Abstract 3415: Real Time Three-Dimensional Color Doppler Echocardiographic Characterization of Regurgitant Orifice Area in Children with Mitral Regurgitation
Introduction: Current tools for assessing mitral valve regurgitation (MR) in children are extrapolated from adult studies. Geometrical assumptions and complexity of measurements render them unreliable. Children have co-existent complex haemodynamic characteristics such as highly compliant cardiac chambers, size variation with growth, and obstructive or regurgitant lesions or shunts.
Hypothesis: The vena contracta area (VCA) located at the region between the proximal laminar flow acceleration zone and the distal turbulent regurgitant jet spray visualized in 3 dimensional planes could characterise the complex geometry of the regurgitant orifice area (ROA).
Methods: Prospectively acquired images (Philips IE33) stored as full volume loops were analyzed offline using Q-lab 4.1 software. Using multiplane review and black/white suppression tools, MR jet was identified in peak systole. Planes were adjusted to optimize images. Sections were made at right angles to the longitudinal axis of the jet. Transverse plane was manipulated for both the longitudinal images to interrogate the narrowest VCA as an indirect measure of ROA. When more than one jet was present, individual jets were interrogated separately. ROA was indexed to body surface area (IROA), and mitral valve annular dimensions in systole and diastole. These indices were correlated to the clinical status score based on clinical symptoms, x-ray and 2D findings.
Results: Seventeen patients were studied between November 2004 and January 2006. Mean age was 6.5 years (r=1 month–17.4 years) Mean IROA was 1.2cm2 /m2 (r=0.23–3.4) Indexed systolic valve annulus area was 6.6cm2/m2 (r=1.9–13.9) and indexed diastolic valve annulus area was 3.6cm2/m2 (r=1.2–11.9). There was good correlation between IROA and clinical status score (r=0.878, P<0.01), pulmonary venous hypertension score (r=0.843P<0.01), and 2D findings (r=0.874, P<0.01) There was good inter(r=0.94,P<0.01) and intra observer (r=0.92, P<0.01 correlation.
Conclusion: IROA is a consistent measure of MR which correlates well with established tools. IROA less than 0.6 depicts mild, 0.6–1.39 moderate and >1.39 severe MR It is an easily applicable clinical tool for accurate grading and monitoring the severity of MR in children.