Reply to Wang et al.

We appreciate the comments from Dr. Wang and his colleagues regarding our study on polyglycolic acid (PGA) sheets after gastric endoscopic submucosal dissection (ESD) [1]. We would like to address their comments briefly below.

Wang et al. suggested that fibrin glue should be sprayed before applying PGA sheets onto the ESD ulcer. However, we are concerned that fibrinogen might dissipate from the ulcer during the delivery of the PGA sheets. In our opinion, it would be better to deliver PGA sheets and then spray the fibrin glue. As for bleeding cases, PGA sheets remained on the ESD ulcer even in cases that required emergency endoscopy. Therefore, in this study, detachment of the PGA sheet did not seem to be the cause of bleeding. Postoperative management was described in the methods section of our paper, to which we refer readers. Although complete closure of the defect after ESD might be an effective method for the management of complications associated with ESD [2] [3] [4], there is still insufficient evidence concerning the prevention of post-ESD bleeding. A direct comparison between PGA shielding and complete closure would be next on the research agenda. Finally, we totally agree with Wang et al. that the small sample size in this study might have led to an underestimation of the effect of PGA shielding, although the sample size was objectively calculated based on the pilot study by Tsuji et al. [5]. However, considering the speed of patient enrollment and the fact that at the beginning of the study only a few centers had adopted the PGA shielding method, we had no choice but to limit the sample size. Now that use of the PGA shielding method has become more widespread in Japan, and risk factors for post-ESD bleeding have become clearer, another study with a larger sample size should be considered in order to reassess the efficacy of the PGA shielding method.

• References

• 1 Kataoka Y, Tsuji Y, Hirasawa K. et al. Endoscopic tissue shielding to prevent bleeding after endoscopic submucosal dissection: a prospective multicenter randomized controlled trial. Endoscopy 2019; 51: 619-627
• 2 Wang J, Zhao L, Wang X. et al. A novel endoloop system for closure of colonic mucosal defects through a single-channel colonoscope. Endoscopy 2017; 49: 803-807
• 3 Tashima T, Ohata K, Sakai E. et al. Efficacy of an over-the-scope clip for preventing adverse events after duodenal endoscopic submucosal dissection: a prospective interventional study. Endoscopy 2018; 50: 487-496
• 4 Nishizawa T, Akimoto T, Uraoka T. et al. Endoscopic string clip suturing method: a prospective pilot study (with video). Gastrointest Endosc 2018; 87: 1074-1078
• 5 Tsuji Y, Fujishiro M, Kodashima S. et al. Polyglycolic acid sheets and fibrin glue decrease the risk of bleeding after endoscopic submucosal dissection of gastric neoplasms (with video). Gastrointest Endosc 2015; 81: 906-912