Prospective Validation of Detection and Quantitative Assessment of Chronic Aortic

Regurgitation by a Combined Echocardiographic and Doppler Method

Xavier Borras, MD, Francese Carreras, MD, Josep M. Auge, MD, and Guillem Pons-Llad6, MD, Barcelona, Spain

To establish the accuracy of Doppler echocardiography in the assessment of chronic aortic regurgitation (AR), 87 patients were included in a two-step prospective study. In a first consecutive series of 56 patients, two-dimensional directed M-mode echocardiography and pulsed wave Doppler (PWD) studies were performed within a 24-hour interval of a conventional contrast aortic angiography, which showed AR in 46 patients. Sensitivity and specificity of PWD in the detection of AR were both 100%. To quantitate AR, a left ventricular outflow tract (LVOT) PWD mapping was scored. Significant differences between 1, 2, and 3 to 4 angiographic grades of AR were obtained. As some overlap existed between groups, a multifactorial analysis of PWD and echocardiographic measurements was performed: optimal discrimination was obtained when a new score combining LVOT mapping by PWD, diastolic left ventricular diameter, and aortic root dimension was considered. A prospective validation of this combined echocardiographic-Doppler method was then applied on a second group of 31 catheterized patients with AR. Correlation obtained (r = 0.86; P < 0.001) confirmed the accuracy of this new method in the prediction of the severity of AR. (J AM Soc ECHO 1988;1:422-9.)

Quantitation of aortic regurgitation (AR) is a chal­lenge for noninvasive diagnostic methods. Measure­ment of left ventricular dimension by echocardiog­raphy proved to be useful in identifying those pa­tients with more severe forms of AR requiring surgical treatment,I but as an indirect marker, this measurement is rarely used as a sole basis in the quan­titative assessment of the lesion. More recently, Doppler techniques have been extensively applied to the diagnosis and quantitation of the lesion.2

-7

The purpose of our study was partly to assess pro­spectively the value of pulsed Doppler and echocar­diographic measurements, either alone or in com­bination, in the diagnosis and quantitation of chronic AR by comparison with aortic angiography. A quan­titative method derived from this analysis, combining selected M-mode echocardiography and pulsed wave

From the Cardiology Department, Hospital de la Santa Creu i Sant Pau, Universitat Autonoma de Barcelona.

Reprint requests: X. Borris, MD, Department de Cardiologia, Hospital de la Santa Creu i Sant Pau, Avda. P. Claret 167,08025 Barcelona, Spain.

422

Doppler (PWD) measurements, was prospectively validated as a second part of the study on a new series of patients.

METHODS

The study comprised a total of 87 consecutive adult patients submitted for a diagnostic cardiac catheter­ization. The first part of the study was performed on the first 56 patients (group 1), 19 with rheumatic valvular heart disease (age 56 ± 11 years), 27 with degenerative isolated aortic valve disease (age 58 ± 10 years), and 10 with coronary heart disease (age 54 ± 8 years). Part two was performed on 31 patients (group 2), all with a well-defined clinical diagnosis of chronic AR, rhc;:umatic origin in 13 pa­tients (age S4± 10 years) and degenerative origin in 18 (age 57 ± 9 years). In this group the grade of AR was predicted, previously to aortic angiog­raphy, by application of the noninvasive method that was derived from the results obtained in the first part of the stUdy. All the patients were in a clinically stable situation.

Volume 1 Number 6 November-December 1988 Echo Doppler assessment of aortic regurgitation 423

Figure 1 Two-dimensional echocardiographic apical long-axis view showing nine preselected points specifically interrogated by pulsed wave Doppler. Same approach was also applied in every case on five-chamber apical view.

Doppler echocardiograpbic studies

Complete real-time guided M-mode and pulsed Doppler examination was performed (previously to the angiographic study) with a Honeywell Ultra­imager system and a 3.5 MHz transducer for echo­cardiographic purposes and a 2.25 MHz probe for the PWD study. StandardM-mode echocardiograph­ic measurements included systolic and diastolic left ventricular diameters, aortic root and left atrial di­ameters, left ventricular total mass,8 mitral E point septal separation, and the presence or absence of a diastolic fluttering on the anterior mitral leaflet.

