Eur J Cardiothorac Surg 1999;15:127-133
© 1999 Elsevier Science NL
Three-dimensional color Doppler for assessing mitral regurgitation during valvuloplasty
Raffaele De Simonea,*,
Gerald Glombitzab,
Christian-Friedrich Vahla,
Jörg Albersa,
Hans-Peter Meinzerb,
Siegfried Hagla
a Department of Cardiac Surgery, University of Heidelberg, Heidelberg, Germany
b Department of Medical and Biological Informatics, Deutsches Krebsforschungszentrum, Heidelberg, Germany
Received 21 September 1998;
received in revised form 7 December 1998;
accepted 16 December 1998.
* Corresponding author. University of Heidelberg, Abteilung für Herzchirurgie, Im Neuenheimer Feld, 120 D-69120 Heidelberg, Germany. Tel.: +49-6221-56-6272; fax: +49-6221-56-5585; e-mail: r.de.simone@urz.uni-heidelberg.de
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Abstract
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Objective: Transesophageal color Doppler (or 2D Doppler) is the most widely used technique for intraoperative assessment of mitral valve repair. However, the most severe mitral regurgitations produce eccentric jet flows which cannot be assessed by 2D imaging. Up to now the indications for surgical intervention and intraoperative decisions after valve repair have been based on 2D Doppler examinations. Aim of this study was to compare conventional 2D Doppler to three-dimensional (3D) Doppler for assessing residual regurgitation in patients after mitral valvuloplasty. Methods: Twenty-four patients were referred to surgery for mitral valve repair. They underwent transesophageal echocardiography and 3D data acquisition during mitral valve reconstruction. Conventional assessment of mitral valve regurgitation, measured by color Doppler jet area, was compared to the volume of regurgitant jets obtained by 3D Doppler. Regurgitant volume and fraction were measured by pulsed Doppler and two-dimensional echocardiography. The 3D reconstructions of color Doppler data were accomplished by means of the `Heidelberg Raytracing Algorithm' developed at our institution. Results: The jet areas did not show any significant correlation to the regurgitant fraction (r=45; P=NS) or regurgitant volumes (r=0.40; P=NS). In contrast the jet volumes correlated significantly to regurgitant fraction (r=0.71; P<0.01) and regurgitant volume (r=0.85; P<0.01). The reproducibility analysis of repeated jet volume and jet area measurements also showed that the parameter jet volume has a lower variability and higher agreement of repeated measurements than jet area. Conclusions: Three-dimensional color Doppler flow imaging revealed the complex geometry of eccentric regurgitant jets and showed that the assessment of mitral regurgitation, based on conventional 2D Doppler, can be misleading. This new technique has a great potential for becoming a reference method for assessing mitral valve repair.
Key Words: Mitral valve regurgitation • Mitral valvuloplasty • Color Doppler echocardiography • Transesophageal echocardiography • Intraoperative echocardiography • Three-dimensional color Doppler
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Introduction
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Intraoperative assessment of the mitral valve regurgitation following reconstructive procedures is usually performed on the basis of subjective estimation of the jet size by two-dimensional color Doppler [1][2]. Previous studies showed that color Doppler echocardiography cannot assess the severity of mitral valve regurgitation in patients with eccentric regurgitant jets [3]. A new technique that allows the three-dimensional reconstruction of color Doppler data has been developed at our institution [4]. Preliminary studies showed that the volume of regurgitant jets measured by 3D Doppler provides a useful parameter for quantitative assessment of mitral regurgitation [5].
The aim of this study was to assess the feasibility of intraoperative examinations by three-dimensional color Doppler and to establish whether the measurements of regurgitant jet volumes can be a reliable and reproducible technique for judging the adequacy of mitral valve repair after reconstruction.
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Materials and methods
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We studied 24 consecutive patients, who were referred to surgery for mitral valve repair, underwent transesophageal echocardiographic examinations during cardiac surgery. The patients had moderate to severe mitral regurgitation. Fourteen patients had sinus rhythm, ten patients had atrial fibrillation. The examinations were obtained prior and after surgery. Intraoperative decision to carry out a mitral valve replacement was met in seven patients without any attempt for repair. Seventeen patients underwent mitral valve repair: six had quadrangular resection of posterior leaflet and ring annuloplasty, two underwent isolated posterior leaflet resection, two had a triangular resection of the anterior leaflet and ring annuloplasty, three patients had anterior and posterior leaflet repair associated with ring annuloplasty.
