e0608 A nitinol occluder and a special delivery device for patent ductus arteriosus (PDA) closure

Background Nitrol occluders used for patent ductus arteriosus (PDA) may result in the stenosis of aortic and pulmonary artery when applied for smaller-sized children. The present study sought to design and develop an improved nitinol occluder and delivery system, and to verify the reliability and safety of this device on canine model of PDA. Methods A canine PDA model was established by anastomosing the internal jugular vein with the left pulmonary artery and the descending aorta in an end-to-side fashion. The effects of the novel nitinol occluder and its delivery system were followed-up for 6 months after the closure. Results PDA was successfully established in 10 out of 18 dogs and was treated by transcatheter occlusion with the novel nitinol occluder. Postoperative echocardiography showed that the location and shape of the occluder were normal without any regurgitation. Morphological examination revealed that the surface of the occluder was covered by a grey membrane-like tissue, which was identified as endothelial tissue by histological and electron microscopy examinations. There was no corrosion or severe inflammation on the nitinol wire surface. Three to six months after implantation, the occluder surface was completely endothelialized. Conclusion The novel nitinol occluder can be safely and effectively used for PDA closure, providing a high success rate with few complications, and good biocompatibility.