Abstract 4364680: Characteristics associated with poor long-term outcomes in patients with Fontan palliation

Background: Although survival after Fontan palliation for single ventricle heart disease has improved, long-term Fontan circulatory failure (FCF) remains a significant clinical concern, contributing to late morbidity and mortality. Many patients ultimately require heart transplantation (HT) or die due to FCF-related complications. Factors associated with adverse long-term FCF outcomes are not well established. Objective: To identify demographic, clinical, and diagnostic factors associated with death or the need for HT in patients with Fontan palliation. Methods: We conducted a retrospective, single-center case-control study of patients who underwent Fontan palliation at our institution between 2000 and 2023. Cases were defined as patients who survived their Fontan surgical admission but later died or required HT. Controls were matched 2:1 or 3:1 based on the year of Fontan surgery. Conditional logistic regression was used to identify clinical, echocardiographic, and hemodynamic variables at the time of Fontan palliation associated with death or HT. Results: We identified 53 cases (26 deaths and 27 HT) and matched them with 151 controls. The median time from Fontan surgery to death or HT was 8.6 years (IQR 3.8–13.8 years). On univariate analysis, significant pre-Fontan/perioperative factors associated with death/HT included systemic right ventricular (RV) morphology, higher hemi-Fontan/Glenn pressures, and hospital LOS >14 days during the post-Fontan surgical admission. On multivariable analysis, all three factors remained independently associated with eventual death/HT: systemic RV morphology (adjusted odds ratio [aOR] 5.54, 95% confidence interval [CI] 1.77–17.3, p=0.003), hemi-Fontan/Glenn pressures > 12 mmHg (aOR 3.92, 95% CI 1.60–9.61, p=0.003), and hospital LOS >14 days (aOR 6.57, 95% CI 2.27–19.0, p=0.001). Other pre-Fontan hemodynamic variables such as ventricular end-diastolic pressure and pulmonary vascular resistance were not significantly associated with death/HT. Additionally, discharge echocardiographic parameters following Fontan completion such as ventricular function or atrioventricular valve regurgitation showed no significant association with death/HT. Conclusion: In this study, systemic RV morphology, elevated hemi-Fontan/Glenn pressures, and prolonged LOS after Fontan surgery were independently associated with eventual death or HT. These findings aid in identifying high-risk patients who warrant closer surveillance in the post-Fontan period.