Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China.
J Biomech. 2013 Sep 27;46(14):2388-93. doi: 10.1016/j.jbiomech.2013.07.032. Epub 2013 Jul 30.
We hypothesize that after implantation the much elevated water filtration rate of venous grafts may cause aggravated concentration polarization of low density lipoproteins (LDLs), in turn lead to the accelerated atherogenesis of the grafts. To verify the hypothesis, we numerically simulated the transport of LDLs in various models of arterial bypasses with different grafts (veins or arteries) and geometrical configurations. The results showed that the venous grafts might endure abnormally high lipid infiltration/accumulation within the vessel wall due to severely elevated luminal surface LDL concentration. When compared to the conventional bypass models, the S-type bypass had the lowest luminal surface LDL concentration along its host artery floor, but the highest degree of risk to develop atherosclerotic lesions in its venous graft. Among the three conventional bypass models, the one with 30° anastomosis had the lowest risk to develop atherosclerosis in the venous graft. In conclusion, when compared with the bypass models with arterial grafts, the venous bypass models had rather high levels of LDL concentration polarization (cw) in the vein grafts, especially at the early stages of implantation. This might result in high infiltration/accumulation of LDLs within the walls of the venous grafts, leading to a fast genesis/development of atherosclerosis there.
我们假设，静脉移植物的水过滤率升高可能会导致低密度脂蛋白（LDL）的浓度极化加剧，从而加速移植物的动脉粥样硬化形成。为了验证这一假设，我们在不同的旁路模型中对 LDL 的传输进行了数值模拟，这些旁路模型使用了不同的移植物（静脉或动脉）和几何结构。结果表明，静脉移植物可能会因为腔内 LDL 浓度的异常升高而在血管壁内承受异常高的脂质浸润/积累。与传统旁路模型相比，S 型旁路在其宿主动脉底部的腔内 LDL 浓度最低，但在静脉移植物中发生动脉粥样硬化病变的风险最高。在三种传统旁路模型中，30°吻合的旁路模型在静脉移植物中发生动脉粥样硬化的风险最低。总之，与使用动脉移植物的旁路模型相比，静脉旁路模型在静脉移植物中的 LDL 浓度极化（cw）水平相当高，尤其是在植入的早期阶段。这可能导致 LDL 在静脉移植物壁内的浸润/积累增加，从而导致那里的动脉粥样硬化快速发生/发展。
