title: Experimental study of the Spider™ patent foramen ovale occluder.
abstract: OBJECTIVE
  To evaluate the feasibility, safety and efficacy of the Spider™ patent foramen ovale (PFO) occluder for the treatment of PFOs in an animal model.
  
  
  METHODS
  The foramen ovale was punctured to establish an animal model of a PFO. Under fluoroscopic guidance, the PFO was occluded with the Spider PFO occluder. The piglets were electively sacrificed at months 1, 2, 3, 6 and 12 after occlusion for macroscopic and microscopic examination.
  
  
  RESULTS
  PFOs were successfully created and occluded percutaneously in 20 piglets. All piglets recovered from the procedure in good condition and completed follow-up. Macroscopic examination of all hearts showed complete closure of the PFO. The position of each device was correct. All devices were completely covered and embedded in pale and smooth tissue. There was no evidence of interference with adjacent structures of the heart or valves. The occluder was partially covered by endocardium after 1 month, almost completely covered by fresh endocardium after 3 months, and embedded within thick fibrous tissues and fresh vessels after 6 months. The tissue covering both occluder discs demonstrated some infiltration of inflammatory cells, including patches of lymphocyte aggregation. This inflammatory cell reaction diminished with increasing distance from the device. Furthermore, the number of inflammatory cells decreased gradually during follow-up and eventually, at 6-month follow-up, the inflammatory response was no longer visible. The 12-month histological findings did not differ from the 6-month findings.
  
  
  CONCLUSIONS
  Transcatheter closure of PFO with the Spider PFO occluder is effective and safe in an animal model. These results support further investigation of this device in animals and, if the results are confirmed, in human clinical trials.
authors.affiliation: Department of Cardiology, Guangdong General Hospital and Guangdong Cardiovascular Institute, Guangzhou, China. yszcj74@163.com
authors.forename: Caojin
authors.initials: C
authors.lastname: Zhang
authors.forename: Yigao
authors.initials: Y
authors.lastname: Huang
authors.forename: Stefan
authors.initials: S
authors.lastname: Bertog
authors.forename: Tao
authors.initials: T
authors.lastname: Huang
authors.forename: Wenhui
authors.initials: W
authors.lastname: Huang
authors.forename: Xinsheng
authors.initials: X
authors.lastname: Huang
authors.forename: Donglan
authors.initials: D
authors.lastname: Luo
mesh_terms: D000818:Animals; D013504:Cardiovascular Surgical Procedures / Q000295:instrumentation* / Q000379:methods; D005240:Feasibility Studies; D005500:Follow-Up Studies; D054092:Foramen Ovale, Patent / Q000209:etiology / Q000601:surgery*; D023421:Models, Animal; D011677:Punctures / Q000009:adverse effects; D055989:Septal Occluder Device / Q000009:adverse effects; D013552:Swine; D013556:Swine, Miniature; D016896:Treatment Outcome