Endoscopic management of intraprocedural bleeding during endoscopic interventions.

Endoscopic resection techniques have evolved over time, allowing effective and safe resection of the majority of pre-malignant and early cancerous lesions in the gastrointestinal tract. Bleeding is one of the most commonly encountered complications during endoscopic resection, which can interfere with the procedure and result in serious adverse events. Intraprocedural bleeding is relatively common during endoscopic resection and, in most cases, is a mild and self-limiting event. However, it can interfere with the completion of the resection and may result in negative patient-related outcomes in severe cases, including the need for hospitalization and blood transfusion as well as the requirement for radiological or surgical interventions. Appropriate management of intraprocedural bleeding can improve the safety and efficacy of endoscopic resection, and it can be readily achieved with the use of several endoscopic hemostatic tools. In this review, we discuss the recent advances in the approach to intraprocedural bleeding complicating endoscopic resection, with a focus on the various endoscopic hemostatic tools available to manage such events safely and effectively.

The contribution of EUS to the management of endoscopic and surgical complications.

Endoscopic Ultrasound (EUS) stands as a remarkable innovation in the realm of gastroenterology and its allied disciplines. EUS has evolved to such an extent that it now assumes a pivotal role in both diagnosis and therapeutics. In addition, it has developed as a tool which is also capable of addressing complications arising from endoscopic and surgical procedures. This minimally invasive technique combines endoscopy with high-frequency ultrasound, facilitating, high-resolution images of the gastrointestinal tract and adjacent structures. Complications within the gastrointestinal tract, whether stemming from endoscopic or surgical procedures, frequently arise due to disruption in the integrity of the gastrointestinal tract wall. While these complications are usually promptly detected, there are instances where their onset is delayed. EUS plays a dual role in the management of these complications. Firstly, in its ability to assess and increasingly to definitively manage complications through drainage procedures. It is increasingly employed to manage post-surgical collections, abscesses biliary strictures and bleeding. Its high-resolution imaging capability allows precise real-time visualisation of these complications.

Capsule endoscopy and panendoscopy: A journey to the future of gastrointestinal endoscopy.

In 2000, the small bowel capsule revolutionized the management of patients with small bowel disorders. Currently, the technological development achieved by the new models of double-headed endoscopic capsules, as miniaturized devices to evaluate the small bowel and colon [pan-intestinal capsule endoscopy (PCE)], makes this non-invasive procedure a disruptive concept for the management of patients with digestive disorders. This technology is expected to identify which patients will require conventional invasive endoscopic procedures (colonoscopy or balloon-assisted enteroscopy), based on the lesions detected by the capsule, i.e., those with an indication for biopsies or endoscopic treatment. The use of PCE in patients with inflammatory bowel diseases, namely Crohn's disease, as well as in patients with iron deficiency anaemia and/or overt gastrointestinal (GI) bleeding, after a non-diagnostic upper endoscopy (esophagogastroduodenoscopy), enables an effective, safe and comfortable way to identify patients with relevant lesions, who should undergo subsequent invasive endoscopic procedures. The recent development of magnetically controlled capsule endoscopy to evaluate the upper GI tract, is a further step towards the possibility of an entirely non-invasive assessment of all the segments of the digestive tract, from mouth-to-anus, meeting the expectations of the early developers of capsule endoscopy.

Safety and efficacy of dexmedetomidine vs. midazolam in complex gastrointestinal endoscopy: A systematic review and meta-analysis.

