Percutaneous closure of veno-venous collaterals in adult patients with univentricular physiology after Fontan palliation: Single centre experience and systematic review.

Background: The Fontan operation resulted in improved survival of patients with congenital heart defects not equipped to sustain biventricular circulation. Long-term complications are common, such as veno-venous collaterals (VVC). The aim of this study was to evaluate patient characteristics, percutaneous treatment strategy and (short-term) outcomes in adult Fontan patients with VVC, and review literature to date. Methods: In this single-centre retrospective observational cohort study, patients who underwent percutaneous VVC closure between 2017 and 2023 were identified. Results: Thirteen patients underwent percutaneous VVC closure (77 % female, age at intervention 24 ± 4 years, 77 % systemic left ventricle, 77 % extracardiac tunnel, median conduit size 16 [16-20]mm). Indications for closure were symptoms and/or significant exercise-related hypoxia. Mean Fontan pressure was 10±4 mmHg. The VVC originated from tributaries of the vena cava superior (VCS) and connected to pulmonary veins (8 VVC, 32 %), VCS to systemic atrium (3 VVC, 12 %), VCS to coronary sinus (3 VVC, 12 %) and tributaries of vena cava inferior to pulmonary veins (11 VVC, 44 %). Twenty-three VVC were occluded using coils and/or plugs. No periprocedural complications occurred. At first follow-up at least 6 months after closure (n = 11), 9 patients (82 %) reported symptom reduction. Saturation at rest and peak exercise increased significantly (96 ± 3 to 98 ± 1 %, p = 0.040; 89 ± 3 to 93 ± 5 %, p = 0.024, respectively). Exercise capacity remained unchanged. Conclusions: VVC typically connect the tributaries of the vena cava inferior and/or superior with the pulmonary veins. Low Fontan pressures do not exclude the presence of VVC. Percutaneous closure of VVC is technically feasible, safe, and associated with symptom reduction and a significant rise in resting and exercise oxygen saturation.