Novel through-the-scope suture closure of colonic EMR defects (with video)

BACKGROUND AND AIMS

Large colon polyps removed by EMR can be complicated by delayed bleeding. Prophylactic defect clip closure can reduce post-EMR bleeding. Larger defects can be challenging to close using through-the-scope clips (TTSCs), and proximal defects are difficult to reach using over-the-scope techniques. A novel, through-the-scope suturing (TTSS) device allows direct closure of mucosal defects without scope withdrawal. The goal of this study was to evaluate the rate of delayed bleeding after the closure of large colon polyp EMR sites with TTSS.

METHODS

A multicenter retrospective cohort study was performed involving 13 centers. All defect closure by TTSS after EMR of colon polyps ≥2 cm from January 2021 to February 2022 were included. The primary outcome was rate of delayed bleeding.

RESULTS

A total of 94 patients (52% female; mean age, 65 years) underwent EMR of predominantly right-sided (n = 62 [66%]) colon polyps (median size, 35 mm; interquartile range, 30-40 mm) followed by defect closure with TTSS during the study period. All defects were successfully closed with TTSS alone (n = 62 [66%]) or with TTSS and TTSCs (n = 32 [34%]), using a median of 1 (interquartile range, 1-1) TTSS system. Delayed bleeding occurred in 3 patients (3.2%), with 2 requiring repeated endoscopic evaluation/treatment (moderate).

CONCLUSION

TTSS alone or with TTSCs was effective in achieving complete closure of all post-EMR defects, despite a large lesion size. After TTSS closure with or without adjunctive devices, delayed bleeding was seen in 3.2% of cases. Further prospective studies are needed to validate these findings before wider adoption of TTSS for large polypectomy closure.

A135 ENDOSCOPIC SUBMUCOSAL DISSECTION OF GASTRIC ADENOMAS AND EARLY CARCINOMAS

Background

Management of gastric adenoma and early gastric cancer requires endoscopic resection. This can often be achieved with endoscopic mucosal resection (EMR), which has been shown to be effective with a good safety profile. One disadvantage of EMR is that it is often completed piecemeal, leading to indeterminant margins and higher rates of recurrences that require additional intervention. Endoscopic submucosal dissection (ESD) is a more advanced endoscopic resection technique that has been shown to be more effective than EMR at en-bloc resection. ESD requires high technical proficiency but it is becoming more widely available in western countries.

Purpose

The purpose of this study is to report on the outcomes and rates of complications of gastric ESD completed in a tertiary centre in British Columbia.

Method

All gastric ESD was completed by a senior therapeutic endoscopist who has previously received training in Japan. Retrospective data were collected on all gastric ESD procedures done in St. Paul’s Hospital from May 7th, 2015, when the procedure first became available, to Aug 30th, 2022. Inclusion criteria were all adults who have undergone ESD for resection of a gastric lesion. Exclusion criteria were patients younger than 18. Data collected included demographic variables, polyp characteristics, procedural outcomes, and complications.

Result(s)

A total of 49 ESD procedures were completed. The mean size of the resected lesions was 25.3 mm (range: 5 – 100 mm). Technical success, defined as successful resection of all polypoid tissue, was achieved in 48/49 procedures (98.0%). En bloc resection was achieved in 42/48 (87.5%) completed ESD. The rate of R0 resection was also 42/48 (87.5%). Curative resection, defined as technically successful ESD with an R0 margin and no lymphovascular invasion, was achieved in 41/49 (83.7%) of the cases. In our cohort, 8 patients had adenocarcinoma, 5 of which had a curative resection with no evidence of recurrence. None of the ESD resulted in any intra-procedural or delayed perforation. 5/49 (10.2%) patients had clinically significant post-endoscopic resection bleeding. Out of 37 patients that completed follow-up, 3 (8.1%) had recurrence, and all of them were managed endoscopically. 4/49 (8.2%) of patients required surgery post-ESD.

Conclusion(s)

In our cohort, ESD is an effective endoscopic resection modality for gastric lesions with a high rate of technical success and curative resection. Despite a deeper plane of resection versus other endoscopic resection modalities, its complication rate remains low. Although ESD requires high technical proficiency, its favorable outcomes along with low rates of complication make ESD highly feasible for the resection of gastric lesions. Further research will be needed to study the implementation and outcomes of

ESD in a western setting.

Please acknowledge all funding agencies by checking the applicable boxes below

None

Disclosure of Interest

None Declared

A131 ENDOSCOPIC SUBMUCOSAL DISSECTION OF COLORECTAL ADENOMAS AND EARLY ADENOCARCINOMAS: OUTCOMES FROM BRITISH COLUMBIA

Background

Endoscopic resection is the standard of care for the management of colorectal polyps. Larger and more complex polyps require endoscopic mucosal resection (EMR). While complications have been low, EMR is often piecemeal, resulting in indeterminant margins and often a higher recurrence rate. Endoscopic submucosal dissection (ESD) is an advanced endoscopic resection technique with a higher rate of en bloc resection. While more data exist for the resection of gastric lesions with ESD, ESD is becoming more widely used in western countries for the resection of colorectal lesions.