A real-time PWD mapping of the left ventricular outflow tract (LVOT) was performed from two or­thogonal cross-sectional apical views: five-chamber and long-axis. In each view three levels of the LVOT were considered (immediately subaortic, middle LVOT defined by the free edge of the anterior mitral valve, and intraventricular), where nine preselected points (Figure I) were interrogated for the presence or absence of aortic regurgitant flow, defined by a diastolic flow signal starting immediately after the end of the systolic flow and characterized by a broad spectral frequency with an aliasing phenomenon on the display resulting from the high maximal velocities

of the jet. On the basis of previous observations in our laboratory,9,10 suggesting that duration and in­tensity of mitral and tricuspid regurgitant flow sig­nals by pulsed Doppler are related to the severity of the lesion, an attempt was made to recognize differ­ent Doppler patterns of regurgitant flow also in AR. Two patterns could be distinguished as follows: type 1, characterized by a flow signal of decreas­ing intensity along diastole (Figure 2, A); and type 2, in which an intense homogeneous flow signal was recorded during the whole diastolic period (Fig­'ure 2, B).

A score was designed adding the results from each of the nine described points on each apical view, where values were assigned as follow: 0 if no diastolic flow signal was elicited, 1 when a type 1 regurgitant flow waS observed, and 2 if a type 2 was present. The results obtained in either the long-axis or the five-chamber apical view were compared with the angiographic degree of AR. Furthermore, a global score resulting from the addition of the results in each view was also compared with angiography to see if an improvement in the quantitative assessment of the lesion could be obtained. Reproducibility of the method was tested by comparison of the results

424 Borras et al.

Journal of the American Society of

Echocardiography

Figure 2 Types of aortic regurgitation signal by pulsed wave Doppler. A, Pattern 1, char­acterized by diastolic flow signal of decreasing intensity. B, Pattern 2, showing intense ho­mogeneous flow signal along diastole.

obtained by two independent observers in 12 of the patients.

Invasive studies

Diagnostic cardiac catheterization was done within 24 hours after the echocardiographic-Doppler study,

including a contrast aortography perfonned in a right anterior oblique projection in each case. Aortic in­sufficiency, when present, was graded semiquanti­tatively on the 0 to 4 scale (none, mild, moderate,

- severe, massive) 11 by agreement between two expe­rienced observers, unaware of the noninvasive results.

Volume 1 Number 6 November-December 1988

PWD SCORE APICAL L-A

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Echo Doppler assessment of aortic regurgitation 425

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Figure 3 Distribution of scores obtained by pulsed wave Doppler (PWD) mapping according to different angiographic degrees of aortic regurgitation. A, Apical long-axis view. B, Five­chamber apical view. Statistically significanc differences were obtained between 1, 2, and 3 to 4 angiographic degrees, although considerable overlap between groups existed.

Statistics

Statistical analysis of the results was perfonned with Student's t test for unpaired data, linear correlation with Snedecor's test, and rank nonparametric Spear­man's correlation test, each one applied when ap­propriate. A discriIniI1ant multifactorial analysis was used to obtain the most discriminative combination of parameters. Statistical significance was considered when p < 0.05.

RESULTS

Of the 56 patients included in group 1, AR was proved to be present by angiography in 46 patients, 43 patients had valvular heart disease, and three had ischemic heart disease. Coexistent significant aortic stenosis (peak to peak gradient over 50 mrn Hg) waS deemed to be present in 28 of these patients.

When the described M-mode echocardiographic measurements were correlated with the angiographic degree of AR, no statistically significant differences between contiguous degrees of AR were demon­strated (Student's t test), although left ventricular

diastolic dimension and aortic root diameter proved to be the most discriminative between groups (Ta­ble 1).

PWD detection of AR was 100% sensitive and specific. Distribution of patients according to the de­gree of regurgitation at angiography and the scores obtained by PWD either on the long-axis or the five­chamber apical views showed significant differences between angiographic grades 1,2, and 3 to 4 of AR (Student's t test), although considerable overlapping

_existed (Figure -3). No improvement was shown when a global score adding the results from each one of the views was applied. No significant differences were present when results from two separate ob­servers were compared (r :;: 0.99; P < 0.001, Sne­decor's test) .

