title: A computational model of the fetal circulation to quantify blood redistribution in intrauterine growth restriction.
abstract: Intrauterine growth restriction (IUGR) due to placental insufficiency is associated with blood flow redistribution in order to maintain delivery of oxygenated blood to the brain. Given that, in the fetus the aortic isthmus (AoI) is a key arterial connection between the cerebral and placental circulations, quantifying AoI blood flow has been proposed to assess this brain sparing effect in clinical practice. While numerous clinical studies have studied this parameter, fundamental understanding of its determinant factors and its quantitative relation with other aspects of haemodynamic remodeling has been limited. Computational models of the cardiovascular circulation have been proposed for exactly this purpose since they allow both for studying the contributions from isolated parameters as well as estimating properties that cannot be directly assessed from clinical measurements. Therefore, a computational model of the fetal circulation was developed, including the key elements related to fetal blood redistribution and using measured cardiac outflow profiles to allow personalization. The model was first calibrated using patient-specific Doppler data from a healthy fetus. Next, in order to understand the contributions of the main parameters determining blood redistribution, AoI and middle cerebral artery (MCA) flow changes were studied by variation of cerebral and peripheral-placental resistances. Finally, to study how this affects an individual fetus, the model was fitted to three IUGR cases with different degrees of severity. In conclusion, the proposed computational model provides a good approximation to assess blood flow changes in the fetal circulation. The results support that while MCA flow is mainly determined by a fall in brain resistance, the AoI is influenced by a balance between increased peripheral-placental and decreased cerebral resistances. Personalizing the model allows for quantifying the balance between cerebral and peripheral-placental remodeling, thus providing potentially novel information to aid clinical follow up.
authors.affiliation: BCNatal - Barcelona Center for Maternal-Fetal and Neonatal Medicine (Hospital Clínic and Hospital Sant Joan de Déu), IDIBAPS, University of Barcelona, and Centre for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain; Physense, DTIC, Universitat Pompeu Fabra, Barcelona, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Garcia-Canadilla
authors.affiliation: University Hospital and Research Institute Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Paula A
authors.initials: PA
authors.lastname: Rudenick
authors.affiliation: BCNatal - Barcelona Center for Maternal-Fetal and Neonatal Medicine (Hospital Clínic and Hospital Sant Joan de Déu), IDIBAPS, University of Barcelona, and Centre for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain.
authors.forename: Fatima
authors.initials: F
authors.lastname: Crispi
authors.affiliation: BCNatal - Barcelona Center for Maternal-Fetal and Neonatal Medicine (Hospital Clínic and Hospital Sant Joan de Déu), IDIBAPS, University of Barcelona, and Centre for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain.
authors.forename: Monica
authors.initials: M
authors.lastname: Cruz-Lemini
authors.affiliation: Physense, DTIC, Universitat Pompeu Fabra, Barcelona, Spain.
authors.forename: Georgina
authors.initials: G
authors.lastname: Palau
authors.affiliation: Physense, DTIC, Universitat Pompeu Fabra, Barcelona, Spain.
authors.forename: Oscar
authors.initials: O
authors.lastname: Camara
authors.affiliation: BCNatal - Barcelona Center for Maternal-Fetal and Neonatal Medicine (Hospital Clínic and Hospital Sant Joan de Déu), IDIBAPS, University of Barcelona, and Centre for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain.
authors.forename: Eduard
authors.initials: E
authors.lastname: Gratacos
authors.forename: Bart H
authors.initials: BH
authors.lastname: Bijnens
authors.affiliation: Physense, DTIC, Universitat Pompeu Fabra, Barcelona, Spain; ICREA, Barcelona, Spain.
authors.forename: Bart H
authors.initials: BH
authors.lastname: Bijens
mesh_terms: D001011:Aorta / Q000502:physiology; D003198:Computer Simulation; D005260:Female; D005317:Fetal Growth Retardation / Q000503:physiopathology*; D005333:Fetus / Q000098:blood supply*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D020768:Middle Cerebral Artery / Q000502:physiology; D008955:Models, Cardiovascular; D010920:Placenta / Q000098:blood supply*; D011247:Pregnancy; D011263:Pregnancy Trimester, Third / Q000502:physiology