血流导向支架对兔腹主动脉的影响

Effect of flow diverting stents on the abdominal aorta in rabbits

目的观察血流导向支架置入兔腹主动脉后3个月的影像学和病理学变化,评估支架对兔正常动脉的安全性。方法通过术前造影显示左肾动脉开口以远的腹主动脉,将金属覆盖率35%～45%的血流导向支架置入20只新西兰大白兔腹主动脉内。术后4周对兔均行静脉DSA检查,3个月时对所有兔行动脉DSA检查,并将其全部处死后行病理学检查。测量并比较不同时间点造影显示的支架置入处腹主动脉直径的变化,分析其新生内膜与支架局部金属覆盖率的关系。结果支架置入前、置入后即刻、4周和3个月腹主动脉平均直径分别为(3.47±0.44)、(3.65±0.40)、(3.57±0.36)和(3.51±0.30)mm。不同时间点间比较,差异有统计学意义(P=0.009)。新生内膜均完全覆盖支架网丝,这些新生内膜平均厚度为(95±42)μm,主要由平滑肌细胞、胶原纤维及少量巨噬细胞组成。新生内膜厚度与支架局部金属覆盖率呈正相关(r=0.523,P=0.001)。结论血流导向支架置入术后3个月,兔腹主动脉轻微内膜增厚。血流导向支架置人对兔正常血管是安全的。

Objectives To observe the radiological and pathological changes of flow diverting sent implanting into abdominal aortae of rabbits at 3 months and to evaluate the safety of stents for normal arteries of rabbits. Methods The abdominal aorta beyond the left renal artery opening was showed via preoperative angiogTaphy. The flow diverting stents with metal coverage of 35% to 45% were implanted into the abdominal aortae of 20 New Zealand white rabbits. Intravenous digital subtraction angiography was performed at 4 weeks after the procedure. Arterial digital subtraction angiography was performed for all the animals at 3 months and they were sacrificed for histopathologiea] examination. The angiography showed that the diameter changes of abdominal aortae on the stenting sites at different time points were measured and compared. The relationship between the neointima and the metal coverage of local stent were analyzed. Results The mean diameter of the abdominal aortae before stenting, immediately after stenting, at 4weeks, and at 3 months were 3.47 ±0.44 mm, 3.65 ±0.40 mm, 3.57 ±0.36 mm, and 3.51 ±0. 30 ram, respectively. There were significant differences among the different time points （ P = 0. 009 ）. The neointima fully covered the stents with a mean thickness of 95± 42μm. They were predominantly composed of smooth muscle cells, collagen fibers, and a small amount of maerophages. The neointimal thickness was positively correlated with the local coverage of the metal stents （ r = 0. 523 ; P = 0. 001 ）. Conclusion Three months after the implantation of flow diverting stents, the abdominal aorta intima thickened slightly, and the stents were safety for normal arteries of rabbits.