Colon capsule endoscopy versus CT colonography in FIT-positive colorectal cancer screening subjects: a prospective randomised trial-the VICOCA study.

BACKGROUND: Colon capsule endoscopy (CCE) and CT colonography (CTC) are minimally invasive techniques for colorectal cancer (CRC) screening. Our objective is to compare CCE and CTC for the identification of patients with colorectal neoplasia among participants in a CRC screening programme with positive faecal immunochemical test (FIT). Primary outcome was to compare the performance of CCE and CTC in detecting patients with neoplastic lesions. METHODS: The VICOCA study is a prospective, single-centre, randomised trial conducted from March 2014 to May 2016; 662 individuals were invited and 349 were randomised to CCE or CTC before colonoscopy. Endoscopists were blinded to the results of CCE and CTC. RESULTS: Three hundred forty-nine individuals were included: 173 in the CCE group and 176 in the CTC group. Two hundred ninety individuals agreed to participate: 147 in the CCE group and 143 in the CTC group. In the intention-to-screen analysis, sensitivity, specificity and positive and negative predictive values for the identification of individuals with colorectal neoplasia were 98.1%, 76.6%, 93.7% and 92.0% in the CCE group and 64.9%, 95.7%, 96.8% and 57.7% in the CTC group. In terms of detecting significant neoplastic lesions, the sensitivity of CCE and CTC was 96.1% and 79.3%, respectively. Detection rate for advanced colorectal neoplasm was higher in the CCE group than in the CTC group (100% and 93.1%, respectively; RR = 1.07; p = 0.08). Both CCE and CTC identified all patients with cancer. CCE detected more patients with any lesion than CTC (98.6% and 81.0%, respectively; RR = 1.22; p = 0.002). CONCLUSION: Although both techniques seem to be similar in detecting patients with advanced colorectal neoplasms, CCE is more sensitive for the detection of any neoplastic lesion. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02081742 . Registered: September 16, 2013.

Polyp fingerprint: automatic recognition of colorectal polyps' unique features.

BACKGROUND: Content-based image retrieval (CBIR) is an application of machine learning used to retrieve images by similarity on the basis of features. Our objective was to develop a CBIR system that could identify images containing the same polyp ('polyp fingerprint'). METHODS: A machine learning technique called Bag of Words was used to describe each endoscopic image containing a polyp in a unique way. The system was tested with 243 white light images belonging to 99 different polyps (for each polyp there were at least two images representing it in two different temporal moments). Images were acquired in routine colonoscopies at Hospital Clínic using high-definition Olympus endoscopes. The method provided for each image the closest match within the dataset. RESULTS: The system matched another image of the same polyp in 221/243 cases (91%). No differences were observed in the number of correct matches according to Paris classification (protruded: 90.7% vs. non-protruded: 91.3%) and size (< 10 mm: 91.6% vs. > 10 mm: 90%). CONCLUSIONS: A CBIR system can match accurately two images containing the same polyp, which could be a helpful aid for polyp image recognition.

Antibiotic Prophylaxis Is Not Required for Endoscopic Ultrasonography-Guided Fine-Needle Aspiration of Pancreatic Cystic Lesions, Based on a Randomized Trial.

BACKGROUND & AIMS: Guidelines recommend routine antibiotic prophylaxis for patients undergoing endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA) of pancreatic cysts, but there is conflicting evidence for its necessity. We investigated whether performing the procedure without antimicrobial prophylaxis increases the incidence of infection. METHODS: We performed a multicenter, randomized, noninferiority trial to compare prophylaxis with ciprofloxacin vs placebo in patients with a pancreatic cyst requiring EUS-FNA at multiple centers in Spain. From September 2014 to June 2018, patients were randomly assigned to groups that received the prophylaxis with ciprofloxacin (n = 112) or saline solution (n = 114, placebo). We recorded patients' demographic data, lesion characteristics, and procedure data and followed patients for 21 days. A total of 205 patients completed the trial (90.7%), receiving ciprofloxacin or the control, with no statistically significant differences in demographics, baseline data, or procedure characteristics between groups. The primary outcome was FNA-related infection. Secondary outcomes were incidence of fever, procedure complications, and medication-related adverse events. RESULTS: The only case of FNA-related infection (0.44%) occurred in a patient in the placebo group (0.87%); this patient developed acute pancreatitis and bacteremia after the procedure. Prevention of infection was not inferior in the control group; the difference between proportions was 0.87% (95% confidence interval, -0.84% to 2.59%). There were no differences between groups in fever (2 patients in each group: 1.78% vs 1.76%; P = 1.00) or other adverse events. CONCLUSIONS: In a randomized trial of patients undergoing EUS-FNA for pancreatic cyst evaluation, we found the risk of infection to be low. The incidence of infections did not differ significantly with vs without ciprofloxacin prophylaxis. (ClinicalTrials.gov, Number: NCT02261896).

