Cardiovascular Outcomes in Fontan Patients With Right vs Left Univentricular Morphology: A Multicenter Study.

Background: There is a paucity of data on long-term outcomes after Fontan palliation in patients with a dominant morphological univentricular right (uRV) vs left (uLV) ventricle.
Objectives: The purpose of this study was to compare the incidence of atrial arrhythmias, thromboembolic events, cardiac transplantation, and death following Fontan palliation in patients with uRV vs uLV.
Methods: The Alliance for Adult Research in Congenital Cardiology conducted a multicenter retrospective cohort study on patients with total cavopulmonary connection Fontan palliation across 12 centers in North America. All components of the composite outcome, that is, atrial arrhythmias, thromboembolic events, cardiac transplantation, and death, were reviewed and classified by a blinded adjudicating committee. Time-to-event analyses were performed that accounted for competing risks.
Results: A total of 384 patients were followed for 10.5 ± 5.9 years. The composite outcome occurred in 3.7 vs 1.7 cases per 100 person-years for uRV (N = 171) vs uLV (N = 213), respectively ( P  < 0.001). In multivariable analyses, uRV conferred a >2-fold higher risk of the composite outcome (HR: 2.17, 95% CI: 1.45-3.45, P  < 0.001). In secondary analyses of components of the primary outcome, uRV was significantly associated with a greater risk of cardiac transplantation or death (HR: 9.09, 95% CI: 2.17-38.46, P  < 0.001) and atrial arrhythmias (HR: 2.17, 95% CI: 1.20-4.00, P  = 0.010) but not thromboembolic events (HR: 1.64, 95% CI: 0.86-3.16, P  = 0.131).
Conclusions: Fontan patients with uRV vs uLV morphology have a higher incidence of adverse cardiovascular events, including atrial arrhythmia, cardiac transplantation, and all-cause mortality.
Competing Interests: The TACTIC study was funded by an investigator-initiated unrestricted grant from Boehringer Ingelheim. The sponsor had no role in the study design, data collection, analysis, interpretation, writing of the paper, and decision to submit the manuscript for publication. Dr Dib is supported by the 10.13039/501100003100French Federation of Cardiology (FFC) and 10.13039/501100009597ADETEC grants. Dr Khairy is supported by the André Chagnon research chair in electrophysiology and congenital heart disease. All other have reported that they have no relationships relevant to the contents of this paper to disclose.
(© 2024 The Authors.)