Incidence, pathophysiology and treatment of Failing Fontan after the total cavopulmonary connection

P. Gaebert¹, T. Schaeffer², H. Staehler³, P. Heinisch³, A. Hager³, P. Ewert⁴, J. Hörer³, M. Ono^3
1MS, Munich, Bayern ²Dr., Munich, Bayern ³German Heart Center Munich, Munich, Bayern ⁴Professor, Munich, Bayern

Purpose: Failing Fontan is resulting from decompensated Fontan circulation and poses a significant clinical challenge. A wide range of diverse manifestations and hemodynamic phenotypes can occur. This study aims to improve patient outcomes by comprehensively understanding the incidence, pathophysiology, risk factors and treatment of failing Fontan after total cavopulmonary connection (TCPC).

Methods: We performed a retrospective analysis of 635 patients who underwent TCPC between May 1994 and December 2022 at our institution. Patients who underwent TCPC conversion from classic Fontan procedure were excluded from this study. Onset of failing Fontan was defined by the following categories: postoperative diagnosis of protein losing enteropathy (PLE) or plastic bronchitis (PB), New York Heart Association (NYHA) class IV or NYHA class III > one year, unscheduled hospital admissions for heart failure symptoms and evaluation/listing for transplantation (HTx). Incidence of failing Fontan was evaluated using competing analysis, and pre- and perioperative factors associated with the onset of failing Fontan were identified using Cox regression models. Therapies including catheter and surgical interventions after onset of failing Fontan were evaluated, and survival after onset of failing Fontan was estimated by the Kaplan-Meier method. NT-pro BNP data were collected at various time points and compared using Z-log values.

Results: The median age and weight at the TCPC was 2.3 (1.8-3.3) years and 12 (11-14) kg, respectively. During follow-up of median 5.5 years after TCPC, 76 patients presented with failing Fontan with a median period of 3.6 years. Manifestations included PLE in 34, hospital readmission in 28, NYHA III>1 year in 18, PB in 16, evaluation for HTx in 14 and NYHA IV in 4. The competing plot of death and Fontan failure are shown in Figure 1. The total incidence of failing Fontan was 1.48 per 100 Pt-years. Factors for the development of failing Fontan were hypoplastic left heart syndrome (hazard ratio (HR): 1.78, p=0.02), dominant right ventricle (HR: 2.64, p< 0.01), Heterotaxy (HR: 2.55, p=0.03), longer ICU (HR: 1.03, p< 0.01) and hospital stay (HR:1.02, p=0.01), and prolonged pleural effusion (HR: 1.86, p< 0.01). A total of 72 interventions were performed in 59 patients, comprising balloon/stent in TCPC pathway (n=49), closure of aortopulmonary/venovenous collaterals (n=24), and atrioventricular valve repairs (n=8). The survival after onset of Fontan failure was 77% at 10 years (Figure 2). The Z-log NT-proBNP value was similar before TCPC (p=0.508), but higher in patients with failing Fontan after the onset (p=0.021) compared with those without.

Conclusion: Failing Fontan was observed continuously after TCPC and incidence of Fontan failure was 1.5 per 100 patient-years. Dominant RV, HLHS, Heterotaxy and perioperative variables, such as prolonged pleural effusion and longer ICU/hospital stay, were significant risks for late failing Fontan. Surgical and catheter interventions were mandatory for the treatment of failing Fontan. Survival after onset of failing Fontan was 77 % at 10 years. Z-log values of NT-proBNP was significantly higher in patients with failing Fontan, compared to those without. Z-log values of NT-proBNP might become a useful marker for the onset of the failing Fontan.

Identify the source of the funding for this research project: No fund was used