Treatment of malignant biliary obstruction with polyurethane-covered Wallstents

This study was undertaken to determine the safety, efficacy, and performance of polyurethane-covered Wallstents in the treatment of malignant biliary obstruction.

This pilot study included 30 patients with malignant biliary obstruction. Palliative decompression of the obstructed bile duct was attempted with a polyurethane-covered Wallstent that is a prototype. Patients with hilar obstructions were excluded. All stents were inserted percutaneously. Kaplan-Meier analysis was used to determine stent patency.

Effective biliary decompression was achieved in all patients initially. No acute stent-related complications occurred. The 30-day mortality rate was 20%. During follow-up, 11 stent occlusions occurred; therefore, the occlusion rate was 37%. The patency rates after 1, 3, 6, and 12 months were 96%, 69%, 47%, and 31%, respectively. Tumor growth through the stent covering that was proven both histologically and by biopsy observed in two patients, causing stent occlusion in one of them. Other reasons for stent occlusion were distal tumor ingrowth (n = 1) and biopsy-proven granulation tissue inside the stent (n = 2). Otherwise, the reasons for stent occlusion remained unclear.

This prototype of a covered stent did not provide better results than did conventional uncovered stents in patients with malignant biliary obstruction. The covering did not effectively prevent tumor ingrowth in at least two patients. The stent also seems prone to premature occlusion.