High-Performing Fontan Patients: A Fontan Outcome Registry by Cardiac Magnetic Resonance Imaging Study.

Background: Fontan patients exhibit decreased exercise capacity. However, there is a subset of high-performing Fontan (HPF) patients with excellent exercise capacity.
Objectives: This study aims to: 1) create a Fontan-specific percent predicted peak VO ₂ tool using exercise data; 2) examine clinical factors associated with HPF patients; and 3) examine late outcomes in HPF patients.
Methods: Patients in the multi-institutional Fontan Outcomes Registry Using CMR Examination above the age of 8 years who had a maximal exercise test were included. An HPF patient was defined as a patient in the upper Fontan-specific percent predicted peak VO ₂ quartile. Multivariable logistic regression was employed to investigate factors associated with the HPF and Cox regression was used to examine the association between HPF patients and late outcomes (composite of death or listing for cardiac transplant).
Results: The study included 813 patients (mean age: 20.2 ± 8.7 years). An HPF patient was associated with left ventricular morphology (OR: 1.50, P  = 0.04), mixed morphology (OR: 2.23, P  < 0.001), and a higher ejection fraction (OR: 1.31 for 10% increase, P  = 0.01). Patients with at least moderate atrioventricular valve regurgitation, protein-losing enteropathy, or who were using psychiatric medications, were less likely to be an HPF patient. After a mean follow-up of 3.7 years, 46 (5.7%) patients developed a composite endpoint. HPF had a lower risk of death or listing for cardiac transplant (HR: 0.06 [95% CI: 0.01-0.25]).
Conclusions: Patients with HPF have more favorable outcomes when compared to patients with lower exercise capacity. This large registry data highlights the role of exercise testing in providing personalized care and surveillance post-Fontan.
Competing Interests: The FORCE registry is funded through a grant from 10.13039/100020415Additional Ventures and Evan’s Heart. The project described was supported by the 10.13039/100000002National Institutes of Health through Grant Number UL1 TR001857, KL2 TR001856, and/or TL1 TR001858. Dr Rathod received research grant support from Mezzion Pharmaceuticals as the Global PI for the FUEL-2 trial which is a drug RCT in Fontan patients. Dr Alsaied is a center PI for the same trial and also receives similar grant support. The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
(© 2024 The Authors.)