Three-dimensional echocardiographic acquisitions were performed by using a commercially available system (Sonos 2500, Hewlett-Packard, Andover, USA) with a multiplanar transesophageal probe. The 3D acquisitions were obtained by rotating the transesophageal transducer which was steered by a step motor. The acquisition was accomplished by increments of 2 degrees until to obtain 90 heart cycles. The time needed for obtaining the complete multiplanar data set ranged from 53 s to 3 min and 47 s (mean 1 min, 58 s) according to the spatial resolution of the data and according to the heart rate of the patients. The 3D acquisition was triggered to the ECG and the respiratory cycle. The acquisition of one heart cycle occurs only if RR intervals are within the range set prior to starting the 3D examination. The Doppler data, which carried information on velocity and turbulence, were separately stored on magneto-optical disks. The jets were was classified according to their spatial spreading within the left atrium [3]. The central jets originated from the middle of the mitral valve and did not strike atrial walls (Fig. 1
). The eccentric jets were directed toward the atrial walls or along the mitral valve leaflets (Fig. 2
Fig. 3
Fig. 4
).
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Fig. 1. Transesophageal two-dimensional color Doppler. Right, central regurgitant jets. Left, eccentric regurgitant jets. LA, left atrium; LV, left ventricle; m, mitral valve.
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Fig. 2. Left, conventional 2D Doppler showing a central regurgitant jet. Right, 3D reconstruction of a central jets does not provide additional information about the geometry and the spreading of the regurgitant flow into the left atrium. Systolic flow in the left ventricular outflow tract (LVOT) can be visualized. LA, left atrium; LV, left ventricle; m, mitral valve.
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Fig. 3. Regurgitant jet in a patient with prolapse of the anterior mitral leaflet. Left, conventional 2D color Doppler; Right, 3D color Doppler. conventional 2D Doppler is not able to entirely visualize the regurgitant jet. (Abbreviations as in previous figures.)
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Fig. 4. Regurgitant jet in a patient with prolapse of the posterior mitral leaflet, mainly directed along the atrial surface of the anterior leaflet. Left, conventional 2D color Doppler; right, 3D color Doppler disclose additional details. (Abbreviations as in previous figures.)
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The regurgitant volumes and fractions were measured by pulsed Doppler and two-dimensional echocardiography [6]. The aortic stroke volume was calculated from the product of the time-velocity integral and the aortic annulus area; the forward mitral stroke volume was calculated from the product of the time-velocity integral and the mean mitral valve area [7] (Table 1). The mitral regurgitant stroke volume was calculated by subtracting the aortic flow from the mitral forward flow; the mitral regurgitant fraction (%) was calculated by dividing the mitral regurgitant volume by the total diastolic mitral flow [8]. Regurgitant jet areas were traced on the systolic frame from the 2D images taken at the rotation angle where the greatest area could be measured. The maximal jet area included the turbulent portion of the color flow signals. An average of five consecutive heartbeats was used for measurements. Left atrial size was measured by M-mode echocardiography. The volumes of the regurgitant jet were calculated from the 3D Doppler datasets by an automatic count of the voxels containing high velocity and turbulence. The 3D reconstructions of Doppler data were obtained by means of the `Heidelberg Raytracing Algorithm', initially developed at our institutions [9][10] for visualizing computed tomographic and magnetic resonance images.
Statistical analysis
Linear regression analysis was used to describe the correlations of jet volumes areas with the regurgitant fractions and volumes. All data are reported as mean±SD. Differences were considered statistically significant at a value of P<0.01. Interpretative variabilities of jet volume and jet area measurements were tested over 34 perioperative (24 preoperative and ten postoperative) examinations studied by two independent investigators. Interobserver and intraobserver reproducibility of jet volume and jet area measurements were analyzed in 24 examinations. Variability was expressed as percent difference: reading 1-reading 2/mean of both readingsx100. The method of Bland and Altman [11] was used for assessing the repeatability [12] of the jet areas and the jet volumes methods for assessing mitral valve regurgitation.
