What is the role of the Lumen-Apposing Metal Stent (LAMS) procedure in treating gallstones?

Role of Lumen-Apposing Metal Stent (LAMS) Procedure in Treating Gallstones

Endoscopic ultrasound-guided gallbladder drainage (EUS-GBD) using lumen-apposing metal stents (LAMS) is an effective alternative to percutaneous drainage for high-risk surgical patients with gallstone-related acute cholecystitis, offering fewer adverse events, lower pain scores, and reduced need for reinterventions. 1

Indications for LAMS in Gallstone Management

• EUS-GBD with LAMS is indicated for patients with acute cholecystitis who are poor surgical candidates due to significant medical comorbidities 1
• Particularly beneficial for patients with:
  • Uncovered metal biliary stents 1
  • Malignant obstruction of the cystic duct 1
  • High-volume cholelithiasis requiring therapeutic intervention 1
• Not recommended in cases of gallbladder perforation, biliary peritonitis, large-volume ascites, or significant coagulopathy 1

Technical Aspects of the LAMS Procedure

• Two approaches for performing EUS-GBD with LAMS:
  • Non-cautery enhanced method: Requires puncturing the gallbladder with a fine-needle aspiration needle, followed by guidewire insertion, track dilation, and stent placement under fluoroscopic guidance 1
  • Direct method (cautery-enhanced): Allows direct entry into the gallbladder and stent deployment without device exchange 1
• LAMS sizes typically used include:
  • Saddle lengths of 10 and 15 mm
  • Inner diameters of 10,15, and 20 mm
  • Bilateral anchor flanges of 21,24, and 29 mm 1
• For safe deployment, the distance between the enteral puncture site and gallbladder lumen should be less than 10 mm 1

Efficacy for Gallstone Management

• Technical success rates of 95.1-98% for EUS-GBD with LAMS 2, 3
• Clinical success rates of 91.6-96.3% 2
• Allows for subsequent gallstone management through the created fistula:
  • 56% of patients experience spontaneous stone passage through the LAMS 1
  • Remaining patients can undergo stone removal with retrieval baskets or laser lithotripsy 1
  • Overall stone clearance rate of 88% after an average of 1.25 cholecystoscopy sessions 1
• Even giant gallstones can be successfully managed through LAMS using endoscopic laser lithotripsy 4

Advantages Over Percutaneous Drainage

• Lower postprocedure pain scores (2.5 vs 6.5 for percutaneous drainage) 3
• Shorter hospital stays (3 days vs 9 days) 3
• Significantly fewer repeat interventions (0.2 vs 2.5 per patient) 3, 5
• Lower risk of recurrent cholecystitis compared to percutaneous drainage (relative risk: 1.089 vs 2.02) 1
• Fewer adverse events (16% vs 44%) 5

Post-Procedure Management Options

• Two main approaches after resolution of cholecystitis:
  1. Follow-up peroral cholecystoscopy at 4-6 weeks:
     • Exchange LAMS for double pigtail plastic stents for long-term fistula maintenance 1
     • Complete stone removal if not passed spontaneously 1
  2. Permanent LAMS placement:
     • Suitable for frail patients and those refusing a second procedure 1
     • Long-term outcomes show low delayed adverse events (7.1%) 1
     • 3-year stent patency of 86% 1

Adverse Events and Limitations

• Overall adverse event rate of 10.6-27.6%, including:
  • Procedural complications (4.9%): stent misdeployment, bleeding 2, 6
  • Follow-up complications (5.7%): stent dislodgement, blockage, leak, peritonitis 2
• Mortality rate of 3.9%, predominantly due to ongoing sepsis 1
• Procedure requires advanced EUS training with a learning curve of approximately 19-25 procedures 1
• Currently an off-label use of LAMS technology in the United States 1

Future Directions

• More data needed for FDA approval of LAMS specifically for gallbladder drainage 1
• Emerging applications include use as a salvage maneuver for biliary drainage 1
• Potential for endoscopic management of symptomatic gallstones to become more mainstream, though cholecystectomy remains the standard of care 1

Training Requirements

• Procedure should be performed by experts in advanced therapeutic EUS 1
• Recommended training progression:
  • First achieve competency with LAMS for pancreatic fluid collections (≥10 successful independent deployments) 1
  • Then progress to significantly distended gallbladders with no intervening tissue 1