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Background High quality esophagogastroduodenoscopy (EGD) depends on the ability to appropriately visualize upper gastrointestinal (GI) mucosa pathology. Evaluation can be limited by the presence of mucus, foam, bubbles and solid materials. Currently, there is no standardized method to assess mucosal visualization for use in clinical or research settings. Aims To develop and establish the content validity of the Toronto Upper Gastrointestinal Cleaning Score (TUGCS) and evaluate its interrater reliability. Methods An international panel of endoscopy experts rated potential items and their associated anchors for importance as indicators of adequacy of mucosal visualization during EGD. The survey utilized a Likert scale (1 (strongly disagree) to 5 (strongly agree)). The Delphi process was repeated until consensus was reached. Consensus was defined priori as ≥80% of experts in a given round scoring ≥4 on all survey items. To assess content validity, 48 EGD procedures were evaluated in real-time by two endoscopist reviewers using the TUGCS at a single institution. The interrater agreement between assessments was calculated for TUGCS total scores using intraclass correlation coefficient, one-way random effects model (ICC 1,1). Results Fourteen experts agreed to be part of the Delphi panel. An anatomical framework representing the upper GI mucosa and anchors for each mucosal portion representing various levels of visibility was generated through systematic review. Three survey rounds, with response rates of 100%, 100% and 71% respectively, achieved consensus. The final TUGCS includes four anatomical areas (fundus, body, antrum, duodenum) and mucosal visualization anchors ranging from 0 to 3 (Figure 1). TUGCS was used to assess foregut cleaning in 48 procedures (Table 1). The mean TUGCS for staff and trainee were 8.1 (±2.4) and 8.1 (±2.6), respectively. The ICC was 0.78 (95% confidence interval 0.62–0.88) indicating good reliability. Conclusions We developed and generated content validity evidence for the TUGCS through rigorous Delphi methodology, reflective of practice across different centres. Planned as future research is a video survey distributed to endoscopists internationally to further validate the TUGCS to create a tool that may be used to judge mucosal visualization for EGD in research and clinical settings. Funding Agencies None

Background Afferent limb syndrome is obstruction of a biliary-enteric limb following pancreaticoduodenectomy. In the past, treatment was limited to surgery or insertion of a percutaneous transhepatic biliary drainage tube. A more recent approach to treatment is Endoscopic Ultrasound (EUS)-guided gastrojejunostomy using a lumen apposing metal stent (LAMS). It was first described in two single case reports in 2015 and has been growing in its application. We present a case series of 2 patients where afferent limb syndrome was successfully managed with EUS guided gastrojejunostomy using LAMS. Aims 1-To demonstrate a novel technique for diagnosis and management of afferent limb syndrome. Methods Case # 1- 79 year old female post Whipple’s surgery for ampullary carcinoma, presented two years after surgery with significant nausea and vomiting. CT scan showed obstruction of the afferent loop suspicious for local tumor recurrence. Patient underwent EUS-guided gastrojejunostomy with successful insertion of 20 x 10 mm (AXIOS EC, Boston Scientific) stent. Case # 2-. A 51 year old male with pancreatic CA status post Whipple surgery presented with worsening abdominal pain and nausea. CT scan confirmed afferent limb syndrome. He underwent EUS- guided gastrojejunostomy with successful placement of 10 x 10 mm (AXIOS EC, Boston Scientific). Results Case #1: Patient improved dramatically within days and resumed oral diet. Fourteen days later, an upper endoscopy was performed in order to assess the stricture via an anterograde approach. The adult Olympus HQ gastroscope was advanced through the AXIOS stent into the afferent limb to the level of the stenosis where a tight stricture was seen. Multiple biopsies taken and were negative for malignancy. Four weeks later, she continued to tolerate oral diet well with no abdominal pain or discomfort. Case # 2: Patient continued to do well clinically 12 weeks post operation. Follow-up upper endoscopy was performed to determine the etiology of the obstruction but due to a sharp angulation, the gastroscope could not be advanced through the AXIOS stent. As such, we advanced an adult Olympus 1T gastroscope down to the site of the AXIOS stent and then utilized the Spyglass DS system to advanced deep into the afferent limb to the level of the stricture and took multiple biopsies for diagnostic purposes. Conclusions Interventional endoscopic management of afferent limb syndrome has been evolving in the past few years with EUS guided LAMS gastrojejunostomy becoming a well stablished modality. We have demonstrated this technique with subsequent endoscopic anterograde assessment. In one of these cases, this anterograde assessment was performed using the cholangioscope in conjunction with the gastroscope to overcome unfavorable angulated anatomy which to our knowledge has not been described in the literature previously. Funding Agencies None

