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

为探讨小腿血管重建术后吻合口内膜增生的发病机制，对端侧吻合口局部切应力进行了测定，并对吻合口内膜增生进行了免疫组织学研究。采用兔双侧颈总动脉端侧吻合术，在此基础上制作紫外光透明单体模型进行血流显示，并用光致变色染料法测量局部剪应力。在平均流动条件下，顶板和近底板的剪应力为0~1dyne/cm2。在峰值流态下，峰值速度点向底板移动，驻点向远端移动。切应力近端为-1~-3达因/厘米~2，远端为16~29达因/厘米~2。(2)吻合口内膜增生的免疫组织学检查：端侧吻合后一周，给予BrdU(5-溴-2‘-脱氧尿苷)。免疫组织化学方法检测吻合口细胞分裂的分布。头、趾侧BrdU阳性细胞率流入时为10%，流出时为5%~8%，盲袋和底袋流入时为6%~9%，盲袋为4%~9%。BrdU阳性细胞率最高的部位是足底(对趾)16%，流出端2%~4%，是内膜增生的好发部位之一。这一点也与流体动力学中的流动停滞点相对应。此时的切应力很低，在心动周期中从正值振荡到负值。提示切应力振荡与基底动脉内膜增生的发生有密切关系。

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.