Numerical simulation of the influence of venous valve geometric structure on mechanical indices in the Peri-thrombotic Area

Venous valve geometric structure significantly influences thrombotic flow regime. The fluid region near the thrombus (Peri-thrombotic Area) is an important physical space for thrombus evolution, and establishing a computational fluid dynamics (CFD) numerical model for analysis in this region is important. However, it is how the venous valve geometric structure affects mechanical indices in the Peri-thrombotic Area that has not been fully investigated. In this study, we focus on the Peri-thrombotic Area, propose a bio-hydrodynamic model in which the venous valve is treated as a hyperelastic material, the thrombus as a porous medium, the blood as a Carreau fluid. We further employ numerical analysis to compare the influence of different venous valve geometric structures on flow regime under fluid-solid interaction. Abnormalities in valve length and curve are common geometric variations in valve structure, and these abnormalities affect the flow regime and mechanical indices of the Peri-thrombotic Area. The results showed that the maximum pressure difference reaches 54.9% as the valve length changed, and the maximum flow rate difference reached 61.1% as the curvature shifted. Heterogeneity in the valve geometric structure leads to alterations in the length and constriction degree of the narrow channel between the valve leaflets, consequently causing abnormalities in mechanical indices in the Peri-thrombotic Area. This study demonstrates that considering valve structure can predict the mechanical state in the Peri-thrombotic Area, which provides assistance for the treatment of venous thrombosis and other venous diseases.