Association Between Hemodynamic Parameters and Gut Microbiota in Fontan Circulation: A Cross-Sectional Study

Area of Science:

• Cardiovascular Physiology
• Microbiome Research
• Gastroenterology

Background:

• The Fontan operation, a palliative procedure for complex congenital heart disease, leads to chronic hemodynamic alterations, notably central venous hypertension.
• These hemodynamic changes are hypothesized to contribute to gut dysbiosis, an imbalance in the gut microbiota.

Purpose of the Study:

• To compare gut microbiota profiles between individuals who have undergone the Fontan operation and healthy controls.
• To investigate the relationship between catheter-measured hemodynamic parameters, liver function, and gut microbial alterations in Fontan patients.

Main Methods:

• A cross-sectional study involving 23 Fontan patients and 23 matched healthy controls.
• Collection of stool samples from all participants for gut microbiota analysis.
• 16S rRNA gene sequencing was employed to characterize microbial communities.

Main Results:

• Fontan patients displayed significant gut dysbiosis, characterized by reduced microbial evenness and altered beta-diversity compared to controls.
• Fontan patients showed increased abundances of inflammation-associated bacteria and decreased levels of beneficial short-chain fatty acid-producing genera.
• Elevated pulmonary and Fontan-circuit pressures, along with greater transpulmonary gradients, correlated with lower microbial diversity and depletion of beneficial taxa. Higher serum albumin indicated better liver status and more favorable microbial profiles.

Conclusions:

• Fontan patients exhibit a distinct gut microbiota disruption pattern associated with their hemodynamic and hepatic burden.
• A graded association exists among circulatory congestion, liver involvement, and gut dysbiosis, supporting a hemodynamic-gut-liver axis in Fontan physiology.
• Specific bacterial taxa may serve as potential biomarkers for risk stratification and therapeutic guidance in Fontan patients.