title: Hemodynamic Impact of Superior Vena Cava Placement in the Y-Graft Fontan Connection.
abstract: BACKGROUND
  A Fontan Y-shaped graft using a commercially available aortoiliac graft has been used to connect the inferior vena cava (IVC) to the pulmonary arteries. This modification of the Fontan procedure seeks to improve hepatic flow distribution (HFD) to the lungs. However, patient-specific anatomical restrictions might limit the space available for graft placement. Altering the superior vena cava (SVC) positioning is hypothesized to provide more space for an optimal connection, avoiding caval flow collision. Computational modeling tools were used to retrospectively study the effect of SVC placement on Y-graft hemodynamics.
  
  
  METHODS
  Patient-specific anatomies (N = 10 patients) and vessel flows were reconstructed from retrospective cardiac magnetic resonance (CMR) images after Fontan Y-graft completion. Alternative geometries were created using a virtual surgery environment, altering the SVC position and the offset in relation to the Y-graft branches. Geometric characterization and computational fluid dynamics simulations were performed. Hemodynamic factors (power loss and HFD) were computed.
  
  
  RESULTS
  Patients with a higher IVC return showed less sensitivity to SVC positioning. Patients with low IVC flow showed varied HFD results, depending on SVC location. Balanced HFD values (50% to each lung) were obtained when the SVC lay completely between the Y-graft branches. The effect on power loss was patient specific.
  
  
  CONCLUSIONS
  SVC positioning with respect to the Y-graft affects HFD, especially in patients with lower IVC flow. Careful positioning of the SVC at the time of a bidirectional Glenn (BDG) procedure based on patient-specific anatomy can optimize the hemodynamics of the eventual Fontan completion.
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta.
authors.forename: Maria
authors.initials: M
authors.lastname: Restrepo
authors.affiliation: School of Material Sciences and Engineering, Georgia Institute of Technology, Atlanta.
authors.forename: A Colleen
authors.initials: AC
authors.lastname: Crouch
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Haggerty
authors.affiliation: College of Computing, Georgia Institute of Technology, Atlanta.
authors.forename: Jarek
authors.initials: J
authors.lastname: Rossignac
authors.affiliation: Division of Pediatric Cardiology, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia.
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Slesnick
authors.affiliation: Division of Cardiothoracic Surgery, Department of Surgery, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia.
authors.forename: Kirk R
authors.initials: KR
authors.lastname: Kanter
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta. Electronic address: ajit.yoganathan@bme.gatech.edu.
authors.forename: Ajit P
authors.initials: AP
authors.lastname: Yoganathan
mesh_terms: D000293:Adolescent; D000714:Anastomosis, Surgical / Q000379:methods; D001807:Blood Vessel Prosthesis; D002648:Child; D002675:Child, Preschool; D018729:Fontan Procedure / Q000379:methods*; D006330:Heart Defects, Congenital / Q000175:diagnosis / Q000601:surgery*; D006352:Heart Ventricles / Q000002:abnormalities*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D011184:Postoperative Period; D011474:Prosthesis Design; D011651:Pulmonary Artery / Q000601:surgery*; D016896:Treatment Outcome; D014683:Vena Cava, Superior / Q000601:surgery*