A discriminant multifactorial statistical analysis demonstrated that the combination of the data ob­tained from PWD mapping at the three considered levels, either on the long-axis or the five-chamber apical view, and the two most discriminative echo­cardiographic measurements described (left ventric­ular diastolic dimension and aortic root diameter) further improved the discrimination between differ"

426 Borras et aI.

J oumal of the American Society of

Echocardiography

Table 1 Distribution of M-mode echocardiographic measurements according to aortic regurgitation angiographic grades

LVDd LVDs LV mass LA Ao E-S Grade (mm) (mm) (gm) (mm) (mm) (mm) Mitral Fluttering· (%)

1 53 ± 8 37 ± 11 375 ± 200 49 ± 11 31 ± 6 14 ± 12 6/10 (60) 2 56 ± 12 34 ± 11 360 ± 200 48 ± 11 34 ± 6 8 ± 8 3/5 (60) 3 63 ± 12 44±11 420 ± 135 42 ± 11 38 ± 7 16 ± 5 101l(} (100) 4 68 ± 6 · 47 ± 7 540 ± 115 45 ± 8 38 ± 2 22 ± 11 6/6 (100)

LVDd, Diastolic left ventricular diameter; LVDs, systolic left ventricular diameter; LV, left ventricular diameter; LA, left atrial diameter; Ao, aortic root diameter; E·S, E·septum distance. No statistically signjficant differences were obtained between contiguous angiographic degrees of aortic regurgitation. " Patients with mitral stenosis are excluded.

Table 2 Combined echocardiographic and PWD score

AR signal detection by PWD

Points

Subvalvular (first level) 1 LVOT (second level) 1 Left ventricle (third level) 2*

Diastolic left ventricular diameter > 55 mm 1 Aortic root diameter >35 ~ 1

AR, Aortic regurgitation; PWD, pulsed wave Doppler; LVOT, left ven· tricular outflow tract. *Only one point is added if a pattern 1 of AR is obtained.

ent degrees of AR. The results of this analysis allowed the design of a simplified score: when either a type 1 or 2 AR signal by PWD was detected exclusively at any point in the first level (subvalvular), one point was given; when an AR signal was detected at the second level (middle LVOT), one point was added; a signal detected at the third level (intraventricular) added one point if the AR signal was a pattern 1 (Figure 2, A) and two points were added if a ho­mogeneously intense signal was elicited (pattern 2, Figure 2, B); an M-mode left ventricular diastolic diameter over 55 mm added one point; and finally an M-mode aortic root diameter over 35 mm added one more point. The maximal score was thus six points (Table 2). Results of the application of this new score in the quantitative assessment of AR showed a better discrimination between angio­graphic groups than the PWD mapping alone (Fig­ure 4).

Prospective Validation of the Combined Echocardiographic and Doppler Method

To validate this combined echocardiographic­Doppler method, 31 new patients (group 2) with the clinical diagnosis of chronic AR were prospec­tively studied before a cardiac catheterization was

performed. In all patients AR was actually proved at angiography, and a significant aortic stenosis was also demonstrated in 19 of these patients. On the basis of the results of the application of the simplified score (Figure 4), a prediction of the angiographic degree of AR was attempted by considering that an AR grade 1/4 was present when one or two points were obtained at the echocardiographic-Doppler score; AR grade 2/4 was predicted when the score was 3 or 4; and finally, AR grades 3/4 or 4/4 were con­sidered to be present when the score was 5 or 6. The correlation between the noninvasive method and the angiographic results was r = 0.86, P < 0.001 (rank nonparametric Spearman's correlation test) (Figure 5). In four cases an AR angiographically graded 1/4 was considered by combined echocardiography and Doppler as being 2/4. In three cases with severe AR by angiography (3/4 to 4/4), the combined echocardiographic-Doppler method quantified the degree of the lesion as 2/4; in all of these patients a severe aortic stenosis was associated with AR, with a nonenlarged and hypertrophied left ventricle. Thus in no cases was an angiographically severe AR deemed as mild with combined echocardiography and Doppler.

DISCUSSION

The noninvasive assessment of AR has been at­tempted by application of different ultrasonic meth­ods. A fine fluttering of the anterior mitral valve leaf­let was the first echocardiographic sign described in AR,12 although its sensitivity is highly dependent on the direction of regurgitant aortic flowY Although widely used in clinical practice, mainly because of its specificity, the sensitivity of this sign is not higher than the cardiac auscultation. 14

,15 Left ventricular di­mension Py echocardiography increases with the se­verity of the lesion in chronic AR, and it has been

Volume 1 Number 6 November-December 1988

ECHO-DOPPLER SCORE

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Figure 4 Distribution of simplified echocardiographic Doppler score according to different angiographic degrees of aortic regurgitation.

applied as a marker of the timing of surgeryl but is rarely used as a sole quantitative indicator. Doppler techniques have increased the diagnostic accuracy in the detection of AR, and many different methods have been described in the quantitative assessment of the lesion/-7,16-2o but none of them combined Doppler and echocardiographic measurements, al­though such a combination would appear logical, as it represents a more integrated approach to the problem.