Purpose

The purpose of this study is to report on the outcomes and rates of complications for colorectal ESD completed in a tertiary centre in British Columbia.

Method

All colorectal ESD was completed by a senior therapeutic endoscopist who has previously received training in Japan. Retrospective data were collected on all colorectal ESD procedures done in St. Paul’s Hospital from July 11th, 2016, when the procedure first became available, to Aug 30th, 2022. Inclusion criteria were all adults who have undergone ESD for resection of a colorectal lesion. Exclusion criteria were patients younger than 18. Data collected included demographic variables, polyp characteristics, procedural outcomes, and complications.

Result(s)

A total of 39 ESD procedures were completed. The mean size of the resected lesion was 30.4 mm (range: 5 – 60 mm). Technical success, defined as successful resection of all polypoid tissue, was achieved in 35/39 procedures (89.7%). En-bloc resection was achieved in 27/35 (77.1%) of the completed ESD. The rate of R0 resection was 22/35 (62.9%). Curative resection, defined as technically successful ESD with R0 margin and no lymphovascular invasion, was achieved in 23/39 (59.0%) of the cases and the majority of the patients with non-curative resection that underwent endoscopic surveillance had no recurrence on follow-up. In our cohort, 3/39 (7.7%) patients had adenocarcinoma. None of the ESD resulted in any intra-procedural or delayed perforation. 3/39 (7.7%) patients had clinically significant post-endoscopic resection bleeding. Out of 24 patients that completed follow-up, 4 (16.7%) had recurrence at the resection site that was managed endoscopically. 4/39 (10.3%) of patients required surgery post-ESD.

Conclusion(s)

In our cohort, ESD is an effective endoscopic resection modality for the management of colorectal adenomas and early adenocarcinoma with a high rate of technical success and low rates of complications. Although the rate of curative resection was low, most were the result of R1 or Rx resection and a majority of the follow-ups in this subgroup demonstrated no further recurrence. The rate of en bloc resection is high, especially given the average size of adenomas in this cohort. Although ESD requires high technical proficiency, its favorable outcomes and low complication rates make ESD highly feasible for the resection of colorectal lesions.

Please acknowledge all funding agencies by checking the applicable boxes below

None

Disclosure of Interest

None Declared

Endoscopic holmium laser lithotripsy for therapy of Bouveret syndrome

Video 1Video of holmium laser lithotripsy procedure.

Cost-effective analysis of preliminary single-operator cholangioscopy for management of difficult biliary stones

Background and study aims  Single-operator peroral cholangioscopy (SOC) is a therapeutic modality for difficult biliary stone disease. Given its high success rate and increasing availability, analysis of the economic impact of early SOC utilization is critical for clinical decision-making. Our aim is to compare the cost-effectiveness of different first and second-line endoscopic modalities for difficult-to-treat choledocholithiasis. Patients and methods  A decision-tree model with a 1-year time horizon and a hypothetical cohort of 200 patients was used to analyze the cost-effectiveness of SOC for first, second and third-line intervention in presumed difficult biliary stones. We adopted the perspective of a Canadian tertiary hospital, omitting recurrence rates associated with endoscopic retrograde cholangiopancreatography (ERCP). Effectiveness estimates were obtained from updated meta-analyses. One-way sensitivity analyses and probabilistic sensitivity analyses were also performed to assess how changes in key parameters affected model conclusions. Results  First- and second-line SOC achieved comparable clinical efficacy from 96.3 % to 97. 6 % stone clearance. The least expensive strategy is third-line SOC (SOC-3: $800,936). Performing SOC during the second ERCP was marginally more expensive (SOC-2: $ 816,584) but 9 % more effective. The strategy of first-line SOC incurred the highest hospital expenditures (SOC-1: $ 851,457) but decreased total procedures performed by 16.9 % when compared with SOC-2. Sensitivity analysis was robust in showing SOC-2 as the most optimal approach. Conclusions  Second-line SOC was superior to first and third-line SOC for treatment of difficult biliary stones. When based on meta-analysis of non-heterogeneous trials, SOC-2 is more cost-effective and cost-efficient. Our study warrants a larger pragmatic effectiveness trial.

Elevated serum ferritin in non-alcoholic fatty liver disease is not predictive of fibrosis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is common with widely ranging severity. Non-invasive risk scores for risk stratification are recommended but misclassify a significant proportion of patients. In situations where non-invasive risk scores do not provide guidance, referral is typically made to a Hepatologist for transient elastography or liver biopsy. Serum ferritin is elevated in many patients with NAFLD related to dysmetabolic and inflammatory hyperferritinemia. Ferritin is widely available and part of a standard workup for chronic liver disease.

METHODS

To explore the association of ferritin and risk of fibrosis in NAFLD, we reviewed patients diagnosed with NAFLD at the hepatology clinic of the Vancouver General Hospital between the years of 2015 and 2018. We collected data on 317 patients retrospectively assessing for a relationship between serum ferritin and elastography score.