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Results
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Preoperative regurgitant fraction and volumes were 44.6%±16.7% and 50.9±20.4 ml, respectively. Jet area and jet volumes were 7.2±2.5 cm2 and 44.6±20.6 cm3. Left atrium diameter was 49±8.6 mm. Seven patients underwent mitral valve replacement, 17 patients underwent mitral valve repair. Postoperative regurgitant Jet area and jet volumes were 1.4±0.5 cm2 and 12.6±9.2 cm3. The regression analysis of jet area did not show significant correlations with the regurgitant fraction (r=0.45; P=NS) or the regurgitant volume (r=0.40; P=NS). In contrast, the jet volume showed significant correlations with the regurgitant fraction (r=0.71; P<0.01) and the regurgitant volume (r=0.85; P<0.001). The left atrial size was not significantly correlated to the jet volumes (r=0.41; SEE=0.87; P=NS). Intra- and interobserver variability of regurgitant jet areas were 8.5±6.4%, 10.1±6.7%, respectively. Intra- and interobserver variability of jet volumes were 3.2±1.8% and 4.4±3.2%. Bland Altmann analysis of repeated jet area measurements showed that most of the plots of the differences lie outside the agreement intervals (Fig. 5
A). In contrast, more than 95% of the plots of repeated jet volume measurements are distributed inside the agreements limits (Fig. 5B).
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Fig. 5. Bland Altmann analysis of repeated jet area (panel A) and jet volume measurements (panel B). The figure shows that most of the plots of the differences lie outside the agreement intervals. In contrast, more than 95% jet volume measurements are distributed inside the agreements limits.
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The 3D images of the regurgitant jets were visualized by showing the systolic frames with the largest jet volume. The rotation of the observer from 0° to 360° around the 3D images was simulated by a movie that showed the details, direction and morphology of the jets. The comparison of the 3D images to conventional 2D images of the regurgitant jets showed that 3D Doppler is able to provide additional information on the direction and geometry of the regurgitant flow. The 3D reconstructions and jet volume measurements were obtained in 3–5 min.
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Discussion
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Three-dimensional (3D) echocardiography has been mainly applied for assessing intracardiac anatomy [13][14] and for quantifying intracavitary heart volumes [15]. Three-dimensional reconstruction of Doppler signals is a controversial topic still under investigation [16][17]. Until now color Doppler data could only be visualized in gray-scale [16]. These previous techniques were not able to separate cardiac structures from intracavitary flow since they used video signals. The video signals did not contain the Doppler data with flow velocities information. Three-dimensional color Doppler, a new technique developed at our institution, allowed for the first time the 3D visualization and the volumetric quantification of intracardiac blood flow [4][5]. In addition, 3D Doppler allows now for the analysis of the single Doppler velocities inside the color flow area and is able to distinguish cardiac structures from blood flow. A fully automated procedure provides the segmentation and the measurements of the jet volume, which are independent of manual tracing. This parameter has shown to be useful for clinical quantification of mitral regurgitation [4][5].
The present study is an attempt to introduce previously accomplished technical advances of the ultrasound diagnostic technique [4][5] into the surgical procedure for mitral valve repair. The comparison between the conventional 2D technique, as described by 2D jet area, and 3D color Doppler clearly showed that the volumes of regurgitant jets are significantly related to conventional non-invasive methods for quantitative assessment of mitral regurgitation. Despite these non-invasive methods have been validated in previously published studies [6][7][8], there is common agreement that no gold standard method is available for the clinical measurement of regurgitant volumes [18][19]. Invasive methods for calculating mitral regurgitant volumes are obtained by subtracting the volume measured by thermodilution, or indicator dilution method, from the volume measured by angiography; in addition, angiography is very dependent on assumptions about the left ventricular geometry. Pulsed Doppler methods for assessing regurgitant fractions and volumes are based on the assumptions that the cross-sectional aortic and mitral orifices remain constant during the ejection and filling phases, respectively. In addition, these methods are based on the hypothesis that aortic ejection flow and the mitral diastolic filling are laminar. Despite the fact that they cannot provide a reliable numerical quantification of regurgitant volumes, these methods have been largely used in clinical study and they still provide useful data for assessing the degree of mitral regurgitation. In clinical settings there is still no technique which is able to measure effective regurgitant volume.
