Biliary stent occlusion--a problem solved with self-expanding metal stents? European Wallstent Study Group

The main limitation in the endoscopic palliation of malignant biliary obstruction is due to stent blockage. One of the factors thought to be of importance is the diameter of the endoprosthesis. In this paper, we report the results of a multicenter European study with a one cm diameter self-expanding metal stent (Wallstent) in 103 patients with malignant biliary obstruction. Insertion of the stent following guidewire positioning was successful in 97.1% of the patients without any cases of de novo cholangitis developing after the endoscopic procedure. The median follow-up for the entire group was 145 days. In all but 3 patients, the stent expanded to more than 80% of its maximum diameter. Two patients had ongoing cholangitis after stent insertion. Long-term complications manifested by late cholangitis, were seen in 18% of the cases after a median interval of 125 days. The occlusion rate by biliary sludge was 5% after a median time period of 175 days which is substantially less than the 21% occlusion rate reported for polyethylene stents. In conclusion, our results show that the Wallstent can be easily placed in distal and mid-CBD strictures after guidewire passage, with most of the patients having a- good drainage effect. The occlusion rate by biliary sludge is significantly less than for conventional polyethylene stents, but the occlusion by tumor ingrowth is substantial. A disadvantage is the high cost of the Wallstent. Further randomized trials will be required to determine the cost-benefit ratio for the use of this stent.