Segmentation of Tricuspid Valve Leaflets From Transthoracic 3D Echocardiograms of Children With Hypoplastic Left Heart Syndrome Using Deep Learning

Hypoplastic left heart syndrome (HLHS) is a severe congenital heart defect in which the right ventricle and associated tricuspid valve (TV) alone support the circulation. TV failure is thus associated with heart failure, and the outcome of TV valve repair are currently poor. 3D echocardiography (3DE) can generate high-quality images of the valve, but segmentation is necessary for precise modeling and quantification. There is currently no robust methodology for rapid TV segmentation, limiting the clinical application of these technologies to this challenging population. We utilized a Fully Convolutional Network (FCN) to segment tricuspid valves from transthoracic 3DE. We trained on 133 3DE image-segmentation pairs and validated on 28 images. We then assessed the effect of varying inputs to the FCN using Mean Boundary Distance (MBD) and Dice Similarity Coefficient (DSC). The FCN with the input of an annular curve achieved a median DSC of 0.86 [IQR: 0.81–0.88] and MBD of 0.35 [0.23–0.4] mm for the merged segmentation and an average DSC of 0.77 [0.73–0.81] and MBD of 0.6 [0.44–0.74] mm for individual TV leaflet segmentation. The addition of commissural landmarks improved individual leaflet segmentation accuracy to an MBD of 0.38 [0.3–0.46] mm. FCN-based segmentation of the tricuspid valve from transthoracic 3DE is feasible and accurate. The addition of an annular curve and commissural landmarks improved the quality of the segmentations with MBD and DSC within the range of human inter-user variability. Fast and accurate FCN-based segmentation of the tricuspid valve in HLHS may enable rapid modeling and quantification, which in the future may inform surgical planning. We are now working to deploy this network for public use.

Association of Digoxin With Preserved Echocardiographic Indices in the Interstage Period: A Possible Mechanism to Explain Improved Survival?

Background For patients with hypoplastic left heart syndrome, digoxin has been associated with reduced interstage mortality after the Norwood operation, but the mechanism of this benefit remains unclear. Preservation of right ventricular (RV) echocardiographic indices has been associated with better outcomes in hypoplastic left heart syndrome. Therefore, we sought to determine whether digoxin use is associated with preservation of the RV indices in the interstage period. Methods and Results We conducted a retrospective cohort study of prospectively collected data using the public use data set from the Pediatric Heart Network Single Ventricle Reconstruction trial, conducted in 15 North American centers between 2005 and 2008. We included all patients who survived the interstage period and had echocardiographic data post‐Norwood and pre‐Glenn operations. We used multivariable linear regression to compare changes in RV parameters, adjusting for relevant covariates. Of 289 patients, 94 received digoxin at discharge post‐Norwood. There were no significant differences in baseline clinical characteristics or post‐Norwood echocardiographic RV indices (RV end‐diastolic volume indexed, RV end‐systolic volume indexed, ejection fraction) in the digoxin versus no‐digoxin groups. At the end of the interstage period and after adjustment for relevant covariates, patients on digoxin had better preserved RV indices compared with those not on digoxin for the ΔRV end‐diastolic volume (11 versus 15 mL, P =0.026) and the ΔRV end‐systolic volume (6 versus 9 mL, P =0.009) with the indexed ΔRV end‐systolic volume (11 versus 20 mL/BSA 1.3 , P =0.034). The change in the RV ejection fraction during the interstage period between the 2 groups did not meet statistical significance (−2 versus −5, P =0.056); however, the trend continued to be favorable for the digoxin group. Conclusions Digoxin use during the interstage period is associated with better preservation of the RV volume and tricuspid valve measurements leading to less adverse remodeling of the single ventricle. These findings suggest a possible mechanism of action explaining digoxin’s survival benefit during the interstage period.

Hypoplastic Left Heart Syndrome: Diagnostic Difficulties in Prenatal Period

The article discusses the possible diagnostic errors in the hypoplastic left heart syndrome (HLHS) with mitral atresia and intact interventricular septum. “Atrioventricular canal defects” can be commonly and mistakenly diagnosed the prenatal period in such cases. The aspects and possibilities of differential diagnosis of these defects in the prenatal period are discussed. Ultrasound sign is presented in the article, we have named it “hockey stick with puck” that characterizes the retrograde blood flow in the aortic arch. This sign is diagnosed by color Doppler mapping of the sagittal section of the ductus arteriosus and can serve as a marker of mitral/aortic atresia.