Abstract 4125294: Fontan-Related Lymphatic Complications are Associated with Extracardiac Outcomes and Morbidity

Background: Patients born with single ventricle anatomy palliated with the Fontan procedure are at risk of lymphatic complications (LC), including plastic bronchitis, protein losing enteropathy, ascites, and hypoalbuminemia. The mechanism of LC, associated risk factors, and impact on outcomes are not well understood. Aim: We aimed to describe the prevalence of Fontan-related LC, expand on their association with previously reported risk factors, and explore the impact on mortality and transplantation. Methods: We performed a single-center, retrospective, cross-sectional cohort study of patients with Fontan circulation seen between 2009-2022, including those with cardiac catheterization and echocardiography within six months. Univariate comparisons were completed comparing those with and without LC. Results: A total of 144 Fontan patients were included with mean age of 23.6±11.9 years, with average of 18.8±10.5 years after their Fontan. Of those, 68 patients (48.6%) had at least one LC. There was no difference in demographic or anthropometric data in those with versus without LC, however patients with LC had their Fontan at an older age (5.6 vs 3.8 years, p =0.001). The presence of LC was associated with higher likelihood of thromboembolism (25% vs 7.9%, p =0.005), arrhythmia (45.6% vs 21.1%, p =0.002), lower estimated glomerular filtration rate (102.0±25.5 vs 111.6±17.9, p =0.02) and higher Fontan mean pressures noted on catheterization (14.8±3.8 vs 12.1±3.8 mmHg, p <0.001). Notably, LC were not related to the presence of moderate to severe ventricular dysfunction or moderate to severe atrioventricular valve regurgitation. Fontan patients with LC had higher rates of transplantation (25.4% vs 4%, p <0.001) and mortality (18% vs 4%, p =0.006). Conclusions: Fontan-related LC are associated with extra-cardiac morbidities and greater transplant and mortality rates. Our study suggests that LC are associated with venous congestion and not necessarily dependent on cardiac function.