Safety and efficacy of argon plasma coagulation trimming of malpositioned and migrated biliary metal stents: A controlled study in the porcine model

BACKGROUND: Argon plasma coagulation (APC) has been used to trim uncovered Elgiloy((R)) stents, but the extent of thermal damage and bile duct injury is not known. The goal of this study was to evaluate the safety and efficacy of APC for this application. METHODS: Eight Elgiloy((R)) (covered and uncovered) and four nitinol stents were deployed in the bile duct at ERCP in 12 anesthetized pigs. In nine pigs, the excess distal ends were trimmed in vivo using short bursts of APC. Three pigs served as controls. Bile ducts and stent specimens were then harvested for gross and histological examinations by a single-blinded pathologist. RESULTS: APC effectively trimmed all the stents. Seven APC-treated bile ducts and three controls showed epithelial distortion consistent with pressure injury from stent expansion. Two APC-treated bile ducts showed mild thermal injury. The damage was superficial, extending to a maximum depth of 0.1 mm with rare foci involving subepithelial connective tissue. CONCLUSION: APC at indicated settings effectively cuts covered and uncovered Elgiloy((R)) as well as nitinol stents, but can cause biliary epithelial injury secondary to conduction of heat and electrical energy. Proper technique and settings should be followed and short bursts of energy judiciously applied in order to minimize this danger.