No one of the sevt:n M-mode echocardiographic measurements considered in our study was able to distinguish between contiguous angiographic de­grees of AR (Table 1), although the left ventricular diastolic dimension and the aortic root diameter were the most discriminative. Whereas the increase of the left ventricular diameter could be considered as a direct hemodynamic consequence of a chronic AR, this cause-effect relationship is not so easy to establish with the dilation of the aortic root, provided that this finding can be the cause and not a consequence of the regurgitation.21

The PWD mapping of the LVOT is the method chosen by most authors in the noninvasive quanti­tation of AR.4,5,22 When we have assessed such a technique alone, our results have readily reproduced those reported by others, although a clear overlap between different angiographic degrees of AR has been observed (Figure 3).

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Echo Doppler assessment of aortic regurgitation 427

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Figure 5 Correlation between aortic regurgitation angiographic degrees and those obtained by com­bined echocardiographic-Doppler method (r = 0.863, P < 0.001, rank nonparametric Spearman's correlation test).

The combination of a simplified PWD mapping, considering exclusively the sampling of blood flow at three different levels, either from long-axis or five­chamber apical views, with the two M-mode echo­cardiographic measurements proved to be the most discriminative and allowed the design of a new fea­sible score (Table 2). A further test of this method, performed prospectively in a different series of pa­tients, showed its usefulness as an indicator of se­verity of AR. Discrepancies could be considered as clinically irrelevant, provided that on one hand, echocardiographic-Doppler overestimation of the le­sion only included four cases with angiographically

. mild AR that was considered moderate; conversely, when in three cases the degree of AR was underes­timated (from 3/4 to 4/4 at angiography to 2/4 by combined echocardiography and Doppler), a severe aortic stenosis with a non-enlarged left ventricle was also present. In fact, in these latter cases, doubt would arise as to whether aortography is a good reference for quantitation of AR. As it has been stated,23 when the left ventricle is highly hypertrophied and non­dilated, the angiographic assessment of AR might overestimate the degree of the lesion, showing a rel­atively intense opacification of the left ventricle with a small amount of dye contrast.

It is important to emphasize that the method we

428 Borras et al.

have developed would probably be inappropriate in acute AR, provided the lack of significant chamber dilation in these cases, even with severe lesions, should lead to an underestimation of the degree of regurgitation by our scoring method. Conversely, the association of a moderate AR with a dilated left ven­tricle unrelated to the valve disease would represent another potential pitfall for the method, as the degree of AR could be, in this case, overestimated.

Two-dimensional color-coded Doppler would the­oretically simplifY the quantitation of a regurgitant lesion. Nevertheless, the assessment of the regurgi­tant volume is not readily accomplished by the mea­surement of the regurgitant color Doppler flow area in studies performed in vitro.24 In the clinical setting similar results have been described,25 the most prom­ising outcome having been obtained at the expense of a rather complex methodology.26 Moreover, de­tailed studies on the intraobserver and interobserver reproducibility for the measurement of the color Doppler aortic regurgitant jet area have been recently reported showing significant observer differences.27

A more integrated approach combining conventional Doppler and echocardiographic data therefore still seems desirable.

In conclusion, PWD is highly accurate in the di­agnosis of chronic AR, its quantitation being feasible by the combination of a simple PWD mapping of the LVOT with M-mode echocardiographic mea­surements of left ventricular and aortic root di­ameters, representing a new practical diagnostic approach.

The technical assistance of Montserrat Prat (nurse so­nographer) is gratefully acknowledged.

REFERENCES

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2. Esper RJ. Detection of mild aortic regurgitation by range­gated pulsed Doppler echocardiography. Am J Cardiol 1982;50:1037-43.

3. Quifiones MA, Young JB, Waggoner AD, Ostojic MC, Ri­beiro LTG, Miller RR. Assessment of pulsed Doppler echo­cardiography in detection and quantification of aortic and mitral regurgitation. Br Heart J 1980;44:612-20.

4. Ciobanu M, Abbasi AS, Allen M, Hermer A, Spellberg R. Pulsed Doppler echocardiography in the diagnosis and esti­mation of severity of aortic insufficiency. Am J Cardiol 1982;49:339-43.

