Morbidity and mortality in adults with a Fontan circulation beyond the fourth decade of life

Aims To evaluate the late outcomes of adults (above 35 years) with a Fontan-type circulation, for whom current data on morbidity and mortality are lacking. Methods and results Data were collected retrospectively on consecutive patients with Fontan circulation above the age of 35 years followed in three European specialist centres. Overall, 115 Fontan patients were included [median age 35 (range 35-48) years, 47.8% female]. The most common underlying congenital heart disease diagnosis was tricuspid atresia (n = 58, 50.4%), and the age at first Fontan completion was 9.1 (interquartile range 5.0-15.8) years. Almost two-thirds (61.7%) of patients had undergone an atriopulmonary Fontan, and 23.5% had received a total cavopulmonary connection. One-third required repeat surgery or intervention. Most patients (55.9%) were in New York Heart Association functional class II or class I (30.6%), 76 (66.1%) patients had experienced at least one arrhythmia, and eight (7.0%) protein-losing enteropathy. At a median follow-up of 5.0 (2.4-10.3) years, 15 (13.0%) patients were referred for transplantation assessment and 19 (16.5%) patients died, mainly from heart failure (84.2%). Univariable predictors of death or transplantation included lower serum albumin level [hazard ratio (HR) 1.09 per g/L decrease, 95% confidence interval (CI): 1.04-1.15, P = 0.0009], prior heart failure admission (HR 4.28, 95% CI:1.75-10.44, P = 0.001), prior atrial tachycardia or flutter (HR 3.02, 95% CI: 1.23-7.38, P = 0.02), and baseline pulmonary vasodilator therapy (HR 8.59, 95% CI:1.05-70.13, P = 0.04). Lower serum albumin and prior atrial tachycardia or flutter remained significant on bivariable analysis. Conclusion Our study highlights the significant morbidity and mortality in older adults with a Fontan-type circulation, emphasizing the need for lifelong specialist surveillance with frequent risk stratification, close monitoring, and early consideration for transplantation assessment. Lay summary This study sheds light on the complex medical journey of adults living with the outcomes of Fontan surgery-a procedure performed in early childhood. These individuals have reached the milestone of their forties and beyond, yet they confront an array of significant health challenges that necessitate lifelong, individualized congenital heart disease care. The key findings are as follows: .While adults with Fontan circulation are living longer, they are at high risk of death, mainly due to heart failure. They also face a host of other health issues, including the need for additional surgeries or interventions. Nearly two-thirds have experienced some form of heart rhythm problem, and a substantial number eventually require evaluation for a heart transplant .Heart transplants within this group were rare, which may be linked to the various barriers to transplantation in the Fontan population. Moreover, those with multiple indicators of advanced disease have a heightened risk of life-threatening events, reinforcing the critical need for personalized and continuous specialist care designed to meet their distinct health requirements.