Supplementary Material for: Effect of Antithrombotic Therapy and Long Endoscopic Submucosal Dissection Procedure Time on Early and Delayed Postoperative Bleeding

<p><b><i>Background:</i></b> Recent updated guidelines of the Japanese Society of Gastroenterology recommend the use of a single dose of antiplatelet agents in patients undergoing endoscopic submucosal dissection (ESD). However, the postoperative bleeding risk after gastric ESD associated with the continuation or interruption of antithrombotic therapy remains controversial. We aimed to evaluate whether certain factors including interrupted antithrombotic therapy could affect early and delayed post-ESD bleeding risk. <b><i>Methods:</i></b> Three hundred sixty-four patients with gastric neoplasms were treated with ESD at our hospital between October 2005 and December 2012. Seventy-four patients with interrupted antithrombotic therapy were undertaken with ESD. Early and delayed postoperative bleeding patterns were estimated. Various clinical characteristics such as gender, age, tumor location, tumor size, ESD procedure time, platelet count, and comorbidity were evaluated. <b><i>Results:</i></b> There was a significant difference (<i>p</i> = 0.042) in the ESD procedure time between the patients with postoperative bleeding and those without it. There was no significant difference in postoperative bleeding between the patients on antithrombotic therapy and not on it. Moreover, interrupted antithrombotic therapy and platelet count were significantly (<i>p</i> = 0.0461 and <i>p</i> = 0.0059, respectively) associated with early postoperative bleeding in multivariate analysis. In addition, in univariate analysis, ESD procedure time was significantly (<i>p</i> = 0.041) associated with delayed postoperative bleeding. <b><i>Conclusions:</i></b> Antithrombotic therapy and prolonged ESD procedure time were significantly associated with early and delayed postoperative bleeding, respectively.