Relationship between topical shear stress ofend-to-side vascular anastomosis and pathogenesis of anastomotic intimal hyperplasia

为探讨腿部血管重建术后吻合口内膜增生的发病机制，测定端侧吻合口局部剪应力，并对吻合口内膜增生进行免疫组织学研究。研究了剪切应力对血管壁重构的影响。(A)端侧吻合局部剪应力测量兔双侧颈总动脉端侧吻合，在此吻合基础上制作UV透明单体模具进行血流显示，并采用光致变色染色法测量局部剪应力。在平均流动条件下，顶板和底板近端剪切应力为0 ~ 1 dyne/cm2。在峰值工况下，峰值速度点向底板移动，驻点向纵深移动。近端剪力为-1 ~ -3 dyne/cm2，远端剪力为16 ~ 29 dyne/cm2。(B)吻合口内膜增生的免疫组织学检查端侧吻合1周后，兔给予BrdU（5-溴-2′-脱氧尿苷）。用免疫组织学方法观察吻合口细胞分裂分布。帽/趾侧BrdU阳性细胞率流入时为10%，流出时为5 ~ 8%；盲袋和底侧在入水口为6 ~ 9%，在盲袋处为4 ~ 9%。地板末端（相对于脚趾）的峰值为16%，流出处为2%至4%。对趾的地板是内膜增生的首选部位之一，BrdU阳性细胞的比例很高。这一点也对应于流体力学中的流动滞止点。此时的剪切应力较低，在心脏周期中由正向负振荡。提示切应力振荡与底内膜增生的发病机制密切相关。

To investigate the pathogenesis of anastomotic intimal hyperplasia after vascular reconstructive surgery in legs, topical shear stress was measured in end-to -side anastomosis, and the immunohistological study was carried out on anastmotic intimal hyperplasia. The influence of shear stress on remodeling of vascular walls was examined.(A) Measurement of topical shear stress in end-to-side anastomosisEndo-to-side anastomosis was carried out between the bilateral common carotid arteries of a rabbit, Based on this anastomosis, a UV transparent monomer mold was made for flow visualization, and topical shear stress was measured by the photochromic dye method. In the mean flow condition, shear stress was 0 to 1 dyne/cm2 at the roof and proximal floor. In the peak flow condition, the peak velocity point shifted toward the floor and the stagnation point moved distally. Shear stress was -1 to -3 dyne/cm2 on the proximal floor and 16 to 29 dyne/cm2 on the distal floor.(B) Immunohistological examination of anastomotic intimal hyperplasiaOne week after end-to-side anastomosis, BrdU (5-bromo-2'-deoxyuridine) was administered to the rabbit. Distribution of cell division at the anastomosis was measured by the immunohistological method. The rate of BrdU positive cells on the hood/toe side was 10% at inflow and 5 to 8% at outflow; that of blind pouch and floor side was 6 to 9% at inflow and 4 to 9% in blind pouch. There was a peak of 16% at the end of floor (against toe) and 2 to 4% at outflow.Floor against toe, which is one of preferable sites of intimal hyperplasia, had a high rate of BrdU positive cells. This point also corresponded to the flow stagnation point in fluid dynamics. Shear stress at this point was low and oscillated from a positive to a negative value in the cardiac cycle. It is suggested that there is a close relationship between shear stress oscillation and thepathogenesis of floor intimal hyperplasia.