OBJECTIVE: This study aims to perform a meta-analysis to evaluate the safety and efficacy of dexmedetomidine versus midazolam for complex digestive endoscopy procedures, with the goal of offering comprehensive clinical evidence. METHODS: Following predefined inclusion criteria, five databases were systematically searched, with a focus on identifying randomized controlled trials (RCTs) that compared the administration of dexmedetomidine and midazolam during complex digestive endoscopy procedures. The statistical software Stata 15.1 was employed for meticulous data analysis. RESULTS: Sixteen RCTs were encompassed, involving a total of 1218 patients. In comparison to the midazolam group, dexmedetomidine administration was associated with a reduced risk of respiratory depression (RR=0.25, 95 %CI: 0.11-0.56) and hypoxemia (RR=0.22, 95 %CI: 0.12-0.39). Additionally, the dexmedetomidine group exhibited lower incidence rates of choking (RR=0.27, 95 %CI: 0.16-0.47), physical movement (RR=0.16, 95 %CI: 0.09-0.27), and postoperative nausea and vomiting (RR=0.56,95 %CI: 0.34-0.92). Patients and endoscopists in the dexmedetomidine group reported higher levels of satisfaction (patient satisfaction: SMD=0.73, 95 %CI: 0.26-1.21; endoscopist satisfaction: SMD=0.84, 95 %CI: 0.24-1.44). The incidence of hypotension and anesthesia recovery time did not significantly differ between the two groups (hypotension: RR=1.73,95 %CI:0.94-3.20; anesthesia recovery time: SMD=0.02, 95 %Cl: 0.44-0.49). It is noteworthy that the administration of dexmedetomidine was associated with a significant increase in the incidence of bradycardia in patients. CONCLUSION: Compared to midazolam, dexmedetomidine exhibits a favorable safety profile for use in complex gastrointestinal endoscopy by significantly reducing the risk of respiratory depression and hypoxemia. Despite this, dexmedetomidine is associated with a higher incidence of bradycardia. These findings underscore the need for further research through larger, multi-center studies to thoroughly investigate dexmedetomidine's safety and efficacy.

Intravenous metoclopramide for increasing endoscopic mucosal visualization in patients with acute upper gastrointestinal bleeding: a multicenter, randomized, double-blind, controlled trial.

Acute upper gastrointestinal hemorrhage (UGIH) is the most common emergency condition that requires rapid endoscopic treatment. This study aimed to evaluate the effects of pre-endoscopic intravenous metoclopramide on endoscopic mucosal visualization (EMV) in patients with acute UGIH. This was a multicenter, randomized, double-blind controlled trial of participants diagnosed with acute UGIH. All participants underwent esophagogastroduodenoscopy within 24 h. Participants were assigned to either the metoclopramide or placebo group. Modified Avgerinos scores were evaluated during endoscopy. In total, 284 out of 300 patients completed the per-protocol procedure. The mean age was 62.8 ± 14.3 years, and 67.6% were men. Metoclopramide group achieved a higher total EMV and gastric body EMV score than the other group (7.34 ± 1.1 vs 6.94 ± 1.6; P = 0.017 and 1.80 ± 0.4 vs 1.64 ± 0.6; P = 0.006, respectively). Success in identifying lesions was not different between the groups (96.5% in metoclopramide and 93.6% in placebo group; P = 0.26). In the metoclopramide group, those with active variceal bleeding compared with the control group demonstrated substantial improvements in gastric EMV (1.83 ± 0.4 vs 1.28 ± 0.8, P = 0.004), antral EMV (1.96 ± 0.2 vs 1.56 ± 0.6, P = 0.003), and total EMV score (7.48 ± 1.1 vs 6.2 ± 2.3, P = 0.02). Pre-endoscopic intravenous metoclopramide improved the quality of EMV in variceal etiologies of UGIH, which was especially prominent in those who had signs of active bleeding based on nasogastric tube assessment.Trial Registration: Trial was registered in Clinical Trials: TCTR 20210708004 (08/07/2021).

Life-threatening Gastrointestinal Bleeding from a Dieulafoy's Lesion in the Duodenum: A Case Report.

Dieulafoy's lesion is a rare cause of gastrointestinal bleeding, accounting for approximately 1-2% of all cases of gastrointestinal bleeding. Dieulafoy's lesion usually occurs in the lesser curvature of the stomach within six centimeters of the gastroesophageal junction. On the other hand, extragastric Dieulafoy's lesions are uncommon. Diagnosing an extragastric Dieulafoy's lesion by endoscopy can be challenging because of its small size and obscure location. The key elements for an accurate diagnosis include heightened awareness and a careful early endoscopic evaluation following a bleeding episode. Various endoscopic hemostatic techniques can be used for treatment. This paper presents a case of successful hemostasis using argon plasma coagulation for a life-threatening duodenal Dieulafoy's lesion.

Cronkhite-Canada syndrome with esophagus involvement and six-year follow-up: A case report.

