title: Retrievable covered nitinol stents: experiences in 108 patients with malignant esophageal strictures.
abstract: OBJECTIVE
  The authors report their experience with three types of retrievable covered nitinol stents in patients with malignant esophageal strictures.
  
  
  METHODS
  Three types of retrievable covered nitinol stents were designed. Type A stents were placed in 45 patients, type B stents were placed in 29 patients, and type C stents were placed in 34 patients. The stents were removed with use of a stent retrieval set under fluoroscopic guidance when the stents caused complications. Stent patency, symptom relief, survival rate, and complications were analyzed relative to stent type and radiation therapy.
  
  
  RESULTS
  The timing of radiation and the stent type have significant effects on occurrence of complications such as stent migration and fistula formation (P =.002 and P = 0.029, respectively). Complications were significantly more frequent in patients with the type B stent than those with type A or type C stents (P =.008). Patients who underwent radiation therapy before stent placement or who underwent no radiation therapy experienced substantially less complications than those who underwent radiation therapy after stent placement (P =.005 and P <.001, respectively). The survival period was significantly longer in patients who underwent radiation therapy after stent placement than in the other groups (P =.034). Stents were removed from 15 patients (14%) 2 days to 16 weeks (mean, 4 weeks) after stent placement as a result of severe pain (n = 7), stent migration (n = 6), or stent deformity (n = 2). Stent removal was well tolerated in all patients.
  
  
  CONCLUSIONS
  Use of retrievable covered nitinol stents seems to be a safe and effective method of treatment in patients with malignant esophageal strictures. However, removal of the stents was needed in 14% of the patients because of complications. Patients who underwent radiation therapy after stent placement and those with the type B stent experienced more complications than other patients.
authors.affiliation: Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap-dong, Songpa-gu, Seoul 138-736, Korea. hysong@www.amc.seoul.kr
authors.forename: Ho-Young
authors.initials: HY
authors.lastname: Song
authors.forename: Deok Hee
authors.initials: DH
authors.lastname: Lee
authors.forename: Tae-Seok
authors.initials: TS
authors.lastname: Seo
authors.forename: Sung-Bae
authors.initials: SB
authors.lastname: Kim
authors.forename: Hwoon-Yong
authors.initials: HY
authors.lastname: Jung
authors.forename: Jong-Hoon
authors.initials: JH
authors.lastname: Kim
authors.forename: Seung-Il
authors.initials: SI
authors.lastname: Park
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000497:Alloys; D004867:Equipment Design; D004938:Esophageal Neoplasms / Q000150:complications* / Q000401:mortality / Q000532:radiotherapy; D004940:Esophageal Stenosis / Q000209:etiology / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010166:Palliative Care; D012044:Regression Analysis; D015607:Stents / Q000009:adverse effects*; D016019:Survival Analysis
chemical_list: D000497:Alloys; C013616:nitinol