Background Management of large colorectal polyps is increasingly complex with the expansion of endoscopic techniques, including endoscopic submucosal dissection (ESD), endoscopic mucosal resection (EMR), and endoscopic full thickness resection. Adjudicating lesions in an effort to select the optimal resection method is hugely dependent on the information included within the referral. At our institution, a referral pathway based on photo and/or video documentation was created to facilitate the timely assessment and treatment of large colorectal polyps. To date, little is known about quality of referrals for endoscopic resection of large colorectal polyps. Purpose Our study aimed to assess the adjudication process and quality of referrals for endoscopic resection of large colorectal polyps at our advanced endoscopy referral center. Method We conducted a single-center prospective study of consecutive colorectal polyps referred for EMR from March 2021 to March 2022. Cases selected upfront for ESD were excluded. Referral information, intraprocedural data and histology was captured. No procedural and histology data were captured if EMR does not occur after adjudication. The outcome was defined as the frequency of adequate referrals. A referral was deemed adequate if it contained: sufficient photo or video documentation, description of any characteristics that increase the difficulty of endoscopic resection, accurate polyp localization/size estimate (with Result(s) During the study period, 213 referrals were received for colorectal polyps and underwent adjudication for EMR: 211 underwent EMR; 2 underwent ESD despite being triaged for EMR. Only 5% (10/213) of referrals were deemed to be adequate. Only 34% (73/213) contained any photo or video documentation and only 13% (28/213) photos/videos were of sufficient quality for adjudication. Difficult location or polyp characteristics, if present, were accurately described in 86.7% of referrals (183/211) of referrals. The accurate polyp location was described 80.6% of the time (170/211). Polyp size was estimated in 50.2% (107/213) of referrals. Amongst referrals with size estimated, the size was accurate in 73.8% of the time (79/107). On histological evaluation, 35.1% (74/211) of polyps had AD or SMI. Amongst polyps with AD or SMI, 48.6% (36/74) had endoscopic appearance suggestive of HGD/IMCa/SMI but only 69.4% (25/36) of these polyps with high-risk endoscopic features were accurately predicted based on the referral information. Conclusion(s) Referrals for large colorectal polyps often lack important clinical information. This significantly impairs the ability to adjudicate polyps for triage and resection and may negatively impact patient outcomes. To improve referral adequacy and patient outcomes, we plan to evaluate the impact of polyp adjudication on EMR success. Please acknowledge all funding agencies by checking the applicable boxes below None Disclosure of Interest None Declared