RESULTS

Two hundred twenty-four patients were included in the final analysis. Median ferritin was 145 µg/L (IQR 62-311). Median liver stiffness was 5.2 kPa with 14.3% of patients having liver stiffness ≥8.7 kPa and 17.4% ≥ 8.0 kPa. ROC curve analysis using a liver stiffness ≥8.0 kPa as a cutoff for F2 fibrosis showed an AUROC of 0.54 for serum ferritin levels. At a cut-off of both 300 µg/L; and 450 µg/L median liver stiffness did not differ significantly in those with ferritin above the cutoff (ferritin ≥300 µg/L; p = 0.099, ferritin ≥450 µg/L; p = 0.12). Ferritin was significantly higher in male patients (198 versus 91 µg/L; p = 0.0001). There was a weak linear association between AST and ferritin levels.

CONCLUSION

In this cohort of 224 patients with NAFLD, serum ferritin was not predictive of significant liver fibrosis.

A98 FECAL LEUKOCYTE ESTERASE: AN ALTERNATIVE BIOMARKER TO FECAL CALPROTECTIN IN INFLAMMATORY BOWEL DISEASE

Background

Fecal calprotectin (FC) is a non-invasive biomarker used in inflammatory bowel disease (IBD) management and risk stratification of non-specific gastrointestinal symptoms. Leukocyte esterase is an inexpensive and widely available point-of-care inflammatory marker present on urinalysis test strips.

Aims

We aim to assess the diagnostic accuracy of fecal leukocyte esterase (FLE) relative to FC and endoscopy and demonstrate its use as an alternative biomarker for IBD.

Methods

In this prospective cohort study, 70 patients who had FC ordered as part of standard clinical care also received FLE testing. FLE levels were compared to various FC cut-off values, endoscopy and pathology findings as gold standard.

Results

As the FC cut-off increased from 50 to 500 μg/g, FLE sensitivity increased from 67% to 95% while the specificity decreased from 86% to 76%. The area under the receiver operating characteristic (AUROC) increased from 0.79 to 0.90. An FLE of ≥1+ had the best test characteristics. Amongst patients who underwent endoscopic evaluation, FLE demonstrated an identical sensitivity (75%) and specificity (86%) to FC in predicting endoscopic inflammation. AUROC was 0.80 for FLE and 0.85 for FC with an optimal cut-off of ≥2+ and 301 μg/g, respectively. When used to distinguish between active IBD and no/inactive IBD patients, FLE had a sensitivity of 84% and specificity of 90%, comparable to the 84% and 83%, respectively, of FC. AUROC was 0.88 for FLE and 0.91 for FC with an optimal cut-off of ≥2+ and 145 μg/g, respectively

Conclusions

FLE demonstrates adequate correlation and comparable accuracy to FC in predicting endoscopic inflammation and distinguishing between patients with active versus inactive IBD.

Funding Agencies

None

A86 COST-EFFECTIVE ANALYSIS OF PRELIMINARY SINGLE-OPERATOR CHOLANGIOSCOPY IN MANAGEMENT OF DIFFICULT STONES

Background

Single-operator peroral cholangioscopy (POC) is a therapeutic modality for difficult biliary stone disease. Given its high success rate and increasing availability, analysis of the economic impact of early POC utilization is critical for clinical decision-making.

Aims

We aim to compare the cost-effectiveness of different first and second-line endoscopic modalities for difficult-to-treat choledocholithiasis.

Methods

A decision tree model with a 1-year time horizon and a hypothetical cohort of 200 patients was used to analyze the cost-effectiveness of POC for first, second and third-line intervention in presumed difficult biliary stones. We adopted the perspective of a Canadian tertiary hospital, omitting complications and recurrence rates associated with ERCP. Effectiveness estimates were obtained from updated meta-analyses. One-way sensitivity analyses and probabilistic sensitivity analyses were also performed to assess how changes in key parameters affected model conclusions.

Results

First and second-line POC achieved comparable clinical efficacy from 95.5% to 96.5% stone clearance. The least expensive strategy is third-line POC (POC-3: $769,151). Performing POC during the second ERCP was marginally more expensive (POC-2: $770,832) but 9% more effective. The strategy of first-line POC incurred the highest hospital expenditures (POC-1: $848,141) but decreased total procedures performed by 13.4% when compared with POC-2. Sensitivity analysis was robust in showing POC-2 as the most optimal approach.

Conclusions

Second-line POC was superior to first and third-line POC for treatment of difficult biliary stones. When based on meta-analysis of non-heterogeneous trials, POC-2 is more cost-effective and cost-efficient. Our study warrants a larger pragmatic effectiveness trial.

Funding Agencies

None

Non-alcoholic fatty liver disease (NAFLD) in Filipino North American patients: Results from a multi-ethnic cohort

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is more prevalent in certain ethnicities due to a combination of genetic, environmental, and metabolic factors. North American Filipino populations may have lifestyle and metabolic risk factors for NAFLD; however, the prevalence of NAFLD in this group is unknown. We sought to determine whether Filipino patients are over-represented in a multi-ethnic NAFLD cohort and describe their clinical presentation, primarily compared to other ethnicities in the same geographical region and secondarily compared to Manila-based Filipino patients.

