NOVEL STARCH-BASED POLYSACCHARIDE SUBMUCOSAL INJECTION SOLUTION RESULTS IN DECREASED BLEEDING AND ADVERSE EVENTS IN EMR AND ESD.

Introduction
In Endoscopic Mucosal Resection (EMR) and Endoscopic Submucosal Dissection (ESD), submucosal lifting agents optimize safety and successful removal of target lesions. Crystalloid-oil emulsion solutions (COES) have been used in place of saline injection but have potential for peri-procedural bleeding. Starch-based polysaccharide solutions (SPS), which in powder form are used as an effective clotting agent in GI tract bleeding, are now available as an alternative lifting agent. This study compares SPS to COES injected cases to assess outcomes in patients undergoing EMR and ESD.

Methods
This is a retrospective study of patients who underwent EMR or ESD of colonic lesions and received submucosal injection of either a SPS or a COES at a single academic hospital from 03/2021 to 11/2023. 84 patients were included in the COES group and 102 in the SPS group. Patient clinical data, procedure data, outcomes and pathology reports were extracted from chart review. Subgroup analysis was performed to control for lesion size and location. Right-sided lesions were defined as lesions found in the cecum, ascending colon or transverse colon. Intraprocedural bleeding was defined as bleeding during a procedure requiring hemostatic intervention. Adverse events were instances of perforation or post-procedure GI bleed. Data was analyzed in IBM SPSS 26 using t testing for comparing averages and chi square testing for comparing proportions.

Results
Successful resection was achieved in all 182 patients . Average ages were 67 and 68 in the SPS and COES group, respectively. Average lesion size in SPS group was 2.6 cm vs 2.4 cm in COES group. Average procedure time was 93 minutes in SPS group vs 115 minutes in COES group (p < 0.05). Intraprocedural bleeding was 24.2% higher in COES group (p < 0.01). SPS resulted in less intraprocedural bleeding for polypectomy of polyps ≥ 2cm (p < 0.01) and polyps ≥ 4cm (p < 0.01). Adverse events were 8.75% more frequent in the COES group (p = 0.01). All 4 instances of bowel perforation in the study sample occured in the COES group. In the right-sided colon, intraprocedural bleeding occurred 22.1% (p < 0.01) more frequently for all polyps and 17.2% (p = 0.02) more frequently for polyps > 2 cm in the COES group. En bloc resection was achieved 21.3% more frequently in patients receiving SPS submucosal injection (p < 0.01).

Conclusion
SPS submucosal injection may be beneficial over COES, as it is associated with lower intraprocedural bleeding and adverse events, including bowel perforation. Also shorter procedure time and more frequent en bloc resections were noted in our series. SPS leads to significantly less negative outcomes when conducting EMR or ESD of polyps larger than 2 cm as well as polyps in the right-sided colon.