Does preservation of antegrade pulmonary blood flow reduce pulmonary arteriovenous malformations after bidirectional Glenn? A retrospective observational study.

BACKGROUND: Pulmonary arteriovenous malformations (PAVMs) are a recognised cause of progressive cyanosis following bidirectional superior cavopulmonary anastomosis (BDG). The role of antegrade pulmonary blood flow (APBF) in preventing PAVM formation remains controversial. While preserved APBF may improve oxygen saturation and pulmonary artery growth, its protective effect against PAVMs is uncertain. Increasing evidence suggests that exclusion of hepatic venous blood from the pulmonary circulation, rather than absence of pulsatile flow, may be the primary mechanism underlying PAVM development. Therefore, management of APBF after BDG should be individualized.

METHODS: This retrospective observational study included children with univentricular physiology who underwent BDG before 4 years of age with a minimum follow-up of two years. Patients were divided into two groups based on the presence or interruption of APBF. Clinical data, oxygen saturation, echocardiographic findings, pulmonary artery dimensions, and imaging evidence of PAVMs were analysed using computed tomography angiography and/or cardiac catheterisation. Outcomes were compared between groups.

RESULTS: Sixty patients were included. PAVMs occurred in 26.7% of patients with interrupted APBF and 23.3% with preserved APBF (p = 0.766). Oxygen saturation was higher in the preserved APBF group but not statistically significant. Pulmonary artery dimensions and pressures were comparable, and all patients remained suitable for Fontan completion. Cyanosis was more frequent in the APBF-interrupted group.

CONCLUSIONS: Preserved APBF improves oxygen saturation but does not reduce PAVM incidence. Hepatic venous exclusion appears to be the primary determinant of PAVM development, supporting individualized surgical decision-making.