Lumen-apposing Metal Stent With or Without Coaxial Plastic Stent for Treatment of Walled-off Pancreatic Necrosis

The aim of the study is to compare endoscopic ultrasound guided transmural drainage using lumen-apposing metal stent with (1.) or without (2.) coaxial plastic stent in the management of walled-off pancreatic necrosis. The usage of LAMS has been evaluated as a safe and effective method for the drainage of walled-off pancreatic necrosis in various studies. However, complications such as bleeding, infection due to stent obstruction, stent migration, or buried stent syndrome have been reported. A preventive measure to minimize adverse events related to LAMS insertion by means of placing an anchoring DPS through the LAMS have been suggested but there has been no prospective randomized study to assess the utility of such measure to date.

The study is to be conducted at a tertiary institution with an expertise in treating hepato-pancreato-biliary diseases. The main timeframe of the study is 3 weeks following LAMS insertion with or without DPS. All LAMS will be extracted 3 weeks after the initial procedure. The extraction will be preceded by a CT scan of the abdomen to assess whether the DPS needs to be left in place/ inserted in patients with incomplete resolution of the collection. In addition, material from the collection will be collected for cultivation at every endoscopic intervention to assess colonization by microbial flora over time. All patients will be closely followed with clinical, laboratory, and radiological assessment for 12 months in total.

Our experience has shown failure of the (2.) method in 70 % of patients so far. Assuming a clinically significant difference to be a reduction to 40 % in failed patients using the (1) method, the required study population size was calculated to 62 patients (31 in both arms) by power analysis (at standard alpha and beta values). The final number was set to 70 as a safety measure.

Inclusion criteria

• walled-off pancreatic necrosis (WON) indicated for endoscopical drainage
• signed informed consent form

Exclusion criteria

• patient disagreement with the study
• types of collections other than WON
• drainage with stents other than LAMS
• previous attempts at drainage of WON
• severe coagulopathy or thrombocytopenia