The Impact of Fontan Circulatory Failure on Heart Transplant Survival: A 20-Center Retrospective Cohort Study

BACKGROUND: Fontan circulatory failure (FCF) is a chronic state in palliated single ventricle heart disease with high morbidity and mortality rates, including heart failure, multisystem end-organ disease, and need for heart transplant. Specific FCF morbidities have not been rigorously defined, limiting study of how FCF morbidities affect pre–heart transplant and post–heart transplant outcomes. We hypothesized that FCF-related morbidities affect survival from heart transplant waitlisting through 1 year after heart transplant. METHODS: This 20-center, retrospective cohort study collected demographic, medical/surgical history, waitlist, and peri- and post–heart transplant data, and a priori defined FCF-specific morbidities, in Fontan patients who were listed for heart transplant from 2008 through 2022. Univariate 2-group statistics compared surviving individuals with those who died anytime from waitlisting to 1 year after heart transplant, died on the waitlist, or underwent transplant and died within 1 year after transplant. Using covariates from both univariate analyses, multivariable logistic regression determined the primary study outcome of independent FCF risk factors for death between waitlist and 1 year after heart transplant. RESULTS: Of 409 waitlisted patients, 24 (5.9%) died on the waitlist. Of the 341 (83.4%) who underwent transplant, 27 (8.5%) did not survive to 1 year. Univariate risk factors for waitlist death included higher aortopulmonary collateral burden, >1 hospitalization in the previous year, younger age, sleep apnea, higher New York Heart Association class, nonenrollment in school or work, and single-parent home. Risk factors for 1-year post–heart transplant mortality included hypoplastic left heart syndrome diagnosis, patent fenestration, anatomic Fontan obstruction, clinical cyanosis (pulse oximetry <90%), polycythemia, portal variceal disease, mental health condition requiring treatment, and higher human leukocyte antigen class II panel reactive antibody. Of the patients not surviving from waitlisting to 1 year after heart transplant, independent risk factors for death included >1 hospitalization in the year before waitlisting (adjusted odds ratio, 2.0 [95% CI, 1.0–4.1]; P=0.05) and clinical cyanosis (adjusted odds ratio, 5.0 [95% CI, 1.8–13.4]; P=0.002). CONCLUSIONS: Patients with Fontan palliation selected for heart transplant have substantial mortality rates from waitlisting through transplant. Among FCF-specific morbidities, cyanosis is associated with worsened survival and necessitates further study. Clinical morbidity of any type requiring repeated hospital admission also should prompt consideration of heart transplant.