Risk Factors for Delayed Hemorrhage after Colonic Endoscopic Mucosal Resection in Patients Not on Antithrombotic Therapy: Retrospective Analysis of 3,844 Polyps of 1,660 Patients.

BACKGROUND/AIMS: Colonic endoscopic mucosal resection (EMR) is safe for patients without antithrombotic therapy; however, EMR is associated with several risks. This study was performed to evaluate the risk of delayed hemorrhage in patients undergoing EMR without antithrombotic therapy.

METHODS: In the present retrospective single-center study, 1,792 patients without antithrombotic therapy underwent colonic EMR from March 2012 to December 2016 at the Saga Medical Centre Koseikan. Risk factors were evaluated with respect to patient and lesion characteristics, the endoscopist's experience, and preventive hemoclips. Delayed hemorrhage was defined as bleeding for which emergency endoscopic hemostasis was applied >24 h after EMR.

RESULTS: Among the 1,792 patients, 1,660 with 3,844 tumors were evaluated. Delayed hemorrhage occurred in 43 patients (2.6%) and 46 polyps (1.2%). Preventive hemoclips were applied in 996 patients (60.0%). Univariate analysis indicated that delayed hemorrhage occurred more frequently in young patients (3-39 years, p < 0.001, 40-59 years, p = 0.005) compared to > 60 years and in association with large polyps (> 10 mm, p = 0.003), hemoclip (p = 0.019), and pedunculated polyps (p = 0.024). Multivariate analysis indicated that risk factors for hemorrhage were young age (age of 3-39 years p < 0.001, 40-59 years, p = 0.005) and large polyps (> 10 mm, p < 0.001). The risk of delayed hemorrhage was increased by an estimated 8% with a 1-mm increase in polyp size.

CONCLUSION: The present study suggests that young age (under 60 years old) and large polyp size are risk factors for causing delayed hemorrhage after colonic EMR in patients without antithrombotic therapy.