Caruso Maria Vittoria, Serra Raffaele, Perri Paolo, Buffone Gianluca, Caliò Francesco Giuseppe, DE Franciscis Stefano, Fragomeni Fragomeni
Department of Medical and Surgical Sciences, "Magna Graecia" University, Viale Europa, Catanzaro, Italy.
Department of Mechanical, Energetic and Management Engineering, University of Calabria, Rende, Italy.
Acta Bioeng Biomech. 2017;19(3):42-52.
Hemodynamics has a key role in atheropathogenesis. Indeed, atherosclerotic phenomena occur in vessels characterized by complex geometry and flow pattern, like the carotid bifurcation. Moreover, lifestyle is a significant risk factor. The aim of this study is to evaluate the hemodynamic effects due to two sedentary lifestyles - sitting and standing positions - in the carotid bifurcation in order to identify the worst condition and to investigate the atherosclerosis incidence.
The computational fluid dynamics (CFD) was chosen to carry out the analysis, in which in vivo non-invasive measurements were used as boundary conditions. Furthermore, to compare the two conditions, one patient-specific 3D model of a carotid bifurcation was reconstructed starting from computer tomography. Different mechanical indicators, correlated with atherosclerosis incidence, were calculated in addition to flow pattern and pressure distribution: the time average wall shear stress (TAWSS), the oscillatory shear index (OSI) and the relative residence time (RRT).
The results showed that the bulb and the external carotid artery emergence are the most probable regions in which atherosclerotic events could happen. Indeed, low velocity and WSS values, high OSI and, as a consequence, areas with chaotic-swirling flow, with stasis (high RRT), occur. Moreover, the sitting position is the worst condition: considering a cardiac cycle, TAWSS is less than 17.2% and OSI and RRT are greater than 17.5% and 21.2%, respectively.
This study suggests that if a person spends much time in the sitting position, a high risk of plaque formation and, consequently, of stenosis could happen.
血流动力学在动脉粥样硬化发病机制中起关键作用。事实上，动脉粥样硬化现象发生在具有复杂几何形状和血流模式的血管中，如颈动脉分叉处。此外，生活方式是一个重要的危险因素。本研究的目的是评估两种久坐生活方式——坐姿和站姿——对颈动脉分叉处血流动力学的影响，以确定最不利的情况并研究动脉粥样硬化的发病率。
选择计算流体动力学（CFD）进行分析，其中将体内非侵入性测量用作边界条件。此外，为了比较这两种情况，从计算机断层扫描开始重建了一个特定患者的颈动脉分叉三维模型。除了血流模式和压力分布外，还计算了与动脉粥样硬化发病率相关的不同力学指标：时间平均壁面剪应力（TAWSS）、振荡剪切指数（OSI）和相对停留时间（RRT）。
结果表明，球部和颈外动脉起始处是最有可能发生动脉粥样硬化事件的区域。事实上，出现了低速和低壁面剪应力值、高OSI，以及因此而产生的具有混沌涡流和停滞（高RRT）的区域。此外，坐姿是最不利的情况：考虑一个心动周期，TAWSS小于17.2%，OSI和RRT分别大于17.5%和21.2%。
本研究表明，如果一个人长时间处于坐姿，发生斑块形成以及因此发生狭窄的风险可能会很高。
Zotero 插件