三种覆膜支架治疗犬颈动脉囊状动脉瘤的实验研究

目的 探讨颅内覆膜支架治疗犬颈动脉囊状动脉瘤的可行性、安全性和疗效。方法 采用外科手术方法在20只犬中建立犬颈动脉囊状动脉瘤模型36枚，应用血管内技术放置聚氨酯膜支架(PUM-SSS)、可膨胀聚四氟乙烯膜支架(ePTFEM-SSS)、生物膜支架(BM-SSS)各12枚，支架置人后即刻及术后2、4和12周分别进行血管造影随访，并进行组织病理学检查及统计学分析。结果PUM-SSS、ePTFE-SSS和BM-SSS的完全开放率分别为25．O％、41．7％和91．7％，PuM-SSS、ePTFE-SSS分别和BM-SSS比较有非常显著的差异。组织学分析表明，支架置放后2周BM-SSS内皮化开始，12周3种支架内皮化基本完成；所有治疗的动脉瘤瘤腔内均见血栓形成，载瘤动脉内膜增厚；支架附着处血管见不同程度的细胞变性；金属支架未见到腐蚀。结论 覆膜支架是一种新的简单、安全、有效的治疗犬颈动脉囊状动脉瘤的方法。生物膜支架具有更好的血液相容性和血管开通率，是一种较理想的覆膜支架。

Treatment of experimental saccular aneurysms of carotid arteries with three kinds of covered stents in canine models

Objective To assess the effectiveness and safety and biocompatibility of balloon-expanding stainless steel stents (SSS) covered with polyurethane membrane (PUM), expanding poly teflon ester membrane(ePTFEM)and biomembrane (BM) in the treatment of experimental saccular aneurysms of carotid arteries in canine models.Methods 36 experimental saccular aneurysms of carotid arteries in 20 canines were created successfully by sugery. Experimental aneurysms were treated with covered stents including twelve PUM-SSS, twelve ePTFEM-SSS and twelve BM-SSS for each twelve canines repectively. They were placed endovascularly in the common carotid arteries covering the orifice of aneurysms. Follow up angiography was performed immediately after the procedure and 2, 4 and 12 weeks afterwards under the control of conventional anticoagulation. The animals were then sacrificed for histopathologic and statistical investigation. Results 36 stents were placed successfully in the target arteries. The complete patency rates of PUM-SSS, ePTFEM-SSS and BM-SSS were 25.0%, 41.7% and 91.7% respectively. Histological analysis indicated that all treated aneurysmal pouches were filled with thrombus. Stent wires were found to be located deep within the vessel wall and encased by extension of the tunica intima. Endothelialization of BM-SSS groups already began at the 2nd week which was earlier than that of PUM-SSS and ePTFEM-SSS. Various degrees of degenerative cells were seen under the transmission electron microscopy without surface erosion of stents. Conclusion Placement of covered stent endovascularly is expedient, safe, and effective. BM-SSS provides the best mechanical behavior, physiochemical stability, anticoagulative ability and biocompatibility.