life-threatening PR, fewvalidation studies have been conducted. Further-more, validation of echo/Doppler methods measuringPR is limited by the uncommon use of angiographyor other methods to diagnose this condition. Echo-cardiographic and Doppler parameters that areuseful in the evaluation of PR are listed in Table 9.


Evaluation of the RV outflow tract and pulmonaryvalve by 2D echocardiography is possible from theparasternal and subcostal views. Identification ofanatomic abnormalities associated with PR, suchas abnormalities of cusp number (quadricuspid orbicuspid valves), motion (doming or prolapse) or


structure (hypoplasia, dysplasia or absence of thepulmonary valve) may help define the mechanism ofregurgitation and yield clues to its severity. Visuali-zation of the entire pulmonary valve is more difficultthan the mitral, aortic and tricuspid valves. However,dilatation of the pulmonary artery, frequently ob-served in pulmonary hypertension, allows easiervisualization of the valve. Inability to fully visualizethe pulmonary valve may limit the quantitation ofpulmonary regurgitation. Lastly, evaluation of thesize and function of the RV in the absence ofpulmonary hypertension provides an indirect in-dicator to the significance of PR and adaptation ofthe RV to the volume overload state.

Doppler Methods

Color Flow Doppler

Color Doppler flow mapping is the most widely usedmethod to identify PR. A diastolic jet in the RVoutflow tract, beginning at the line of leaflet co-aptation and directed toward the right ventricle isdiagnostic of PR (Fig. 8). Although color Doppler isideally suited to determine the jet size and spatialorientation, many of the factors used to evaluate theseverity of regurgitation (jet size, extent and duration)will be determined by a combination of the regur-gitant volume and the driving pressure (gradientbetween the pulmonary artery and the RV). Regur-gitant jets seen in normal pulmonary valves, consid-ered a variation of normal, are usually very small,‘spindle-shaped’ and originate centrally from thepulmonary leaflet coaptation site (Fig. 8)[91]. Initialstudies attempted to quantify pulmonary regurgitationbymeasuring jet length[91]. Jets!10mm in lengthweretrivial while larger jets were associated with heartdisease. However, jet length is highly dependent onthe driving pressure gradient between the pulmonaryartery and the RV, and is therefore not a reliableindex of severity. Assessing the entire jet area byplanimetry should, theoretically, fare better than thejet length alone. Planimetered jet areas, indexed for

Table 9. Echocardiographic and Doppler parameters used in the evaluation of pulmonary regurgitationseverity: utility, advantages and limitations.

Parameter Utility/advantages Disadvantages

RV size RV enlargement sensitive for chronic significantPR. Normal size virtually excludes significant PR

Enlargement seen in other conditions

Paradoxical septal motion(volume overload pattern)

Simple sign of severe PR Not specific for PR

Jet length d color flow Simple Poor correlation with severity of PRVena contracta width Simple quantitative method that works

well for other valvesMore difficult to perform; requires good imagesof pulmonary valve; lacks published validation

Jet deceleration rate d CW Simple Steep deceleration not specific for severe PRFlow quantitation d PW Quantitates regurgitant flow and fraction Subject to significant errors due to difficulties of

measurement of pulmonic annulus and a dynamicRVOT; not well validated

CW Z continuous wave; RV Z right ventricle; PR Z pulmonic regurgitation; RVOT Z right ventricular outflow tract.


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Figure 8. Example of color flow and continuous wave Doppler recording in a case with mild pulmonary regurgitation (PR)and another with severe PR. In the mild PR, color Doppler shows a small spindle-shaped PR jet in the right ventricularoutflow tract. CW recording of the jet shows a slow deceleration of the PR velocity. In the case with severe PR, a large andwide PR jet is seen by color Doppler (arrow). Continuous wave Doppler recording shows a steep deceleration of thediastolic PR velocity, with early termination of PR flow (arrow). LA Z left atrium; RV Z right ventricle.


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body surface area, correlated well with PR severitycompared to angiography. However, a high degreeof variability and overlap among different grades ofregurgitation was observed[92]. In cases of severepulmonary regurgitation, the full extent of theregurgitant jet may not be appreciated from theparasternal position; subcostal imaging may benecessary to fully appreciate its full extent.Although not systematically validated for the

pulmonary valve, the vena contracta width isprobably a more accurate method to evaluate theseverity of PR by color Doppler, similar to otherregurgitant lesions. Some investigators have used thePR jet width in the serial assessment of pulmonaryhomografts, but standards for pulmonary venacontracta width have not been established[93]. It isimportant to note that in cases of severe PR, whereequalization of diastolic pulmonary artery and RVpressures occurs early in diastole, the color jet areacan be brief and misleading at first glance. In thiscase, the large width of the vena contracta andfindings by PW and CWDoppler (see below) alert theobserver to the severity of regurgitation (Fig. 8).


CW Doppler is frequently used to measure the end-diastolic velocity of PR and thus estimate pulmonaryartery end-diastolic pressure. However, there is noclinically accepted method of quantifying pulmonaryregurgitation using CW Doppler. Similar to AR, the

density of the CW signal provides a qualitativemeasure of regurgitation[51]. A rapid decelerationrate, while consistent with more severe regurgitation,is influenced by several factors including RV diastolicproperties and filling pressures. In severe PR, a rapidequalization of RV and pulmonary artery pressurescan occur before the end of diastole. Thus, an intensesignal of ‘to and fro’ flow in the shape of a ‘sinewave’, with termination of flow in mid to late diastolecan be seen (Fig. 8). This finding, however, is notspecific for severe PR, as early and rapid equilibra-tion of diastolic pressures is also seen in patients withlow pulmonary artery end-diastolic pressure and/orelevated RV diastolic pressure (e.g. RV infarction).However, the intensity of the PR signal, colorDoppler characteristics of the jet and pulmonic flowquantitation in the RV outflow tract by PW Dopplerhelp differentiate these entities.

