Fontan pathway growth: a quantitative evaluation of lateral tunnel and extracardiac cavopulmonary connections using serial cardiac magnetic resonance.
BACKGROUND
Typically, a Fontan connection is constructed as either a lateral tunnel (LT) pathway or an extracardiac (EC) conduit. The LT is formed partially by atrial wall and is assumed to have growth potential, but the extent and nature of LT pathway growth have not been well characterized. A quantitative analysis was performed to evaluate this issue.


METHODS
Retrospective serial cardiac magnetic resonance data were obtained for 16 LT and 9 EC patients at 2 time points (mean time between studies, 4.2 ± 1.6 years). Patient-specific anatomies and flows were reconstructed. Geometric parameters of Fontan pathway vessels and the descending aorta were quantified, normalized to body surface area (BSA), and compared between time points and Fontan pathway types.


RESULTS
Absolute LT pathway mean diameters increased over time for all but 2 patients; EC pathway size did not change (2.4 ± 2.2 mm vs 0.02 ± 2.1 mm, p < 0.05). Normalized LT and EC diameters decreased, while the size of the descending aorta increased proportionally to BSA. Growth of other cavopulmonary vessels varied. The patterns and extent of LT pathway growth were heterogeneous. Absolute flows for all vessels analyzed, except for the superior vena cava, proportionally to BSA.


CONCLUSIONS
Fontan pathway vessel diameter changes over time were not proportional to somatic growth but increases in pathway flows were; LT pathway diameter changes were highly variable. These factors may impact Fontan pathway resistance and hemodynamic efficiency. These findings provide further understanding of the different characteristics of LT and EC Fontan connections and set the stage for further investigation.
The Wallace H. Coulter Department of Biomedical Engineering at Georgia Institute of Technology and Emory University, Atlanta, Georgia.
Maria
M
Restrepo
The Wallace H. Coulter Department of Biomedical Engineering at Georgia Institute of Technology and Emory University, Atlanta, Georgia.
Lucia
L
Mirabella
School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia.
Elaine
E
Tang
The Wallace H. Coulter Department of Biomedical Engineering at Georgia Institute of Technology and Emory University, Atlanta, Georgia.
Christopher M
CM
Haggerty
The Wallace H. Coulter Department of Biomedical Engineering at Georgia Institute of Technology and Emory University, Atlanta, Georgia.
Reza H
RH
Khiabani
Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts.
Francis
F
Fynn-Thompson
Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts.
Anne Marie
AM
Valente
Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts.
Doff B
DB
McElhinney
Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
Mark A
MA
Fogel
The Wallace H. Coulter Department of Biomedical Engineering at Georgia Institute of Technology and Emory University, Atlanta, Georgia. Electronic address: ajit.yoganathan@bme.gatech.edu.
Ajit P
AP
Yoganathan
D000293:Adolescent; D057791:Cardiac Imaging Techniques; D002648:Child; D005069:Evaluation Studies as Topic; D018729:Fontan Procedure / Q000379:methods*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D011651:Pulmonary Artery / Q000254:growth & development* / Q000601:surgery*; D012189:Retrospective Studies; D014683:Vena Cava, Superior / Q000254:growth & development* / Q000601:surgery*; D055815:Young Adult