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Energetic implications of vessel growth and flow changes over time in Fontan patients

Maria Restrepo1, Elaine Tang2, Christopher M Haggerty1

  • 1The Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, Atlanta, Georgia.

The Annals of Thoracic Surgery
|December 3, 2014
PubMed

Insights

In single-ventricle patients, Fontan circulation vessel diameters did not keep pace with body growth over time. This mismatch increased energy losses, impacting long-term Fontan-associated risks.

Area of Science:

  • Pediatric Cardiology
  • Cardiovascular Physiology
  • Medical Imaging

Background:

  • Aging patients with single-ventricle physiology face increasing long-term complications.
  • Limited data exists on the temporal changes in anatomy and hemodynamics of single-ventricle patients.
  • Understanding these changes is crucial for predicting long-term outcomes.

Purpose of the Study:

  • To quantify changes in vessel growth and flow rates over time in Fontan patients using cardiac magnetic resonance.
  • To assess the impact of these changes on hemodynamics and long-term outcomes.

Main Methods:

  • Studied 48 patients with Fontan circulation (lateral tunnel or extracardiac conduit) using serial cardiac magnetic resonance scans (average 5.1-year interval).
  • Reconstructed total cavopulmonary connection anatomy and flow variables, normalized to body surface area.
  • Utilized computational fluid dynamics to model hemodynamic efficiency (indexed power loss).

Main Results:

  • Absolute vessel diameters increased, but normalized diameters decreased over time.
  • Vessel mean flow rates remained constant, despite proportional increases with body surface area.
  • Indexed power loss significantly increased, particularly in patients with decreasing normalized left pulmonary artery diameter.

Conclusions:

  • This is the largest serial cardiac magnetic resonance Fontan cohort study to date.
  • Fontan vessel diameters did not match somatic growth, leading to increased energy losses over time.
  • Increased energy losses indicate a potential worsening of hemodynamic efficiency impacting long-term Fontan outcomes.
Abstract

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