Endoscopic Lifting Agents: AGA Issues Practice Update

The American Gastroenterological Association (AGA) has released a comprehensive clinical practice update on lifting agents for endoscopic surgery.

Published in Clinical Gastroenterology and Hepatology, the commentary reviews available agents and provides clinically relevant commentary on their indications and use — with the caveat that it is not a formal systematic review but rather empirical advice for endoscopists. No formal rating of the quality of evidence or strength of recommendations was performed.

Led by Tobias Zuchelli, MD, a clinical associate professor at Michigan State University and a gastroenterologist at the Henry Ford Health System in Detroit, the expert panel noted that endoscopists are increasingly resecting precancerous lesions and early cancers of the gastrointestinal tract.

“Although new endoscopic procedures have been developed, there had not been much in terms of high-quality guidance on lifting agents,” panelist Amit V. Patel, MD, a professor of medicine at Duke University and director of Endoscopy at Durham Veterans Affairs Medical Center in Durham, North Carolina, told Medscape Medical News. “With our better understanding and use of techniques, this commentary was timely. It summarizes the available data on the topic and includes our clinical experiences.”

Filling that knowledge gap, the document reviews in detail the timing and methods of agent injection according to procedure type, including the dynamic needle approach, the empirical merits of different agents such as saline (with or without blue contrast) and viscous agents, as well as lift-enhancing assistive devices — for example, the ERBEJET 2 high-pressure water jet, an adjustable hydrosurgical device to facilitate lifting. A chart provides an at-a-glance summary of agents and their pros and cons.

“The feedback from gastroenterologists so far has been quite positive on social media and on GI channels,” Patel said.

Endoscopic resection has evolved from snare polypectomy to endoscopic mucosal resection (EMR) and now, endoscopic submucosal dissection (ESD). The primary benefit of submucosal lifting is the creation of a separating submucosal cushion between the lesion and muscularis propria (MP), which reduces the risk for immediate or delayed perforation of the muscle. Adding a contrast agent also demarcates lesion margins and stains the submucosa, which is fundamental to ESD and allows for assessment of MP injury during EMR.

For decades, homemade solutions were used to lift lesions before removal, with the sentinel agent being normal saline, later mixed with a blue contrast agent, usually indigo carmine or methylene blue. The authors noted that some endoscopists performing ESD start the submucosal injection and incision using a prepackaged viscous solution. “The endoscopist may continue with the viscous fluid or transition to saline or another less expensive solution,” they wrote.

Saline tends to dissipate more quickly than viscous solutions, however. In 2015, the polymer compound SIC-8000 became the first FDA-approved submucosal injection agent. Since then, several other fluids have come on the market, although homemade agents remain available.

Among the update’s recommendations, the fluid selected for EMR should be determined by lesion size, predicted histology, and endoscopist preference. Based on the US Multi-Society Task Force (USMSTF) on Colorectal Cancer, submucosal injection is optional for nonpedunculated colorectal lesions (NPCRLs) of intermediate size (10-19 mm).

Cold snare polypectomy without submucosal injection was later found to be non-inferior to other resection methods utilizing submucosal injection for NPCRLs ≤ 15 mm. 

The update noted that the USMSTF considers EMR first-line therapy for most NPCRLs ≥ 20 mm and advocates viscous solutions as preferred, while the use of lifting agents for pedunculated polyps is generally at the discretion of the endoscopist.

For Patel, the main “clinical pearls” in the update are adding a contrast agent to normal saline, using a viscous agent for cold EMR, and manipulating the injection needle first tangentially and then dynamically toward the lumen to maximize separation of the lesion.

In terms of the ideal, an optimal lifting solution would be readily available, inexpensive, and premixed, providing a sustained submucosal cushion. “However, this ideal solution currently does not exist. Injection fluids should, therefore, be selected based on planned resection method, predicted histology, local expertise and preferences, and cost,” the panelists wrote.

Added Patel, “A lot of the agents out there check most of these boxes, but we’re hoping for further development toward the ideal.”

Offering a nonparticipant’s perspective on the overview, Wasseem Skef, MD, a gastroenterologist at UTHealth Houston, found the update very useful. “It always helps to have the literature summarized,” he told Medscape Medical News. “It’s a pretty balanced review that pulls together the various options but allows people to stick to their preferred practice.”

In his practice, the lifting agent selected depends on the type of resection. “Viscous agents are generally more popular for EMR-type resections,” Skef said. One unanswered question, he noted, is whether adding a hemostatic agent would be superior to a viscous agent alone. “But overall, this is a nice summary of available agents. Gastroenterologists should consider these different options if doing procedures like EMR.”

This review was sponsored by the AGA Institute. 

Zuchelli is a consultant for Boston Scientific. Patel consults for Medpace, Renexxion, and Sanofi. Co-author Douglas K. Rex consults for Olympus, Boston Scientific, Braintree Laboratories, Norgine, Acacia Pharmaceuticals, Laborie Medical, Sebela Pharmaceuticals, Medtronic, Exact Sciences, and ERBE. He reported receiving research support from Olympus Corporation, Medivators, and Erbe USA and has an ownership interest in Satisfai Health. Skef reported having no relevant disclosures.