METHODS

A cross-sectional study was conducted with patients with NAFLD who were followed at the Hepatology Clinic at Vancouver General Hospital, Canada, from January 2015 to August 2018. Data were extracted for clinicodemographic data, ethnicity, anthropometric measures, blood work, and transient elastography (TE). External comparison data was obtained online from the Metro Vancouver census and a NAFLD study conducted in Manila, Philippines.

RESULTS

Of 317 patients meeting inclusion criteria for the study, 224 patients had complete datasets. The mean age was 51.1 years, and 50% were female. There were 139 (62%) Caucasian and other ethnicity patients, 55 (25%) Asian patients, and 30 (13%) Filipino patients. Compared to other ethnic groups, the Filipino group had similar clinical characteristics, including NAFLD fibrosis scores and TE. Of included NAFLD patients, the proportion of Filipino patients (13.39%) was significantly greater than the proportion of Filipino residents in Metro Vancouver (5.52%, p <0.01). Our Filipino Canadians seemed to be younger, with fewer females and a lower proportion of diabetes mellitus, but a higher proportion of hypertension than the previously reported cohort from Manila.

CONCLUSIONS

While Filipino patients have not previously been examined in multi-ethnic NAFLD studies, they may represent a high-risk population. Further research is needed to clarify the prevalence and presentation of NAFLD in Filipino Canadian patients, as this appears to be a significant health issue in this community.

Comparing the performance of Fibrosis-4 and Non-Alcoholic Fatty Liver Disease Fibrosis Score with transient elastography scores of people with non-alcoholic fatty liver disease

BACKGROUND: With the rate of non-alcoholic fatty liver disease (NAFLD) on the rise, the necessity of identifying patients at risk of cirrhosis and its complications is becoming ever more important. Liver biopsy remains the gold standard for assessing fibrosis, although costs, risks, and availability prohibit its widespread use with at-risk patients. Transient elastography has proven to be a non-invasive and accurate way of assessing fibrosis, although the availability of this modality is often limited in primary care settings. The Fibrosis-4 (FIB-4) and Non-Alcoholic Fatty Liver Disease Fibrosis Score (NFS) are scoring systems that incorporate commonly measured lab parameters and BMI to predict fibrosis. METHOD: In this study, we compared FIB-4 and NFS scores with transient elastography scores to assess the accuracy of these inexpensive and readily available scoring systems in detecting fibrosis. RESULTS: Using an NFS score cut-off of –1.455 and a FibroScan score cut-off of ≥8.7 kPa, the NFS score had a negative predictive value of 94.1%. Using a FibroScan score cut-off of ≥8.7 kPa, the FIB-4 score had a negative predictive value of 91.6%. CONCLUSION: The NFS and FIB-4 are non-invasive, inexpensive scoring systems that have high negative predictive value for fibrosis compared with transient elastography scores. These findings suggest that the NFS and FIB-4 can provide adequate reassurance to rule out fibrosis in patients with NAFLD and can be used with select patients to circumvent the need for transient elastography or liver biopsy.

A67 DELAYED PRESENTATION AND SURGICAL MANAGEMENT OF PRIMARY PNEUMOCOCCAL PERITONITIS

Background

S. pneumoniae intraabdominal infections are rare in healthy individuals, but the literature reveals a female dominance for primary peritonitis in the early post-partum period. Limited studies exist evaluating the timing of surgical management.

Aims

We present a case of primary pneumococcal peritonitis in which the presentation and surgical intervention was delayed.

Methods

A case chart review and literature review was conducted.

Results

A 41-year-old female with a spontaneous vaginal delivery 4 months prior presented with progressive abdominal pain, distention, and emesis over 10 days. She was septic with a firm, distended abdomen and rebound tenderness. A CT revealed significant panenteritis and ascites. She received intravenous fluids and was empirically started on ceftriaxone, vancomycin and metronidazole. The gastrointestinal virus panel, stool cultures and C. difficile toxin were negative. However, her blood cultures revealed Strep. pneumoniae and the purulent peritoneal fluid contained gram-positive cocci. Despite sensitivity to ceftriaxone, and several paracenteses, her ascites, pain and new fever continued. Twenty-eight days after admission, she underwent a laparoscopic abdominal lysis of adhesions and drainage of three intraabdominal abscess collections. Cultures of the purulent peritoneal fluid were negative. She was stepped down to amoxicillin-clavulanate and discharged six weeks after symptom onset.

Despite the development of pneumococcal vaccines, worldwide S. pneumoniae is a common pathogen with high morbidity and mortality. It is a rare cause of intraabdominal infections; however, primary peritonitis has been widely recognized in children. Prior to antibiotics, the mortality of pneumococcal peritonitis was 31.5–100%. Secondary pneumococcal peritonitis is established in adult patients with cirrhosis, nephrotic syndrome and immunocompromised conditions. In healthy individuals, pneumococcal peritonitis often mimics appendicitis and is diagnosed with positive blood cultures. The majority of primary pneumococcal peritonitis cases occur in females, are associated with the early post-partum period (less than two months), IUD placement, and pelvic inflammatory disease. Theories of pathogenesis include direct hematogenous spread or translocation. Transient colonization of the genital tract after IUD placement or during the post-partum period may allow for ascension from the fallopian tubes into the peritoneum. The majority of cases undergo surgery within one week of symptom onset. While it has not been studied in randomized trials, early surgical intervention for source control may decrease morbidity and hospital stay.

