title: Malignant gastric outlet obstructions: treatment by means of coaxial placement of uncovered and covered expandable nitinol stents.
abstract: OBJECTIVE
  To assess whether coaxial placement of uncovered and covered expandable nitinol stents overcomes the disadvantages of the increased migration rate seen with covered stents and the tumor ingrowth seen in uncovered stents in the treatment of malignant gastric outlet obstructions.
  
  
  METHODS
  Two types of expandable nitinol stent were designed: an uncovered stent and a covered stent. Under fluoroscopic guidance, the uncovered and covered stents were placed coaxially with complete overlap in 39 consecutive patients with malignant gastric outlet obstruction caused by stomach cancer. Food intake capacity was graded on a scale of 0-4. Stent patency rate was estimated by the Kaplan-Meier method.
  
  
  RESULTS
  Technical success rate was 97% (38 of 39 patients). After stent placement, food intake capacity improved at least one grade in 36 patients. Stent migration occurred in three patients (8%), that is, partial (n = 2) or complete (n = 1) upward migration of the inner covered stent into the stomach. Two of these patients were treated by placement of an additional covered stent. During the mean follow-up period of 134 days (range, 15-569 d), 10 patients developed recurrent symptoms of obstruction with tumor overgrowth being the most common cause. Nine underwent placement of an additional covered stent with good results. The median period of primary stent patency was 157 days (mean, 278 d). The 30-, 60-, and 180-day patency rates were 97%, 91%, and 39%, respectively. Four patients (10%) died within 1 month after the procedure.
  
  
  CONCLUSIONS
  Coaxial stent placement technique seems to contribute to decreasing the migration rate of the stent and decrease the rate of recurrent obstruction by preventing or delaying tumor ingrowth.
authors.affiliation: Department of Diagnostic Radiology, College of Medicine, Kosin University, Pusan, Korea.
authors.forename: Gyoo-Sik
authors.initials: GS
authors.lastname: Jung
authors.forename: Ho-Young
authors.initials: HY
authors.lastname: Song
authors.forename: Tae-Seok
authors.initials: TS
authors.lastname: Seo
authors.forename: Seon-Ja
authors.initials: SJ
authors.lastname: Park
authors.forename: Ja-Young
authors.initials: JY
authors.lastname: Koo
authors.forename: Jin-Do
authors.initials: JD
authors.lastname: Huh
authors.forename: Young Duk
authors.initials: YD
authors.lastname: Cho
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000497:Alloys; D004867:Equipment Design; D005240:Feasibility Studies; D005260:Female; D005548:Foreign-Body Migration / Q000517:prevention & control; D017219:Gastric Outlet Obstruction / Q000209:etiology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015607:Stents / Q000009:adverse effects; D013274:Stomach Neoplasms / Q000150:complications*
chemical_list: D000497:Alloys; C013616:nitinol