title: Flow simulations and validation for the first cohort of patients undergoing the Y-graft Fontan procedure.
abstract: OBJECTIVE
  In this study, with the use of computational fluid dynamics, we evaluate the postoperative hemodynamic performance of the first cohort of patients undergoing a handcrafted Y-graft Fontan procedure and validate simulation predictions of hepatic blood flow distribution against in vivo clinical data.
  
  
  METHODS
  An 18-12 × 2-mm handcrafted Y-graft modification of the Fontan procedure was performed in 6 patients. Early (at the time of discharge) and 6-month postoperative 3-dimensional magnetic resonance imaging data were collected. Patient-specific models were constructed for flow simulations.
  
  
  RESULTS
  Hepatic blood flow distribution varied among patients. Lung perfusion data (n = 3) showed good agreement with simulations. Postoperative asymmetry in hepatic blood flow distribution was reduced 6 months postoperatively. In 1 patient, low wall shear stress was found in the left limb of the Y-graft, corresponding to the location of subsequent thrombosis in the patient.
  
  
  CONCLUSIONS
  The credibility and accuracy of simulation-based predictions of postoperative hepatic flow distribution for the Fontan surgery have been validated by in vivo lung perfusion data. The performance of the Y-graft design is highly patient-specific. The anastomosis location is likely the most important factor influencing hepatic blood flow distribution. Although the development of thrombosis is multifactorial, the occurrence in 1 patient suggests that simulations should not solely consider the hepatic blood flow distribution but also aim to avoid low wall shear stress in the limbs.
authors.affiliation: Department of Pediatrics (Cardiology), Stanford University, Palo Alto, Calif. Electronic address: wgyang@stanford.edu.
authors.forename: Weiguang
authors.initials: W
authors.lastname: Yang
authors.affiliation: Department of Radiology, Stanford University, Palo Alto, Calif.
authors.forename: Frandics P
authors.initials: FP
authors.lastname: Chan
authors.affiliation: Department of Cardiothoracic Surgery, Stanford University, Palo Alto, Calif.
authors.forename: V Mohan
authors.initials: VM
authors.lastname: Reddy
authors.affiliation: Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, Calif.
authors.forename: Alison L
authors.initials: AL
authors.lastname: Marsden
authors.affiliation: Department of Pediatrics (Cardiology), Stanford University, Palo Alto, Calif; Department of Bioengineering, Stanford University, Palo Alto, Calif.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Feinstein
mesh_terms: D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D003198:Computer Simulation; D018729:Fontan Procedure / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D006330:Heart Defects, Congenital / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D006439:Hemodynamics; D006801:Humans; D008102:Liver Circulation; D008279:Magnetic Resonance Imaging; D008955:Models, Cardiovascular; D011474:Prosthesis Design; D011651:Pulmonary Artery / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D011652:Pulmonary Circulation; D011859:Radiography; D012039:Regional Blood Flow; D013997:Time Factors; D016896:Treatment Outcome; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*