CORRESPONDENCE

Color and Spectral Modes of Tissue DopplerImaging Have Similar Diagnostic Utility butDifferent Numerical Values

To the Editor:

The conclusion made by McCulloch et al1 thatestimation of left ventricular filling pressure by colortissue Doppler could lead to significant errors whencompared with estimation by spectral tissue Dopp-ler is misleading and is not supported by the datapresented. The authors did not demonstrate that theestimate of left ventricular filling pressure by theratio of mitral inflow early diastolic velocity to earlymitral annular diastolic velocity (E/E’) using spectralDoppler is more accurate than estimates using vali-dated cut-off values for color tissue Doppler. Theminimum requirement for evaluating the superiorityof one method relative to another is to have anindependent standard for validation, and this wasnot done. Published studies including those thatused catheterization data for validation showed dif-ferent cut-off values for elevated pressure for E/E’using spectral Doppler evaluation of the medialcompared with lateral aspects of the mitral annu-lus.2,3 Likewise there are published data that shownormal and abnormal values for E/E’ using colortissue Doppler.4,5 The first implication of thesepublications is that interpretation should be basedon reference values that are specific for annular site,age, and technique.

An important fact not addressed by the authors isthe interobserver and intraobserver variability andreproducibility of spectral compared with colortissue Doppler. If tracking a specific segment of theannulus more precisely as is possible with colortissue Doppler results in more accurate data, as isthe experience in our laboratory, the lower rawvalues do not invariably represent an underestima-tion of the true velocity.

Lastly, a good correlation of E/E’ to filling pres-sures does not automatically mean a good agreementwith catheter-measured pressures in unselected par-ticipants,6,7 hence, the authors recommendationthat a single method be used for all clinical applica-tions may be unrealistic.

Kofo O. Ogunyankin, MD, FACC, FASEDivision of Cardology

Queen’s UniversityKingston General HospitalKingston, Ontario, Canada

REFERENCES

1. McCulloch M, Zoghbi WA, Davis R, Thomas C, Dokainish H.Color tissue Doppler myocardial velocities consistently under-estimate spectral tissue Doppler velocities: impact on calcula-

tion peak transmitral pulsed Doppler velocity/early diastolic

tissue Doppler velocity (E/Ea). J Am Soc Echocardiogr 2006;19:744-8.

2. Nagueh SF, Middleton KJ, Kopelen HA, Zoghbi WA, Qui-nones MA. Doppler tissue imaging: a noninvasive technique forevaluation of left ventricular relaxation and estimation of fillingpressures. J Am Coll Cardiol 1997;30:1527-33.

3. Sohn DW, Chai IH, Lee DJ, et al. Assessment of mitralannulus velocity by Doppler tissue imaging in the evaluationof left ventricular diastolic function. J Am Coll Cardiol1997;30:474-80.

4. Nikitin NP, Witte KKA, Thackray SDR, de Silva R, Clark AL,Cleland JGF. Longitudinal ventricular function: normal valuesof atrioventricular annular and myocardial velocities measuredwith quantitative two-dimensional color Doppler tissue imag-ing. J Am Soc Echocardiogr 2003;16:906-21.

5. Wang M, Yip GWK, Wang AYM, et al. Peak early diastolicmitral annulus velocity by tissue Doppler imaging adds inde-pendent and incremental prognostic value. J Am Coll Cardiol2003;41:820-6.

6. Ogunyankin KO, Londry CC, Pritchett SB, Malik PG. Areserial estimates of left ventricular filling pressure by differentechocardiographic modalities reliable [abstract]? J Am SocEchocardiogr 2003;16:540.

7. Ogunyankin KO, Londry CC, Pritchett SB, Malik PG. Reliableprediction of mean left ventricular diastolic pressure may re-quire a stepwise approach [abstract]. J Am Soc Echocardiogr2003;16:540.

doi:10.1016/j.echo.2006.08.020

Response to: “Color and Spectral Modes ofTissue Doppler Imaging Have Similar Diag-nostic Utility but Different Numerical Values”

To the Editor:

The authors would like to thank Dr Ogunyankinand colleagues for their comments. With respect tothe use of color rather than spectral tissue Doppler(TD), our article does not state, nor imply, thatcolor TD is less accurate than spectral TD for theestimation of left ventricular (LV) filling pressures.Rather, the article states that if a user of color TDis referring to reference values for peak transmitralearly diastolic velocity/TD early diastolic annularvelocity (E/Ea) that were validated using spectralTD, interpretative errors could result.1 Indeed, theBland-Altman plot in the article (Figure 3) illustratesthe numeric overestimation of the absolute value ofE/Ea using color, rather than spectral, TD. This isentirely distinct from stating that color TD ratherthan spectral TD is less accurate for the estimationof LV filling pressures. Furthermore, Dr Ogunyankinstates in the letter that, “. . . there are published datathat show normal and abnormal values for E/E’ usingcolor tissue Doppler.” In fact, these two referencedstudies (references 4 and 5 in Dr Ogunyankin’sletter) do not establish normal and abnormal valuesof color TD–derived E/Ea for the estimation of LVfilling pressures; there are no such data in either of

these articles.2,3 Rather, there is a paucity of pub-

1411

Journal of the American Society of Echocardiography1412 Correspondence November 2006

lished data validating a specific color TD–derivedE/Ea cut-off value for elevated LV filling pressures usinginvasive hemodynamics as a reference standard. It isfor this reason that we state in the conclusion of ourstudy that, “Further studies establishing the relation-ship of color E/Ea to invasively measured LV fillingpressures are, therefore, needed.”1