White-Light Endoscopy Is Adequate for Lynch Syndrome Surveillance in a Randomized and Noninferiority Study.

BACKGROUND & AIMS: Dye-based pancolonic chromoendoscopy is recommended for colorectal cancer surveillance in patients with Lynch syndrome. However, there is scarce evidence to support its superiority to high-definition white-light endoscopy. We performed a prospective study assess whether in the hands of high detecting colonoscopists, high-definition, white-light endoscopy is noninferior to pancolonic chromoendoscopy for detection of adenomas in patients with Lynch syndrome. METHODS: We conducted a parallel controlled study, from July 2016 through January 2018 at 14 centers in Spain of adults with pathogenic germline variants in mismatch repair genes (60% women; mean age, 47 ± 14 years) under surveillance. Patients were randomly assigned to groups that underwent high-definition white-light endoscopy (n = 128) or pancolonic chromoendoscopy (n = 128) evaluations by 24 colonoscopists who specialized in detection of colorectal lesions in high-risk patients for colorectal cancer. Adenoma detection rates (defined as the proportion of patients with at least 1 adenoma) were compared between groups, with a noninferiority margin (relative difference) of 15%. RESULTS: We found an important overlap of confidence intervals (CIs) and no significant difference in adenoma detection rates by pancolonic chromoendoscopy (34.4%; 95% CI 26.4%-43.3%) vs white-light endoscopy (28.1%; 95% CI 21.1%-36.4%; P = .28). However, pancolonic chromoendoscopy detected serrated lesions in a significantly higher proportion of patients (37.5%; 95% CI 29.5-46.1) than white-light endoscopy (23.4%; 95% CI 16.9-31.4; P = .01). However, there were no significant differences between groups in proportions of patients found to have serrated lesions of 5 mm or larger (9.4% vs 7.0%; P = .49), of proximal location (11.7% vs 10.2%; P = .68), or sessile serrated lesions (3.9% vs 5.5%; P = .55), respectively. Total procedure and withdrawal times with pancolonic chromoendoscopy (30.7 ± 12.8 minutes and 18.3 ± 7.6 minutes, respectively) were significantly longer than with white-light endoscopy (22.4 ± 8.7 minutes and 13.5 ± 5.6 minutes; P < .001). CONCLUSIONS: In a randomized parallel trial, we found that for Lynch syndrome surveillance, high-definition white-light endoscopy is not inferior to pancolonic chromoendoscopy if performed by experienced and dedicated endoscopists. ClinicalTrials.gov no: NCT02951390.

Endocuff-assisted colonoscopy for surveillance of serrated polyposis syndrome: a multicenter randomized controlled trial.

BACKGROUND AND STUDY AIMS: Serrated polyposis syndrome (SPS) is a condition with high risk for colorectal cancer. The Endocuff device has been shown to increase adenoma detection in the general and screening population. We aimed to ascertain whether Endocuff-assisted colonoscopy increases detection of serrated lesions in comparison with standard colonoscopy during the surveillance of patients with SPS.  METHODS: In a multicenter randomized controlled study, patients who met SPS criteria I and/or III under surveillance (previous resection of all serrated lesions ≥ 4 mm) were consecutively randomly allocated 1:1 to Endocuff-assisted colonoscopy or standard colonoscopy, performed by expert endoscopists. The main outcome was the mean number of serrated lesions detected per patient. RESULTS: 122 patients (standard colonoscopy n = 60; Endocuff-assisted colonoscopy n = 62; 59 % men; mean age 60.6 (standard deviation [SD] 7.5) were included at 4 centers. Baseline variables (demographic data, SPS phenotype, colorectal cancer [CRC] history, cumulative polyps, and follow-up), cecal intubation rate, and withdrawal time were similar between groups. There was no statistically significant difference between Endocuff-assisted colonoscopy and standard colonoscopy for the mean number of serrated lesions detected per patient: 5.8 (95 % confidence interval [95 %CI] 4.4 - 7.2) and 5.0 (3.9 - 6.1), respectively (P = 0.36). There were also no differences between Endocuff-assisted and standard colonoscopy for detection of sessile serrated lesions (mean number per patient 2.5 [1.3 - 3.6] vs. 2.0 [1.1 - 3.0], P = 0.54) and adenomas (0.9 [0.5 - 1.3] vs. 0.5 [0.3 - 0.7], P = 0.12). CONCLUSION: Use of Endocuff-assisted colonoscopy did not significantly increase the number of serrated lesion detected per patient during surveillance of SPS.

Rectal Aberrant Crypt Foci in Humans Are Not Surrogate Markers for Colorectal Cancer Risk.

