Hemodynamics of the hepatic venous three-vessel confluences using particle image velocimetry.

Despite rapid advancements in the patient-specific hemodynamic analysis of systemic arterial anatomies, limited attention has been given to the characterization of major venous flow components, such as the hepatic venous confluence. A detailed investigation of hepatic flow structures is essential to better understand the origin of characteristic abnormal venous flow patterns observed in patients with cardiovascular venous disease. The present study incorporates transparent rapid-prototype replicas of two pediatric hepatic venous confluence anatomies and two-component particle image velocimetry to investigate the primary flow structures influencing the inferior vena cava outflow. Novel jet flow regimes are reported at physiologically relevant mean venous conditions. The sensitivity of fluid unsteadiness and hydraulic resistance to multiple-inlet flow regimes is documented. Pressure drop measurements, jet flow characterization, and blood damage assessments are also performed. Results indicate that the orientation of the inlets significantly influences the major unsteady flow structures and power loss characteristics of this complex venous flow junction. Compared to out-of-plane arranged inlet vessel configuration, the internal flow field observed in planar inlet configurations was less sensitive to the venous inlet flow split. Under pathological flow conditions, the effective pressure drop increased as much as 77% compared to the healthy flow state. Experimental flow field results presented here can serve as a benchmark case for the surgical optimization of complex anatomical confluences including visceral hemodynamics as well as for the experimental validation of high-resolution computational fluid dynamics solvers applied to anatomical confluences with multiple inlets and outlets.