Computational Models of Aortic Coarctation in Hypoplastic Left Heart Syndrome: Considerations on Validation of a Detailed 3D model

Advancement in computational simulation and validation of congenital heart disease: a review

The improvement in congenital heart disease (CHD) treatment and management has increased the life expectancy in infants. However, the long-term efficacy is difficult to assess and thus, computational modelling has been applied for evaluating this. Here, we provide an overview of the applications of computational modelling in CHD based on three categories; CHD involving large blood vessels only, heart chambers only, and CHD that occurs at multiple heart structures. We highlight the advancement of computational simulation of CHD that uses multiscale and multiphysics modelling to ensure a complete representation of the heart and circulation. We provide a brief future direction of computational modelling of CHD such as to include growth and remodelling, detailed conduction system, and occurrence of myocardial infarction. We also proposed validation technique using advanced three-dimensional (3D) printing and particle image velocimetry (PIV) technologies to improve the model accuracy.

Modeling of coarctation of aorta in human fetuses using 3D/4D fetal echocardiography and computational fluid dynamics

OBJECTIVES

We sought to develop a hemodynamic model of aortic and ductal arches using computational fluid dynamics (CFD) and 3D/4D spatio-temporal image correlation (STIC) fetal echocardiography and to investigate the hemodynamics of coarctation of aorta (CoA) in human fetuses using this approach.

METHODS

We obtained 3D/4D STIC fetal echocardiographic images of the aortic and ductal arches (DA) in five normal fetuses. Based on these images, we simulated the hemodynamics in the two arches using CFD. Subsequently, we reduced the dimensions of aortic isthmus from 100% to 85%, 70%, 55%, 40%, and 25% of the original dimension digitally. Numerical simulation was repeated in each condition, and flow profile, velocity, pressure, and wall shear stress (WSS) were compared with those of the baseline normal aortic and ductal arches.

RESULTS

With the progressive narrowing in the aortic isthmus, there were alterations in the flow profile, velocity, pressure, and WSS. The downstream vortexes disappeared, and the double helix profile became single helix. When the aortic isthmus reduced by 55% in dimension, there was an exponential increase in velocity and WSS and decrease in pressure.

CONCLUSIONS

The aortic and ductal arch geometry and flow lead to the alterations in flow profile, velocity, pressure, and WSS in the aortic isthmus in normal and CoA models, which are conductive of ductal issue migration into these areas. A 55% reduction in the dimension of aortic isthmus is associated with exponential change in velocity, pressure, and WSS, a probable threshold for hemodynamically significant CoA.