Lumped Parameter Liver Simulation to Predict Acute Hemodynamic Alterations Following Partial Resections

Abstract

Partial liver resections are routinely performed in living donor liver transplantation and to debulk tumors in liver malignancies. Due to the complexity of the interconnected hepatic vasculature, pre- and intra-operative decisions on vessel reconstruction for adequate inflow and outflow are challenging. Pre-operative evaluation of hepatic vasculature has predominantly been limited to radiological imaging and has failed to account for post-resection hepatic hemodynamic alterations. Substantial evidence suggests post-surgical increase in local volume flow rate enhances shear stress, signaling hepatic regeneration that is critical for hepatic volume restoration. However, excessive shear stress from extensive hepatic volume reduction has been postulated to result in small for size syndrome and liver failure. Predicting alterations in shear stress, flow velocity, and speed throughout the liver is particularly challenging due to the dendritic architecture of the portal and arterial vasculature that spans several orders of magnitude in diameter. Therefore, we developed a mathematical lumped parameter model implementing realistic heterogeneities in hepatic inflow/outflow of the human liver to simulate surgical resection alterations in perfusion across all hepatic segments. Our model is parameterized based on clinical measurements, relies on only a single free parameter, and accurately captures established blood perfusion characteristics. We quantify changes in volume flow rate, average blood flow velocity, and wall shear stress following variable, realistic liver resections and make comparisons to the intact liver. Our numerical model runs on a laptop in minutes and can be adapted to individualized patient-specific anatomy, providing a substantial advancement towards a novel computational tool for assisting pre- and intra-operative surgical decisions for liver resections.

Lumped parameter liver simulation to predict acute haemodynamic alterations following partial resections

“…The simulation codes developed for this study are publicly available online from the Zenodo repository: https://doi. org/10.5281/zenodo.7490383 [93]. The specific simulation data used to generate the plots in this manuscript are publicly available online from the Zenodo repository: https://doi.org/10.5281/zenodo.8392688.…”