Conclusions

Primary pneumococcal peritonitis has a female predominance and can occur later in the post-partum period than previously reported. Surgery should be considered early to achieve source control and improve patient outcomes.

Funding Agencies

None

A204 PATIENT FACTORS AND STONE FEATURES AS PROGNOSTIC PREDICTORS IN BILIARY STONE LITHOTRIPSY BY SINGLE-OPERATOR CHOLANGIOPANCREATOSCOPY

Background

Single-operator cholangiopancreatoscopy (SOC) is a therapeutic modality for pancreaticobiliary stone disease that is refractory to traditional ERCP. SOC is still considered a relatively novel technology with limited access in many centers and significant associated costs. Thus, it is imperative to understand the influence patient-based factors and ancillary actions have on the outcome of SOC.

Aims

We hope to determine if the differences in clinical outcomes amongst cohorts suffice to indicate a re-evaluation of SOC in unfavourable patient populations. We present a series of patients who underwent SOC for biliary stone lithotripsy at a tertiary center with exploratory analysis of factors related to efficacy and adverse events.

Methods

This is a retrospective, descriptive case series. Cases were identified via query of the electronic medical record between March 2016 and May 2019. We evaluated patient demographics, past medical history, clinical presentation, disease characteristics, complication rates, and patient outcomes. Descriptive statistics are reported.

Results

25 unique patients underwent a total of 44 SOC procedures. Mean age was 68 (range 22–88). 13 patients were male. 29 procedures involved a stone in the Common Bile Duct (CBD), 5 in the Common Hepatic & Intrahepatic Ducts (CIHD), 4 in the Pancreatic Duct (PD) and 6 in the Cystic Duct (CD). Symptomatic improvement was achieved in 100% of patients. After a single session, 22.7% of procedures resulted in complete clearance and 59.1% of cases led to partial fragmentation. CBD stones however had an 86.2% clearance rate, compared to an 88–91% success rate in literature. The total complication rate was 16% across age and sex groups. The most common complication was bacteremia in 4 (9.1%) cases. Undifferentiated complication rates were highest with CD stones, while bacteremia was most likely with PD stones. A strong trend was noticed between past SOC procedures and increasing ongoing stone burden, with repeat SOC required less often in patient’s with fewer past SOC procedures. We further observed poorer fragmentation rates for PD stones and a rising trend for repeat SOCs for proximal CBD stones.

Conclusions

SOC is useful against difficult biliary stones and can provide therapeutic relief without theoretical risks associated with surgery and ERCP. While our study was underpowered to provide generalizable statistics, it is one of the few studies that showed the influence certain comorbidities, stone characteristics and age have on the efficacy and safety of SOC. Our data illustrates the relative effect location and stone-size has on fragmentation and complications rates. Poorer outcomes are more frequent in those with systemic comorbidities and previous surgeries, and rates of complications and failed fragmentation are further exacerbated by age.

Funding Agencies

None

A122 WATER EXCHANGE FACILITATES HIGH CECAL INTUBATION RATE FOLLOWING INCOMPLETE COLONOSCOPY

Background

Incomplete colonoscopy is a complex problem that negatively affects the success of colon cancer screening programs. Failure to intubate the cecum is associated with a significant risk of missed colorectal cancer and increases costs through missed diagnoses and salvage investigations. Water exchange (WE) colonoscopy is associated with a high rate of patient comfort and cecal intubation (CI) and may be of value in preventing and following up on incomplete colonoscopy.

Aims

To estimate effectiveness of WE colonoscopy as initial salvage of incomplete colonoscopy.

Methods

All patients referred to the Kelowna Gastroenterology group for incomplete colonoscopy between Jan 2010 to Dec 2019 were included. Demographic, clinical, procedural, and pathological information were collected via retrospective chart review. Patients underwent WE colonoscopy by a single endoscopist. The outcomes evaluated were CI rate, sedation requirements, and adenoma detection.

Results

116 patients met study criteria and underwent WE colonoscopy after a previously failed or incomplete colonoscopy for technical reasons. The mean age was 66 years (range 21–89). 83 (72%) patients were female. 53 (46%) patients had previous abdominal surgery, and 42 (36%) had previous pelvic surgery. 65 (56%) patients had previous bowel disease. 81 (70%) patients had previously incomplete conventional air insufflation (AI) colonoscopy, 9 (8%) patients had previously incomplete WE colonoscopy, and 5 (4%) patients underwent unsuccessful combination of WE and AI colonoscopy. 17 (15%) patients had previously incomplete flexible sigmoidoscopy, and 4 (3%) patients had previously incomplete water immersion colonoscopy. The most common cause of unsuccessful CI was redundant colon (n=39, 34%) followed by strictures/angulations (n=16, 14%). 105 (91%) patients underwent repeat WE colonoscopy only, while 7 (6%) patients had combination WE and AI colonoscopy and 4 (3%) patients had concurrent gastroscopy. CI was successful in 114 (98%) patients and unsuccessful in 2 (2%) patients. 87 (75%) study patients received conscious sedation, 16 (14%) opted for no sedation, and 7 (6%) attempted no sedation then switched to conscious sedation. 5 patients (4%) required general anesthesia. CI was achieved in all 16 unsedated patients. 236 polyps were identified in 79 (68%) patients, 2 (1%) of which were malignant.

