Long-Term Outcomes and Novel Diagnostics in Fontan and Congenital Heart Disease

Overview

Recent studies highlight that extracardiac conduit Fontan patients have lower long-term atrial arrhythmia risk compared to lateral tunnel Fontan. Increased BMI in adult Fontan patients correlates with adverse ventricular remodeling, especially in morphologic left ventricles. Additionally, maternal salivary metabolomics combined with AI shows promise as a non-invasive prenatal screening tool for cyanotic congenital heart disease.

Background

The Fontan procedure is a palliative surgery for single-ventricle congenital heart disease, with extracardiac conduit (ECC) and lateral tunnel (LT) as common surgical variants. Long-term outcomes and complications such as arrhythmias remain critical concerns. Body mass index (BMI) may influence ventricular remodeling in adult Fontan patients, impacting clinical management. Early and accurate prenatal detection of congenital heart disease (CHD), particularly cyanotic forms, is essential for optimizing perinatal care, with emerging technologies exploring non-invasive biomarkers.

Data Highlights

Ventricular CMR volumes and mass by BMI category (median values):

Maternal saliva metabolomics AI model performance for cyanotic CHD detection:

Key Findings

• At 15-year follow-up, ECC Fontan patients had significantly lower rates of the composite outcome (19.8%) compared to LT patients (32.4%), driven mainly by reduced atrial arrhythmias.
• Freedom from atrial arrhythmia and composite adverse events was significantly higher in ECC patients at 5, 10, and 15 years (P < 0.0001).
• In adults with Fontan circulation, higher BMI was independently associated with increased ventricular end-diastolic volume and mass, particularly in morphologic left ventricles.
• Higher BMI correlated with elevated ventricular end-diastolic and Fontan pressures, indicating adverse hemodynamic effects.
• Maternal salivary metabolomic profiling combined with AI achieved high accuracy in detecting cyanotic CHD prenatally, with AUC ~0.82, sensitivity 92.5%, and specificity 87.0%.
• Lipid metabolism dysregulation was a predominant metabolic signature linked to fetal cyanotic CHD, supporting biological plausibility of the metabolomic findings.

Clinical Implications

The ECC Fontan approach may be preferred to reduce long-term atrial arrhythmia burden in single-ventricle patients. Weight management should be emphasized in adult Fontan patients to mitigate ventricular remodeling and hemodynamic compromise, especially in those with morphologic left ventricles. Maternal salivary metabolomics combined with AI offers a promising, non-invasive screening adjunct for early prenatal detection of cyanotic CHD, potentially improving referral and management strategies.

Conclusion

These studies collectively advance understanding of long-term Fontan outcomes, the impact of BMI on ventricular remodeling, and innovative non-invasive prenatal diagnostics for congenital heart disease, informing clinical decision-making and patient care.

References

1. FORCE Registry Study 2026 -- Long-Term Outcomes: Extracardiac Conduit vs. Lateral Tunnel Fontan
2. FORCE Registry Analysis 2026 -- BMI and Ventricular CMR Characteristics in Adult Fontan Patients
3. Prospective Study 2026 -- Maternal Saliva Metabolomics and AI for Prenatal Detection of Cyanotic CHD