Quantification of mitral-valve regurgitation in a paediatric population by real-time three-dimensional echocardiography

Abstract

Evaluation of mitral-regurgitation (MR) severity in infants is challenging. Real-time three-dimensional echocardiography (RT3DE) allows accurate left-ventricular volumetric measurements in adults. To validate RT3DE by measuring stroke volume in a normal paediatric population, then to use this new method to calculate regurgitant volume in paediatric patients with MR. Fifty-four patients, aged one week to 19 years, (29 without and 25 with MR) had two-dimensional echocardiography coupled with RT3DE left-ventricular volumetric acquisition. Stroke volume was calculated by the Doppler method at the aortic annulus (SV(D)). End-systolic and end-diastolic left-ventricular volumes were measured using the QLab semi-automated method; three-dimensional stroke volume (SV(3D)) was calculated as their difference. In the MR group, regurgitant volume was calculated by the PISA method (RV(PISA)) and as the difference between SV(3D) and SV(D) (RV(3D)). Regurgitant fraction was also evaluated by these methods (RF(PISA) and RF(3D)). Measurement feasibility was 88%. In the normal group, SV(3D) (27.9+/-18.1 ml) was highly correlated with SV(D) (30.7+/-19.6 ml; r=0.98; p<0.000). In the MR group, RV(PISA) (15.7+/-14.4 ml) and RV(3D) (11.0+/-10.2 ml) were well correlated (r=0.83; p<0.001). Regurgitant fractions were also well correlated (RF(PISA)=30.4+/-17.0%; RF(3D)=24.3+/-15.9%; r=0.79, p=0.006). RT3DE is a simple, rapid and reliable method for evaluating stroke volume in children and may, therefore, be useful for evaluating regurgitant volume and fraction in paediatric patients with MR.