Stent placement of gastroenteric anastomoses formed by magnetic compression

PURPOSE: To evaluate the use of stents for prolonging the patency of gastroenteric anastomoses (GEA) induced by magnet compression. MATERIALS AND METHODS: Rare earth magnets were inserted perorally and serially in 15 dogs so as to mate across the gastric and jejunal walls. After magnet excretion, the resulting GEA was identified endoscopically, dilated (n = 1), and stented with bare (n = 2) or partially covered (n = 6) flared 10-mm or 12-mm Z stents. The GEA was followed at 2-4-week intervals for patency; malfunctioning shunts were irrigated, or dilated with angioplasty balloons. Gross and histologic examination of the anastomotic tissues was performed in 14 animals. RESULTS: Magnet pairs were excreted in 5-7 days. Of the 19 magnet placements in 15 animals, stent placement was not possible because of early GEA closure (n = 6), failure to locate (n = 2), pancreatic abscess (n = 1), and magnet perforation with peritonitis (n = 1). Estimated duration of GEA patency was 19 days; after balloon dilation, 46-64 days with bare Z stents, and 58-147 days (mean, 90 days) with partially covered Z stents. Shunt function was commonly hindered by bezoars. Stent narrowing or occlusion was caused by tissue overgrowth through bare stents (n = 2), between covered stent struts and through partially detached membrane (n = 2). Serious morbidity (n = 2) was due to malpositioned magnets across the pancreas in one animal and gastric perforation in the other. One dog was euthanized because of unsuspected kidney infection. CONCLUSION: Partially covered stents significantly extend the anatomic patency rate of magnetic GEA to 7 weeks or more. Functional patency is frequently impaired by bezoars. Ongoing improvements ill covered stent design should provide longer-term GEA patency.