ObjectivesEvaluation of Helicobacter pylori infection status (non‐infection, past infection, current infection) has become important. This study aimed to determine the usefulness of the Kyoto classification of gastritis for diagnosing H. pylori infection status by endoscopy.MethodsIn this prospective study, 498 subjects were recruited. Seven well‐experienced endoscopists blinded to the history of eradication therapy performed the examinations. Endoscopic findings were assessed according to the Kyoto classification of gastritis: diffuse redness, regular arrangement of collecting venules (RAC), fundic gland polyp (FGP), atrophy, xanthoma, hyperplastic polyp, map‐like redness, intestinal metaplasia, nodularity, mucosal swelling, white and flat elevated lesion, sticky mucus, depressive erosion, raised erosion, red streak, and enlarged folds. We established prediction models according to a machine learning procedure and compared them with general assessment by endoscopists using the Kyoto classification of gastritis.ResultsSignificantly higher diagnostic odds were obtained for RAC (32.2), FGP (7.7), and red streak (4.7) in subjects with non‐infection, map‐like redness (12.9) in subjects with past infection, and diffuse redness (26.8), mucosal swelling (13.3), sticky mucus (10.2) and enlarged fold (8.6) in subjects with current infection. The overall diagnostic accuracy rate was 82.9% with the Kyoto classification of gastritis. The diagnostic accuracy of the prediction model was 88.6% for the model without H. pylori eradication history and 93.4% for the model with eradication history.ConclusionsThe Kyoto classification of gastritis is useful for diagnosing H. pylori infection status based on endoscopic findings. Our prediction model is helpful for novice endoscopists. (UMIN000016674).

Background and Aim: Prophylactic clipping has been widely used to prevent post-procedural bleeding in colon polypctomy. However, its efficiency has not been confirmed and there is no consensus on the usefulness of prophylactic clipping. The aim of the present study was to evaluate the preventive effect of prophylactic clipping on post-polypectomy bleeding.Methods: A multicenter randomized controlled study was conducted from January 2012 to July 2013 in Japan. Patients who had polyps <2 cm in diameter were divided into a clipping group and a non-clipping group by cluster randomization. After endoscopic polypectomy, patients allocated to the clipping group underwent prophylactic clipping, whereas the procedure was completed without clipping in patients allocated to the nonclipping group. Occurrence of post-polypectomy bleeding was compared between the two groups.Results: Seven hospitals participated in this study. A total of 3365 polyps in 1499 patients were evaluated. The clipping group consisted of 1636 polyps in 752 patients, and the non-clipping group consisted of 1729 polyps in 747 patients. Postpolypectomy bleeding occurred in 1.10% (18/1636) of the cases in the clipping group, and in 0.87% (15/1729) of those in the nonclipping group. The difference was -0.22% (95% confidence interval [CI]: -0.96, 0.53). Upper limit of the 95% CI was lower than the noninferiority margin (1.5%), and we could thus prove non-inferiority of non-clipping against clipping.Conclusion: Prophylactic clipping is not necessary to prevent post-polypectomy bleeding for polyps <2 cm in diameter.

Background: The cold polypectomy (CP) technique has been increasingly used in recent years. However, there have been few studies about post-polypectomy bleeding (PPB) in patients who underwent CP and who were on antithrombotic drugs. The objective of this study was to determine the safety of CP in patients on antithrombotic medication. Methods: The subjects were patients who underwent CP in our hospital between April 2014 and March 2016. PPB rates were examined in relation to the use of antithrombotic medication. Results: CP was performed to remove 2,466 polyps in 1,003 patients. There were 549 polyps (22.3%) in186 patients in the antithrombotic group and 1,917 polyps (77.7%) in 817 patients in the non-antithrombotic group. PPB occurred in 0.55% (3/549) of patients in the antithrombotic group and in 0.10% (2/1,917) of patients in the non-antithrombotic group, showing no significant difference (p = 0.07). Patients in the antithrombotic group in whom PPB occurred included 1 aspirin user with 1 polyp and 1 aspirin plus clopidogrel user with 2 polyps. No PPB occurred in patients on other antithrombotic agents or receiving heparin bridging. There was no significant difference between PPB rates in patients with small polyps (6–9 mm) in the antithrombotic and non-antithrombotic groups, but there was a significant difference between PPB rates in the 2 groups for patients with diminutive group (1–5 mm). Conclusion: CP is a safe procedure even in patients on antithrombotic medication.

Background/Aims: Delayed bleeding is among the adverse events associated with therapeutic gastrointestinal endoscopy. The aim of this study was to evaluate risk factors for delayed bleeding after gastrointestinal endoscopic resection in patients receiving oral anticoagulants as well as to compare the rates of occurrence of delayed bleeding between the oral anticoagulants used. Methods: We retrospectively analyzed a total of 772 patients receiving anticoagulants. Of these, 389 and 383 patients were receiving direct oral anticoagulants (DOACs) and warfarin, respectively. Therapeutic endoscopic procedures performed included endoscopic submucosal dissection (ESD), endoscopic mucosal resection, polypectomy, and cold polypectomy. Results: Delayed bleeding occurred in 90 patients (11.7%) with no significant difference between the DOAC and warfarin groups (9.5 and 13.8%, respectively). Delayed bleeding occurred significantly more frequently with apixaban than with rivaroxaban (13.5 vs. 6.4%; p < 0.05). A multivariate analysis identified continued anticoagulant therapy (OR 2.29), anticoagulant withdrawal with heparin bridging therapy (HBT; OR 2.18), anticoagulant therapy combined with 1 antiplatelet drug (OR 1.72), and ESD (OR 3.87) as risk factors for delayed bleeding. Conclusion: This study identified continued anticoagulant therapy, anticoagulant withdrawal with HBT, anticoagulant therapy combined with 1 antiplatelet drug, and ESD as risk factors for delayed bleeding after therapeutic endoscopy in patients receiving oral anticoagulants. Delayed bleeding rates were not significantly different between those receiving DOACs and warfarin. It was also suggested that the occurrence of delayed bleeding may vary between different DOACs and that oral anticoagulant withdrawal should be minimized during therapeutic gastrointestinal endoscopy, given the thromboembolic risk involved.

Prospective studies were performed to characterize parotid and parapharyngeal tumours using dynamic magnetic resonance (MR) imaging. Bolus injection of gadopentetate dimeglumine and a short SE sequence were used to evaluate 23 masses including seven pleomorphic adenomas, seven Warthin's tumours and nine malignant tumours. Contrast enhancement profiles helped to distinguish the different types of parotid and parapharyngeal tumours. Gradual increase in intensity during the first 260 s after the injection was characteristically found in pleomorphic adenomas and adenoid cystic carcinomas. Conversely, all Warthin's tumours showed a rapid increase during the first 20 s followed by a decrease in signal intensity. The other malignant tumours showed a rapid increase during the first 20 s followed by gradual decrease or increase at a slow rate. We suggests that the gradual increase in signal intensity of pleomorphic adenoma and adenoid cystic carcinoma may be due to their hypovascularity and an abundance of interstitial regions rich in connective tissue-type mucin. Dynamic MRI shows promise in tissue characterization of parotid and parapharyngeal tumours.