Quantification of functional mitral regurgitation by real-time 3D echocardiography: comparison with 3D velocity-encoded cardiac magnetic resonance.
OBJECTIVE
The aim of this study was to evaluate feasibility and accuracy of real-time 3-dimensional (3D) echocardiography for quantification of mitral regurgitation (MR), in a head-to-head comparison with velocity-encoded cardiac magnetic resonance (VE-CMR).


BACKGROUND
Accurate grading of MR severity is crucial for appropriate patient management but remains challenging. VE-CMR with 3D three-directional acquisition has been recently proposed as the reference method.


METHODS
A total of 64 patients with functional MR were included. A VE-CMR acquisition was applied to quantify mitral regurgitant volume (Rvol). Color Doppler 3D echocardiography was applied for direct measurement, in "en face" view, of mitral effective regurgitant orifice area (EROA); Rvol was subsequently calculated as EROA multiplied by the velocity-time integral of the regurgitant jet on the continuous-wave Doppler. To assess the relative potential error of the conventional approach, color Doppler 2-dimensional (2D) echocardiography was performed: vena contracta width was measured in the 4-chamber view and EROA calculated as circular (EROA-4CH); EROA was also calculated as elliptical (EROA-elliptical), measuring vena contracta also in the 2-chamber view. From these 2D measurements of EROA, the Rvols were also calculated.


RESULTS
The EROA measured by 3D echocardiography was significantly higher than EROA-4CH (p < 0.001) and EROA-elliptical (p < 0.001), with a significant bias between these measurements (0.10 cm(2) and 0.06 cm(2), respectively). Rvol measured by 3D echocardiography showed excellent correlation with Rvol measured by CMR (r = 0.94), without a significant difference between these techniques (mean difference = -0.08 ml/beat). Conversely, 2D echocardiographic approach from the 4-chamber view significantly underestimated Rvol (p = 0.006) as compared with CMR (mean difference = 2.9 ml/beat). The 2D elliptical approach demonstrated a better agreement with CMR (mean difference = -1.6 ml/beat, p = 0.04).


CONCLUSIONS
Quantification of EROA and Rvol of functional MR with 3D echocardiography is feasible and accurate as compared with VE-CMR; the currently recommended 2D echocardiographic approach significantly underestimates both EROA and Rvol.
Marsan
Nina Ajmone
NA
Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.
Westenberg
Jos J M
JJ
Ypenburg
Claudia
C
Delgado
Victoria
V
van Bommel
Rutger J
RJ
Roes
Stijntje D
SD
Nucifora
Gaetano
G
van der Geest
Rob J
RJ
de Roos
Albert
A
Reiber
Johan C
JC
Schalij
Martin J
MJ
Bax
Jeroen J
JJ
D000368:Aged; D018618:Echocardiography, Doppler, Color; D019560:Echocardiography, Three-Dimensional; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013318:Stroke Volume; D016277:Ventricular Function, Left