Simulação computacional do escoamento sanguíneo em artérias coronárias com stents farmacológicos

Abstract

Drug-eluting stents effectiveness depends on the interaction between blood flow in the arterial lumen and drug transport into adjacent tissue, which can be represented as a porous medium dominated by diffusive mechanisms that play a central role in the absorption and distribution of active compounds. Traditional models often assume Newtonian blood flow and isotropic tissue diffusion, simplifications that may compromise accuracy, especially in small-diameter arteries where non-Newtonian effects and diffusion anisotropy are significant. Comprehensive frameworks incorporating these aspects remain scarce and lack robust numerical validation. In this work, a unified computational model coupling fluid flow and drug transport in stented arteries is proposed, using Navier-Stokes equations for lumen and the Brinkman equations for porous tissue. Advection–diffusion equations govern drug transport in the lumen, while tissue transport is described by a modified diffusion equation incorporating an anisotropic diffusivity tensor. Stabilized finite element methods based on SUPG and PSPG formulations are employed to solve the coupled system, ensuring accuracy in convection-dominated regimes. The methodology is validated against benchmark literature data. The model studied examines how blood rheology and tissue anisotropy influence drug distribution, as well as comparing the effects of different stent geometries on drug flow patterns and penetration. The results demonstrate that rheology primarily affects local distributions in non-aerodynamic geometries, while anisotropic diffusion significantly alters tissue concentration profiles and penetration estimates compared to the isotropy assumption.