Tips for Lumen-Apposing Metal Stents

Educational Objectives

The goal of this program is to improve use of lumen-apposing metal stents (LAMS) delivery systems. After hearing and assimilating this program, the clinician will be better able to:

1. Optimize use of a LAMS delivery system.

Summary

Know your LAMS: the AXIOS lumen-apposing metal stent (LAMS; the only one available in the United States) delivery platform requires use of just one operator, one hand, one device, and one puncture; one hub advances and retracts the sheath, while another hub deploys the flanges; sheath advancement and retraction only occur with hub coupling; the LAMS is compressed by the sheath; locks ensure safe deployment, with alternation between locked and unlocked positions; one lock couples the sheath and inner catheter, facilitating hub coupling and retraction of the deployed distal flange; another lock prevents inner catheter movement during sheath retraction for flange deployment; proximal and distal flanges are independently released; the deployment process — the distal flange is released, with audible hub autoclicking upon successful deployment; the proximal flange is then released under endoscopic guidance; a black band marker on the sheath tip ensures precision and is visible on any imaging modality

Know your target: target dimensions include the minimum cross diameter and the minimum long diameter; the long diameter represents the trajectory of the puncture path; the minimum cross diameter must be longer than the flange diameter; the minimum long diameter must be longer than the runway (distance required for safe distal flange deployment); flange diameter is ≈2-fold greater than the lumen diameter (6-20 mm); a runway length of 32 mm is needed for safe deployment of a 10-mm LAMS; as a 2 cm runway is necessary for placement of a 6-mm LAMS within the bile duct (BD), do not drain the BD unless dilated ≈2 cm; a “push” technique (a modification of the standard “pull” technique) is needed to drain smaller BDs

Target contents: ensure the presence of a sufficient pocket of liquid for distal flange deployment; avoid thermal contact with solid components, which absorb thermal heat and impose resistance; shadowing indicates presence of calcium; do not attempt deployment in a gallbladder filled with stones; a 20-mm LAMS is suitable for draining walled-off pancreatic necroses; consider a 15-mm LAMS in a patient with gallbladder stones to allow spontaneous passage of stones or to facilitate lithotripsy; with aid of a 19-Ga fine needle aspiration needle, preinfuse saline to optimize the target

Interposed tissue: interrogate the distance, and assess for vessels or signs of poor adherence; consider using a 15-mm LAMS if the distance is >10 mm; ensure absence of vessels within 15 mm on each side of the puncture point for a 20-mm LAMS; presence of a fat plane indicates poor adherence

Know your cautery: ensure the current is set to "cutting" mode; increase voltage if penetration is difficult or for fibrotic tissue; slowly advance the catheter with steady pressure, and stop advancement if interposed gas impairs ultrasonography view (bubbling indicates target entry); disconnect the cautery cable immediately after target entry

Know when to preload with a guidewire: not usually needed, though enhances safety and helps retain access; recommended for individuals unfamiliar with LAMS; marking the guidewire tip at the sheath tip enables nose cone deflection away from the opposite wall (beneficial for, eg, BD drainage, restricted runway); orient distal flange deployment toward the desired target

Know how to manage maldeployment: type 1 — most common (occurs in ≈67% of cases); in type 1A, the proximal flange has not been deployed, permitting possible resheathing of the distal flange; in type 1B, the proximal flange has been deployed, necessitating LAMS removal; type 2 — type 2A permits insertion of a second stent if a guidewire is present, preferably with use of a LAMS >10 mm; in type 2B, guidewire is absent, and LAMS removal is required; surgical consultation is ideal, though patients are often fine despite target puncture; type 3 — typically requires surgery; over-the-scope clipping is preferable to ensure closure after the procedure

Readings

Armellini E, Metelli F, Anderloni A, et al. Lumen-apposing-metal stent misdeployment in endoscopic ultrasound-guided drainages: a systematic review focusing on issues and rescue management. World J Gastroenterol. 2023;29(21):3341-3361. doi:10.3748/wjg.v29.i21.3341; Binmoeller KF, DeSimio T, Donovan R. Design considerations of the AXIOS stent and electrocautery enhanced delivery system. Tech Innov Gastrointest Endosc. 2020;22(1):3-8. doi:10.1016/j.tgie.2019.150653; Fugazza A, Andreozzi M, de Marco A, et al. Endoscopy ultrasound-guided biliary drainage using lumen apposing metal stent in malignant biliary obstruction. Diagnostics (Basel). 2023;13(17):2788. doi:10.3390/diagnostics13172788; Parsa N, Nieto JM, Powers P, et al. Endoscopic ultrasound-guided drainage of pancreatic walled-off necrosis using 20-mm versus 15-mm lumen-apposing metal stents: an international, multicenter, case-matched study. Endoscopy. 2020;52:211-19. doi:10.1055/a-1096-3299.

Disclosures

For this program, members of the faculty and planning committee reported nothing relevant to disclose.

Acknowledgements

Dr. Binmoeller was recorded at the 2024 Cedars-Sinai International Endoscopy Symposium, held January 25-27, 2024, in Los Angeles, CA, and presented by Cedars-Sinai Medical Center. For information on upcoming CME activities from this presenter, please visit https://cedars.cloud-cme.com. Audio Digest thanks the speakers and presenters for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0.50 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0.50 CE contact hours.

Lecture ID:

GE381501

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.