Background Non-ampullary duodenal adenomas, which can present sporadically or in the context of a polyposis syndrome, carry a risk of progression to carcinoma in a similar sequence to colorectal adenomas. Complete endoscopic resection is recommended as first line as a less invasive alternative to surgical rsection. Identifying recurrence rates of non-ampullary duodenal polyps after endoscopic resection, and patient and polyp characteristics associated with recurrence is important in determining the best method of resection and guiding endoscopic surveillance. Purpose To determine the technical success rate of endoscopic resection of non-ampullary duodenal polyps, complication rates, rate of residual and recurrent polyps, and identify factors associated with polyp recurrence. Method All adult patients (≥18 years) that underwent endoscopic resection of non-ampullary duodenal polyps at St. Michael’s Hospital, a Canadian tertiary referral center, from January 2010 to June 2021 were retrospectively identified. Descriptive statistics were calculated for variables of interest and Chi-square, t-test or U-Mann Whitney tests were used to compare variables as appropriate. Bi-variate regression analysis was utilized to determine co-variables associated with recurrence. Result(s) A total of 300 patients underwent endoscopic resection of duodenal polyps. Table 1 describes patient demographics, polyp and procedural characteristics and characteristics associated with recurrence. Nearly all cases were technically successful (96%, n=286/299). Clinically significant intraprocedural bleeding occurred in 22% (n=65/300) of patients, and deep mural injury occurred in 3% (n=7/284) of patients. Delayed post-procedural bleeding occurred in 9% of patients (n=26/279). The median time to first surveillance EGD was 4 months. Polyp recurrence occurred in 28% (n=50/180) of patients. Of the patients with polyp recurrence, 82% (n=42/50) were successfully managed endoscopically. On univariate analysis, polyp size (OR 1.03, 95% CI 1.01-1.06), piecemeal resection (OR 1.63, 95% CI 0.17-0.82), intraprocedural bleeding (OR 2.28, 95% CI 1.09-4.74), and high-grade dysplasia (HGD) or intramucosal adenocarcinoma (IMCa) on final histology (OR 3.46, 95% CI 1.64-7.33) were significantly associated with polyp recurrence. On multivariate analysis, only HGD/IMCa on final histology was significant (OR 3.41, 95% CI 1.38-8.47). Image Conclusion(s) Endoscopic resection of duodenal polyps can be safely performed with high technical success, however recurrence is a significant concern. Advanced histology was a significant predictor of polyp recurrence and highlights the importance of accurate pre-resection endoscopic characterization to correctly identify lesions at increased risk that may benefit from alternative resection methods such as ESD or hot rather than cold EMR, and which may require closer follow-up. Future work to develop predictive models of recurrence are needed to better stratify patient risk. Please acknowledge all funding agencies by checking the applicable boxes below None Disclosure of Interest None Declared

Background Magnification endoscopy and magnification narrow-band imaging are image enhanced endoscopy technologies that may allow for the diagnosis of advanced neoplasia in the GI tract on the basis of imaging characteristics. Recently, the Unified Magnifying Endoscopic Classification (UMEC) has been developed, which unified the criteria for the esophagus, stomach, and colon. UMEC divides optical diagnosis into one of the three categories: non-neoplastic, intramucosal neoplasia, and deep submucosal invasive cancer. Purpose The objective of this study is to educate North American endoscopists on the use of the UMEC schema, and to ascertain performance of the UMEC framework among North American endoscopists. Method Using UMEC, five North American endoscopists (>1000 procedures) without prior training in magnifying endoscopy independently diagnosed previously collected endoscopic image set of the esophagus, stomach, and colon. The endoscopists were trained on the use of UMEC via an eleven-minute training video with exemplars of each element of UMEC from esophagus, stomach, and colon. All endoscopists were blinded to white-light and non-magnifying NBI findings as well as histopathological diagnosis. The diagnostic performance of UMEC was assessed while using the gold standard histopathology as a reference. Result(s) A total of 299 gastrointestinal lesions (77 esophagus, 92 stomach, and 130 colon) were assessed using UMEC. For esophageal squamous cell carcinoma, the sensitivity, specificity, and accuracy for all 5 endoscopists ranged from 65.2% (95% CI: 50.9–77.9) to 87.0% (95% CI: 75.3–94.6), 77.4% (95% CI: 60.9–89.6) to 96.8% (95% CI: 86.8–99.8), and 75.3% to 87.0%, respectively. For gastric adenocarcinoma, the sensitivity, specificity, and accuracy for all 5 endoscopists ranged from 94.9% (95% CI: 85.0–99.1) to 100%, 52.9% (95% CI: 39.4–66.2) to 92.2% (95% CI: 82.7–97.5), and 73.3% to 93.3%, respectively. For colorectal adenocarcinoma, the sensitivity, specificity, and accuracy for all 5 endoscopists ranged from 76.2% (95% CI: 62.0–87.3) to 83.3% (95% CI: 70.3–92.5), 89.7% (95% CI: 82.1–94.9) to 97.7% (95% CI: 93.1–99.6), and 86.8% to 90.7%, respectively. Image Conclusion(s) UMEC is a simple and practical classification that can be used to introduce and educate endoscopists to magnification narrow-band imaging and optical diagnosis. Please acknowledge all funding agencies by checking the applicable boxes below CAG Disclosure of Interest M. R. A. Fujiyoshi Grant / Research support from: 2022 CAG/AbbVie Education Research Grant, Y. Fujiyoshi: None Declared, N. Gimpaya: None Declared, R. Bechara: None Declared, T. Jeyalingam: None Declared, N. Calo: None Declared, N. Forbes: None Declared, R. Khan: None Declared, M. Atalla: None Declared, A. Toshimori: None Declared, Y. Shimamura: None Declared, M. Tanabe: None Declared, J. Mosko: None Declared, H. Inoue: None Declared, S. Grover: None Declared

