Lu Sen, Zhang Shusheng
Institute of Thermal Science of Technology, Shandong University, Jinan, China.
Biorheology. 2019;56(4):253-263. doi: 10.3233/BIR-190215.
Atherosclerotic lesions develop preferentially at certain sites in the human arterial system, such as the inner wall of curved segments and the outer wall of bifurcations. Local wall shear stress (WSS) and concentration of low density lipoprotein (LDL) have been identified as two important factors contributing to these lesions.
To determine if a connection exists between arterial curvature and the formation of atherosclerosis.
A set of 3-D vessel models with different bend angles was constructed. By comparing blood flow, WSS, and LDL aggregation, the influence of bend curvature on atherosclerotic lesions was assessed.
Upon increasing arterial bending, low WSS regions were formed at the outer wall of the junction between straight and curved segments, as well as the inner wall of curved segments. However, high LDL concentrations only appeared at the inner wall of the bend region. A connection between secondary flow and LDL concentration was observed; high LDL concentration regions had stronger secondary flow. Higher water infiltration velocity could enhance LDL aggregation, while blood non-Newtonian properties, by easing secondary flow, diminished its aggregation.
Under the same flow rate, a larger bend angle increased flow resistance, lowered WSS, and increased LDL surface concentrations, thus indicating an increased risk of atherosclerosis.
动脉粥样硬化病变优先在人类动脉系统的某些部位发展，如弯曲段的内壁和分叉处的外壁。局部壁面剪应力（WSS）和低密度脂蛋白（LDL）浓度已被确定为促成这些病变的两个重要因素。
确定动脉曲率与动脉粥样硬化形成之间是否存在关联。
构建一组具有不同弯曲角度的三维血管模型。通过比较血流、WSS和LDL聚集情况，评估弯曲曲率对动脉粥样硬化病变的影响。
随着动脉弯曲度增加，在直段与弯曲段交界处的外壁以及弯曲段的内壁形成了低WSS区域。然而，高LDL浓度仅出现在弯曲区域的内壁。观察到二次流与LDL浓度之间存在关联；高LDL浓度区域的二次流更强。较高的水渗透速度可增强LDL聚集，而血液的非牛顿特性通过减轻二次流来减少其聚集。
在相同流速下，更大的弯曲角度会增加流动阻力，降低WSS，并增加LDL表面浓度，从而表明动脉粥样硬化风险增加。
