Membrane Degradation of Covered Stents in the Upper Gastrointestinal Tract: Frequency and Clinical Significance
Received 26 June 2007; received in revised form 28 September 2007; accepted 29 September 2007.
Purpose
To evaluate the frequency, clinical significance, and predictive factors of membrane degradation of covered stents in the upper gastrointestinal (UGI) tract.
Materials and Methods
From 1996 to 2006, 166 stents were removed from 151 patients. Indications for stent removal included temporary stent placement for esophageal cancer before radiation therapy or radiation-chemotherapy (n = 53), stent migration (n = 40), temporary stent placement for a benign UGI stricture (n = 32), pain (n = 21), recurrent obstruction (n = 16), incomplete stent expansion (n = 1), recurrent transesophageal fistula (n = 2), and aspiration (n = 1). Removed stents were examined to evaluate possible causes of membrane degradation. Multivariate analysis was performed to determine the predictive factors of membrane degradation.
Results
Degradation of the covering membrane occurred in 14 of the 166 stents (8%). Recurrent obstruction due to tumor ingrowth (n = 7) and reopening of the transesophageal fistula (n = 1) through the degraded membrane occurred in eight stents (5%). At multivariate logistic regression analysis, the type of covering membrane (P = .018), stricture location (P = .006), and duration of stent placement (P = .002) were significantly associated with degradation of the covering membrane.
Conclusions
Degradation of the covering membrane after stent placement in the UGI tract is not an uncommon event, and recurrent obstruction or fistula can occur through the degraded membrane. A polyurethane membrane is not biostable and dissolves over time, particularly in the gastroduodenal area.
aDepartment of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap-2dong, Songpa-gu, Seoul 138-736, Republic of Korea
bDepartment of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap-2dong, Songpa-gu, Seoul 138-736, Republic of Korea
cDepartment of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap-2dong, Songpa-gu, Seoul 138-736, Republic of Korea
dDepartment of Thoracic and Cardiovascular Surgery, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap-2dong, Songpa-gu, Seoul 138-736, Republic of Korea.
Address correspondence to H.Y.S.
None of the authors have identified a conflict of interest.
ABSTRACT