Effects of stent shape on focal hemodynamics in intracranial atherosclerotic stenosis: A simulation study with computational fluid dynamics modeling

Abstract

Background and aimsThe shape of a stent could influence focal hemodynamics and subsequently plaque growth or in-stent restenosis in intracranial atherosclerotic stenosis (ICAS). In this preliminary study, we aim to investigate the associations between stent shapes and focal hemodynamics in ICAS, using computational fluid dynamics (CFD) simulations with manually manipulated stents of different shapes.MethodsWe built an idealized artery model, and reconstructed four patient-specific models of ICAS. In each model, three variations of stent geometry (i.e., enlarged, inner-narrowed, and outer-narrowed) were developed. We performed static CFD simulation on the idealized model and three patient-specific models, and transient CFD simulation of three cardiac cycles on one patient-specific model. Pressure, wall shear stress (WSS), and low-density lipoprotein (LDL) filtration rate were quantified in the CFD models, and compared between models with an inner- or outer-narrowed stent vs. an enlarged stent. The absolute difference in each hemodynamic parameter was obtained by subtracting values from two models; a normalized difference (ND) was calculated as the ratio of the absolute difference and the value in the enlarged stent model, both area-averaged throughout the arterial wall.ResultsThe differences in focal pressure in models with different stent geometry were negligible (ND<1% for all cases). However, there were significant differences in the WSS and LDL filtration rate with different stent geometry, with ND >20% in a static model. Observable differences in WSS and LDL filtration rate mainly appeared in area adjacent to and immediately distal to the stent. In the transient simulation, the LDL filtration rate had milder temporal fluctuations than WSS.ConclusionsThe stent geometry might influence the focal WSS and LDL filtration rate in ICAS, with negligible effect on pressure. Future studies are warranted to verify the relevance of the changes in these hemodynamic parameters in governing plaque growth and possibly in-stent restenosis in ICAS.

Computational modeling of low‐density lipoprotein accumulation at the carotid artery bifurcation after stenting

“…The absence of follow‐up data has limited the study for any direct comparison between the predicted LDL accumulation and restenosis, especially the LDL concentration values around the stent strut. A few previous articles simulated the LDL transport in the other parts of the stented artery, such as Gai et al, 68 Liu et al, 69 and Escuer et al 70 However, none of the articles proposed the LDL concentration values in the stented area. Nonetheless, the similarity of the three articles is that the normalized LDL concentration around the stent struts is way higher than in the other endothelium wall, which is also predicted in the present study.…”

Comparative analysis of RADAR vs. conventional techniques for AVF maturation in patients with blood viscosity and vessel elasticity-related diseases through fluid-structure interaction modeling: Anemia, hypertension, and diabetes

“…However, due to the complexity of viscosity-dependent blood behavior associated with anemia, further studies are needed to better understand its influence on AVF maturation. Additionally, diseases related to blood properties, such as low-density lipoprotein, could significantly affect surgical outcomes [ 77 ] and should be considered in future research. Despite the presence of these co-morbidities, the RADAR technique has demonstrated its efficacy in providing more favorable hemodynamic alterations for AVF maturation.…”

The Role of the Low-Density Lipoprotein/High-Density Lipoprotein Cholesterol Ratio as an Atherogenic Risk Factor in Young Adults with Ischemic Stroke: A Case—Control Study

“…In intracranial arteries, the local geometry of arteries and stents can significantly influence the LDL filtration rate. The roles of anatomic/geometric variation, hemodynamic parameters and dyslipidemia, as well as their interaction, in the development of intracranial artery disease and stroke deserve further exploration [ 15 ]. This study examined the TC/HDL-C ratio, known to be an atherogenic risk factor in coronary heart disease for young ischemic stroke patients, due to similar pathophysiological mechanisms.…”