Gut Dysbiosis in Patients With Fontan Circulation

Background: The process underlying Fontan pathophysiology is multifactorial and may include gut dysbiosis (GD). We investigated the presence of GD and elucidated its correlation with Fontan pathophysiology. Methods and Results: Gut microbiomes of 155 consecutive patients with Fontan pathophysiology and 44 healthy individuals were analyzed using 16S rRNA sequencing of bacterial DNA extracted from fecal samples. GD was evaluated on the basis of alpha and ss diversities of the gut microbiome and was compared with natural log-transformed C-reactive protein, hemodynamics, von Willebrand factor antigen (a bacterial translocation marker), Mac-2 binding protein glycosylation isomer (a liver fibrosis indicator), peak oxygen uptake, and heart failure hospitalization. Patients with Fontan exhibited GD in terms of alpha and ss diversities as compared with controls (P<0.01). Reduced alpha diversity was associated with a failed hemodynamic phenotype, hypoxia, high natural log-transformed C-reactive protein levels, and elevated von Willebrand factor antigen and Mac-2 binding protein glycosylation isomer levels (P<0.05-0.01). In addition to elevated von Willebrand factor antigen and hypoxia, decreased alpha diversity was independently correlated with a high natural log-transformed C-reactive protein level (P<0.05), which was associated with liver imaging abnormalities and a heightened risk of heart failure hospitalization (P<0.01 for both). Conclusions: Patients with Fontan pathophysiology exhibited GD compared with healthy individuals, and GD was linked to failed hemodynamics and systemic inflammation with a poor prognosis. Therefore, GD may play a pivotal role in a failing Fontan status, including Fontan-associated liver disease, through GD-associated systemic inflammation.