BACKGROUND: Cronkhite-Canada syndrome (CCS) is a rare, noninherited disease characterized by gastrointestinal polyposis with diarrhea and ectodermal abnormalities. CCS polyps are distributed through the whole digestive tract, and they are common in the stomach and colon but very uncommon in the esophagus. CASE SUMMARY: Here, we present a case of a 63-year-old man with skin hyperpigmentation accompanied by diarrhea, alopecia, and loss of his fingernails. Laboratory data indicated anemia, hypoalbuminemia, hypocalcemia, hypokalemia, and positive fecal occult blood. Endoscopy showed numerous polyps scattered throughout the digestive tract, including the esophagus. He was treated with nutritional support and glucocorticoids with remission of his symptoms. CONCLUSION: Comprehensive treatment led by hormonal therapy can result in partial or full remission of clinical symptoms. Treatment should be individualized for each patient according to their therapy response. Surveillance endoscopy is necessary for assessing mucosal disease activity and detecting malignant transformation.

Pediatric endoscopy: how can we improve patient outcomes and ensure best practices?

INTRODUCTION: Strategies to promote high-quality endoscopy in children require consensus around pediatric-specific quality standards and indicators. Using a rigorous guideline development process, the international Pediatric Endoscopy Quality Improvement Network (PEnQuIN) was developed to support continuous quality improvement efforts within and across pediatric endoscopy services. AREAS COVERED: This review presents a framework, informed by the PEnQuIN guidelines, for assessing endoscopist competence, granting procedural privileges, audit and feedback, and for skill remediation, when required. As is critical for promoting quality, PEnQuIN indicators can be benchmarked at the individual endoscopist, endoscopy facility, and endoscopy community levels. Furthermore, efforts to incorporate technologies, including electronic medical records and artificial intelligence, into endoscopic quality improvement processes can aid in creation of large-scale networks to facilitate comparison and standardization of quality indicator reporting across sites. EXPERT OPINION: PEnQuIN quality standards and indicators provide a framework for continuous quality improvement in pediatric endoscopy, benefiting individual endoscopists, endoscopy facilities, and the broader endoscopy community. Routine and reliable measurement of data, facilitated by technology, is required to identify and drive improvements in care. Engaging all stakeholders in endoscopy quality improvement processes is crucial to enhancing patient outcomes and establishing best practices for safe, efficient, and effective pediatric endoscopic care.

Early postoperative endoscopy for predicting anastomotic leakage after minimally invasive esophagectomy: A large-volume retrospective study.

BACKGROUND: Anastomotic leakage is one of the most severe adverse events of minimally invasive esophagectomy for esophageal cancer. Early postoperative endoscopy is considered to be the most objective means to diagnose anastomotic leakage, but its safety is questioned by clinicians. This study aimed to evaluate the safety and effectiveness of early postoperative endoscopy in predicting anastomotic leakage. METHODS: Patients who underwent minimally invasive esophagectomy (from January 2017 to June 2021) in our center were identified and divided into early postoperative endoscopy and control groups according to whether they underwent early postoperative endoscopy within 72 hours after surgery. Propensity score matching was used to balance baseline characteristics. The incidence of postoperative adverse events was compared between the 2 groups, risk variables for anastomotic leakage were identified using logistic regression, and abnormal endoscopic findings related to anastomotic leakage occurrence were explored. RESULTS: A total of 436 patients were enrolled, of whom 134 underwent early postoperative endoscopy. One hundred and thirty-two pairs were matched by propensity score matching, and baseline characteristics were well-balanced. Both before and after propensity score matching, early postoperative endoscopy did not increase the incidence of postoperative adverse events (chyle leak, hypoproteinemia, pneumonia, etc) and in-hospital mortality. Notably, the incidence of anastomotic leakage (9.8% vs 22.7%) and the length of mean postoperative hospital stay (17.6 vs 20.9 days) was significantly decreased in the early postoperative endoscopy group. Finally, based on the findings under early postoperative endoscopy, we found that gastric graft ischemia is related to a higher incidence of anastomotic leakage (P = .023). CONCLUSION: Early postoperative endoscopy does not increase postoperative adverse events after minimally invasive esophagectomy and may guide early prediction and intervention strategies for anastomotic leakage in patients undergoing minimally invasive esophagectomy.

High risk stigmata and treatment strategy for acute lower gastrointestinal bleeding: a nationwide study in Japan.

