Examination of hemodynamic environments of carotid stenosis with computational fluid dynamics

Abstract

IntroductionCarotid arterial geometry is an independent risk factor for carotid stenosis, in which hemodynamics, classically low oscillatory shear stress, is thought to be involved. However, there are few reports indicating quantitative analyses of hemodynamic environments in carotid stenosis. Thus, we are conducting a prospective clinical study with computational fluid dynamic techniques, and 454 cases of carotid stenosis have been registered to date. Here, we focused on unilateral stenotic cases among them and compared hemodynamic distributions between stenotic and non‐stenotic sides. We also examined hemodynamic distributions of carotid arteries after releasing stenosis by carotid endarterectomy.MethodsHemodynamic distributions were examined using ANSYS‐CFX software. Patient‐specific arterial geometries and inflow velocities were obtained from 3‐dimensional computed tomographic angiography and carotid ultrasound Doppler examinations, respectively.ResultsIn both the stenotic area and the area proximal to the stenotic area, hemodynamic metrics indicating the magnitude of time‐averaged wall shear stress (TAWSS) were significantly higher compared with the non‐stenotic side (p=0.0027 and 0.0007, rspectively), whereas WSS disturbance‐based metrics, i.e. oscillating shear index (OSI, p=0.0006 and 0.0008) and normalized transverse WSS (NtransWSS, p<0.0001 and p=0.0029), were rather lower. However, in the region distal to the stenotic area, OSI (p=0.0009) and NtransWSS (p=0.0021), but not TAWSS (p=0.4564), were significantly higher as compared with the same area of non‐stenotic side (Figure). WSS gradient on carotid bulb after carotid endarterectomy was significantly higher compared with controls (p=0.037), suggesting that the carotid arteries may primarily have geometric risks for stronger hemodynamic stress.ConclusionsThe results suggested that hemodynamic environments in carotid stenosis are more complex than previously thought. High WSS in the stenotic area and enhanced WSS disturbance downstream of the stenotic area may be associated with progression of stenosis and plaque rupture.Support or Funding InformationThis study is supported by the Grant‐in‐Aid for the Japanese National Hospital Organization Multi‐Center Clinical Research, AMED under Grant Number JP15gm0810006h0301, and JSPS KAKENHI Grant Number 15K10323.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.