Pulsed Doppler

In the evaluation of PR, pulsed Doppler interrogationof velocity can be useful at the level of the pulmonicannulus and in the pulmonary artery[94e96]. If thevelocity of the PR jet is not aliased by PW Doppler,its contour and timing can be evaluated similar toCW Doppler (above), with identical implications[97].Pulsed Doppler assessment of the forward and

reverse flows in the pulmonary artery has been usedto calculate regurgitant volume and regurgitantfraction[95,96]. If the diameter of the pulmonary arteryis assumed to be constant, then the ratio of the




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reverse to forward velocity time integral can be usedto estimate the percent of regurgitant flow[95].Although differences in regurgitation fraction wereobserved among groups with various severity of PR,a considerable overlap was seen and standards forpulmonary artery regurgitant fraction have not beenestablished[96]. Furthermore, this method is not validin patients with pulmonic stenosis because of post-stenotic turbulent flow.As previously discussed, pulsed Doppler can be

used to calculate stroke volume at different annularsites. The pulmonic annulus, however, is probably themost difficult site to measure because of its poorvisualization and the changing size of the RV outflowtract during the cardiac cycle. It is recommended tomeasure the pulmonic annulus during early ejection(two to three frames after the R wave on the ECG),just below the pulmonic valve[98,99]. Although notvalidated for quantitation of PR, flows at thepulmonic annulus can be compared to other sites toderive quantitative parameters of regurgitation (re-gurgitant volume and fraction). Clinically, this isfeasible provided that particular attention is taken toimage well the area of the pulmonic annulus and thusminimize errors of its measurement.

Role of TEE

The main pulmonary artery is an anterior structureand is often imaged as well or even better withtransthoracic echocardiography compared to thetransesophageal approach. The role of TEE istherefore limited in assessing severity of PR.

Integrative Approach to Assessment ofPulmonary Regurgitation Severity

A comprehensive approach to the evaluation of PRseverity is recommended, similar to other valvular


regurgitation. Since there is insufficient data onquantitation of PR to recommend a clinically vali-dated quantitative approach, the evaluation is gener-ally qualitative and should include the variousparameters discussed above (Table 10). Color Dopp-ler is the best screening modality and accuratelyidentifies trivial and mild pulmonary regurgitation asthin, small jets with a ‘pin-point’ origin. These lesionsare readily differentiated from more severe degrees ofPR. In addition to color Doppler, an evaluation ofthe pulmonic valve, RV size and function helpselucidate the etiology of the regurgitation and theadaptation to the volume overload. CW Doppler ofthe PR jet and TR jet, if available, should beroutinely recorded to provide supportive evidencefor the degree of regurgitation and estimation ofpulmonary pressure. Quantitation of the vena con-tracta by color Doppler and regurgitant fraction withpulsed Doppler, although helpful, needs furthervalidation. Despite these limitations, clinically usefulqualitative estimates of PR regurgitation are feasiblein the majority of cases.

Conclusions

Echocardiography with Doppler has become the firstline approach to the evaluation and management ofvalvular heart disease. While 2D echocardiographyprovides an assessment of valvular structure, mech-anism of regurgitation and adaptation to the volumeoverload state, Doppler allows in the same setting,a comprehensive evaluation of the severity of re-gurgitation using qualitative and quantitative meth-ods from color flow and spectral Doppler. In general,regurgitation may present a challenge for mostdiagnostic techniques because of the dynamic natureof lesion and its dependence on various hemodynam-ic and physiologic conditions. For all valvularregurgitation, an integrative approach of 2D and

Table 10. Echocardiographic and Doppler parameters useful in grading pulmonary regurgitation severity.


Pulmonic valve Normal Normal or abnormal AbnormalRV size Normal* Normal or dilated DilatedyJet size by color Dopplerz Thin (usually !10 mm in length)

with a narrow originIntermediate Usually large, with a wide origin;

may be brief in durationJet density and decelerationrate d CWx

Soft; slow deceleration Dense; variabledeceleration

Dense; steep deceleration, earlytermination of diastolic flow

Pulmonic systolic flow comparedto systemic flow d PW{

Slightly increased Intermediate Greatly increased

CW Z continuous wave Doppler; PR Z pulmonic regurgitation; PW Z pulsed wave Doppler; RA Z right atrium; RF Z regurgitantfraction; RV Z right ventricle.*Unless there are other reasons for RV enlargement. Normal 2D measurements from the apical four-chamber view: RV medio-lateral end-diastolic dimension %4.3 cm, RV end-diastolic area %35.5 cm2 (reference [89]).yException: acute PR.zAt a Nyquist limit of 50e60 cm/s.xSteep deceleration is not specific for severe PR.{Cut-off values for regurgitant volume and fraction are not well validated.



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Doppler parameters is recommended to achieve anaccurate evaluation of the severity of the lesion andits clinical significance. This takes into accountphysiologic conditions that could alter the accuracyof certain parameters, emphasizes the quality of theprimary data and allows internal verification of theinterpretation.Echocardiographic evaluation of cardiac adapta-

tion to the volume overload offers, along with carefulassessment of symptoms, an ideal tool for manage-ment of valvular regurgitation and timing of surgery.With the recent advances in digital echocardiogra-phy, comparison of serial images can now beperformed readily side-by-side for a more preciseassessment of interval change in these adaptiveprocesses and for better timing of surgery. In thenear future, with advances in real-time 3D imaging,the spatial distribution of the valve regurgitation willbe more readily available, enhancing measurementsof flow convergence, vena contracta and the regur-gitant jet for improved quantitation of valvularregurgitation.

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