TRANSECTION OF METAL STENTS USING ARGON PLASMA COAGULATION

Background: Placement of self‐expandable metallic stents has become the preferred palliative treatment for patients with unresectable malignant biliary obstruction. Metallic stents provide longer patency compared with plastic stents. Distal malposition or migration of metallic stents sometimes occurs, but it is often difficult to remove them. We evaluated the efficacy and safety of argon plasma coagulation (APC), and the optimum conditions for cutting metallic stents (Wallstent). Methods: We wrapped porcine small intestines around a metallic Wallstent with and without silicon lining membrane (Permulume®), leaving the distal portion unwrapped to resemble the protrusion of the biliary metallic stent from the ampulla of Vater. APC irradiation was applied to the metallic stent at 1 cm from the edge of the wrapped small intestine at 30, 60 and 99 watts (W) for 3 or 6 s. Results: Metallic Wallstent with the silicone‐based membrane Permalume® was cut at 30 W power, whereas more than 60 W power was required to cut the bare metallic wire. The irradiation of APC (flow rate at 2.0 L/min) at 30 W to the covered metallic stent transected the metallic mesh stent not only under dry but also under wet conditions (moisturized stent). Irradiation of APC caused no gross damage to the small intestines irrespective of the power applied and duration of irradiation. Conclusions: Our results suggest that APC is efficacious and safe for endoscopic sectioning of wire mesh stents at low power (30 W) without gross damage to the surrounding pancreaticobiliary tissues.