Acute cholecystitis in high-risk surgical patients is commonly managed with percutaneous trans-hepatic gallbladder drainage (PT-GBD). However, long-term adverse events, tube dysfunction, and recurrent cholecystitis remain significant concerns. This retrospective multicenter observational study compares long-term outcomes of conversion from PT-GBD to endoscopic ultrasound-guided gallbladder drainage (EUS-GBD) with lumen-apposing metal stents (LAMS) versus standard management in high-risk surgical patients with acute cholecystitis.

Acute cholecystitis is a common and potentially severe condition that often requires timely intervention, particularly in high-risk surgical patients who are not suitable candidates for cholecystectomy. In this population, percutaneous trans-hepatic gallbladder drainage (PT-GBD) is widely used as an effective minimally invasive treatment, providing rapid clinical improvement and high technical success rates. However, despite its short-term efficacy, PT-GBD is associated with significant long-term limitations, including tube dysfunction or dislodgement, patient discomfort related to the external catheter, and a relatively high incidence of recurrent cholecystitis and other adverse events.

Endoscopic ultrasound-guided gallbladder drainage (EUS-GBD) using lumen-apposing metal stents (LAMS) has emerged as an alternative minimally invasive approach that allows internalization of gallbladder drainage. This technique has the potential to improve patient quality of life, reduce catheter-related complications, and decrease the incidence of recurrent biliary events. Conversion from PT-GBD to EUS-GBD has been proposed as a strategy to overcome the limitations of long-term percutaneous drainage. Preliminary evidence suggests that such a conversion is technically feasible and associated with favorable clinical outcomes, including reduced adverse events and improved long-term management.

Nevertheless, the available literature is limited, and comparative data between conversion to EUS-GBD using LAMS and standard management after PT-GBD are scarce. In particular, only a limited number of studies have specifically evaluated outcomes following conversion with LAMS, and no large comparative studies have definitively assessed its impact on long-term adverse events and clinical outcomes.

This multicenter retrospective observational study aims to compare the long-term outcomes of two management strategies in high-risk surgical patients with acute cholecystitis who previously underwent PT-GBD: (1) conversion to EUS-GBD using LAMS and (2) standard management without conversion. All consecutive eligible patients treated with PT-GBD will be retrospectively identified and included according to predefined inclusion and exclusion criteria.

The primary objective of the study is to evaluate the incidence of adverse events at 1 year in patients undergoing PT-GBD to EUS-GBD conversion compared with those receiving standard management. Secondary objectives include the assessment of technical success, clinical success, procedural adverse events, 30-day adverse events, 1-year incidence of stent dysfunction, biliary adverse events, recurrent cholecystitis, biliary reintervention rate, readmission rate, biliary-related mortality, and overall survival.

Data will be collected from participating centers using standardized case report forms, including demographic characteristics, clinical variables, procedural details, and follow-up outcomes. Patients will be followed for at least 1 year to assess the occurrence of adverse events and other clinical endpoints.

The study is conducted in accordance with the principles of the Declaration of Helsinki and Good Clinical Practice guidelines. Approval from the relevant Ethics Committees will be obtained at each participating center prior to data collection.

Inclusion Criteria:

• Age >18 years
• Patients considered unfit for surgery after multidisciplinary discussion
• Patients who underwent PT-GBD for acute cholecystitis

Exclusion Criteria:

• Patients with improved general conditions who become fit for laparoscopic cholecystectomy
• Use of anticoagulants that cannot be discontinued
• Coagulation and/or platelet hereditary disorders and/or INR >1.5, PLT <50,000
• Absolute contraindication for EUS-GBD
• Post-surgical altered upper gastrointestinal anatomy
• Malignant biliary obstruction

The study population includes adult patients (≥18 years) with acute cholecystitis who were considered high-risk for surgery and managed with percutaneous trans-hepatic gallbladder drainage (PT-GBD). All patients were deemed unfit for cholecystectomy after multidisciplinary evaluation. Eligible patients are retrospectively identified from participating centers and include all consecutive cases undergoing PT-GBD during the study period. The population reflects a real-world cohort of frail patients with significant comorbidities. Two groups are defined based on subsequent management: conversion to endoscopic ultrasound-guided gallbladder drainage (EUS-GBD) with lumen-apposing metal stent (LAMS) versus standard management.

Individual participant data (IPD) will not be shared. The study involves retrospective data collected and data sharing is limited by institutional policies and data protection regulations. De-identified aggregate data may be made available upon reasonable request to the corresponding author, subject to approval by the study investigators and participating centers.