The best strategy to achieve optimal growth of pulmonary artery branches (PAs) in functionally univentricular heart (FUH) between partial cavopulmonary connection (PCPC) and total cavopulmonary connection (TCPC) is still controversial, especially the preservation of anterograde pulmonary blood flow (APBF).

To model the growth of PA in FUH between PCPC and TCPC and to assess whether APBF promotes this growth. Then to determine whether the maintenance of an APBF is associated with higher morbidity and mortality.

We retrospectively included all patients with FUH who underwent cardiac catheterization before PCPC and TCPC between 2004 and 2021. A linear regression model was used to model PA growth. We compared mortality and morbidity outcomes between the APBF group and no APBF group using the Kaplan–Meier method.

In total, 118 children with FUH with a median follow-up of 8.8years were included, 49 (41.5%) had maintained APBF. PA branch growth can be considered continuous and linear over time [fractional polynomials (P=0.2)], estimated at β=8.5 [0.7–16.2] mm²/year. In multivariate analysis, maintaining an APBF was the only factor associated with increased PA branch growth [β=55.9 (21.8; 90) mm² (P=0.01)], regardless of TCPC timing (Fig. 1). Before PCPC, there was no difference in mean pulmonary artery pressure (mPAP) between groups with and without APBF. Between PCPC and TCPC, there was no significant increase in mPAP [13.2 (12–16) vs. 14.1 (12.4–15.8), P=0.3] or transpulmonary pressure gradient [7.2 (5.2–9.3) vs. 6.9 (4.6–9.1), P=0.6] in the APBF group. There was no difference in survival at 6years after TCPC between the group with APBF [87.6, 95% CI (65.6%–95.9%)] and the group without APBF [82.3 95% CI (67.8–90.6)]. No difference was also found when comparing morbidity characteristics between the two groups, such as length of hospital stay after TCPC (P=0.7), chylothorax (P=0.81), hemodynamic contraindications to fenestration closure (P=0.9), failing Fontan rate (P=0.38).

PAs growth between PCPC and TCPC is significant and can be considered linear over time. By maintaining APBF, growth potential can be achieved much more quickly and without additional risk of morbidity or mortality.