Objectives: Fontan circulation, while life-saving for patients with a single ventricle, is associated with long-term complications due to passive pulmonary flow and elevated systemic venous pressure, leading to end-organ damage. A key pathological driver is the maldistribution of hepatic blood flow, which can result in pulmonary arteriovenous malformations. This study aims to investigate a novel surgical configuration for Fontan completion designed to protect the pulmonary vasculature by achieving more physiological flow patterns, reducing hemodynamic energy loss, and ensuring the delivery of hepatic regenerative factors to both lungs.

Methods: This computational fluid dynamics study utilized patient-specific geometries reconstructed from magnetic resonance imaging scans of five patients with a non-fenestrated extracardiac Fontan. An alternative surgical configuration was created by offsetting the superior vena cava anastomosis towards the left pulmonary artery and the inferior vena cava anastomosis toward the right pulmonary artery. A trajectory optimization problem was solved to generate the new vessel geometries. Time-resolved, patient-specific inflow boundary conditions were applied. The Navier‒Stokes equations were solved using a Discontinuous Galerkin Finite Element Method, incorporating wall compliance. The optimization primary goals were the reduction in energy loss and peak wall shear stress. The distribution of hepatic flow (a surrogate for hepatic factor delivery) to each lung was quantified by solving an advection-diffusion problem for a passive scalar.

Results: Compared to the original surgical configuration, the proposed offset geometries resulted in a statistically significant reduction in time-averaged energy loss (P = 0.0081). The energy loss decreased by 15%–20% across the cohort, with improvements ranging from 5%–30% for individual patients. Peak wall shear stress, a marker of vascular wall stress, was reduced by 6%–11% in the partial offset configuration and by 7%–29% in the full offset configuration for four of the five patients. Notably, the novel configuration successfully delivered hepatic flow to both lungs in all patients, with the right lung receiving 55%–83% and the left lung receiving 17%–45% of the inferior vena cava flow, thereby preventing complete hepatic flow deprivation to either lung.

Conclusion: This study demonstrates that a surgically created offset between the superior and inferior vena cava anastomoses in the Fontan circulation is a viable regenerative strategy. By significantly reducing energy loss and peak wall shear stress while ensuring balanced delivery of hepatic factors to both lungs, this novel surgical approach has the potential to protect the pulmonary vasculature from pathological remodeling and preserve long-term Fontan function.