5. Veyrat C, Ameur A, Gourtchiglouian C, Lessana A, Abitbol G, Kalmanson D. Calculation of pulsed Doppler left ventric­ular outflow tract regurgitation index for grading the severity of aortic regurgitation. Am Heart J 1984;108:507-15.

Journal of the American Society of

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6. Masuyama T, Kodama K, Kitabatake A, et al. Noninvasive evaluation of aortic regurgitation by continuous wave Dopp­ler echocardiography. Circulation 1986;73:460-6.

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10. Carreras F, Borras X, Auge JM, Pons-Llad6 G. Pulsed Dopp­ler assessment of tricuspid regurgitation: usefulness of re­gurgitant signal patterns for estimation of severity. Angiology 1988;39: 788-94.

11. Yang SS, Bentivoglio LG, Maranhao V, Goldberg H. As­sessment of valvular regurgitation. In: Yang SS, Mentivoglio LG, Maranhao V, Goldberg H, eds. From cardiac catheter­ization data to hemodynamic parameters. 2nd ed. Philadel­phia: F. A. Davis, 1978:205-6.

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13. Nakao S, Tanaka H, Tahara M, et al. A regurgitant jet and echocardiographic abnormalities in aortic regurgitation: an experimental study. Circulation 1983;67:860-5.

14. Meyers DG, Olson TS, Hansen DA. Auscultation, M-mode echocardiography and pulsed Doppler echocardiography compared with angiography for diagnosis of chronic aortic regurgitation. Am J CardioI1985;56:811-2.

15. Graybum PA, Smith MD, Handshoe R, Friedman BJ, DeMaria AN. Detection of aortic insufficiency by standard echocardiography, pulsed Doppler echocardiography, and auscultation: a comparison of accuracies. Ann Intern Med 1986;104:599-605.

16. Touche T, Prasquier R, Nitenberg A, Zuttere D, Gourgon R. Assessment and follow-up of patients with aortic regur­gitation by an updated Doppler echocardiographic measure­ment of the regurgitant fraction in the aortic arch. Circulation 1985;72:819-24.

17. Goldberg SJ, Allen HD. Quantitative assessment by Doppler echocardiography of pulmonary or aortic regurgitation. Am J CardioI1985;56:131-5.

18. Diebold D, Peronneau P, Blanchard D, et al. Noninvasive quantification of aortic regurgitation by Doppler echocardi­ography. Br Heart J 1983;49:167-73.

19. Zhang Y, Nitter-Hauge S, Ihlen H, Rootwelt K, Myhre E. Measurement of aortic regurgitation by Doppler echocardi­ography. Br Heart J 1986;55:32-8.

20. Hoffmann A, Pelsterer M, Stulz P, et al. Noninvasive grading of aortic regurgitation by Doppler ulttasonography. Br Heart J 1986;55:283-5.

21. Leech G], Guiney TE, Davies MJ, Parker DJ. Echocardiog­raphy of the aortic valve. In: Rijsterborgh H, ed. Echocar­diography. The Hague: Martinus Nijhoff Publishers, 1981: 39-53.

22. Toguchi M, Ichimiya S, Yokoi K, Hibi N, Kambe T. Clinical investigation of aortic insufficiency by means of pulsed Dopp­lerechocardiography. Jpn Heart J 1981;22:537-50.

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23. Croft CH, Lipscomb K, Mathis K, et al.Limitations of qual­itative angiographic grading in aortic or mitral regurgitation. Am J CardioI1973;31:696-705.

24. Tamura T, Valdes-Cruz LM, Salm DJ. In vitro studies of the accuracy of velocity determination and spatial resolution of a color flow mapping Doppler system [Abstract]. J Am Coll CardioI1986;7:59A. .

25. Miyatake K, Okamoto M, Kinoshita N, et al. Clinical appli­cations of a new type of real-time two-dimensional Doppler flow imaging system. Am J CardioI1984;54:857-68.

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Echo Doppler assessment of aortic regurgitation 429

26. Perry GJ, Helmcke F, Nanda NC, Byard C, Soto B. Evalu­ation of aortic insufficiency by Doppler color flow mapping. J Am Coll Cardiol 1987;9:952-9.

27. Smith MD, Graybum PA, Spain MG, De Maria AN. Ob" server variability in the quantitation of Doppler color flow jet areas for mitral and aortic regurgitation. J Am Coll Cardiol 1988;3:579-84.

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