Background and study aims: Metal billiary stents have been shown to be superior to plastic stents with regard to patency and the risk of dislocation. However, tumor ingrowth through the mesh continues to be a significant problem. We report here on our preliminary experience with covered metal stents.
Patients and methods: Ten patients (mean age 68 years) with malignant biliary obstruction, who were not considered to be surgical candidates, received a partially covered Wallstent. The patients were followed up prospectively for one year, including laboratory tests, abdominal ultrasound, and plain abdominal radiographs during the first three months, and by monthly telephone interview thereafter.
Results: Stent insertion was technically successful in all patients, and led to a reduction in bilirubin levels from 8.4 mg/dl to 0.7 mg/dl. The mean survival of the patients was 7.5 months after the diagnosis of malignancy, and six months after stent insertion; only two patients were still alive after 12 months. During the observation period, four patients suffered from stent dysfunction for periods of one to nine months. These dysfunctions included three stent occlusions, which were successfully treated by inserting plastic stents, and one dislocation, which was treated by endoscopic replacement of the stent. There appeared to be a correlation between the narrowest stent diameter immediately after release and stent dysfunction.
Conclusion: Covering biliary metal stents is a potential solution to prevent tissue ingrowth. However, current prototypes need to be improved in order to achieve this goal.