title: Blood Flow Simulations for the Design of Stented Valve Reducer in Enlarged Ventricular Outflow Tracts.
abstract: Tetralogy of Fallot is a congenital heart disease characterized over time, after the initial repair, by the absence of a functioning pulmonary valve, which causes regurgitation, and by progressive enlargement of the right ventricle outflow tract (RVOT). Due to this pathological anatomy, available transcatheter valves are usually too small to be deployed there. To avoid surgical valve replacement, an alternative consists in implanting a reducer prior to or in combination with the valve. It has been shown in animal experiments to be promising, but with some limitations. The effect of a percutaneous pulmonary valve reducer on hemodynamics in enlarged RVOT is thus studied by computational modeling. To this aim, blood flow in the RVOT is modeled with CFD coupled to a simplified valve model and 0D downstream models. Simulations are performed in an image-based geometry and boundary conditions tuned to reproduce the pathological flow without the device. Different device designs are built and compared with the initial device-free state, or with the reducer alone. Results suggest that pressure loss is higher for the reducer alone than for the full device, and that the latter successfully restores hemodynamics to a healthy state and induces a more symmetric flow in the pulmonary arteries. Moreover, pressure forces on the reducer and on the valve have the same magnitudes. Migration would occur towards the right ventricle rather than the pulmonary arteries. Results support the thesis that the reducer does not introduce clinically significant pressure gradients, as was found in animal experiments. Such study could help transfer to patients.
authors.affiliation: Weierstrass Institute for Applied Analysis and Stochastics, Mohrenstrasse 39, Berlin, 10117, Germany. caiazzo@wias-berlin.de.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Caiazzo
authors.affiliation: Institut de Mécanique des Fluides de Toulouse, INPT, UPS, Université de Toulouse, Toulouse, France. romain.guibert@imft.fr.
authors.forename: Romain
authors.initials: R
authors.lastname: Guibert
authors.affiliation: Service de Cardiologie Pédiatrique, Hôpital Necker-Enfants Malades, Paris, France. younes.boudjemline@nck.ap-hop-paris.fr.
authors.forename: Younes
authors.initials: Y
authors.lastname: Boudjemline
authors.affiliation: INRIA Paris-Rocquencourt and Sorbonne Universités UPMC Univ. Paris 6, Laboratoire J.-L. Lions, Paris, France. irene.vignon-clementel@inria.fr.
authors.forename: Irene E
authors.initials: IE
authors.lastname: Vignon-Clementel
mesh_terms: D000465:Algorithms; D001783:Blood Flow Velocity / Q000502:physiology; D003198:Computer Simulation; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008955:Models, Cardiovascular; D066230:Patient-Specific Modeling; D011474:Prosthesis Design; D011651:Pulmonary Artery / Q000503:physiopathology; D011664:Pulmonary Valve / Q000503:physiopathology / Q000601:surgery*; D015607:Stents; D013771:Tetralogy of Fallot / Q000503:physiopathology* / Q000601:surgery; D014694:Ventricular Outflow Obstruction / Q000601:surgery*
keywords: Device design; Multi scale blood flow simulations; Percutaneous pulmonary valve replacement; Repaired tetralogy of fallot; Right ventricle outflow tract (RVOT)