Abstract 2205: Predictors of Functional Status following Fontan Palliation: Development of a Fontan Functional Score
Background: Despite improvements in surgical outcomes following Fontan palliation, functional status varies considerably among survivors. We sought to identify pre- and peri-operative patient characteristics associated with overall function following Fontan.
Methods and Results: We analyzed data from 546 Fontan survivors enrolled in the NHLBI-sponsored Pediatric Heart Network Fontan Cross-sectional Study. Mean age at enrollment was 12.0±3.4 yr (range 6.4–18.9); age at Fontan was 3.4±2.1 yr (0.7–17.5) and time since Fontan was 8.7±3.4 yr (1.1–17.3). A Fontan Functional Score (FFS) was calculated for each subject by averaging the percentile ranks of:
ventricular EF on echo,
maximal O2 consumption on exercise testing,
Child Health Questionnaire Physical Summary Score, and
b-type natriuretic peptide.
Mean FFS was 49±18 (range 3–88). Multivariate linear regression was used to identify associations between FFS and historical variables. After adjustment for time since Fontan, lower FFS (worse status) was associated with: female sex (p=0.02), right ventricular (RV) morphology (p<0.001), higher pre-Fontan ventricular EDp (p<0.001) and lower O2 saturation (p=0.03), older age at volume unloading surgery (p=0.04), lower caregiver income (p=0.002) and higher education level (p<0.001), and, in subjects who did not undergo Stage II surgery, arrhythmias post-Fontan (p<0.001). The model explained 23% of the variation in the FFS. The following variables were not independently associated with the FFS: surgical center, age, weight, fenestration and length of hospital stay at Fontan, and number of post-Fontan surgeries or interventions. The model was validated using 71 randomly selected subjects excluded from initial analysis. FFS predicted from this model modestly correlated (R=0.24, p=0.04) with FFS calculated from the dataset, concordant with the variation in FFS explained by the model.
Conclusions: Female sex, RV morphology, higher pre-Fontan EDp, lower O2 saturation, lower caregiver income, and post-Fontan arrhythmias predict worse functional status following Fontan. Future studies are needed to explore the predictive value of the Fontan Functional Score to identify patients at risk for late adverse events, including transplant.