The advent of color Doppler echocardiography provided the clinical cardiologists with a sort of non-invasive angiography [20]. Color Doppler (2D-Doppler) is a very useful technique for studying mitral valve regurgitation in clinical settings, but the quantification of the severity of mitral regurgitation has been commonly based on the semiquantitative evaluation of color Doppler examinations [20][21][22]. The indications for surgical intervention and intraoperative decisions after valve repair [3][23][24][25] have been based on the subjective assessment of regurgitant jet size. In addition, color Doppler may underestimate the degree of mitral regurgitation particularly in patients with eccentric jets, who are the majority of those referred to mitral valve repair.
An important finding from this study is the higher reproducibility of jet volume measurements when compared to conventional jet areas. Three-dimensional Doppler measurements of jet volumes is fully independent of manual controls by the examiners and provides precise measurements of the regurgitant jet volumes. The human bias is only due to the acquisition phase. This procedure is accomplished in two steps: (1) the extraction of turbulence and high-velocity components from the Doppler data, and (2) the measurement of voxels containing turbulence and high-velocity.
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Conclusions
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The absence of a gold standard for the assessment of valve regurgitation is a major limitation of all clinical investigations on mitral regurgitation [6][7][8][18][19][20][21][22]. The aim of the present study was not the exact quantification of mitral regurgitant volume, which has been approached by a great number of clinical and experimental studies [6][7][8][18][19][20][21][22], but rather to investigate the clinical application of this new technique in the operating theater, and discuss the possibility of using this tool as an adjunct to intraoperative diagnostic instruments at disposition of the cardiac surgeon during valve repair. The fundamental limitation of color Doppler, which displays blood flow velocities instead of flow volumes remains unresolved, and still need further investigations in experimental conditions. Nevertheless, the clinical potential of 3D Doppler is evident. It is exactly the color Doppler property of displaying velocities and turbulences that allowed us to visualize in three dimensions the pathological flows inside the heart. The volume measurements of regurgitant jets are based on calculation of the spatial distribution of pathological velocity patterns inside the heart chambers. For these reasons, the volume of regurgitant jets has to be considered an indirect index of mitral regurgitation, and, since a gold standard for comparison is not available in clinical practice, its clinical value need further investigations.
The images obtained by this technique disclosed new perspectives for the intraoperative diagnosis of mitral valve repair, and allowed a clear visualization of the pathological flows inside the heart chambers. Three-dimensional color Doppler provides quantitative measurements of mitral regurgitation which are more accurate and reproducible than conventional color Doppler.
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Acknowledgments
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This work was supported by German National Foundation for Scientific Research (SFB 414).
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Footnotes
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1 Presented at the 12th Annual Meeting of the European Association for Cardio-thoracic Surgery, Brussels, Belgium, September 20–23, 1998. 
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References
|
|---|
- Maurer G., Czer L.S.C., Chaux A. Intraoperative Doppler color flow mapping for assessment of valve repair for mitral regurgitation. Am J Cardiol 1987;60:333-341.[Medline]
- De Simone R., Lange R., Tanzeem A., Gams E., Saggau W., Hagl S. Intraoperative transesophageal echocardiography for the evaluation of mitral, aortic and tricuspid valve repair. A tool to optimize the surgical outcome. Eur J Cardio-thorac Surg 1992;6:665-673.[Abstract]
- Chen C., Thomas J.D., Anconina J., Harrigan P., Mueller L., Picard M.H., Levine R.A., Weyman A.E. Impact of impinging wall jet on color Doppler quantification of mitral regurgitation. Circulation 1991;84:712-720.[Abstract/Free Full Text]
- De Simone R., Glombitza G., Albers J., Nakamura G., Merdes M., Mayer A., Makabe M., Meinzer H.P., Vahl C.F., Hagl S. Three-dimensional reconstruction and quantitative analysis of color Doppler jets in original color coding (abstract). Echocardiography 1997;14(6):S31.
- De Simone, R., Glombitza, G., Vahl, C.F., Albers, J., Meinzer, H.P., Hagl, S. Assessment of mitral regurgitant jets by three-dimensional color Doppler. Ann Thorac Surg 1998; in press.
