Local complications of acute pancreatitis include acute peripancreatic liquid collection, pancreatic pseudocyst, acute necrotic collection, and walled-off necrosis (WON). Pseudocyst and walled-off necrosis are considered chronic complications and are treated invasively in case of being symptomatic. Endoscopic transluminal drainage involves the formation of a channel between the gastrointestinal system and the lumen of the collection and placement of a stent. Lumen-apposing metal stents (LAMS) are becoming more widespread in practice and are widely replacing plastic stents. Endoscopic transluminal necrosectomy is the next step in endoscopic intervention if drainage is not sufficient to resolve the collection. In this study, we compared the treatment outcomes of patients with chronic peripancreatic collections treated endoscopically by implantation of LAMS at the Department of Gastroenterology and Hepatology, Department for Internal Diseases, University Hospital Center “Sestre Milosrdnice” in the period from November 2016 to November 2023. 52 patients were treated in that period, of which 62% were male and 38% were female. The average age of the subjects was 57.7 ± 11.9 years. In 49 (94%) cases, the collections were WONs, while the remaining were pancreatic pseudocysts (6%). The etiology of pancreatitis was mostly biliary (87%). The technical success of the procedure was 100% and the clinical success was 96%. Of the 52 patients included in the analysis, significant complications of the procedure were observed in only 6% of the patients along with two cases of death. Patients suffered from a significant decrease in body mass during treatment, but no decrease in skeletal muscle mass was observed. 27% of patients had sarcopenia both before and after the endoscopic treatment, which showed that sarcopenia indeed occurs in this condition, but also that it can be prevented from worsening or even developing by adequate treatment and nutritional intervention, especially by high protein intake.