Optimal definition of coagulation syndrome after colorectal endoscopic submucosal dissection: a post hoc analysis of randomized controlled trial

Purpose Endoscopic clipping closure after colorectal endoscopic submucosal dissection (ESD) did not reduce the incidence of post-ESD coagulation syndrome (PECS) in our recent randomized controlled trial (RCT); however, the definition of PECS is still controversial. The aim of this study is to establish optimal definition of PECS with additional analysis of RCT based on another definition. Methods In this multicenter, single-blind RCT, individuals were randomly assigned to colorectal ESD followed by endoscopic clipping closure or non-closure. In this post hoc analysis, the definition of PECS was modified as both localized abdominal pain on visual analogue scale and inflammatory response (fever or leukocytosis), from either localized abdominal pain or inflammatory response in the original study. All participants underwent a computed tomography after ESD, and PECS was classified into type I, conventional PECS without extra-luminal air, and type II, PECS with peri-luminal air. Results A total of 155 patients (84 in the non-closure group and 71 in the closure group) were analyzed. As a result of criteria modification, 21 type I PECS and four type II PECS cases in the original study, which included patients with clear pain and inflammatory response, were downgraded to no adverse event and simple peri-luminal air, respectively. The frequency of PECS showed no significant difference between non-closure and closure groups. Conclusion Clipping closure after colorectal ESD does not reduce the incidence of PECS regardless of the diagnostic criteria. Either localized abdominal pain or inflammatory response might be optimal criteria of PECS (UMIN000027031). Trial registration number UMIN000027031 Date of registration April 18, 2017