The importance of hemodynamics in stented vessels: A conceptual model for predicting restenosis using the time-averaged shear stress

The role of hemodynamics has often been overlooked in mathematical modeling aimed at replicating the restenosis process in stented arteries. This study seeks to address this gap by proposing a simplified model of tissue growth driven by the distribution of mean shear stress acting on the vessel wall. Using an iterative sequence of three-dimensional Computational Fluid Dynamics simulations applied to idealized coronary and femoral arteries, combined with a semi-empirical parametrization of endothelium growth, we demonstrated that the progression of restenosis can be effectively modeled and differentiated according to the intensity of time-varying flow velocities. Notably, restenosis develops faster in the femoral artery (approximately 17 days) compared to the coronary artery (approximately 25 days). The progress of tissue accretion is well defined by the evolution of time-averaged wall shear stress. After an initial decrease (triggering phase), significant increases in wall shear stress are observed during the main accretion phase until the shear stress eventually recovers a sufficient level to arrest the process (stabilization phase). This process, attributed to varying hemodynamic conditions within the stent, highlights the significant influence of local flow dynamics and emphasizes the necessity of accurately modeling both the anatomical structure and the corresponding hemodynamics of arteries when predicting in-stent restenosis.