Safety and efficacy of a metal stent covered with a silicone membrane containing integrated silver particles in preventing biofilm and sludge formation in endoscopic drainage of malignant biliary obstruction: a phase 2 pilot study

Abstract

Background and Aims: Membrane-covered self-expandable metal stents (SEMSs) have been developed to prolong the patency of stents by reducing tissue hyperplasia or tumor ingrowth. However, their effectiveness is attenuated by stent clogging as a result of biofilm formation on the inner surface of the membrane. The aim of this pilot study was to evaluate the efficacy and safety of SEMSs covered with a silicone membrane containing integrated silver particles (Ag-P) in malignant distal biliary obstruction. Methods: Twenty-four patients who underwent SEMS placement because of malignant distal biliary obstruction were enrolled in this single-center pilot study. The main outcomes were technical success, clinical success, adverse events, stent patency, and survival. Results: The technical and clinical success rates were 100% and 91.7% (22 of 24), respectively. The rates of early and late adverse events were 22.7% and 36.4%, respectively. The primary reintervention rate was 27.3% (6 of 22). Only 1 case involving stent malfunction was associated with sludge impaction. Median stent patency was 179 days. During follow-up, there were no serious adverse events or mortality related to the stents or Ag-P. Serum and urine silver concentrations before and after stent placement and at 32 weeks after placement did not differ. All serum and urine silver concentrations were <3 mu g/L (3 ppb) and 5 mu g/L (5 ppb), respectively. Conclusions: SEMSs covered with a silicone membrane containing integrated Ag-Ps may be effective and safe in malignant distal biliary obstruction. Stent dysfunction related to sludge impaction may be less frequent using this new stent.