In situ cooling with ice water for the easier removal of self-expanding nitinol stents

Abstract

Background: It is yet to be determined what effects temperature has on the properties of nitinol in order to simplify the process of removing nitinol self-expanding metal stents (SEMS). Materials and methods: We describe the procedure for removal of SEMS in a total of 11 cases with 9 patients. A study involving cooling of nitinol stents in situ with ice water just before their removal was attempted. Results: All stents were removed successfully. In partially covered and in fully covered stents, the stent rigidity was noticeably reduced following cooling. Stent removal was performed by inversion, which was achieved by pulling on the stent from its distal end. No adverse events were observed during this trial. Conclusion: The higher pliability of the stents after ice-water cooling facilitates stent removal. With this method, a mobilization of all stents by the invagination technique was achieved. The separation of the uncoated stent ends from the intestinal wall by the invagination technique, as well as the mucosal vasoconstriction resulting from the cooling, lead to an easier SEMS removal and may serve to prevent severe bleeding of the mucosal wall during this process.