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Progression in Fontan conduit stenosis and hemodynamic impact during childhood and adolescence
Neil D Patel1, Connie Friedman2, Cynthia Herrington3
1Division of Pediatric Cardiology, Children's Hospital Los Angeles, University of Southern California Keck School of Medicine, Los Angeles, Calif.
Insights
Fontan conduit cross-sectional area (CSA) significantly decreases within months after surgery. Smaller conduit CSA correlates with reduced exercise capacity but not cardiac output or pulmonary artery growth.
Area of Science:
- Pediatric Cardiology
- Congenital Heart Disease
- Cardiac Surgery
Background:
- The Fontan procedure is a palliative surgery for single-ventricle congenital heart defects.
- Long-term outcomes and conduit health are critical for Fontan physiology patients.
Purpose of the Study:
- To analyze changes in Fontan conduit cross-sectional area (CSA) over time.
- To investigate the relationship between Fontan conduit CSA and cardiac output, pulmonary artery growth, and exercise capacity.
Main Methods:
- Retrospective cross-sectional study of 158 patients with extracardiac Fontan.
- Cardiac MRI or catheterization data collected between 2013-2019.
- Analysis of Fontan conduit CSA, Nakata index, cardiac index, and exercise capacity.
Main Results:
- Minimum Fontan conduit CSA decreased by a median of 33% within 9.6 years post-surgery.
- Conduit size reduction was observed as early as 6 months post-Fontan.
- A larger Fontan CSA showed a modest correlation with improved exercise capacity (% predicted oxygen consumption).
Conclusions:
- Fontan conduit CSA diminishes early in the post-operative period.
- Fontan conduit CSA was not associated with cardiac index or pulmonary artery size.
- Fontan conduit CSA correlates with exercise capacity in patients with Fontan physiology.
Objective:
To characterize changes in Fontan conduit size over time and determine if cross-sectional area (CSA) affects cardiac output, pulmonary artery growth, and exercise capacity.
Methods:
We conducted a retrospective cross-sectional study of patients with Fontan physiology who underwent cardiac magnetic resonance imaging or cardiac catheterization between January 2013 and October 2019. We collected Fontan and pulmonary artery measurements, hemodynamic data, and cardiopulmonary exercise test data. We identified 158 patients with an extracardiac Fontan. We measured minimum and mean Fontan conduit CSA and assessed whether these correlated with Nakata index, cardiac index, or exercise capacity.
Results:
Minimum Fontan CSA decreased by a median of 33% (24%, 40%) during a mean follow-up of 9.6 years. Median percentage decrease in Fontan CSA did not differ among 16-, 18-, and 20-mm conduits (P = .29). There was a significant decrease in the minimum Fontan CSA (33% [25%, 41%]) starting less than 1-year post-Fontan. Median Nakata index was 177.6 mm2/m2 (149.1, 210.8) and was not associated with Fontan CSA/BSA (ρ = 0.09, P = .29). Fontan CSA/BSA was not associated with cardiac index (ρ = -0.003, P = .97). A larger Fontan CSA/BSA had a modest correlation with % predicted oxygen consumption (ρ = 0.31, P = .013).
Conclusions:
Fontan conduit CSA decreases as early as 6 months post-Fontan. The minimum Fontan CSA/BSA was not associated with cardiac index or pulmonary artery size but did correlate with % predicted peak oxygen consumption.
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