Conclusions

There is no standardized approach to incomplete colonoscopy. In this cohort of patients with previous failed attempt at colonoscopy, WE as a primary technique was associated with a high success rate with minimal need for general anesthesia and a high rate of polyp detection. A significant rate of colon cancer was identified, similar to that seen in general screening populations.

Funding Agencies

None

A20 DIAGNOSTIC ACCURACY OF A LOW COST, WIDELY AVAILABLE TEST STRIP FOR PREDICTING A POSITIVE FECAL CALPROTECTIN TEST

Background

Fecal calprotectin is a non-invasive test of colonic inflammation used for monitoring inflammatory bowel disease activity and for risk stratifying non-specific colonic symptoms. Calprotectin is a leukocyte specific enzyme. A similar test, leukocyte esterase is used to detect leukocytes in urine and is widely available as a low-cost point-of-care test strip. We hypothesize that an unmodified version of the urine test strip would be highly accurate in predicting a positive fecal calprotectin test in a real world sample of patients.

Aims

To explore a low cost, rapid alternative to the fecal calprotectin test

Methods

All inpatient and outpatient stool samples tested for calprotectin by the Vancouver General Hospital laboratory from February 2020 to November 2020 were included prospectively. Samples were simultaneously tested for fecal leukocyte esterase using an unmodified Roche Cobas Chemstrip urinalysis test strip by central lab personnel. An identical aliquot was sent to LifeLabs for calprotectin as per standard protocol. All samples were suspended in buffer using established laboratory protocols prior to testing. Fecal leukocyte esterase results were reported as 0–4+ based on visual interpretation, calprotectin results were reported as mcg/g of stool. REB review and approval was obtained prior to data collection. Sensitivity, Specificity and AUROC were calculated using Microsoft Excel and JROCFIT.

Results

26 samples were collected. Using a fecal calprotectin greater than 120 mcg/g as a gold standard an AUROC of 0.89 (SE= .06) was calculated. A leukocyte esterase reading of 2+ or greater had the best test characteristics based on ROC curve analysis. Using this cutoff, 21/26 samples were concordant, giving an accuracy of 80.8%, sensitivity of 90.9% and specificity of 73.3%. Positive likelihood ratio was 8.07 and negative likelihood ratio was 0.29. Assuming an AUROC of 0.8, the sample size N=26 is 90% powered (β=0.9) to predict the true AUROC within 0.1 with a type I error rate of .05 (α&lt;.05).

Conclusions

This study suggests application of a prepared stool sample to a urinalysis test strip gives a result highly predictive of a positive fecal calprotectin test. Further results are being collected prospectively to improve the robustness of these preliminary data. Secondary outcomes including comparison to endoscopy and biopsy results where available are planned if an adequate sample size can be accrued. Future studies justifying independent clinical use of leukocyte esterase would require a common gold standard comparator such as endoscopy. Fecal calprotectin testing is not universally insured and is not available as a rapid test strip. Use of fecal leukocyte esterase may reduce costs and shorten time to results if proven to be independently reliable.

Funding Agencies

None

Endoscopic Management of Diminutive Duodenal Neuroendocrine Tumors

INTRODUCTION

Although duodenal neuroendocrine tumors (dNETs) are rare, the incidence, particularly for lesions ≤ 10 mm, continues to rise with the advent of widely available, high-quality endoscopy. Given their rarity and controversy regarding prognostication factors, limited guidelines exist for resection of well-differentiated, ≤ 20-mm dNETs. Importantly, lesions ≤ 10 mm in a duodenal location are ideal for consideration of endoscopic management given both morbidity and technical challenges associated with surgery and their accessibility to a wide range of endoscopic techniques.

OBJECTIVES

The primary objective of this study was to demonstrate the safety and efficacy of the endoscopic resection of dNETs <10 mm in a case series and literature review.

METHODS

We performed a literature review and present a series of nine cases to demonstrate the viability of endoscopic resection for diminutive dNETs as an alternative to surgery.

RESULTS

Our case series included nine well-differentiated diminutive dNETs in seven patients, the majority resected using endoscopic mucosal resection (EMR), 67%, and there was no residual disease at follow-up. The literature review of 178 patients demonstrated that EMR was the most used method of resection of diminutive dNETs, 81%, compared to endoscopic submucosal dissection, 19%. The most common complication was intraoperative bleeding in 9.55%, and only 2.25% of patients had recurrence.

CONCLUSION

While complications may arise with endoscopic resection of diminutive dNETs, they are usually managed endoscopically and compare favorably with the literature on surgical complication rates and typically result in shorter hospitalizations.

