Clinical Investigations
Echocardiography in Children
Visualization and Quantification of the Unrepaired Complete Atrioventricular Canal Valve Using Open-Source Software

https://doi.org/10.1016/j.echo.2022.04.015Get rights and content

Highlights

  • Unrepaired CAVC valves were modeled using open-source software.

  • CAVC annular and PM geometry differs from that of normal mitral valves.

  • Flatter CAVC annulus prerepair was associated with greater regurgitation postrepair.

Background

Repair of complete atrioventricular canal (CAVC) is often complicated by residual left atrioventricular valve regurgitation. The structure of the mitral and tricuspid valves in biventricular hearts has previously been shown to be associated with valve dysfunction. However, the three-dimensional (3D) structure of the entire unrepaired CAVC valve has not been quantified. Understanding the 3D structure of the CAVC may inform optimized repair.

Methods

Novel open-source work flows were created in SlicerHeart for the modeling and quantification of CAVC valves on the basis of 3D echocardiographic images. These methods were applied to model the annulus, leaflets, and papillary muscle (PM) structure of 35 patients (29 with trisomy 21) with CAVC using transthoracic 3D echocardiography. The mean leaflet and annular shapes were calculated and visualized using shape analysis. Metrics of the complete native CAVC valve structure were compared with those of normal mitral valves using the Mann-Whitney U test. Associations between CAVC structure and atrioventricular valve regurgitation were analyzed.

Results

CAVC leaflet metrics varied throughout systole. Compared with normal mitral valves, the left CAVC PMs were more acutely angled in relation to the annular plane (P < .001). In addition, the anterolateral PM was laterally and inferiorly rotated in CAVC, while the posteromedial PM was more superiorly and laterally rotated, relative to normal mitral valves (P < .001). Lower native CAVC atrioventricular valve annular height and annular height–to–valve width ratio before repair were both associated with moderate or greater left atrioventricular valve regurgitation after repair (P < .01).

Conclusions

It is feasible to model and quantify 3D CAVC structure using 3D echocardiographic images. The results demonstrate significant variation in CAVC structure across the cohort and differences in annular, leaflet, and PM structure compared with the mitral valve. These tools may be used in future studies to catalyze future research intended to identify structural associations of valve dysfunction and to optimize repair in this vulnerable and complex population.

Section snippets

Subjects

Institutional databases at the Children’s Hospital of Philadelphia, Boston Children’s Hospital, and Evelina London Children’s Hospital were used to identify patients with CAVC in whom transthoracic apical four-chamber 3DE had been collected for clinical studies. To augment these studies, dedicated acquisitions in the operating room before repair were obtained at the Children’s Hospital of Philadelphia. These studies were obtained with parental consent per an institutional review board–approved

Results

The CAVC leaflets were modeled in end-diastole, mid-systole, and end-systole in all 35 patients. PM analysis was performed in 34 of the 35 patients with CAVC in mid-systole. The median age of the patients with CAVC at echocardiography was 0.3 years (IQR, 0.2-0.3 years). Twenty patients had Rastelli type A anatomy, and 15 patients had Rastelli type C anatomy. Twenty-nine of the 35 patients had trisomy 21. Thirty-two patients had qualitatively normal left ventricular systolic function, two had

Discussion

We present a novel 3DE-based modeling work flow that we have used to visualize and quantify the native CAVC valve before repair. Our major findings are as follows: (1) modeling of the native CAVC valve annulus, leaflets, and PM from 3DE is feasible using our newly released open-source framework; (2) both the PM angle relative to the annulus and the papillary rotational positions in CAVC differ from normal mitral valves; (3) the CAVC annulus is flatter than a normal mitral valve; and (4) a more

Conclusion

Three-dimensional echocardiography–derived modeling and quantifying the 3D structure of the unrepaired CAVC leaflets, annulus, and PMs is feasible using novel software. We demonstrate significant differences in annular, leaflet, and PM structure compared with the normal mitral valve. Further research is needed to identify 3D structural associations of valve dysfunction and inform the development of 3D image–based customized repairs in this vulnerable population.

Acknowledgment

We acknowledge the sonographers at participating institutions for the outstanding images used for this research.

References (34)

Cited by (3)

This work was supported a Pediatric Heart Network Scholars Award (National Institutes of Health grant U24 HL135691), National Institutes of Health grant 1R01HL153166, National Institute of Biomedical Imaging and Bioengineering grant R01EB021391, Big Hearts to Little Hearts, a Children’s Hospital of Philadelphia Cardiac Center Innovation Award, the Cora Topolewski Fund at the Children’s Hospital of Philadelphia Pediatric Valve Center, and the CANARIE Research Software Foundation.

Drs. Paniagua and Vicory are employees of Kitware.

Girish S. Shirali, MD, FASE, served as guest editor for this report.

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