Background Advancements in endoscopy and minimally invasive surgery have led to the development of organ-preserving resection techniques to manage rectal lesions. According to JGES, ESGE, and AGA, endoscopic mucosal dissection (ESD) is typically recommended for Kudo V/JNET 2b pit pattern, LST-NG/Paris Is/IIc/IIa+Is morphology, presence of submucosal fibrosis, and local residual/recurrent adenomas. ESD is not without its limitations including depth of resection, technical difficulty and time. In some instances, a transanal minimally invasive surgery (TAMIS) approach can overcome some of these limitations while also avoiding the morbidity of proctectomy. The ESD-TAMIS approach has been described by two groups in the USA and Germany demonstrating initial safety and feasibility for management of distal rectal adenomas. Purpose We present the first Canadian case to demonstrate the use of a combined ESD-TAMIS for the management of a large post-TAMIS recurrent rectal adenoma, involving the dentate line, not amenable to endoscopic resection or TAMIS alone. Method N/A Result(s) A healthy 78-yr-old woman was referred for consideration of ESD of a large recurrent low rectal adenomatous lesion which had undergone multiple prior endoscopic mucosal and TAMIS resections. Pathology from prior excisions never showed high grade dysplasia (HGD) or intramucosal cancer. The lesion was 4-5cm long and occupied 90% of the circumference of the lumen including the dentate line. It had Paris IIa+Is+IIb components with submucosal fibrosis. The pit pattern was JNET 2a/2b (Fig 1). Given the size and dramatic submucosal scarring, ESD was deemed extremely challenging, time consuming and would likely involve a full thickness resection. Similarly, given that the lesion involved the dentate line and the borders were difficult to delineate, a TAMIS would not be feasible. In collaboration with our surgical colleagues, we proceeded with the ESD-TAMIS. The borders of the lesion were first demarcated and marked endoscopically. Using standard ESD technique, a mucosal incision was performed on the anal side of the lesion, followed by submucosal dissection until sufficient space was created for the TAMIS platform. Then, using TAMIS technique, a full thickness resection was performed. The lesion was successfully removed en-bloc and pinned for pathology. The large size of the defect and proximity to the dentate line prevented surgical closure. Post-op course was complicated by fever successfully managed with antibiotics. Overall, the procedure was well tolerated. The final pathology revealed a tubulovillous adenoma with HGD and extensive submucosal fibrosis. Image Conclusion(s) A transanal endoscopic cooperative surgery combining ESD and TAMIS was safe and effective, combining the advantages of each procedural technique, in providing curative en-bloc resection of a recurrent large near-circumferential low rectal tubulovillous adenoma with HGD involving the dentate line. Here, we present the first reported Canadian case using this novel technique. Please acknowledge all funding agencies by checking the applicable boxes below None Disclosure of Interest None Declared

Background Optical diagnosis relies on the ability of the endoscopist to visualize normal and abnormal patterns on the epithelial surface of the gastrointestinal tract. With ongoing technologic advances in image-enhanced and magnifying endoscopy, there has been more attention given to improving our ability to visually evaluate and classify lesions as this can help guide decisions around resection techniques. However, the accuracy of optical diagnosis of epithelial lesions remains under investigated. Aims To analyse (1) the presence or absence of descriptive details (size, gross morphology, and classification systems used) of lesions of interest within the endoscopy report and (2) the accuracy of the optical diagnosis, when stated, as compared to the final pathology report. Methods This is a single-centre retrospective chart review and quality improvement initiative conducted at St. Michael’s Hospital, Toronto, Ontario. All patients who had polypectomy performed between January 1st, 2019 and December 31st, 2020 for polyp(s) > 10mm in size, were eligible for study inclusion. Patients were excluded if polyps did not meet the size criteria, the polyp was not resected, or absent documentation. Descriptive statistics were conducted. Results 2100 patients had polypectomies during the study period. 714 patients with 833 polyps >10mm in size were included in the data analysis. Estimated size was reported for 93% of polyps, gross morphology for 68%, and a classification system for 72%. All three description parameters were reported for 52% of polyps. Predicted pathology was recorded in 41% of polyps. When documented, the accuracy of optical diagnosis was 71%. Conclusions In our study, the presence of key descriptive details attributed to polyps at the time of polypectomy was lower than expected. In addition, an optical diagnosis was documented in less than half of the time. Finally, the overall accuracy of optical diagnosis was lower than predicted potentially related to the underreporting and underutilization the important predictors of submucosal invasion. Considering that making real-time endoscopic diagnoses has major implications on treatment decisions, it is imperative that we work on these skills to improve patient outcomes (increasing R0 resection rates, decreasing recurrence and avoiding unnecessary surgeries). Through this project, recommendations will be made regarding the implementation of synoptic reporting in addition to guiding future quality improvement initiatives. Funding Agencies None

