Proximal flow convergence region as assessed by real-time 3-dimensional echocardiography: challenging the hemispheric assumption.
OBJECTIVE
Traditionally, a hemispheric assumption for the proximal flow convergence region (PFCR) is used when calculating mitral regurgitant (MR) effective orifice area (EROA). However, 2-dimensional (2D) echocardiography limits evaluation of the complete PFCR contour. Real-time 3-dimensional (3D) echocardiography (RT3D) allows direct assessment of the true PFCR contour. We hypothesized that the PFCR contour is not necessarily hemispheric, but rather hemielliptic, and aimed to apply a hemielliptic calculation, based on the 3D contour of the PFCR for more accurate MR quantification.


METHODS
In all, 50 patients with MR underwent RT3D to characterize PFCR contour as hemispheric or hemielliptic. MR EROA by RT3D-derived PFCR was calculated using a hemielliptic formula using 3D data. The 2D EROA was computed using standard hemispheric assumption. EROAs calculated from 2D and RT3D data were compared with quantitative Doppler EROA (mitral inflow--aortic outflow/MR time-velocity integral), used as an independent comparison.


RESULTS
Only 1 of 50 patients (2%) had a hemispheric PFCR contour by RT3D. The remaining had hemielliptic PFCR contours. Compared with Doppler method, 2D echocardiography significantly underestimated EROA (0.34 +/- 0.14 vs 0.48 +/- 0.25 cm(2), P < .001). RT3D EROA was not significantly different from Doppler EROA (0.52 +/- 0.17 vs 0.48 +/- 0.25, P = not significant). Of 33 patients with Doppler EROA greater than 0.3 cm(2) (> or =moderate-severe MR), 45% (15 of 33) were underestimated as having mild to moderate MR by 2D EROA.


CONCLUSIONS
The true PFCR contour as shown by RT3D is generally not hemispheric but hemielliptic, tracking the orifice contour. Based on this 3D shape, a hemielliptic approach can be used for practical clinical application with improved MR quantification.
Yosefy
Chaim
C
Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114-2696, USA.
Levine
Robert A
RA
Solis
Jorge
J
Vaturi
Mordehay
M
Handschumacher
Mark D
MD
Hung
Judy
J
D000368:Aged; D015150:Echocardiography, Doppler; D019560:Echocardiography, Three-Dimensional / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008943:Mitral Valve / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging / Q000503:physiopathology*; D009200:Myocardial Contraction / Q000502:physiology*; D015588:Observer Variation; D015203:Reproducibility of Results; D012720:Severity of Illness Index