Artificial intelligence and deep learning for small bowel capsule endoscopy

Capsule endoscopy is ideally suited to artificial intelligence-based interpretation given its reliance on pattern recognition in still images. Time saving viewing modes and lesion detection features currently available rely on machine learning algorithms, a form of artificial intelligence. Current software necessitates close human supervision given poor sensitivity relative to an expert reader. However, with the advent of deep learning, artificial intelligence is becoming increasingly reliable and will be increasingly relied upon. We review the major advances in artificial intelligence for capsule endoscopy in recent publications and briefly review artificial intelligence development for historical understanding. Importantly, recent advancements in artificial intelligence have not yet been incorporated into practice and it is immature to judge the potential of this technology based on current platforms. Remaining regulatory and standardization hurdles are being overcome and artificial intelligence-based clinical applications are likely to proliferate rapidly.

A233 VEDOLIZUMAB FOR STEROID & INFLIXIMAB-REFRACTORY ICI-COLITIS

Background

Immune checkpoint inhibitors (ICI), such as anti-PD1, improve survival in melanoma, renal carcinoma and prostate cancer. However, by disinhibiting the immune system, these treatments cause significant immune-related adverse events (irAE), including colitis. For ICI-colitis, guidelines suggest escalating from observation to steroids to infliximab, without strong evidence for additional options should these fail. Vedolizumab has been used in a small number of cases for steroid-refractory or dependent ICI-colitis; only 9 cases have been reported in patients who failed infliximab therapy with a response rate of 67%.

Aims

To discuss a case of ICI-colitis that failed multiple steroid courses and infliximab infusions, but achieved remission with vedolizumab.

Methods

A 65-year-old male with malignant melanoma was randomized to adjuvant nivolumab +/- ipilimumab and developed non-bloody diarrhea. Despite loperamide, diarrhea worsened to 4–5 bowel movements daily. Stool cultures and C. diff were negative and 85mg of daily prednisone was started, while the ICI was held for 8 weeks. After a 2nd steroid taper, diarrhea recurred and the patient received 2 infliximab infusions 18 days apart. Despite initial improvement, biopsies demonstrated colitis and he underwent a 3rd infusion with little response. Clinical and biopsy-confirmed remission was only achieved once 2 vedolizumab infusions were given.

Results

Colitis is the most common ICI irAE, ranging in severity from mild to perforation and death. The incidence of grade 3 and 4 colitis, which require ICI discontinuation, is 1.3% for anti-PD1 and 13.6% in combination therapy. The severity of irAE is positively correlated with malignancy response and stopping ICI risks recurrence. Those that fail irAE medical management may require surgery. Thus, there is an impetus to continue the ICI and provide effective medical management for irAE.

ICI-colitis guidelines are based on the CTCAE diarrhea classification and suggest supportive management and ICI continuation for grade 1. For grade 2, the ICI is held and steroids are started; infliximab is added for grades 3 and 4. However, 33–66% of patients are steroid-refractory or dependent; and patients may be infliximab non-responders, or unable to tolerate systemic side effects.

Vedolizumab, an anti-α4β7-integrin, acts locally to inhibit T cells in the bowel wall, reducing inflammation in IBD. Recent reports, including ours, suggest usefulness in steroid and infliximab-refractory ICI colitis after only 2–4 infusions. When the inflammatory burden is high, the response rate is &gt;80% and given its gut-specificity, side effects are minimal compared to infliximab. Although further evaluation is required, using vedolizumab as second-line therapy is reasonable.

Conclusions

Given vedolizumab’s safety and gut-specificity, it should readily be considered in the treatment of ICI irAE.

Funding Agencies

None

A82 SUCCESSFUL RESECTION OF GRADE 1 DUODENAL NEUROENDOCRINE TUMOURS USING ENDOSCOPIC TECHNIQUES IN TWO CANADIAN HOSPITALS

Background

Given the rarity of duodenal neuroendocrine tumours (dNETs), limited guidelines exist for resection of well-differentiated, ≤10 mm dNETS. As incidence rises, alternatives to surgery are valuable. We present 9 cases of endoscopic dNET resections and a literature review.

Aims

To demonstrate efficacy and safety of endoscopic resection for dNETs ≤10 mm at 2 Canadian hospitals.

Methods

We retrospectively analyzed data on 7 patients that had endoscopic dNET resection from 2013–2018. Endoscopic resection occurred if dNETs were ≤10 mm in diameter, did not extend to the muscularis propria and lymphovascular invasion was absent. WHO 2017 classification was used.

Results

All patients had biopsies and 5 (71%) had EUS prior to resection; 4 females and 3 males underwent resection of 9 dNETs; 2 via cap-assisted snare polypectomy; 4 with cap-assisted band mucosectomy; and 2 over-the-scope clip-assisted resection. The median size was 10 mm (4–11); 6 (67%) dNETS were found in the duodenal bulb, 2 at the D1/D2 junction and 1 in D2 alone. The median age was 68.5 (50–79) years.

All dNETs were submucosal and well-differentiated. The dNETs were resected en bloc, but 3 did not have clear margins. Two procedures were complicated by duodenal perforation; 1 requiring surgery and 18 days in hospital. One case was complicated by bleeding with successful endoscopic hemostasis. The majority (75%) of resections were day procedures.

