Systemic venous collaterals between Glenn and Fontan: prevalence, therapy, and impact on outcomes

This study aimed to evaluate veno-venous collaterals between bidirectional cavopulmonary shunt and total cavopulmonary connection.

Patients who underwent staged total cavopulmonary connection between 1995 and 2022 were reviewed. Veno-venous collaterals between bidirectional cavopulmonary shunt and total cavopulmonary connection were depicted using angiograms. The prevalence of veno-venous collaterals, the risks for the development of veno-venous collaterals, and the impact of veno-venous collaterals on outcomes were analysed.

In total, 586 patients were included. Veno-venous collaterals were found in 72 (12.3%) patients. Majority of veno-venous collaterals originated from the superior caval vein and drained into the inferior caval vein. Before bidirectional cavopulmonary shunt, mean pulmonary artery pressure (16.3 vs. 14.5 mmHg, p = 0.018), and trans-pulmonary gradient (9.5 vs. 8.0 mmHg, p = 0.030) were higher in patients with veno-venous collaterals compared to those without. Veno-venous collaterals intervention was performed in 32 (5.5%) patients, in a median of 29 (16-152) days after bidirectional cavopulmonary shunt. Before total cavopulmonary connection, pulmonary artery pressure (10.3 vs. 9.4 mmHg, p = 0.015) and ventricular end-diastolic pressure (8.4 vs. 7.6 mmHg, p = 0.035) were higher, and arterial oxygen saturation (SaO₂, 80.6 vs. 82.6 %, p = 0.018) was lower in patients with veno-venous collaterals compared to those without. More palliations before total cavopulmonary connection (p < 0.001, odds ratio: 1.689) were an independent risk for the development of veno-venous collaterals. Veno-venous collaterals did not affect survival after total cavopulmonary connection (92.8 vs. 92.7% at 10 years, p = 0.600).

The prevalence of veno-venous collaterals between bidirectional cavopulmonary shunt and total cavopulmonary connection was 12%. Veno-venous collaterals may be induced by the elevated pulmonary artery pressure and trans-pulmonary gradient, and also by more previous palliations. However, they had no impact on clinical outcomes following total cavopulmonary connection.