Outcomes and Post-removal Course of Lumen-Apposing Metal Stent Placement for Peripancreatic Fluid Collections: A Comparative Study of Pancreatic Pseudocysts and Walled-Off Necrosis

Aim: Pancreatic fluid collections (PFCs) are common local complications of pancreatitis that may require interventional therapy. Endoscopic ultrasound (EUS)-guided transluminal drainage from the digestive tract, particularly with lumen-apposing metal stents (LAMS), is the first-line therapy due to its safety and efficacy. However, adverse events and post-removal courses remain uncertain. This study aimed to clarify the characteristics of LAMS placement and its removal, comparing pancreatic pseudocysts (PPC) and walled-off necrosis (WON).

Methods: This single-center retrospective study included 23 patients who underwent transgastric LAMS placement for PFCs under EUS guidance. The patients were categorized into the PPC group (n = 14) and the WON group (n = 9). Backgrounds and clinical outcomes were analyzed and compared.

Results: The mean procedure time was 19 minutes in the PPC group and 25 minutes in the WON group, with no significant difference (p = 0.11). The overall incidence of adverse events during LAMS placement was 14.3% in the PPC group and 33.3% in the WON group, with no significant difference (p = 0.28), but the incidence of infection of noninfected fluid collections was 0% in the PPC group and 55.5% in the WON group, significantly higher in the WON group (p = 0.0016). At the time of LAMS removal, a double-pigtail plastic stent (DPS) was replaced in 53.8% of the PPC group and 57.1% of the WON group. Within one year, 57.1% of the replaced DPS in the PPC group and 25.0% in the WON group became dislocated. There were no adverse events due to the dislocation of the replaced DPS. Adverse events occurred in one patient in each group after LAMS removal: 7.7% in the PPC group and 14.3% in the WON group (p = 0.64), which consisted of peritonitis in the PPC group and recurrent infection of fluid collection in the WON group, and both of these events occurred when the replaced DPS was still in place after LAMS removal.

Conclusions: Although there was no significant difference in the overall incidence of adverse events between PPC and WON, the incidence of infection after LAMS placement was significantly higher in WON. Regarding the replaced DPS, there were some cases of dislocation within one year, but there were no related adverse events. Adverse events occurred even after the removal of LAMS and replacement with DPS, so careful follow-up is required.