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Longitudinal Outcomes of Patients With Single Ventricle After the Fontan Procedure
Andrew M Atz1, Victor Zak2, Lynn Mahony3
1Medical University of South Carolina, Charleston, South Carolina.
Insights
Survival after the Fontan procedure is 90% transplant-free over 12 years, independent of ventricular morphology. Exercise capacity declined, correlating with reduced functional health status in Fontan patients.
Area of Science:
- Pediatric Cardiology
- Congenital Heart Disease
- Adult Congenital Heart Disease
Background:
- Longitudinal data on adult survival post-Fontan procedure are limited.
- The Fontan procedure is a palliative surgery for complex congenital heart defects.
Purpose of the Study:
- To determine transplant-free survival rates in adult Fontan patients.
- To investigate the long-term relationship between ventricular performance and functional health status.
Main Methods:
- Repeated exercise testing, echocardiography, and B-type natriuretic peptide measurements.
- Functional health assessment and medical history review over a mean follow-up of 9.4 years.
- Cox regression analysis to identify risk factors for death or transplantation.
Main Results:
- Transplant-free survival was 90% over 12 years.
- Exercise capacity (maximum oxygen uptake) and ejection fraction decreased, while B-type natriuretic peptide levels increased.
- Poorer exercise performance correlated with lower functional health status scores.
Conclusions:
- Long-term survival in Fontan patients is favorable but associated with declining physiological function.
- Preserving exercise capacity may be a key target for future interventions.
- Ventricular morphology did not impact survival outcomes.
Background:
Multicenter longitudinal objective data for survival into adulthood of patients who have undergone Fontan procedures are lacking.
Objectives:
This study sought to describe transplant-free survival and explore relationships between laboratory measures of ventricular performance and functional status over time.
Methods:
Exercise testing, echocardiography, B-type natriuretic peptide, functional health assessment, and medical history abstraction were repeated 9.4 ± 0.4 years after the Fontan Cross-Sectional Study (Fontan 1) and compared with previous values. Cox regression analysis explored risk factors for interim death or cardiac transplantation.
Results:
From the original cohort of 546 subjects, 466 were contacted again, and 373 (80%) were enrolled at 21.2 ± 3.5 years of age. Among subjects with paired testing, the percent predicted maximum oxygen uptake decreased (69 ± 14% vs. 61 ± 16%; p < 0.001; n = 95), ejection fraction decreased (58 ± 11% vs. 55 ± 10%; p < 0.001; n = 259), and B-type natriuretic peptide increased (median [interquartile range] 13 [7 to 25] pg/mol vs. 18 [9 to 36] pg/mol; p < 0.001; n = 340). At latest follow-up, a lower Pediatric Quality of Life Inventory physical summary score was associated with poorer exercise performance (R2 adjusted = 0.20; p < 0.001; n = 274). Cumulative complications since the Fontan procedure included additional cardiac surgery (32%), catheter intervention (62%), arrhythmia treatment (32%), thrombosis (12%), and protein-losing enteropathy (8%). Since Fontan 1, 54 subjects (10%) have received a heart transplant (n = 23) or died without transplantation (n = 31). The interval risk of death or/cardiac transplantation was associated with poorer ventricular performance and functional health status assessed at Fontan 1, but it was not associated with ventricular morphology, the subject's age, or the type of Fontan connection.
Conclusions:
Interim transplant-free survival over 12 years in this Fontan cohort was 90% and was independent of ventricular morphology. Exercise performance decreased and was associated with worse functional health status. Future interventions might focus on preserving exercise capacity. (Relationship Between Functional Health Status and Ventricular Performance After Fontan-Pediatric Heart Network; NCT00132782).
