Additional pulmonary blood flow strategy at bidirectional Glenn: impact on pulmonary artery growth and long-term Fontan outcomes

OBJECTIVE: Management of additional pulmonary blood (APBF) flow during staged palliation toward Fontan completion remains debated, however it may influence long-term outcomes. To assess whether APBF promotes pulmonary artery (PA) growth before Fontan completion and whether different APBF strategies correlate with distinct long-term outcomes. METHODS: A retrospective single-center study was conducted on 205 patients undergoing Fontan completion between 1989 and 2024. Of these, 98 had APBF (83 antegrade APBF, 15 persistent mBT-shunt). Long-term outcomes included survival and freedom from PA stenting. RESULTS: Pre-Fontan PA diameters were larger in patients with APBF than in those without APBF: LPA 10.70 ± 3.76 mm vs 8.80 ± 3.43 mm (p < 0.0001) and RPA 12.18 ± 3.65 mm vs 10.99 ± 3.65 mm (p = 0.032). Within the APBF group, antegrade flow was associated with larger PA diameters than persistent mBT-shunt: LPA 11.12 ± 3.70 mm vs 9.01 ± 3.51 mm (p < 0.0001) and RPA 12.56 ± 3.67 mm vs 11.12 ± 3.59 mm (p = 0.009). Overall survival was higher in patients with APBF at 20 years (97.5% [95% CI, 83.6%-99.6%] vs 88.2% [95% CI, 75.9%-94.4%], p = 0.032). Freedom from PA stenting at 10 years was 98% (95% CI, 81.7%-96.1%) in patients without APBF, 95% (95% CI, 86.3%-98.5%) in those with antegrade APBF, and 78% (95% CI, 45.9%-92.3%) in those with persistent mBT-shunts. CONCLUSIONS: APBF appears to promote PA growth without increasing pulmonary pressures, but both APBF strategies may be associated with branch PA stenosis, with different timing according to flow type.