外支架通透性对移植血管再狭窄的影响

Effect of external stents with different permeability on vein graft restenosis

目的:研究不同通透性外支架对抑制移植血管再狭窄作用的差别,探讨外支架的结构特性.方法:选取24只健康成年犬,游离适当长度的股静脉并与相应动脉进行替换移植,根据材料的不同(厚0.5mm的涤纶补片及厚0.4mm和0.15mm的聚乙醇酸(PGA)补片)制成3种不同通透性的非限制性外支架,将其包绕于移植血管,分组进行对比研究,术后4,6wk分别切取标本对比移植血管管壁厚度变化及细胞增殖情况.结果:术后4,6wk,0.15mm及0.4mm PGA外支架组相应管壁的内膜厚度4wk:(45±5)mm,(43±11)mm;6wk:(77±6)mm,(71±9)mm.中膜厚度4wk:(48±8)mm,(42±7)mm;6wk:(71±4mm),(53±6)mm,显著低于相应对照组内膜厚度4wk:(89±8)mm;6wk:(145±9)mm;中膜厚度4wk:(83±7)mm;6wk:(123±12)mm(P<0.05).各支架组增殖细胞核抗原(PCNA)阳性细胞数各阶段均低于对照组;PGA外支架组PCNA阳性细胞数低于涤纶外支架组.结论:大通透性的非限制性可降解PGA外支架能在血管移植术后显著减轻血管壁增厚.

AIM： To investigate the effect of external stents with different permeability on dog vein graft thickening at 4 and 6 weeks. METHODS： Interposition grafting of bilateral femoral vein to corresponding aretery was performed in dogs （ 15 - 18 kg, n =24）. Three types of loose-fitting stents with different permeability [0.5 nun Dacron patch, 0.4 mm and 0.15 mm polyglyeolie acid（ PGA）patches] were placed externally around the vein graft on both sides, and a group of veins remained unstented to serve as controls. Four and 6 weeks after surgery, the animals were killed and vein grafts were assessed under the aid of computer for mor- phological changes. RESULTS： At 4 and 6 weeks, the vein grafts fitted with the 0. 15 mmPGA or 0.40 mmPGA stent were demonstrated to hare a statistically signifcant decrease in neointimal thickness[ （4 weeks： （45 ±5）mm, （43±11）mm; 6 weeks： （77 ±6） mm, （71±9）mm] compared with the unstented control grafts[4 weeks： （89 ±8） mm; 6 weeks： （145 ± 10） mm], and also in medial thickenss [ （4 weeks： （48 ±8） mm, （42 ＋7）mm; 6 weeks： （71 ±4） mm, （53 ±6） mm] compared with unsheathed control grafts[4 weeks： （83 ±7） mm; 6 weeks： （123 ±12）mm]. The Dacron stented grafts showed a statistically signifcant reduction in media thickness compared with control grafts, but not in neointimal thickness compared with unstented grafts. The positivity rate of proliferating cell nuclear antigen （PCNA） among external stent group was statistically signifcantly lower than that of the control grafts, and rate of PGA external stent was low when compared with the Dacron group. CONCLUSION： The loose-fitting biodegradable external stent with well permeability reduces dog vein graft thickening at 4 and 6 weeks.