Elucidating the hemodynamic impact of residual stenosis post‐carotid artery stenting: A numerical study

Abstract Background Residual stenosis (RS) and hemodynamics demonstrate a significant correlation with postoperative in‐stent restenosis/thrombosis following carotid artery stenting (CAS). Purpose This study endeavors to elucidate the potential associations between RS and adverse postoperative hemodynamic factors. Methods This study utilized 46 patient‐specific carotid artery models post‐stenting, which were categorized into two groups based on the presence of RS: the normal group (N, n = 23) and the RS group (RS, n = 23). A comparative analysis was conducted to evaluate the discrepancies in geometry and adverse hemodynamic parameters, alongside investigating the potential correlation between hemodynamic and geometric parameters. Results The results reveal that a higher reflux flow volume is discernible in the RS group during low‐velocity phases of the cardiac cycle, concomitant with an augmented extent of areas exposed to oscillatory shear stress and extended particle residence time. Moreover, the adverse hemodynamic parameters exhibit a positive correlation with the degree of stent expansion, stent length in the common carotid artery (CCA), and the distal slope of the RS. Conclusion The distal slope and tortuosity of RS significantly influence the development of adverse hemodynamic conditions post‐stenting, exacerbating the hemodynamic environment near the stenosis. Interestingly, while an extended stent length in the internal carotid artery (ICA) region improves hemodynamics by reducing flow disturbance, a longer stent in the CCA significantly worsens these conditions. Hence, it is prudent to analyze the characteristics of the local lesion regions to optimize the strategy for stent implantation.