The risk of using antiplatelet and/or anticoagulant treatment for hemorrhagic adverse events during EUS-guided biliary drainage

I read with great interest the study by Ogura et al1Ogura T. Nishioka N. Ueno S. et al.Antiplatelet and/or anticoagulant treatment does not increase hemorrhagic adverse events during EUS-guided biliary drainage.Gastrointest Endosc. 2020; 92: 659-666Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar investigating the association between the use of antiplatelet and/or anticoagulant (AC/AP) and the risk of bleeding during EUS-guided biliary drainage. Of 195 patients, 154 (79%) were in the control group and 41 (21%) were in the AC/AP group, and 7 (3.5%) had bleeding events. The authors conclude that the frequency of bleeding events did not differ significantly between the control group (2.6%) and the AC/AP group (7.3%). The study investigates an interesting topic, but I think that some points need to be clarified. First, the bleeding event rate of the AC/AP group was about 3 times that of the control group.1Ogura T. Nishioka N. Ueno S. et al.Antiplatelet and/or anticoagulant treatment does not increase hemorrhagic adverse events during EUS-guided biliary drainage.Gastrointest Endosc. 2020; 92: 659-666Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar “No statistical difference” is probably due to a small sample size. According to this study, we assume that the event rate of bleeding is 3.5% and the relative hazard of the AP/AC group is 3. We need to enroll 471 patients in the control group and 118 patients in the AP/AC group, at least, to reject the null hypothesis with the probabilities of power at .8 and type I error at .05.2Kadam P. Bhalerao S. Sample size calculation.Int J Ayurveda Res. 2010; 1: 55-57Crossref PubMed Google Scholar Second, Table 2 showed variable methodology of the AC/AP disruption. Whereas 22 patients discontinued AC/AP or heparin bridge, 19 patients resumed AC/AP. From Tables 4 and 5, no bleeding event was observed in patients who disrupted AC/AP, but 3 patients (15.8%) resuming AC/AP encountered bleeding events. Clinical physicians were concerned whether no interruption of AC/AP increased the bleeding risk during endoscopy procedures. Therefore, we compared the 19 patients resuming AC/AP with the 154 patients in the control group. In logistic regression analysis, we found that the bleeding risk of patients resuming AC/AP was higher than that in the control group (relative risk, 7.031; 95% CI, 1.444-34.246; P = .026).3Nick T.G. Campbell K.M. Logistic regression.Methods Mol Biol. 2007; 404: 273-301Crossref PubMed Google Scholar The main message is that for patients in whom AP/AC was not interrupted, the bleeding risk of EUS-guided biliary drainage was high. The author disclosed no financial relationships.