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Physiological Fontan procedure

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journal contribution
posted on 30.04.2019, 15:22 by Antonio F. Corno, Matt J. Owen, Andrea Cangiani, Edward J. C. Hall, Aldo Rona
Objective: The conventional Fontan circulation deviates the superior vena cava (SVC=1/3 of the systemic venous return) towards the right lung (3/5 of total lung volume) and the inferior vena cava (IVC=2/3 of the systemic venous return) towards the left lung (2/5 of total lung volume). A “physiological” Fontan deviating the SVC towards the left lung and the IVC towards the right lung was compared with the conventional setting by computational fluid dynamics, studying if this setting achieves a more favorable hemodynamic than the conventional Fontan circulation. Materials and Methods: An in-silico 3D parametric model of the Fontan procedure was developed using idealized vascular geometries with invariant sizes of SVC, IVC, right pulmonary artery (RPA), and left pulmonary artery (LPA), steady inflow velocities at IVC and SVC, and constant equal outflow pressures at RPA and LPA. These parameters were set to perform finite-volume incompressible steady flow simulations, assuming a single-phase, Newtonian, isothermal, laminar blood flow. Numerically converged finite-volume mass and momentum flow balances determined the inlet pressures and the outflow rates. Closed-path numerical integration of energy fluxes across domain boundaries determined the flow energy loss through the Fontan circulation. The comparison evaluated: 1) mean IVC pressure; 2) energy loss rate; 3) kinetic energy maximum value throughout the domain volume. Results: The comparison of the physiological versus conventional Fontan provided these results: 1) mean IVC pressure 13.9mmHg versus 14.1mmHg (= 0.2mmHg reduction); 2) energy loss rate 5.55mW versus 6.61mW (= 16% reduction); 3) kinetic energy 283J/m3 versus 396J/m3 (= 29% reduction). Conclusions: A more physiological flow distribution is accompanied by a reduction of mean IVC pressure and by substantial reductions of energy loss rate, and peak kinetic energy. The potential clinical impact of these hemodynamic changes in reducing the incidence and severity of the adverse long-term effects of the Fontan circulation, in particular liver failure and protein-losing enteropathy, still remains to be assessed and will be the subject of future work.

Funding

The Authors would like to thank Mausumi Debnath, James S. Hawley, and Joseph T. Thursby, students of the Department of Mathematics at the University of Leicester, for their preliminary work at the beginning of the study. This research used the ALICE High Performance Computing Facility at the University of Leicester. Graphical rendering software licenses were originally acquired with EPSRC support on Grant GR/N23745/01. The authors acknowledge the Research Software Engineering (RSE) team support of HPC Midlands Plus, funded by EPSRC grant number EP/K000055/1.

History

Citation

Frontiers in Pediatrics, 2019

Author affiliation

/Organisation/COLLEGE OF LIFE SCIENCES/School of Medicine/Department of Cardiovascular Sciences

Version

VoR (Version of Record)

Published in

Frontiers in Pediatrics

Publisher

Frontiers Media

issn

2296-2360

Acceptance date

29/04/2019

Copyright date

2019

Available date

17/09/2019

Publisher version

https://www.frontiersin.org/articles/10.3389/fped.2019.00196/full

Language

en