title: Chronic in-vivo experience with an endoscopically delivered and retrieved duodenal-jejunal bypass sleeve in a porcine model.
abstract: BACKGROUND
  The role of duodenal bypass as an underlying mechanism of action in gastric bypass surgery has received considerable attention. We report the initial feasibility study of a totally endoscopically delivered and retrieved duodenal-jejunal bypass sleeve in a chronic porcine model.
  
  
  METHODS
  The implant consists of a 60-cm fluoropolymer sleeve that is endoscopically deployed via a coaxial catheter system into the jejunum and fixed in the proximal duodenum with a Nitinol anchor. The system creates a proximal biliopancreatic diversion. Six female Yorkshire pigs were endoscopically implanted; all survived. Four animals (group 1) were slated to survive 90 days, two animals (group 2) for 120 days, and three animals (group 3) underwent sham endoscopy and were survived 120 days. Animals were fed standard dry pig chow 0.5 kg three times daily. Data points included daily general health, weekly weight, serum blood tests (complete blood count, amylase, lipase, liver function tests), and monthly evaluation of anchor/sleeve position/patency by fluoroscopy and endoscopy. Following the in-vivo period, the devices were endoscopically removed and the animals were sacrificed. Duodenal and jejunal tissue samples were assessed histologically.
  
  
  RESULTS
  All six test animals were implanted and explanted without significant adverse events. In group 1, the first animal had no device-related issues. The second animal had a pivoted anchor requiring repositioning at day 63. That animal had no further difficulties. The third animal had an incidental partial rotation of the anchor noted at the 90 day explantation. The fourth animal was incidentally implanted with a crossover of the anchor struts, which was endoscopically corrected on day 14. However, on day 20 the animal had persistent vomiting, and the device was explanted. Both group 2 animals survived 120 days. One animal had a partially rotated anchor but was asymptomatic. The average weight gain between test and sham groups was 0.23 kg/day and 0.42 kg/day, respectively (p = 0.01).
  
  
  CONCLUSIONS
  A totally endoscopic and reversible bypass of the duodenum and proximal jejunum has been achieved for 90-120 days. Initial experience suggests patency of the sleeve and acceptable tissue response. Reduced weight gain in the test animals suggests device efficacy. Further investigation is warranted.
authors.affiliation: Department of Surgery, Tufts New England Medical Center, 800 Washington Street, Box 900, Boston, Massachusetts 02111, USA. mtarnoff@tufts-nemc.org
authors.forename: M
authors.initials: M
authors.lastname: Tarnoff
authors.forename: S
authors.initials: S
authors.lastname: Shikora
authors.forename: A
authors.initials: A
authors.lastname: Lembo
authors.forename: K
authors.initials: K
authors.lastname: Gersin
mesh_terms: D000497:Alloys; D000818:Animals; D020878:Device Removal; D004386:Duodenum / Q000601:surgery*; D016099:Endoscopy, Gastrointestinal; D005240:Feasibility Studies; D005260:Female; D005471:Fluoroscopy; D015390:Gastric Bypass / Q000295:instrumentation* / Q000379:methods*; D007583:Jejunum / Q000601:surgery*; D023421:Models, Animal; D011108:Polymers; D013552:Swine
chemical_list: D000497:Alloys; D011108:Polymers; C013616:nitinol