生物可吸收左心耳封堵器的研制和动物实验评价

Atrial fibrillation is the most common sustained cardiac arrhythmia and it is associated with an increased stroke risk, due mainly to cardiac embolism from the left atrial appendage (LAA). Metal devices have been used successfully for the occlusion of the LAA to prevent embolic events, but concerns remain regarding risk for perforation. The ideal occluder may be a temporary scaffold which can be gradually absorbed in vivo and replaced by ‘‘native’’ tissue. a bioresorbable (BD) LAA occluder could be an effective alternative, as it potentially reduces the long-term risks. The purpose of this study is to develop a LAA occluder made of bioabsorbable materials. The BD occluder consists of a polydioxanone framework and poly-L-lactic acid fabrics. This study is designed to evaluate the mechanical properties and biocompatibility of the occluder in vitro, and the feasibility, effectiveness and safety of the BD occluder for transcatheter closure of LAA in an canine model. The clinical application of this novel occluder may provide an alternative to permanent metal device implants in patients with atrial fibrillation for the prevention of embolic events originating from the LAA.

房颤是最常见的持续心律失常，房颤时左心耳易形成血栓并可脱落导致脑栓塞。金属封堵器已被成功地用于闭合左心耳以预防栓塞事件，但存在迟发心脏穿孔的隐患。理想的封堵器应在完成“桥梁”作用后可被机体降解吸收，由自身组织替代,消除封堵器永久存留体内可能造成的并发症。本课题设计制作了由可降解高分子聚合材料聚对二氧环己酮作为骨架和聚左旋乳酸无纺布生物作为膜的可吸收左心耳封堵器，体外实验评价可吸收封堵器的机械力学特性和生物相容性，并完成封堵器的动物实验，评价经导管植入左心耳可吸收封堵器的可行性、有效性和安全性。研究结果将为可吸收左心耳封堵器的临床应用奠定基础。

研究背景：房颤时左心耳易形成血栓并可脱落导致脑栓塞。金属封堵器已被成功地用于闭合左心耳以预防栓塞事件，但存在磨损周围结构和迟发心脏穿孔等隐患。理想的封堵器应在完成“桥梁”作用后由自身组织替代,消除封堵器永久存留体内可能造成的并发症。.研究目的：设计和制作生物可吸收左心耳封堵器，对其相关性能进行测试，并进行动物实验，评价经导管植入可吸收左心耳封堵器的可行性、有效性和安全性。.研究内容：采用可降解高分子聚合材料聚对二氧环己酮(polydioxanone，PDO)丝和聚左旋乳酸(Poly-L-lactic acid，PLA)无纺布制作及镍钛合金丝制作生物全可吸收或部分可吸收左心耳封堵器。体外测试生物可吸收左心耳封堵器的机械力学性能。在X线引导下经导管将可吸收封堵器用于实验犬的左心耳封堵。术后进行随访，行组织病理学及扫描电镜检查等观察。.结果：1，单纯PDO丝编织制作的全可吸收封堵器在体外及在体动物实验均显示缺乏足够的支撑力以固定在左心耳内。2，由镍钛合金丝制作固定盘，PDO丝制作封堵盘和PLA制作阻隔膜的可吸收左心耳封堵器具有合适的机械力学性能。3，使用配套的输送系统经导管置入可吸收左心耳封堵器。16只犬成功植入可吸收左心耳封堵器。术后1个月时封堵器表面有少量新生组织，术后3个月时新生组织基本覆盖封堵器，与左房结构间有少量空隙，术后6个月新生内皮组织完整，与左房相容性好。术后3个月病理检查见封堵器表面完整内膜结构，可见未吸收的PDO和PLA材料，术后6个月病理检查见封堵器表面完整内膜结构，PDO结构大部分吸收，被纤维组织取代，12个月仅残留少量PDO。.结论：使用生物可吸收左心耳封堵器经导管封堵左心耳是一种可行、安全和有效的治疗手段。封堵器的可吸收材料在体内可逐渐被降解和吸收，并被纤维结缔组织替代。