Fluid-structure interaction simulations of the Fontan procedure using variable wall properties

• Published in: International journal for numerical methods in biomedical engineering Vol. 28; no. 5; pp. 513 - 527
• Main Authors: Long, C. C., Hsu, M-C., Bazilevs, Y., Feinstein, J. A., Marsden, A. L.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.05.2012
• Subjects: Biomechanical Phenomena - physiology; Child; Child, Preschool; Computer Simulation; congenital heart disease; Female; Finite Element Analysis; finite element method; fluid-structure interaction; Fontan Procedure; Heart Defects, Congenital - pathology; Heart Defects, Congenital - physiopathology; Heart Defects, Congenital - surgery; Hemodynamics - physiology; Humans; Male; Models, Cardiovascular; Pressure; Stress, Mechanical; congenital heart disease; Fontan procedure; finite element method; fluid-structure interaction
• ISSN: 2040-7939; 2040-7947
• DOI: 10.1002/cnm.1485

SUMMARY Children born with single ventricle heart defects typically undergo a staged surgical procedure culminating in a total cavopulmonary connection (TCPC) or Fontan surgery. The goal of this work was to perform physiologic, patient‐specific hemodynamic simulations of two post‐operative TCPC patients by using fluid–structure interaction (FSI) simulations. Data from two patients are presented, and post‐op anatomy is reconstructed from MRI data. Respiration rate, heart rate, and venous pressures are obtained from catheterization data, and inflow rates are obtained from phase contrast MRI data and are used together with a respiratory model. Lumped parameter (Windkessel) boundary conditions are used at the outlets. We perform FSI simulations by using an arbitrary Lagrangian–Eulerian finite element framework to account for motion of the blood vessel walls in the TCPC. This study is the first to introduce variable elastic properties for the different areas of the TCPC, including a Gore‐Tex conduit. Quantities such as wall shear stresses and pressures at critical locations are extracted from the simulation and are compared with pressure tracings from clinical data as well as with rigid wall simulations. Hepatic flow distribution and energy efficiency are also calculated and compared for all cases. There is little effect of FSI on pressure tracings, hepatic flow distribution, and time‐averaged energy efficiency. However, the effect of FSI on wall shear stress, instantaneous energy efficiency, and wall motion is significant and should be considered in future work, particularly for accurate prediction of thrombus formation. Copyright © 2012 John Wiley & Sons, Ltd. In this work, we present physiologic, patient‐specific hemodynamic simulations of the postoperative Fontan procedure in two patients. The effects of fluid‐structure interaction with variable wall properties on presumed clinically relevant parameters such as hepatic flow distribution, energy efficiency, and wall shear stress are explored and results are discussed.