Prevention of Delayed Bleeding after Endoscopic Resection using Gel Hemostatic Powder: A Multicentric Open-lapel Prospective Study

Abstract Background Delayed bleeding (DB) after endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) remains a significant clinical problem. This study aimed to evaluate the safety and efficacy of a new gel hemostatic powder (GHP) for the prevention of DB in high-risk patients. Methods A prospective, multicentric, open-label study was conducted at seven Belgian hospitals from 2023 to 2024 in patients undergoing EMR or ESD for lesions over 20 mm with high risk of DB (either anticoagulant or P2Y12RA treated, or undergoing duodenal EMR). The Nexpowder GHP preventive spray was applied to the resected area at the end of the procedure. The primary outcome was the rate of DB within 4 weeks post-procedure. Secondary outcomes included safety, procedure duration, post-procedural pain, and incidence of adverse events. Results Fifty patients were enrolled in the study and treated with endoscopic resection followed by GHP application. The observed DB rate was 22% (11/50), higher than the literature-reported rate of 16%. The hypothesized reduction in DB below 5% was not achieved (p = 0.2472). DB was most common in rectal ESD (n = 3/5; 60%) and duodenal EMR (n = 6/20; 30%). DB typically occurred within the first 10 days post-procedure (median onset 7d). On univariate analysis, the only factor associated with DB risk was lesion size (p = 0.042). No adverse events related to the use of the GHP were reported. Conclusion In this prospective study, GHP demonstrated limited efficacy for the prevention of DB in high-risk patients, with a 22% observed DB rate. Lesion size and location were key predictors of DB.