A recent study by researchers in the Cardiac Center at Children's Hospital of Philadelphia (CHOP) shows that children with Fontan circulation exhibit persistent height and weight deficits for up to eight years after their procedure. The findings were published in The Journal of Pediatrics.
The Fontan operation is a procedure used in patients with single-ventricle congenital heart disease (CHD) and creates a unique physiology by redirecting the flow of oxygenated blood in and out of the heart. As a result, 80% of patients with this type of CHD who undergo the Fontan procedure survive into early adulthood, but side effects include elevated central venous pressure and a chronic state of relatively low cardiac output. Long-term complications include liver fibrosis, a risk for protein-losing enteropathy (PLE), and a negative impact on other organ functions.
Several of the side effects and complications of Fontan circulation are risk factors for poor growth, in particular nitrogen-depleting conditions such as PLE. However, researchers have not determined which specific factors lead to impaired growth in patients with Fontan circulation, nor have they determined the potential for recovery.
To assess growth patterns among patients with Fontan circulation, researchers analyzed a cohort of patients in CHOP's Fontan FORWARD Clinic, a multidisciplinary clinic dedicated to comprehensive care of patients with Fontan circulation that aims to build resilience and improve the quality and duration of their lives. The researchers followed 210 patients from January 2011 through August 2015, evaluating their clinical and lab data, height, and body mass index (BMI). They used the 2000 National Center for Health Statistics Growth Charts to convert height, weight, and BMI to "z scores," which determine the extent which growth is below or above average.
The researchers found that both height and weight z scores in Fontan patients were below average. Children with PLE had more significant height deficits, likely due to multiple risk factors associated with the condition, including severe protein loss, negative nitrogen balance, malabsorption of nutrients and essential vitamins, and treatment with oral steroids.
In examining the patients' lab data, the researchers found that lower levels of alkaline phosphatase and phosphorus levels were correlated with poor growth, providing potential biochemical markers that could help in developing screening tests for high-risk groups.
"Our study shows that children with Fontan circulation - and particularly those with PLE - have diminished growth compared with their peers," said senior author Jack Rychik, MD, Director of the Fetal Heart Program and the Fontan FORWARD Program at CHOP. "Biochemical markers may be helpful in developing screening tests for high-risk groups and determining who might warrant increased surveillance and nutritional and medical interventions. Long-term studies are needed to determine if patients make up some of these height deficits once they reach their final height."
