4647 Features of malignant biliary obstruction affecting the short-term patency of metallic stents, a multicenter study

• Published in: Gastrointestinal endoscopy 2000-04, Vol.51 (4), p.AB192-AB192
• Main Authors: Kim, Dong Ki Lee, H.S., Kim, J.W., Kim, H.K., J.J.Park, S.H.Park, B.M.Yoo, Kim, J.H., Moon, I.H.Roe, Y.S., Myung, S.J.
• Format: Article
• Language: English
• ISSN: 0016-5107; 1097-6779
• DOI: 10.1016/S0016-5107(00)14494-3

Background: Metallic stents are an important addition to therapeutic options for the palliation of malignant biliary obstruction. However, little is known about the physical characteristics of tumors which cause the early obstruction of metallic stents. We studied the relationship of certain characteristics of tumors and the patency of metallic stents. Methods: Wallstents (Microvasive, Boston) were inserted endoscopically in 58 patients(mean age; 70.6±8.6, M:F=32:26) with malignant biliary obstruction due to common bile duct, ampullary and pancreatic cancer or due to metastatic lymph node enlargement. The mean follow up duration was 151 days(range: 60-363). Characteristics of malignant strictures, such as length, type and degree of stricture (easy passage of catheter vs. passage of guide wire), were prospectively analyzed between the patent and obstructed groups. Furthermore, the length of the stent, the time needed for full expansion of the stent (≤1day vs. >1day), and the placement site of the distal end of the stent were evaluated as possible factors affecting the patency of the stent. Results: During the follow-up periods, the overall rate of obstruction was 37.9%(22/58).Among the 22 patients with obstruction, the causes of stent blockage were tumor ingrowth(86.5%), distal overgrowth or embedding of cancer(9%) and sludge(4.5%). Two months after stent insertion, we classified 58 patients into obstructed(n=6) and patent groups(n=52).To evaluate the factors affecting the patency of the stent, we compared various physical characteristics of the eventual stricture and the stent between the two groups. No significant differences in patients age, type of tumor, length and type of stricture, and length of the stent, location of the distal end of the stent were found between the two groups. There were, however, significant differences in the degree of stricture (OD; 0.61, 95% C.I.; 0.49-0.77) and the time needed for full expansion (OD; 1.25, 95% C.I.; 1.05-1.50) of the stent. Conclusions: Our study showed that a tighter stricture and refractoriness to full expansion of the stent within 24 hours of placement were related to early stent obstruction. However, biologic factors of the identifiable tumor should also be considered as possible the causes of early dysfunction of biliary metallic stents.