Patients were followed for 6–12 months with an EGD or chromogrannin A. None of the patients had endoscopic residual disease, but 1 patient required a second procedure to remove a dNET left in situ following the initial resection of 2 dNETs 12 months earlier.

In our literature review of 178 patients, the majority of dNETs were resected by EMR 81% (150/185) versus ESD, similar to our experience. Patients were slightly younger with a mean age of 63.28, and most dNETs (46%) were found in the duodenal bulb. Complications included intraoperative bleeding, perforation and death in 17 (9.55%), 9 (5.06%) and 1 (0.06%) patient(s) respectively. The rate of recurrence was 4/178 (2.25%) and patients had a mean follow up of 26.1 months.

Conclusions

Well-differentiated dNETs ≤10 mm in diameter can be successfully resected endoscopically. Complications can be managed intraoperatively and hospital stay remains minimal.

Funding Agencies

None

A89 IMPLEMENTING ENDOSCOPIC SUBMUCOSAL DISSECTION IN A WESTERN CANADIAN SETTING: OUTCOMES, LEARNING CURVE AND LOGISTICAL CONSIDERATIONS

Background

Endoscopic submucosal dissection (ESD) is an advanced resection technique for large gastrointestinal lesions. ESD was developed in Japan and is popular in countries with gastric cancer screening and a high incidence of gastric cancer. ESD has benefits over endoscopic mucosal resection (EMR) such as increased complete resection, en bloc resection and lower recurrence. However, ESD is a longer procedure and is difficult to master in countries with low incidence of early gastric neoplasia which is the ideal anatomic location for learning. There is increasing interest in using ESD techniques including hybrid ESD/EMR in western centers. Barriers include procedure time, perforation risk and challenges accumulating sufficient experience.

Aims

To present our experience implementing an ESD program in British Columbia including outcomes and logistical considerations of interest.

Methods

All ESD procedures since implementation of the program in May 2015 to July 2019 were included. Descriptive statistics and performance indicators over time are reported. All procedures were performed by a staff endoscopist after specialized training. Procedures were performed at two hospitals in British Columbia. Cases were referred from endoscopists and were assessed with dedicated endoscopy with or without endoscopic ultrasound prior to booking ESD.

Results

40 procedures were performed, though only one procedure was performed in the first year (Mean age 70, 67.5% male). ASA class ranged from 1–4 (mean 2.08). 22 lesions were gastric, 13 were rectal, with the remainder throughout the colon. Mean lesion size was 25mm in maximum dimension (interquartile range 15-30mm). 18 procedures were performed under general anesthesia and the remainder using procedural sedation. Total surgical time ranged from 22 to 398 minutes. Mean surgical time was 104 minutes, or 126 minutes including anesthesia. 50% of procedures were performed using hybrid ESD/EMR technique. R0 resection rate across all cases was 68% (60% for hybrid procedures, 80% for strict ESD). En bloc resection rate was 60%. Recurrence rate was 10%. Complication rate was 7.5% all were post-procedure bleeds requiring hospitalization. No perforations occurred. 3 patients required surgery for incomplete resection or invasive cancer on pathology, 3 required repeat endoscopic resection. Surgical time per cm of lesion improved significantly from the first 10 cases to the last 10 (time per cm resected 75 min to 32 min p&lt;0.006).

Conclusions

ESD is an effective therapy for GI neoplasia. ESD is feasible in a Canadian setting. Hybrid techniques tend to be faster though at the expense of R0 resection. Patient centered outcomes in this sample are favorable and comparable to large ESD series. Monitoring of ESD quality is critical for comparison with standard of care as experience with ESD in Canada grows.

Funding Agencies

None

Internet-Based Patient Education Prior to Colonoscopy: Prospective, Observational Study of a Single Center’s Implementation, with Objective Assessment of Bowel Preparation Quality and Patient Satisfaction

Background

Nonpharmacologic factors, including patient education, affect bowel preparation for colonoscopy. Optimal cleansing increases quality and reduces repeat procedures. This study prospectively analyzes use of an individualized online patient education module in place of traditional patient education.

Aims

To determine the effectiveness of online education for patients, measured by the proportion achieving sufficient bowel preparation. Secondary measures include assessment of patient satisfaction.

Methods

Prospective, single-center, observational study. Adults aged 19 years and over, with an e-mail account, scheduled for nonurgent colonoscopy, with English proficiency (or someone who could translate for them) were recruited. Demographics and objective bowel preparation quality were collected. Patient satisfaction was assessed via survey to assess clarity and usefulness of the module.

Results

Nine hundred consecutive patients completed the study. 84.6% of patients achieved adequate bowel preparation as measured by Boston bowel preparation score ≥ 6 and 90.1% scored adequately using Ottawa bowel preparation score ≤7. 94.2% and 92.1% of patients rated the web-education module as ‘very useful’ and ‘very clear’, respectively (≥8/10 on respective scales).

Conclusions

Our analysis suggests that internet-based patient education prior to colonoscopy is a viable option and achieves adequate bowel preparation. Preparation quality is comparable to previously published trials. Included patients found the process clear and useful. Pragmatic benefits of a web-based protocol such as time and cost savings were not formally assessed but may contribute to greater satisfaction for endoscopists and patients.