Longitudinal development of obesity in the post-Fontan population

An elevated body mass index (BMI) in childhood is a significant risk factor for cardiovascular disease, and it may pose an additional risk to children and adults with palliated univentricular congenital heart disease. However, little is known about longitudinal development of obesity in this population. The objective of this study is to determine the prevalence of overweight (OW) and obese (OB) habitus at the time of Fontan palliative surgery, to track changes in BMI after surgery, and ultimately to determine whether factors such as gender, ethnicity, preoperative heart defect and ventricular dominance are associated with later development of OW or OB.

A retrospective chart review of 84 patients undergoing Fontan palliation was performed. Demographic data including gender, ethnicity, preoperative heart defect and ventricular dominance were recorded. Height, weight and BMI were obtained at the time of Fontan and on a yearly basis post surgery.

At the time of Fontan palliation, 10.7% of patients were OB or OW. During the five years following palliation, the percentage of OB or OW patients trended upward, from 20.3% the year following surgery to 30% at 5 years post Fontan. Repeated measures generalized estimating equation showed a significant association between Hispanic ethnicity and increased BMI Z-scores for the 5 years after Fontan palliation (P<0.001); there was no association between BMI Z-scores and patient sex, lesion or ventricular dominance.

During the first 5 years after Fontan palliation, there is a trend toward increasing percentages of OB and OW patients. In addition, there is a significant association between Hispanic ethnicity and being OW or OB before and after surgery. Further study is needed to determine whether OW/OB status is associated with worse health outcomes in this patient population.