新型生物可降解腔静脉滤器的设计研究

Design of a new biodegradable vena cava filter

目的为了弥补目前临床应用中腔静脉滤器的缺陷,本研究设计了一款新型生物可降解型腔静脉滤器,在肺栓塞危险期度过后,滤器可缓慢的降解、吸收,避免了二次取出手术。方法该款滤器由手工制作,分为上下2部分:上方是由6条聚糖乳酸缝线组成的圆锥形过滤结构;下方是聚己内酯支架,支架展开后实现滤器在腔静脉的中央型固定。在超声引导下,将滤器植入到10只犬体内。术后6周手术取出滤器,下腔静脉和肺组织行病理学检查,观察滤器的降解情况、下腔静脉壁的改变以及滤器的降解产物是否导致医源性肺栓塞。结果本研究手工制作了生物可降解滤器,并成功的植入到10只杂交犬的下腔静脉。术后所有犬均正常存活,未发生异常生命体征及伤口感染,有1例犬出现双下肢肿胀。1滤器移位:所有滤器不同程度的向头端移位。有1例犬的植入滤器移位至右房室孔,剩余的9例,滤器移位小于2 cm,仍位于肾静脉以下。2标本肉眼所见:所有的可降解支架被下腔静脉内皮细胞覆盖,肉眼未见明显的变化。滤器植入处下腔静脉壁增厚,但未出现明显狭窄。8例犬可见可吸收缝线完全降解,1例犬出现可吸收缝线被下腔静脉壁包裹,管腔内可见增生的纤维结缔组织和少量炎性细胞浸润,导致约70%的管腔阻塞。3标本HE染色:9例犬下腔静脉均存在炎性反应,中膜和内膜增厚,肺组织切片未见到降解产物所致的肺动脉栓塞和肺动脉壁的炎性反应。结论本研究成功设计了一款生物可降解腔静脉滤器,并通过动物体内实验证实这款滤器具有良好的生物相容性和可降解性。

Objective To design a new biodegradable vena cava filter which could degrade and be absorbed slowly when the risk of pulmonary embolism（ PE） has passed. Methods The filters were handmade,and consisted of two parts： the cone was constructed of six polyglycolic acid polymer strands anchored to a handmade absorbable stent. Central inferior vena cava fixation were accomplished by the absorbable stent which was made of polycaprolactone. The filters were inserted to the inferior vena cava of ten dogs under ultrasound guidance. The filters were operatively retrieved at 6 weeks after implantation. The inferior vena cava were subsequently analyzed using light microscopy. The lungs were also removed to observe any pulmonary embolism caused by the degradation products of the biodegradable filter. Results Biodegradable vena cava filters were successfully made and implanted in 10 adult dogs. None of the 10 dogs had abnormal vital signs except one dog had lower extremity swelling. 1 Migration： All the filters migrated cephalad. One filter migrated into the right atrioventricular orifice,the other 9 filters migrated cephalad approximately 〈2 cm and remained below the renal vein ostia. 2 Naked-eye observation： In 8 of the 9 remaining filters,the absorbable strands had completely dissolved. One specimen had evidence of incorporated residual strands within the caval wall on gross examination,resulting in 70% stenosis of inferior vena cava. All of the biodegradable stents were embedded into the caval wall. The caval wall became thick at the level of filter placement without significant lumen narrowing. 3 Hematoxylin and eosin（ HE） staining： Intense inflammatory response with significant thickened intima and media was seen on HE staining. There was no evidence of pulmonary embolism or inflammatory response caused by degradation products of the absorbable strands. Conclusion We had designed a biodegradable inferior vena cava filter successfully,the biodegradability and biocompability had been proven through in vivo studies.