BACKGROUND: The rebleeding risks and outcomes of endoscopic treatment for acute lower gastrointestinal bleeding (ALGIB) may differ depending on the bleeding location, type, and etiology of stigmata of recent hemorrhage (SRH) but have yet to be fully investigated. We aimed to identify high risk endoscopic SRH and to propose an optimal endoscopic treatment strategy. METHODS: We retrospectively analyzed 2699 ALGIB patients with SRH at 49 hospitals (CODE BLUE-J Study), of whom 88.6 % received endoscopic treatment. RESULTS: 30-day rebleeding rates of untreated SRH significantly differed among locations (left colon 15.5 % vs. right colon 28.6 %) and etiologies (diverticular bleeding 27.5 % vs. others [e. g. ulcerative lesions or angioectasia] 8.9 %), but not among bleeding types. Endoscopic treatment reduced the overall rebleeding rate (adjusted odds ratio [AOR] 0.69; 95 %CI 0.49-0.98), and the treatment effect was significant in right-colon SRH (AOR 0.46; 95 %CI 0.29-0.72) but not in left-colon SRH. The effect was observed in both active and nonactive types, but was not statistically significant. Moreover, the effect was significant for diverticular bleeding (AOR 0.60; 95 %CI 0.41-0.88) but not for other diseases. When focusing on treatment type, the effectiveness was not significantly different between clipping and other modalities for most SRH, whereas ligation was significantly more effective than clipping in right-colon diverticular bleeding. CONCLUSIONS: A population-level endoscopy dataset allowed us to identify high risk endoscopic SRH and propose a simple endoscopic treatment strategy for ALGIB. Unlike upper gastrointestinal bleeding, the rebleeding risks for ALGIB depend on colonic location, bleeding etiology, and treatment modality.

Risk factors and outcomes of upper gastrointestinal bleeding in hospitalized patients in a tertiary care hospital.

Objective: To determine different aetiologies and outcomes of upper gastrointestinal bleeding in hospitalised patients. METHODS: The retrospective cohort study was conducted at the Aga Khan University Hospital, Karachi, and comprised data from December 2019 to April 2021 related to adult patients of either gender with nongastrointestinal illnesses who developed bleeding at least 24 hours after admission. Data was reviewed for clinical characteristics, cause of bleeding and clinical outcome. Data was analysed using SPSS 23. RESULTS: Among 47,337 hospitalised patients, upper gastrointestinal bleeding was identified in 147(0.3%); 98 (66.7%) males and 49 (33.3%) females. The overall mean age was 62.73±14.81 years (range 20-95 years). Of the total, 125(85%) presented with overt bleeding and 22(15%) with a drop in haemoglobin level. There were 34(23%) patients on aspirin, 36(24%) on dual anti-platelets, 41(28%) on therapeutic anticoagulation, and 81(55%) on prophylactic anticoagulation. There were 7(5%) patients having a history of non-steroidal anti-inflammatory drugs (NSAIDs), and 12(8%) were on steroids. In terms of associated medical conditions, pneumonia, stroke, and acute coronary syndrome were commonly seen with frequency of 29.9%, 8.1% and 7.4% respectively. Overall, 36(24.4%) patients underwent endoscopy, 8(5.4%) had therapeutic measures to control bleeding, 14(9.5%) had bleeding for >48 hours, 89(60.5%) were stepped up to special care. Mortality was seen in 36(24.5%) cases. CONCLUSIONS: Hospital acquired gastrointestinal bleeding was found to be uncommon, and there were several risk factors for such bleeding events.

Water beads ingestion presenting with repeated bowel obstruction in an infant.

An infant presented repeatedly with features of transient bowel obstruction 72 hours after unwitnessed ingestion of water beads. At the third presentation 5 days later, he underwent laparotomy and jejunal enterotomy for retrieval of obstructing water bead in the duodenum. Four other water beads were retrieved. Due to persistent obstructive symptoms, he had a relaparotomy on fourth postoperative day. A further obstructing bead at the duodenojejunal flexure was retrieved. Antegrade upper gastrointestinal endoscopy and retrograde endoscopy through the enterotomy were performed to ensure no further retained water beads. The patient progressed well postoperatively and was discharged home 5 days later. This case highlights the challenges involved in the diagnosis and management of water bead ingestion in children. Children under 2 years are at a higher risk of complications and most require intervention. Palpation alone can miss residual water beads at surgery. Endoscopy including intraoperative enteroscopy could be a useful adjunct.

