左盘无铆型卵圆孔未闭封堵器的实验研究

A novel left-disk with no-hub occluder for percutaneous closure of patent foramen ovale: an experimental study in dogs

目的评价新型左盘无铆型卵圆孔未闭(PFO)封堵器经导管植入的可行性、安全性和有效性,为临床研究提供实验依据。方法取20只健康成年犬,经皮房间隔卵圆窝穿刺、球囊扩张术建立犬PFO模型。将20只犬分为实验组(植入左盘无铆型PFO封堵器)和对照组(植入双铆型PFO封堵器),每组10只。术后1、2、3和6个月分别通过对心脏大体标本、光镜、电镜检查,评价新型封堵器植入后内皮化过程,观察有无残余分流、血栓形成等并发症。结果 20只犬均成功进行了房间隔卵圆窝穿刺和球囊扩张术,右房造影可见对比剂由右房进入左房,成功建立了犬PFO模型。实验组左盘无铆型PFO封堵器植入成功率为10/10,对照组成功率为9/10。19只犬术后1、2、3和6个月分别取出心脏大体标本进行观察,结果显示两组PFO封堵器的位置均无移位,无合金丝断裂,封堵器表面未见血栓形成和赘生物附着。术后1个月实验组封堵器双侧盘面可见薄层透亮组织覆盖,病理和电镜检查证实为纤维组织和内皮细胞,盘面无血栓和赘生物。至术后6个月,封堵器表面组织逐渐增厚,封堵器边缘与周围心脏组织融合。术后1个月对照组封堵器左侧盘面除中央铆钉外可见纤维组织和内皮细胞覆盖,术后6个月1只犬的左盘铆钉上仍无组织覆盖。结论新型左盘无铆型PFO封堵器设计科学,与双铆型PFO封堵器相比较,完全内皮化的时间缩短,可有效的封堵PFO,具有良好的临床应用前景。

Objective To evaluate the feasibility, efficacy, and safety of transcatheter implantation of a novel left-disk with no-hub occluder in treating patent foramen ovale （PFO） in order to provide preliminary experimental clues for further clinical research and application of this device. Methods A total of 20 healthy adult dogs were selected for this study. By percutaneous puncture of the atrial septa and balloon dilation of the fossa ovalis the PFO model was established. The 20 dogs with PFO model were randomly and equally divided into study group （n = 10） and control group （n = 10）. PFO occluder having a left disk with no hub was implanted in the dogs of study group, while implantation of double-hub occluder was carried out in the dogs of control group. Every two dogs from the two groups were sacrificed each time at 1, 2, and 3 months after device implantation, and the remaining dogs of the two groups were sacrificed at 6 months after the procedure. The tissue samples were collected and sent for gross examination as well as optical and electronic microscopy study. The state of endothelialization after implantation of the new type occluder was evaluated, and the occurrence of complications such as residual shunt and superficial thrombus formation was recorded. The results were analyzed. Results By percutaneous puncture of the atrial septa and balloon dilation of the fossa ovalis, the PFO model was successfully established in all dogs. Angiography of the right atrium showed that the contrast medium flowed from the right atrium into the left atrium. Implantation of the PFO oecluder having a left disk with no hub was successfully completed in all 10 dogs （100%） of the study group, whileimplantation of the double-hub occluder was successfully carried out in 9 dogs （90%） of the control group. The 19 dogs were sacrificed at 1, 2, 3 and 6 months after device implantation. Thegross examination of the hearts showed that neither dislocation of PFO occluder nor fracture of the nitinol wire occurred in both groups. No thrombus formation or vegetation on the surface of the occluder was observed. One month after the procedure, the surface of the bilateral disks of the occluder in the study group was covered with thin layer transparent tissue. Histological and electronic microscopy study revealed that the thin layer transparent tissue on the surface was composed of fibrous tissue and endothelial cells. There was no thrombosis or vegetation on the disk surface. Six months after the treatment, the superficial tissue of the occluder became gradually thickened, and the edge of the occluder was fused with the neighboring heart tissue. One month after the treatment in control group, the surface of the left disk of the occluder, except the central hub, was covered mainly with fibrous tissue and endothelial cells, but in one dog the left disk hub was still not covered with tissue at six months after the implantation. Conclusion The design of the new PFO oecluder having a left-disk with no hub is very scientific. Compared with double-hub occluder, the new device can shorten the time of complete endothelialization, effectively occlude the PFO, and has promising prospect in clinical application.（J Intervent Radiol, 2012, 21 ： 833-838）