两类补丁对S型旁路移植影响的血流动力学数值研究

在下肢动脉重建手术中常使用Miller袖口和Taylor补丁来提高术后血管的长期通畅率.相对于传统移植方式,基于旋动流理论建立的S型动脉旁路移植方法可在宿主动脉内产生螺旋流动,有效地减少吻合口内膜增生.为了研究Miller袖口和Taylor补丁在S型动脉旁路移植术中对吻合口流场的影响,通过数值方法建立原始S型、以及分别采用Miller袖口和Taylor补丁的3个S型旁路模型,对比分析其速度场、二次流、螺旋度、壁面切应力等参数.结果表明,原始模型具有紊乱的流场,急剧变化的壁面切应力,在足尖、吻合口相对的宿主动脉底部壁面的血流动力学特性容易引发内膜增生.Miller模型壁面切应力变化稳定,但足尖处的血流动力学较差,容易引起内膜增生.Taylor模型流场最为均匀,壁面切应力变化平缓,吻合口内的高螺旋度面积比例最高.比较而言,在S型股动脉旁路移植手术中采用Taylor补丁可以更好的改善吻合口的流场特性.

Numerical Study of the Influence of Two Kinds of Patches on Homodynamic in an S-type Arterial End-to-side Anastomosis

Miller cuff and Taylor patch are commonly used for lower-extremity arterial bypass grafting to improve the long-term patency after operation. Compare with conventional grafting, a S-type bypass graft, which can produce helical flow in the arterial, can reduce anastomosis intimal hyperplasia. In order to clarify the influence of Miller cuff and Taylor patch on the flow field in the S-type arterial anastomosis, three S-type grafting numerical models, one adopting Miller cuff, one adopting Taylor patch and one without them, were investigated in terms of the flow patterns, second flow, helicity, wall shear stresses and wall shear stresses gradients. The results showed that the primary model features with turbulent flow patterns, rapidly changes of wall shear stresses. The hemodynamics factors at toe and artery bottom are inclied to increase intimal hyperplasia. The wall shear stresses of Miller model change steadily but the hemodynamics at toe perform badly. Taylor model obtained more smooth on the flow patterns, larger high helicity zone and the most uniform wall shear stresses. Therefore, Taylor patch can improve the hemodynamics at the anastomosis in femoral artery bypass graft.