With respect to the comment that reference val-ues for E/Ea using spectral TD may differ using thelateral or septal mitral annulus, this is supported bydata. It is for that reason that our laboratory haspreviously demonstrated that, in patients with re-gional wall-motion abnormalities, E/Ea calculatedusing an average of the septal and lateral mitralannuli has a better correlation with invasively mea-sured pulmonary capillary wedge pressure than E/Eacalculated using either annulus alone.4 With respectto the contention that we do not address interob-server and intraobserver variability, our laboratoryhas previously demonstrated the low variability (5%)using spectral TD for the calculation of E/Ea.5 DrOgunyankin and colleagues also state that, “If track-ing a specific segment of the annulus more preciselyas is possible with color tissue Doppler results inmore accurate data, as is the experience in ourlaboratory, the lower raw values do not invariablyrepresent an underestimation of the true velocity.”Color versus spectral TD is not a question of truevelocity; it is a question of mean versus peak veloc-ity. One of the underlying tenets of our study–thatthe mean myocardial velocities measured usingcolor TD are lower than the peak velocities mea-sured using spectral TD–is based on the physical andtechnical differences between these two TD modal-ities. Color TD measures the velocities in a samplevolume and displays only their mean, whereas spec-tral TD displays all velocities in the sample volumeand the measured velocity is the maximal (peak)velocity, at the outer border of the modal spectrum.Therefore, it is expected that mean myocardialvelocities (color TD) would be lower than the peakvelocities (spectral TD); this is a fundamental prop-erty, not a question of true velocity.

With respect to the statement that E/Ea may notcorrelate well to LV filling pressures in unselectedparticipants, this is true. Indeed, in demonstratingthe correlation of spectral TD–derived E/Ea to inva-sively measured filling pressures, we and othersinitially excluded patients with conditions that may

affect inflow velocity such as mitral stenosis or

prosthetic mitral valves, and patients in nonsinusrhythm.4-7 However, all these studies have anotherthing in common: they demonstrate that spectralTD– derived E/Ea can accurately estimate LV fillingpressures. Lastly, given that E/Ea calculated usingcolor TD is higher–in the same patient at the samepoint in time–than E/Ea calculated using spectralTD, our recommendation that a single TD modal-ity be used for the calculation of E/Ea, referencedto its respective standards, seems quite reason-able.

Marti McCulloch, RDCS, andHisham Dokainish, MD

The Methodist-De Bakey Heart Center andBaylor College of Medicine,

Houston, Texas

REFERENCES

1. McCulloch M, Zoghbi WA, Davis R, Thomas C, Dokainish H.Color tissue Doppler myocardial velocities consistently under-estimate spectral tissue Doppler velocities: impact on calcula-tion of peak transmitral pulsed Doppler velocity/early diastolictissue Doppler velocity (E/Ea). J Am Soc Echocardiogr 2006;19:744-8.

2. Nikitin NP, Witte KKA, Thackray SDR, de Silva R, Clark AL,Cleland JGF. Longitudinal ventricular function: normal valuesof atrioventricular annular and myocardial velocities measuredwith quantitative two-dimensional color Doppler tissue imag-ing. J Am Soc Echocardiogr 2003;16:906-21.

3. Wang M, Yip GW, Wang AY, et al. Peak early diastolic mitralannulus velocity by tissue Doppler imaging adds independentand incremental prognostic value. J Am Coll Cardiol 2003;41:820-6.

4. Rivas-Gotz C, Manolios M, Thohan V, Nagueh SF. Impact ofleft ventricular ejection fraction on estimation of left ventricularfilling pressures using tissue Doppler and flow propagationvelocity. Am J Cardiol 2002;91:780-4.

5. Nagueh SF, Middleton KJ, Kopelen HA, Zoghbi WA, Qui-nones MA. Doppler tissue imaging: a noninvasive technique forevaluation of left ventricular relaxation and estimation of fillingpressures. J Am Coll Cardiol 1997;30:1527-33.

6. Ommen S, Nishimura RA, Appleton CP, et al. Clinical utility ofDoppler echocardiography and tissue Doppler imaging in theestimation of left ventricular filling pressures: a comparativesimultaneous Doppler-catheterization study. Circulation 2000;102:1788-94.

7. Dokainish H, Zoghbi WA, Lakkis NM, et al. Optimal non-invasive assessment of left ventricular filling pressures: a com-parison of tissue Doppler echocardiography and B-type natri-uretic peptide in patients with pulmonary artery catheters.Circulation 2004;109:2432-9.

doi:10.1016/j.echo.2006.07.016