title: Self-expanding metal esophageal stent with anti-reflux mechanism.
abstract: BACKGROUND
  When deployed across the gastroesophageal junction, self-expanding metal esophageal stents can predispose to gastroesophageal reflux. Our aim was to evaluate the efficacy of a self-expanding metal esophageal stent that was modified to prevent gastroesophageal reflux.
  
  
  METHODS
  The polyurethane coating of a metal Z-stent was extended beyond its lower end to form windsock-type valve. The anti-reflux property of this stent was studied in vitro by submerging the stent under water and measuring the pressure required to invert the valve. Esophageal acid exposure time was measured in 5 dogs with a standard and the modified stent placed across the gastroesophageal junction. The modified stent was also placed in 11 patients with cancer of the gastroesophageal junction who were prospectively followed.
  
  
  RESULTS
  The pressure required to invert the valve was directly proportional to the thickness of the valve membrane (48 +/- 0.4 cm water for a 0.0067-inch thick membrane). Esophageal acid exposure time was significantly less with the modified stent as compared with a standard stent (1% +/- 0.3%, 49% +/- 11%, respectively, p = 0.03). Dysphagia score in patients improved from 3.4 +/- 0.1 to 1.1 +/- 0.2 (p < 0.001). Daytime heartburn and regurgitation scores were less than 1 (score 10 = severe). No patient complained of nocturnal reflux symptoms. Karnofsky performance status scale did not improve significantly.
  
  
  CONCLUSIONS
  The efficacy of the modified stent in relieving dysphagia is comparable with a standard stent. It also effectively prevents gastroesophageal reflux.
authors.affiliation: M.C.W. Dysphagia Institute, Medical College of Wisconsin and V.A. Medical Center, Milwaukee, USA.
authors.forename: K S
authors.initials: KS
authors.lastname: Dua
authors.forename: R
authors.initials: R
authors.lastname: Kozarek
authors.forename: J
authors.initials: J
authors.lastname: Kim
authors.forename: J
authors.initials: J
authors.lastname: Evans
authors.forename: B K
authors.initials: BK
authors.lastname: Medda
authors.forename: I
authors.initials: I
authors.lastname: Lang
authors.forename: W J
authors.initials: WJ
authors.lastname: Hogan
authors.forename: R
authors.initials: R
authors.lastname: Shaker
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D003680:Deglutition Disorders / Q000628:therapy*; D004285:Dogs; D004867:Equipment Design; D004938:Esophageal Neoplasms / Q000150:complications; D004943:Esophagogastric Junction; D005069:Evaluation Studies as Topic; D005260:Female; D005764:Gastroesophageal Reflux / Q000517:prevention & control*; D006801:Humans; D008297:Male; D008670:Metals; D008875:Middle Aged; D011446:Prospective Studies; D015607:Stents
chemical_list: D008670:Metals