[A Giant Gastric Perforation Occurring in the Normal Mucosa during Endoscopy in a Patient with Advanced Gastric Cancer].

The incidence of giant gastric perforation occurring during upper gastrointestinal endoscopy is exceedingly rare. Gastric perforation can arise from excessive air insufflation and is more prevalent in elderly patients with atrophic gastritis. Although giant gastric mucosal lacerations during diagnostic endoscopy have occasionally been reported, there are few reports of giant gastric perforation. The authors experienced a giant gastric perforation occurring in the normal mucosa during endoscopy in an 81-year-old woman with advanced gastric cancer. The patient had reduced gastric extensibility due to the advanced gastric cancer surrounding the entire lower part of her stomach. During continuous air insufflation, only the upper part of the stomach became overdistended, resulting in mucosal rupture and perforation. In addition, old age and the presence of atrophic gastritis contributed to the increased risk of mucosal rupture. The patient was treated successfully with endoscopic clips. This paper reports this case with a review of the relevant literature.

Thoracic impedance pneumography in propofol-sedated patients undergoing percutaneous endoscopic gastrostomy (PEG) placement in gastrointestinal endoscopy: A prospective, randomized trial.

STUDY OBJECTIVE: To assess the efficacy of an ECG-based method called thoracic impedance pneumography to reduce hypoxic events in endoscopy. DESIGN: This was a single center, 1:1 randomized controlled trial. SETTING: The trial was conducted during the placement of percutaneous endoscopic gastrostomy (PEG). PATIENTS: 173 patients who underwent PEG placement were enrolled in the present trial. Indication was oncological in most patients (89%). 58% of patients were ASA class II and 42% of patients ASA class III. INTERVENTIONS: Patients were randomized in the standard monitoring group (SM) with pulse oximetry and automatic blood pressure measurement or in the intervention group with additional thoracic impedance pneumography (TIM). Sedation was performed with propofol by gastroenterologists or trained nurses. MEASUREMENTS: Hypoxic episodes defined as SpO2 < 90% for >15 s were the primary endpoint. Secondary endpoints were minimal SpO2, apnea >10s/>30s and incurred costs. MAIN RESULTS: Additional use of thoracic impedance pneumography reduced hypoxic episodes (TIM: 31% vs SM: 49%; p = 0.016; OR 0.47; NNT 5.6) and elevated minimal SpO2 per procedure (TIM: 90.0% ± 8.9; SM: 84.0% ± 17.6; p = 0.007) significantly. Apnea events >10s and > 30s were significantly more often detected in TIM (43%; 7%) compared to SM (1%; 0%; p < 0.001; p = 0.014) resulting in a time advantage of 17 s before the occurrence of hypoxic events. As a result, adjustments of oxygen flow were significantly more often necessary in SM than in TIM (p = 0.034) and assisted ventilation was less often needed in TIM (2%) compared with SM (9%; p = 0.053). Calculated costs for the additional use of thoracic impedance pneumography were 0.13$ (0.12 €/0.11 £) per procedure. CONCLUSIONS: Additional thoracic impedance pneumography reduced the quantity and extent of hypoxic events with less need of assisted ventilation. Supplemental costs per procedure were negligible. KEY WORDS: thoracic impedance pneumography, capnography, sedation, monitoring, gastrointestinal endoscopy, percutaneous endoscopic gastrostomy.

Evaluation of the efficacy and safety of endoscopic band ligation in the treatment of bleeding from mild to moderate gastric varices type 1.

