摘要
目的 对采用聚左旋乳酸 (PLLA)制备生物可降解性血管内支架 (BIS)进行研究 ,并评估其物理学、机械力学性能及其生物相容性。方法 先采用分子量为 10 0 0 0 0U的PLLA制作支架基杆 ,继而对支架基杆造孔和涂膜。支架固化成形后 ,对其主要的物理学和机械力学特性进行测试 ,并将2 2枚Z形BIS置入 11只实验犬的腹主动脉和髂动脉内 ,分期处死动物行病理学观察。结果 制备出螺旋形和Z形 2种型号支架 ,基杆直径为 0 1～ 0 6mm ,支架扩张后直径为 6～ 15mm、长度为 30～ 80mm ;支架径向支持力为 1 6～ 2 0kPa(1kPa=7 5mmHg)、扩张率 (压缩后支架直径与释放后完全展开支架直径的比值 )为 6 0～ 6 5 ,短缩率小于 8%～ 10 % ,表面积与扩张后表面积的比值为 0 16～ 0 18(小于 0 2 ) ,此种支架X线显示性差 ,透视下看不到。支架置入后 1周 ,显微镜下可见支架杆部有少许纤维组织和少量血小板沉着 ;4周 ,支架杆部大部分被新生内膜覆盖 ;8周时支架被内膜完全覆盖 ,未见明显内膜增生 ,管壁光整 ,管腔通畅。图像分析显示 8周后内膜生长趋势减弱。结论 此种BIS的物理学和机械力学特性可满足支架血管内置入的要求 ,特别是Z形BIS更适合于置入、释放。置入动物血管后的早期 ,支架可引起轻度炎性反应 ;8周时 ,支架被内?
Objective To investigate the preparation of a biodegradable intravascular stent (BIS) with poly-l-lactic acid (PLLA), and to evaluate its physical and mechanical properties, as well as its biocompatibility. Methods The study of this BIS was first prepared by PLLA with molecular weight of 100 000 unit as the strut, and then the micro-porous structure was fabricated and the film was coated at the struts. Following the solidified shaping of BIS, the primary physical and mechanical properties of the BIS were tested, and 22 zigzag type BISs were implanted into the aorta and iliac arteries of 11 canines, then they were euthanized according to a fixed timetable for histopathological assessment. Results Two types of BIS (spiral and zigzag) were prepared, and the strut diameter of the BIS was 0.1-0.6 mm, stent diameter of BIS was 6-15 mm, and stent length was 30-80 mm. Of this BIS, the radial strength was 1.6-2.0 kPa (1 kPa=7.5 mm Hg), the dilatable rate was 6.0-6.5, the shortening rate was smaller than 8%-10%, and the proportion of stent surface area to open surface area was 0.16-0.18 (<0.2). But the radio-opacity of the BIS was low and invisible on fluoroscopy. Microscopically, a few fibrous tissues and scarce deposition of blood platelets were evidenced on the struts of BIS within one week after implantation; At 4 wk, most struts were covered by neointima. At 8 wk, the stent was covered completely by neointima, the arterial wall became smooth, and the lumen kept patent, without significant intimal proliferation. After 8 wk, the tendency of neointimal thickening seemed to reduce on images analysis. Conclusion The physical and mechanical characteristics of this BIS may fulfill the desire for intravascular implantation, particularly the zigzag type BIS is more suitable to be deployed. After implanted into animal arteries, this BIS may induce mild inflammation in the early stage, and at 8 wk BIS may be covered completely by neointima, and no significant intimal proliferation is found.
出处
《中华放射学杂志》
CAS
CSCD
北大核心
2003年第11期1036-1042,共7页
Chinese Journal of Radiology
基金
国家自然科学基金资助项目 (3 0 2 70 416)
