title: Temporary self-expanding cardia stents for the treatment of achalasia: an experimental study in dogs.
abstract: BACKGROUND
  To assess the performance, efficiency and optimal removal time of a newly designed temporary retrievable cardia covered stent (TRC-CS) for the treatment of achalasia in a dog model.
  
  
  METHODS
  Eighty-four achalasia-like dog models were randomly divided into seven groups of 12, a control group (CG; no stent insertion), a standard stent control group (NSCG, standard esophageal stent) and five treatment groups (TG, TRC-CS). Stents were retrieved at 4 days after insertion in the NSCG and at 4 days(4 d-TG), 2 weeks(2 w-TG), 1 month(1 m-TG), 3 months(3 m-TG), and 6 months(6 m-TG) in the TGs. Lower esophageal sphincter pressure (LESP) and a timed barium esophagram were assessed before stent insertion, after stent retrieval, and at 1-week, 1-, 3- and 6-month follow-up. Three dogs in NSCG and 4 d-TG were sacrificed for histological examination at each follow-up to investigate the inflammatory reaction after stent insertion.
  
  
  RESULTS
  Stent insertion/removal and the follow-up procedures were well tolerated. At 6-month follow-up, the 2 w-TG and 1 m-TG demonstrated an acceptable stent migration (n = 2 in both TGs vs n = 4 in NSCG, n = 4 in 3 m-TG, and n = 6 in 6 m-TG), improved LESP compared to after benzyl-dimethyltetradecylammonium chloride (BAC) injection (P < 0.05), and improved timed barium height (P = 0.0144 and 0.0409). Mouse -proliferating cell nuclear antigen (PCNA) and α-smooth muscle actin staining revealed no inflammatory reaction difference between the NSCG and 4 d-TG at each follow-up.
  
  
  CONCLUSIONS
  The TRC-CS was effective in the treatment of achalasia in a dog model. LESP measurements, timed barium esophagram studies suggest an optimal stent retrieval time of between 2 w∼1 m.
authors.affiliation: Department of Radiology, The Sixth Affiliated People's Hospital, Medical School of Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Y-Q
authors.initials: YQ
authors.lastname: Zhu
authors.forename: Y-S
authors.initials: YS
authors.lastname: Cheng
authors.forename: M-H
authors.initials: MH
authors.lastname: Li
authors.forename: J-G
authors.initials: JG
authors.lastname: Zhao
authors.forename: F
authors.initials: F
authors.lastname: Li
authors.forename: N-W
authors.initials: NW
authors.lastname: Chen
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D001464:Barium; D004285:Dogs; D004931:Esophageal Achalasia / Q000601:surgery*; D049630:Esophageal Sphincter, Lower / Q000502:physiology; D004947:Esophagus / Q000000981:diagnostic imaging; D005260:Female; D008297:Male; D008365:Manometry; D016612:Paraffin Embedding; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D011859:Radiography; D015607:Stents
chemical_list: D000199:Actins; D018809:Proliferating Cell Nuclear Antigen; D001464:Barium