BACKGROUND: According to practice guidelines, endoscopic band ligation (EBL) and endoscopic tissue adhesive injection (TAI) are recommended for treating bleeding from esophagogastric varices. However, EBL and TAI are known to cause serious complications, such as hemorrhage from dislodged ligature rings caused by EBL and hemorrhage from operation-related ulcers resulting from TAI. However, the optimal therapy for mild to moderate type 1 gastric variceal hemorrhage (GOV1) has not been determined. Therefore, the aim of this study was to discover an individualized treatment for mild to moderate GOV1. AIM: To compare the efficacy, safety and costs of EBL and TAI for the treatment of mild and moderate GOV1. METHODS: A clinical analysis of the data retrieved from patients with mild or moderate GOV1 gastric varices who were treated under endoscopy was also conducted. Patients were allocated to an EBL group or an endoscopic TAI group. The differences in the incidence of varicose relief, operative time, operation success rate, mortality rate within 6 wk, rebleeding rate, 6-wk operation-related ulcer healing rate, complication rate and average operation cost were compared between the two groups of patients. RESULTS: The total effective rate of the two treatments was similar, but the efficacy of EBL (66.7%) was markedly better than that of TAI (39.2%) (P < 0.05). The operation success rate in both groups was 100%, and the 6-wk mortality rate in both groups was 0%. The average operative time (26 min) in the EBL group was significantly shorter than that in the TAI group (46 min) (P < 0.01). The rate of delayed postoperative rebleeding in the EBL group was significantly lower than that in the TAI group (11.8% vs 45.1%) (P < 0.01). At 6 wk after the operation, the healing rate of operation-related ulcers in the EBL group was 80.4%, which was significantly greater than that in the TAI group (35.3%) (P < 0.01). The incidence of postoperative complications in the two groups was similar. The average cost and other related economic factors were greater for the EBL than for the TAI (P < 0.01). CONCLUSION: For mild to moderate GOV1, patients with EBL had a greater one-time varix eradication rate, a greater 6-wk operation-related ulcer healing rate, a lower delayed rebleeding rate and a lower cost than patients with TAI.

Recent Trends in Non-Invasive Methods of Diagnosis and Evaluation of Inflammatory Bowel Disease: A Short Review.

Inflammatory bowel diseases are a conglomerate of disorders causing inflammation of the gastrointestinal tract, which have gained a significant increase in prevalence in the 21st century. As they present a challenge in the terms of diagnosis as well as treatment, IBDs can present an overwhelming impact on the individual and can take a toll on healthcare costs. Thus, a quick and precise diagnosis is required in order to prevent the high number of complications that can arise from a late diagnosis as well as a misdiagnosis. Although endoscopy remains the primary method of evaluation for IBD, recent trends have highlighted various non-invasive methods of diagnosis as well as reevaluating previous ones. This review focused on the current non-invasive methods in the diagnosis of IBD, exploring their possible implementation in the near future, with the goal of achieving earlier, feasible, and cheap methods of diagnosis as well as prognosis in IBD.

The Role of Endoscopy for Primary and Secondary Prophylaxis of Variceal Bleeding.

Cirrhosis is associated with a high morbidity and mortality. One of the most serious and unpredictable complication of cirrhosis, with a high mortality rate, is bleeding from esophagogastric varices. Endoscopic screening of varices followed by primary prophylactic treatment with beta blockers or band ligation in the presence of large esophageal varices will reduce the variceal bleeding rates and thereby reduce mortality risks in those with advanced cirrhosis. There is a paucity of data on primary prophylaxis of gastric varices but secondary prophylaxis includes glue injection, balloon-occluded retrograde transvenous obliteration, or transjugular intrahepatic portosystemic shunting with coil embolization.

Role of Endoscopy in the Diagnosis, Grading, and Treatment of Portal Hypertensive Gastropathy and Gastric Antral Vascular Ectasia.

Portal hypertensive gastropathy (PHG) and gastric antral vascular ectasia (GAVE) are 2 distinct gastric vascular abnormalities that may present with acute or chronic blood loss. PHG requires the presence of portal hypertension and is typically associated with chronic liver disease, whereas there is controversy about the association of GAVE with chronic liver disease and/or portal hypertension. Distinguishing between GAVE and PHG is crucial because their treatment strategies differ. This review highlights characteristic endoscopic appearances and the clinical features of PHG and GAVE, which, in turn, aid in their appropriate management.

Assessment, Resuscitation and Medical Management of Variceal and Nonvariceal Gastrointestinal Bleeding.

Upper gastrointestinal bleeding (UGIB) continues to be an important cause for emergency room visits and carries significant morbidity and mortality. Early resuscitative measures form the basis of the management of patients presenting with UGIB and can improve the outcomes of such patients including lowering mortality. In this review, using an evidence-based approach, we discuss the initial assessment and resuscitation of patients presenting with UGIB including identifying clues from history and physical examination to confirm UGIB, preendoscopic risk assessment tools, the role of early fluid resuscitation, utilization of blood products, use of pharmacologic interventions, and the optimal timing of endoscopy.