- Lewis J.F., Kuo L.C., Nelson J.G., Limacher M.C., Quinones M.A. Pulsed Doppler echocardiographic determination of stroke volume and cardiac output: clinical validation of two new methods using the apical window. Circulation 1984;70:425-431.[Abstract/Free Full Text]
- Ascah K.J., Stewart W.J., Jiang L., Guerrero J.L., Newell J.B., Gillam L.D., Weyman A.E. A Doppler two-dimensional echocardiographic method for quantitation of mitral regurgitation. Circulation 1985;72:377-383.[Abstract/Free Full Text]
- Stewart W.J., Jiang L., Mich R., Pandian N., Guerrero J.L., Weyman A.E. Variable effects of changes in flow rate through the aortic, pulmonary and mitral valves on valve area and flow velocity: Impact on quantitative Doppler flow calculations. J Am Coll Cardiol 1985;6:653-662.[Abstract]
- Meinzer H.P., Meetz K., Scheppelmann D., Engelmann U., Baur H.J. The Heidelberg Raytracing Model. IEEE Comput Graphics Appl 1991;6:34-43.
- Vahl C.F., Meinzer H.P., Hagl S. Three-dimensional presentation of cardiac morphology. Thorac cardiovasc Surg 1991;39:198-204.
- Bland J.M., Altman D.G. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986;1:307-310.[Medline]
- British Standard Institution. Precision of test methods I: guide for the determination and reproducibility for a standard test method (BS 5497, part I). London: BSI, 1979.
- Vogel M., Ho S.Y., Anderson R.H. Comparison of three dimensional echocardiographic findings with anatomical specimens of various congenitally malformed hearts. Br Heart J 1995;73:566-570.[Abstract/Free Full Text]
- Schwartz S.L., Cao Q.L., Azevedo J., Pandian N.G. Simulation of intraoperative visualization of cardiac structures and study of dynamic surgical anatomy with real-time three-dimensional echocardiography. Am J Cardiol 1994;73:501-507.[Medline]
- Siu S.C., Rivera J.M., Guerrero J.L., Handschumacher M.D., Lethor J.P., Weyman A.E., Levine R.A., Picard M.H. Three-dimensional echocardiography. In vivo validation for left ventricular volume and function. Circulation 1993;88:1715-1723.[Abstract/Free Full Text]
- Delabays A., Sugeng L., Pandian N.G., Hsu T.-L., Ho S.-J., Chen C.-H., Marx G., Schwartz S.L., Cao Q.-L. Dynamic three-dimensional echocardiographic assessment of intracardiac blood flow jets. Am J Cardiol 1995;76:1053-1058.[Medline]
- Belohlavek M., Foley D., Gerber T., Greenleaf J., Seward J. Three-dimensional reconstruction of color Doppler jets in the human heart. J Am Soc Ecocardiogr 1994;7:553-560.
- Bolger A.F., Eigler N.L., Maurer G. Quantifying valvular regurgitation: limitations and inherent assumptions of Doppler techniques. Circulation 1988;78:1316-1318.[Free Full Text]
- Croft C.H., Lipscomb K., Mathis K., Firth B.G., Nicod P., Titlton G., Winniford M.D., Hillis L.D. Limitations of qualitative angiographic grading in aortic or mitral regurgitation. Am J Cardiol 1984;53:193-198.
- Omoto R., Yokote Y., Takamoto S., Kyo S., Ueda K., Asano H., Namekawa K., Kasai C., Kondo Y., Koyano A. The development of real-time two-dimensional Doppler echocardiography and its significance in acquired valvular diseases with specific reference to the evaluation of valvular regurgitation. Jpn Heart J 1984;25:325-340.[Medline]
- Sahn D.J. Real-time two dimensional echocardiographic flow mapping. Circulation 1985;71:849-853.[Free Full Text]
- Miyazaki K., Izumi S., Okamoto M., Kinoshita N., Asonuma H., Nakagawa H., Yamamoto K., Takamiya M., Sakakibara H., Nimura Y. Semiquantitative grading of severity of mitral regurgitation by real-time two-dimensional Doppler flow imaging technique. J Am Coll Cardiol 1986;7:82-88.[Abstract]
- De Simone R., Lange R., Sack F.-U., Mehmanesh H., Hagl S. Atrioventricular valves insufficiency and atrial geometry after orthotopic heart transplantation. Ann Thorac Surg 1995;60:1686-1693.[Abstract/Free Full Text]
- De Simone R., Lange R., Tanzeem A., Gams E., Hagl S. Adjustable tricuspid valve annuloplasty assisted by intraoperative transesophageal color Doppler echocardiography. Am J Cardiol 1993;71:926-931.[Medline]
- De Simone, R.. Atlas of transesophageal color Doppler echocardiography and intraoperative imaging. Berlin: Springer, 1994.
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Abstract
Introduction
