Lumen-apposing Metal Stent With or Without Coaxial Plastic Stent for Treatment of Walled-off Pancreatic Necrosis
Lumen-apposing Metal Stent With or Without Coaxial Plastic Stent for Treatment of Walled-off Pancreatic Necrosis
A prospective randomized cohort study to compare whether the placement of a double-pigtail
 plastic stent (DPS) within a lumen-apposing metal stent (LAMS) may improve the efficacy and
 safety of endoscopic ultrasound guided transmural drainage of walled-off pancreatic necrosis
 (WON) and thus prevent potential adverse events related to LAMS insertion.
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