Background Surgical resection with laparoscopic gastric wedge resection is commonly conducted for local management of gastrointestinal stromal tumours (GIST). However, resection margins are often difficult to appreciate for lesions with larger endophytic components. As a result, tumour margins may be compromised or excess tissue resected. Laparoscopic endoscopic cooperative surgery (LECS) was developed in Japan to overcome these technical challenges in the resection of subepithelial lesions, including GISTs. Here, we present a case report of an early Canadian experience utilizing LECS in the management of gastric GIST. Aims To describe a case report of an early Canadian experience of LECS for the resection of a gastric GIST. Methods We performed a review of the literature and describe a case of LECS. Results We present a 70-year-old female referred to our centre for endoscopic resection of a 2.5x2.5cm histologically confirmed gastric GIST (low mitotic index and no known metastases). Repeat endoscopic evaluation at our centre confirmed a 25-30mm subepithelial lesion with both exophytic (small) and endophytic (large) components. After tumour board review, we opted for a LECS approach. In the OR, the lesion was identified endoscopically and marked with a Dual J-Knife (Olympus). The margins were injected with a combination of Voluven, methylene blue, and dilute epinephrine. A circumferential incision was then completed using standard ESD technique. The lesion was subsequently identified laparoscopically, with endoscopic guidance, along the lesser curvature. The lesser omentum was mobilized for clear visualization of the serosa around the lesion. A full thickness incision was made endoscopically along the distal aspect of lesion. Full thickness resection was continued endoscopically for one third of the circumference of the lesion until gastric insufflation became compromised. Full thickness resection was completed laparoscopically under endoscopic guidance with grossly negative margins. The defect was closed with running laparoscopic sutures. Endoscopic leak test was performed which was negative. The specimen was retrieved and follow up pathology demonstrated a GIST with low mitotic index and negative margins without tumour rupture. Conclusions In a review of the literature, LECS appears to minimize tissue resection while maintaining R0 resection rates. This technique is especially useful for subepithelial lesions with larger endophytic and transmural components. It has an excellent safety profile with a less than 5% anastomotic leak rate. As such, the literature supports LECS as a suitable procedure for gastric subepithelial lesions Funding Agencies None

Background Competence in performing polypectomy is increasingly appreciated as a colonoscopy quality metric, as incomplete resection can lead to post-colonoscopy colorectal cancer, particularly for polyps removed using piecemeal endoscopic mucosal resection (EMR). The relationship between training experiences and cognitive competence in polypectomy has not been previously described. Aims We aimed to examine associations between training and assessment experiences, self-reported comfort, and cognitive competence in polypectomy amongst recent graduates of Canadian gastroenterology training programs. Methods An online survey was distributed to recent GI graduates (≤5 years in independent practice). The survey comprised 4 sections: (1) demographics; (2) training and assessment experiences in colonoscopy, polypectomy, and EMR; (3) self-reported comfort in performing aspects of polypectomy outlined in the Direct Observation of Polypectomy Skills Assessment Tool; and (4) performance on a 22-item multiple choice quiz intended to assess cognitive competence in polypectomy (items and correct responses to which were determined a priori based on agreement of two experts). Data was analyzed using descriptive statistics and associations between predictors (demographics, training/assessment experiences, self-reported comfort) and outcomes (quiz score) were assessed using multiple linear regression. Results There were 28 survey respondents, comprising 13 (46%) who trained in advanced endoscopy, 5 (18%) in hepatology, 2 (7%) in motility, 1 (4%) in IBD, 1 (4%) in nutrition, and 6 (21%) with no advanced training. This cohort had a mean (SD) duration in independent practice of 29.0 (18.4) months. Their mean (SD) annual volume of colonoscopy, polypectomy, and EMR in independent practice was 530 (221), 182 (76), 28 (16), respectively and they had completed 525 (203) colonoscopies, 146 (92) polypectomies, and 23 (20) EMRs in their prior training. Their mean (SD) quiz score was 71.9% (13.2%). ANOVA revealed significant score differences based on fellowship history, with those trained in advanced endoscopy achieving the highest scores (81.1%, P=0.01). Multiple linear regression revealed that the number of EMRs completed during training was significantly correlated with quiz performance (B=0.60, P=0.03). Conclusions EMR experience during training appears to be associated with cognitive competence in polypectomy in independent practice. These results suggest increasing exposure to EMR in training may improve polypectomy quality amongst practicing endoscopists. Funding Agencies CAG

