Disputes about the efficacy of polyglycolic acid shielding for prevention of bleeding after endoscopic submucosal dissection

Recently, Kataoka et al. [1] reported that polyglycolic acid (PGA) shielding had limited efficacy for the prevention of bleeding after endoscopic submucosal dissection (ESD). We would like to raise several concerns about this study and would appreciate the authors’ clarification of some details.

First, the authors reported that PGA sheet application was performed by one of two methods (step-by-step method and clip-and-pull method) according to each endoscopist. As claimed, the PGA sheet was first placed. What factors did the authors consider for the further fixation of fibrin glue? Would it be better to spray the fibrin first rather than coat the PGA sheet? Did the PGA sheet tightly cover the mucosa in bleeding cases? Tissue exudate and gastric acid might delay defect healing after ESD. As the foreign body, would the uncovered PGA sheet trigger hemorrhage of superficial vessels during oral intake? The post-operational nursing and endoscopic follow-up should be provided to explain early bleeding for PGA application [2] [3] [4].

Second, complete defect closure was suggested for ESD by the American Gastroenterological Association [5]. The large lesion and exposed defect might be the main cause of post-ESD bleeding. In our practice, clips or purse-suture methods are effective for defect closure and bleeding prevention. Would the authors consider this approach for the further comparison?

Third, we had some concerns about sample calculation. In the introduction, the authors stated that post-ESD bleeding was approximately 5 % with current prevention methods. But they applied 21 % bleeding in the control group during the statistical calculation for patient cohort size. Due to the small sample size, the superiority of PGA shielding was underestimated in this study. More patients should be enrolled to meet the statistical power and discriminate the intervention efficacy.

• 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 Takao T, Takegawa Y, Shinya N. et al. Tissue shielding with polyglycolic acid sheets and fibrin glue on ulcers induced by endoscopic submucosal dissection in a porcine model. Endosc Int Open 2015; 3: E146-151
• 3 Kawata N, Ono H, Takizawa K. et al. Efficacy of polyglycolic acid sheets and fibrin glue for prevention of bleeding after gastric endoscopic submucosal dissection in patients under continued antithrombotic agents. Gastric Cancer 2018; 21: 696-702
• 4 Kikuchi D, Iizuka T, Nomura K. et al. Feasibility of autologous fibrin glue and polyglycolic acid sheets to prevent delayed bleeding after endoscopic submucosal dissection of gastric neoplasms in patients receiving antithrombotic therapy. Gastroenterol Res Pract 2018; 2018: 2174957
• 5 Draganov PV, Wang AY, Othman MO. et al. AGA Institute Clinical Practice Update: endoscopic submucosal dissection in the United States. Clin Gastroenterol Hepatol 2019; 17: 1625