新型^(32)P支架产生“边缘效应”的探讨

The effect of a new kind of^(32) P radioactive stents on the edge stenosis

目的 观察一种新型^(32)P支架是否形成“边缘效应”。方法 32只不锈钢支架,其中16只经Ni-P复合镀法使其载带放射性^(32)P,平均活度为(13.69±5.55)kBq,另外16只以同法镀无放射性的^(31)P作为对照,将2种支架配对并随机安排,分别置入16只新西兰大白兔(A组8只,直接置入支架;B组8只,球囊损伤血管内皮后再置入支架)的两侧髂动脉中。术后30 d,通过血管造影和组织图像分析,评价支架边缘部位的管腔变化及血管内膜的增生程度。结果 A组^(32)P支架和对照支架边缘部位的血管造影、组织图像分析结果差异均无显著性(P均>0.05)。B组^(32)P支架边缘部位的血管内径、管腔面积明显小于对照支架,而血管狭窄程度、内膜面积则大于对照支架(P<0.05,P<0.01)。结论 放射性支架“边缘效应”的形成是血管损伤和支架边缘活度显著降低共同作用的结果。

Objective To evaluate whether the implantation of a new kind of 32 P radioactive stents causes edge stenosis in rabbits. Methods Sixteen 32P-β-emitting stents [average activity (13.69 ± 5.55) kBq] made by chemical electroplating, pared with 16 nonradioactive stents, were placed separately, each in the right or left iliac artery of 2 rabbit groups of 8, group A and group B. The rabbits of group B underwent a preparative intravas-cular balloon dilatation injury in the target arteries. Animals were sacrificed after 30 d and histological analysis and angiography were performed. Results There were no significent difference in the results of angiography and histological analysis between radioactive stents and control stents in group A. In group B, the lumen diameter, lumen area of the artery at the edges of radioactive steins were smaller than that of control stent group; but the percentages of edge stenosis, neointimal area were greater than that of control stent group ( P < 0.05, P < 0.01). Conclusion The formation of edge restenosis is caused by the combination of stent injury and radioactivity falling off at the edge of the stent; and to lessen the artery injury at the edge of stent and/or to increase the radioactivity may prevent the edge stenosis.