Humidification of inspired gas is important for patients receiving respiratory support. High-flow nasal cannula (HFNC) effectively provides temperature and humidity-controlled gas to the airway. We hypothesized that various levels of gas humidification would have differential effects on airway epithelial monolayers. Calu-3 monolayers were placed in environmental chambers at 37°C with relative humidity (RH) < 20% (dry), 69% (noninterventional comparator), and >90% (HFNC) for 4 and 8 hours with 10 L/min of room air. At 4 and 8 hours, cell viability and transepithelial resistance measurements were performed, apical surface fluid was collected and assayed for indices of cell inflammation and function, and cells were harvested for histology (n=6/condition). Transepithelial resistance and cell viability decreased over time (P<0.001) between HFNC and dry groups (P<0.001). Total protein secretion increased at 8 hours in the dry group (P<0.001). Secretion of interleukin (IL)-6 and IL-8 in the dry group was greater than the other groups at 8 hours (P<0.001). Histological analysis showed increasing injury over time for the dry group. These data demonstrate that exposure to low humidity results in reduced epithelial cell function and increased inflammation.

BACKGROUND: Hypothermia with xenon gas has been used to reduce brain injury and disability rate after perinatal hypoxia-ischemia. We evaluated xenon gas therapy effects in an in vitro model with or without hypothermia on cultured human airway epithelial cells (Calu-3). METHODS: Calu-3 monolayers were grown at an air-liquid interface and exposed to one of the following conditions: 1) 21% FiO2 at 37°C (control); 2) 45% FiO2 and 50% xenon at 37°C; 3) 21% FiO2 and 50% xenon at 32°C; 4) 45% FiO2 and 50% xenon at 32°C for 24 hours. Transepithelial resistance (TER) measurements were performed and apical surface fluids were collected and assayed for total protein, IL-6, and IL-8. Three monolayers were used for immunofluorescence localization of zonula occludens-1 (ZO-1). The data were analyzed by one-way ANOVA. RESULTS: TER decreased at 24 hours in all treatment groups. Xenon with hyperoxia and hypothermia resulted in greatest decrease in TER compared with other groups. Immunofluorescence localization of ZO-1 (XY) showed reduced density of ZO-1 rings and incomplete ring-like staining in the 45% FiO2– 50% xenon group at 32°C compared with other groups. Secretion of total protein was not different among groups. Secretion of IL-6 in 21% FiO2 with xenon group at 32°C was less than that of the control group. The secretion of IL-8 in 45% FiO2 with xenon at 32°C was greater than that of other groups. CONCLUSION: Hyperoxia and hypothermia result in detrimental epithelial cell function and inflammation over 24-hour exposure. Xenon gas did not affect cell function or reduce inflammation.

Multichip modules continue to be of interest in applications where speed and thermal performance need to be maximized while weight and size are minimized. One solution to such design criteria is discussed here and its application in a digital CPU, cache control, and memory package is demonstrated. The integration of the various chips into a single interconnect package from each individual package enhances performance. This design characteristics used allowed the development of a processor/memory controller/RAM multichip package capable of routing >2000 nets in less than 22 cm/sup 2/ providing a junction to case thermal performance of 0.1/spl deg/C/watt for the CPU.