Intestinal barrier dysfunction and systemic inflammation in adult patients after Fontan operation without protein-losing enteropathy

Background Patients after Fontan operation are at risk for multisystemic complications. Chronically elevated central venous pressure and reduced cardiac output may promote intestinal congestion and hypoperfusion, potentially leading to intestinal barrier dysfunction, microbial translocation and systemic inflammation. Objectives To investigate biomarkers of intestinal barrier dysfunction and systemic inflammation in adult patients after Fontan operation without protein losing enteropathy (PLE). Methods In this single-center, prospective study adult patients after Fontan operation without PLE and age- and sex-matched healthy controls were enrolled. Intestinal barrier related biomarkers included lipopolysaccharide binding protein (LBP), a marker of endotoxin exposure and host acute phase response, and intestinal fatty-acid binding protein (I-FABP), a marker of enterocyte injury. Systemic inflammation was evaluated using interleukin-6, interleukin-1β, tumor necrosis factor-α, soluble CD14 and C-reactive protein. Results Twenty-six patients after Fontan operation and thirteen healthy controls were included. There were no differences in age (27 ± 6 vs. 28 ± 4 years, p = 0.474) or gender (12 (46%) vs. 6 (46%) women, p = 1.000). Of intestinal barrier dysfunction biomarkers, LBP levels were significantly higher in patients than in healthy controls (median 19.0 (6.9) vs. 12.6 (1.3) ng/mL, p = 0.038), whereas I-FABP levels were similar (median 1.7 (1.0) vs. 1.5 (0.7) ng/mL, p = 0.627). All inflammatory biomarkers were significantly elevated in patients after Fontan operation. Conclusions Adult patients after Fontan operation without PLE showed higher LBP and biomarkers of systemic inflammation, but similar I-FABP, compared to healthy controls. This pattern is consistent with increased endotoxin exposure and low-grade systemic inflammation without evidence of overt enterocyte injury in these complex patients.