Congenital: Fontan: Evolving technology
Virtual surgical planning, flow simulation, and 3-dimensional electrospinning of patient-specific grafts to optimize Fontan hemodynamics

Read at the 43rd Annual Meeting of the Western Thoracic Surgical Association, Colorado Springs, Colorado, June 21-24, 2017.
https://doi.org/10.1016/j.jtcvs.2017.11.068Get rights and content
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Abstract

Background

Despite advances in the Fontan procedure, there is an unmet clinical need for patient-specific graft designs that are optimized for variations in patient anatomy. The objective of this study is to design and produce patient-specific Fontan geometries, with the goal of improving hepatic flow distribution (HFD) and reducing power loss (Ploss), and manufacturing these designs by electrospinning.

Methods

Cardiac magnetic resonance imaging data from patients who previously underwent a Fontan procedure (n = 2) was used to create 3-dimensional models of their native Fontan geometry using standard image segmentation and geometry reconstruction software. For each patient, alternative designs were explored in silico, including tube-shaped and bifurcated conduits, and their performance in terms of Ploss and HFD probed by computational fluid dynamic (CFD) simulations. The best-performing options were then fabricated using electrospinning.

Results

CFD simulations showed that the bifurcated conduit improved HFD between the left and right pulmonary arteries, whereas both types of conduits reduced Ploss. In vitro testing with a flow-loop chamber supported the CFD results. The proposed designs were then successfully electrospun into tissue-engineered vascular grafts.

Conclusions

Our unique virtual cardiac surgery approach has the potential to improve the quality of surgery by manufacturing patient-specific designs before surgery, that are also optimized with balanced HFD and minimal Ploss, based on refinement of commercially available options for image segmentation, computer-aided design, and flow simulations.

Key Words

3D printing
flow dynamics
patient specific model
virtual surgical planning

Abbreviations and Acronyms

3D
3-dimensional
CFD
computational fluid dynamics
HFD
hepatic flow distribution
IVC
inferior vena cava
LPA
left pulmonary artery
MRA
magnetic resonance angiography
MRI
magnetic resonance imaging
Ploss
power loss
RPA
right pulmonary artery
STL
stereo lithography
SVC
superior vena cava
TEVG
tissue-engineered vascular graft

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This work was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health (Grant R21HD090671); the Swiss National Science Foundation (Grant 200021_147193 CINDY); and the Swiss National Centre of Competence in Research, Kidney Control of Homeostasis. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.