Cholecystectomy is considered the standard definitive treatment after an acute biliary event (biliary colic, acute pancreatitis, cholangitis, or choledocholithiasis). However, in elderly patients and/or those with significant comorbidities, surgery is often not feasible, leaving this population at high risk of biliary event recurrence (approximately 25-31% per year without treatment).

EUS-guided gallbladder drainage (EUS-GBD) using a lumen-apposing metal stent (LAMS) is an established endoscopic technique currently recommended for acute cholecystitis in patients unfit for surgery. It creates an internal fistula between the gallbladder and the adjacent digestive tract, allowing direct endoscopic access for stone clearance (cholecystoscopy). This approach could theoretically prevent biliary event recurrence similarly to cholecystectomy.

The DRECON study (DRainaige, Endoscopic ultrasound, CONservative) is a multicenter, randomized, comparative clinical trial evaluating whether EUS-GBD with LAMS reduces biliary recurrence at 1 year compared to conservative managment (CM) in patients unfit for surgery after a biliary event without acute cholecystitis who are candidates for elective cholecystectomy.

Primary hypothesis: EUS-GBD will reduce the risk of biliary event recurrence (biliary colic, acute pancreatitis, cholangitis, choledocholithiasis, or cholecystitis) at 1 year of follow-up compared to conservative management in patients unfit for surgery with gallbladder lithiasis.

Estimated sample: 110 patients (55 per arm). Randomization 1:1 (EUS-GBD vs CM), stratified by centre and prior biliary sphincterotomy. Duration: 24 months recruitment + 12 months follow-up (total 3 years).

Participating centres: Hospital Universitari Mútua de Terrassa (coordinating centre), Hospital Universitari de Bellvitge, Hospital General de Granollers, Hospital Universitari Parc Taulí de Sabadell, Hospital Universitari de la Santa Creu i Sant Pau, Hospital Clínico Universitario de Valencia, Hospital General Universitario Dr Balmis and Complexo Hospitalario Universitario de A Coruña.

Inclusion Criteria:

• Patients ≥ 18 years of age
• Patients who have experienced a benign biliary event (biliary colic, acute pancreatitis, cholangitis, or choledocholithiasis) and are candidates for elective cholecystectomy
• Patients deemed unfuit for surgery (age ≥ 80 years, ASA score ≥ 3, Charlson Comorbidity Index ≥ 5) or who voluntarily refuse surgery
• Diagnosis of lithogenic/lithiasic material in the gallbladder by imaging (biliary sludge, microlithiasis, and/or cholelithiasis)
• Signed informed consent

Exclusion Criteria:

• No signed informed consent
• Prior cholecystectomy
• Biliary event secondary to malignant etiology
• Acute cholecystitis diagnosed according to Tokyo 2018 criteria
• Moderate-to-severe ascites without prior paracentesis
• Perforated gallbladder
• Severe coagulopathy (INR > 1.5) or thrombocytopenia (platelets < 50,000/μL) not correctable
• Any clinical condition preventing sedation
• Patient dependent for daily activities (ECOG ≥ 4)