title: Energetic implications of vessel growth and flow changes over time in Fontan patients.
abstract: BACKGROUND
  As patients with a single-ventricle physiology age, long-term complications inherent to this population become more evident. Previous studies have focused on correlating anatomic and hemodynamic performance, but there is little information of how these variables change with time. Vessel growth and flow rate changes were quantified using cardiac magnetic resonance and their effects on hemodynamics were assessed, which could affect the long-term outcome.
  
  
  METHODS
  Forty-eight patients with a lateral tunnel or extracardiac conduit Fontan who underwent two cardiac magnetic resonance scans (average interval, 5.1 ± 2.3 years) were studied. Total cavopulmonary connection anatomic and flow variables were reconstructed and normalized to body surface area(1/2). Total cavopulmonary connection hemodynamic efficiency (indexed power loss) was obtained through computational fluid dynamic modeling.
  
  
  RESULTS
  Absolute vessel diameters increased with time, normalized diameters decreased, and vessel mean flow rates remained unchanged. Indexed power loss changed significantly in the cohort, as well as in patients in whom the minimum normalized left pulmonary artery decreased. Age at first scan and connection type (lateral tunnel or extracardiac conduit) were not associated with changes in indexed power loss.
  
  
  CONCLUSIONS
  We present the largest serial cardiac magnetic resonance Fontan cohort to date. Although flow rates increased proportionally to body surface area, vessel diameters did not match somatic growth. As a result, energy losses increased significantly with time in the cohort analyzed.
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, Atlanta, Georgia.
authors.forename: Maria
authors.initials: M
authors.lastname: Restrepo
authors.affiliation: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia.
authors.forename: Elaine
authors.initials: E
authors.lastname: Tang
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, Atlanta, Georgia.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Haggerty
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, Atlanta, Georgia.
authors.forename: Reza H
authors.initials: RH
authors.lastname: Khiabani
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, Atlanta, Georgia.
authors.forename: Lucia
authors.initials: L
authors.lastname: Mirabella
authors.affiliation: Westat, Rockville, Maryland.
authors.forename: James
authors.initials: J
authors.lastname: Bethel
authors.affiliation: Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts.
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: Valente
authors.affiliation: Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
authors.forename: Kevin K
authors.initials: KK
authors.lastname: Whitehead
authors.affiliation: Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts.
authors.forename: Doff B
authors.initials: DB
authors.lastname: McElhinney
authors.affiliation: Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Fogel
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, Atlanta, Georgia. Electronic address: ajit.yoganathan@bme.gatech.edu.
authors.forename: Ajit P
authors.initials: AP
authors.lastname: Yoganathan
mesh_terms: D000293:Adolescent; D057791:Cardiac Imaging Techniques; D002648:Child; D002675:Child, Preschool; D005260:Female; D018729:Fontan Procedure; D006439:Hemodynamics; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D011651:Pulmonary Artery / Q000254:growth & development / Q000502:physiology* / Q000601:surgery; D012039:Regional Blood Flow; D012189:Retrospective Studies; D014683:Vena Cava, Superior / Q000254:growth & development / Q000502:physiology* / Q000601:surgery