A pilot investigation of the tricuspid valve annulus in newborns with hypoplastic left heart syndrome

Computed TV annulus strain for patients with HLHS.

Figure 1. Overview of the study, including the echocardiogram image segmentation, mechanics-based analysis results, and the implications of our work. HLHS, Hypoplastic left heart syndrome.

Figure 2. Four-dimensional transthoracic echocardiographic data from a representative newborn with HLHS (patient #1): (A) axial plane, (B) sagittal plane, and (C) coronal plane. D, Illustration of our image segmentation of the TV annulus. HLHS, Hypoplastic left heart syndrome; TV, tricuspid valve; AS, anteroseptal; AP, anteroposterior; PS, posteroseptal.

Figure 3. A, Visual description of the moving least-squares curve fitting to obtain a smoothed representation of the TV annulus. B, Schematic of the 2 diameters of the TV annulus: DSL and DAP. C, Illustration of the calculations of the annular height and the annulus bending angle. D, Representative annulus contours from patient #1 with HLHS at end diastole, showing the strain, strain rate, and relative curvature. TV, Tricuspid valve; DSL, septal-lateral diameter; DAP, anteroposterior diameter; HLHS, hypoplastic left heart syndrome; AS, anteroseptal; AP, anteroposterior; PS, posteroseptal.

Figure 4. Key TV annulus clinical metrics for all newborns with HLHS (n = 8) at the selected time points over the cardiac cycle solid red line: the median, the bounding box: the 25th to 75th percentiles, the whiskers: extension between the maximum and minimum nonoutlier datapoints. Individual patient data points at each time point are visualized with jittering for improved visual clarity. TV, Tricuspid valve; HLHS, hypoplastic left heart syndrome; RVPmin, minimum right ventricular pressure; ED, end diastole; EIVC, end-isovolumetric contraction; ES, end systole; EIVR, end-isovolumetric relaxation; SL, septal-lateral; AP, anteroposterior.

Figure 5. Key TV annulus clinical metrics for all healthy newborns (n = 4) at the selected time points over the cardiac cycle (solid red line: the median, the bounding box: the 25th to 75th percentiles, the whiskers: extension between the maximum and minimum nonoutlier datapoints). Individual patient data points at each time point are visualized with jittering for improved visual clarity. TV, Tricuspid valve; RVPmin, minimum right ventricular pressure; ED, end diastole; EIVC, end-isovolumetric contraction; ES, end systole; EIVR, end-isovolumetric relaxation; SL, septal-lateral; AP, anteroposterior.

Figure 6. Spatial variations of the computed strain along the TV annulus circumference for a representative HLHS newborn (Patient #1) at the selected time points over the cardiac cycle, where the time instant tRVPmin was chosen as the reference configuration (RVPmin). Note that the 0° angle was aligned with the anteroposterior commissure. TV, Tricuspid valve; HLHS, hypoplastic left heart syndrome; AS, anteroseptal; AP, anteroposterior; PS, posteroseptal; RVPmin, minimum right ventricular pressure; ED, end diastole; EIVC, end-isovolumetric contraction; ES, end systole; EIVR, end-isovolumetric relaxation.

Figure 7. Spatial variations of the computed strain along the TV annulus circumference for (A) the studied 8 newborns with HLHS (n = 8), and (B) the 4 healthy newborns (n = 4) (solid lines: mean, shaded regions: standard error of the mean). Note that the 0° angle was aligned with the anteroposterior commissure. TV, Tricuspid valve; HLHS, hypoplastic left heart syndrome; ED, end diastole; EIVC, end-isovolumetric contraction; EIVR, end-isovolumetric relaxation.

Figure E1. Percentage changes in the TV annulus clinical metrics for the HLHS newborns (n = 8) at the selected time points over the cardiac cycle. TV, Tricuspid valve; HLHS, hypoplastic left heart syndrome; ED, end diastole; EIVC, end-isovolumetric contraction; ES, end systole; EIVR, end-isovolumetric relaxation; AP, anteroposterior; SL, septal-lateral.

Figure E2. Percentage changes in the TV annulus clinical metrics for the healthy newborns (n = 4) at the selected time points over the cardiac cycle. TV, Tricuspid valve; ED, end diastole; EIVC, end-isovolumetric contraction; ES, end systole; EIVR, end-isovolumetric relaxation; AP, anteroposterior; SL, septal-lateral.

Figure E3. Spatial variations of the computed strain rate along the TV annulus circumference for (A) the studied 8 newborns with HLHS (n = 8), and (B) the 4 healthy newborns (n = 4) (solid lines: mean, shaded regions: standard error of the mean). Note that the 0° angle was aligned with the anteroposterior commissure. TV, Tricuspid valve; HLHS, hypoplastic left heart syndrome; ED, end diastole; EIVC, end-isovolumetric contraction; ES, end systole; EIVR, end-isovolumetric relaxation.

Figure E4. Spatial variations of the computed relative curvature along the TV annulus circumference for (A) the studied 8 newborns with HLHS (n = 8), and (B) the 4 healthy newborns (n = 4) (solid lines: mean, shaded regions: standard error of the mean). Note that the 0° angle was aligned with the anteroposterior commissure. TV, Tricuspid valve; HLHS, hypoplastic left heart syndrome; ED, end diastole; EIVC, end-isovolumetric contraction; ES, end systole; EIVR, end-isovolumetric relaxation.