Gut, Inflammation and Nutrition in Adult Patients After Fontan Operation

This observational case-control study aims to investigate intestinal barrier dysfunction, systemic inflammation, and nutritional status in adult patients after Fontan operation. Fontan operation, a palliative intervention for complex congenital heart defects, leads to an elevated systemic venous pressure, contributing to systemic complications, including gastrointestinal disturbances and liver disease. While protein-losing enteropathy (PLE) is a known complication, this study focuses on patients without PLE to assess less-studied effects on the gastrointestinal system. The elevated systemic venous pressure in adult patients after Fontan operation may impair the protective and absorptive functions of the gastrointestinal tract. This dysfunction allows bacterial endotoxins to enter the bloodstream, triggering systemic inflammation, which can worsen heart failure, cause malnutrition, and lead to cachexia. Although these outcomes are established in acquired heart failure, there is a lack of studies specifically examining the gastrointestinal consequences in adult patients after Fontan operation without PLE. In this study, adult Fontan patients without PLE will be compared to a control group of healthy adults or adult patients with simple congenital heart defects and normal systemic venous pressure. The study will evaluate intestinal barrier dysfunction, systemic inflammatory responses, and malnutrition through several methods: serum biomarkers (I-FABP, LBP, TNF-α, IL-6, etc.), nutritional assessment including body composition assessment using bioelectrical impedance analysis and measurements of serum microelements, echocardiography, and abdominal ultrasound with liver elastography. The findings of the study will help elucidate the connection between intestinal barrier dysfunction, inflammation, and nutritional status in adult patients after Fontan operation, aiming to improve long-term outcomes for this unique patient population.