INTRODUCTION: Over the past 20 years, aberrant crypt foci (ACF) have emerged as potential precursors and biomarkers for colorectal cancer (CRC). However, data regarding their molecular pathogenesis, as well as their endoscopic and histological identification, remain inconsistent. METHODS: A wide cohort of ACF from 100 control subjects and 100 case patients, including patients with adenoma and CRC, were characterized for endoscopic, morphologic, and molecular features. RESULTS: We observed that among all the endoscopic features evaluated, only the number of large ACF correlated with CRC risk (P = 0.003), whereas the histological classification, as assessed by 2 different pathologists, was inconsistent and did not differ between control and case patients. Moreover, only a few APC and BRAF mutations and no microsatellite instability were detected in our samples. KRAS mutations were detected in 16.3% of ACF samples, which also exhibited increased MGMT hypermethylation. However, none of those events were found to be predictive of CRC risk. DISCUSSION: Although ACF might be preneoplastic lesions of the colon, they are not suitable biomarkers for assessing CRC progression.

GTCreator: a flexible annotation tool for image-based datasets.

PURPOSE: Methodology evaluation for decision support systems for health is a time-consuming task. To assess performance of polyp detection methods in colonoscopy videos, clinicians have to deal with the annotation of thousands of images. Current existing tools could be improved in terms of flexibility and ease of use. METHODS: We introduce GTCreator, a flexible annotation tool for providing image and text annotations to image-based datasets. It keeps the main basic functionalities of other similar tools while extending other capabilities such as allowing multiple annotators to work simultaneously on the same task or enhanced dataset browsing and easy annotation transfer aiming to speed up annotation processes in large datasets. RESULTS: The comparison with other similar tools shows that GTCreator allows to obtain fast and precise annotation of image datasets, being the only one which offers full annotation editing and browsing capabilites. CONCLUSION: Our proposed annotation tool has been proven to be efficient for large image dataset annotation, as well as showing potential of use in other stages of method evaluation such as experimental setup or results analysis.

Computer-aided prediction of polyp histology on white light colonoscopy using surface pattern analysis.

BACKGROUND: This study aimed to evaluate a new computational histology prediction system based on colorectal polyp textural surface patterns using high definition white light images. METHODS: Textural elements (textons) were characterized according to their contrast with respect to the surface, shape, and number of bifurcations, assuming that dysplastic polyps are associated with highly contrasted, large tubular patterns with some degree of bifurcation. Computer-aided diagnosis (CAD) was compared with pathological diagnosis and the diagnosis made by endoscopists using Kudo and Narrow-Band Imaging International Colorectal Endoscopic classifications. RESULTS: Images of 225 polyps were evaluated (142 dysplastic and 83 nondysplastic). The CAD system correctly classified 205 polyps (91.1 %): 131/142 dysplastic (92.3 %) and 74/83 (89.2 %) nondysplastic. For the subgroup of 100 diminutive polyps (≤ 5 mm), CAD correctly classified 87 polyps (87.0 %): 43/50 (86.0 %) dysplastic and 44/50 (88.0 %) nondysplastic. There were no statistically significant differences in polyp histology prediction between the CAD system and endoscopist assessment. CONCLUSION: A computer vision system based on the characterization of the polyp surface in white light accurately predicted colorectal polyp histology.

Development and validation of a scoring index to predict the presence of lesions in capsule endoscopy in patients with suspected Crohn's disease of the small bowel: a Spanish multicenter study.

BACKGROUND: Capsule endoscopy (CE) is the first-line investigation in cases of suspected Crohn's disease (CD) of the small bowel, but the factors associated with a higher diagnostic yield remain unclear. OBJECTIVE: Our aim is to develop and validate a scoring index to assess the risk of the patients in this setting on the basis of biomarkers. PATIENTS AND METHODS: Data on fecal calprotectin, C-reactive protein, and other biomarkers from a population of 124 patients with suspected CD of the small bowel studied by CE and included in a PhD study were used to build a scoring index. This was first used on this population (internal validation process) and after that on a different set of patients from a multicenter study (external validation process). RESULTS: An index was designed in which every biomarker is assigned a score. Three risk groups have been established (low, intermediate, and high). In the internal validation analysis (124 individuals), patients had a 10, 46.5, and 81% probability of showing inflammatory lesions in CE in the low-risk, intermediate-risk, and high-risk groups, respectively. In the external validation analysis, including 410 patients from 12 Spanish hospitals, this probability was 15.8, 49.7, and 80.6% for the low-risk, intermediate-risk, and high-risk groups, respectively. CONCLUSION: Results from the internal validation process show that the scoring index is coherent, and results from the external validation process confirm its reliability. This index can be a useful tool for selecting patients before CE studies in cases of suspected CD of the small bowel.

Endoscopic management of bile leaks after liver transplantation: An analysis of two high-volume transplant centers.

BACKGROUND: Bile leak after liver transplantation (LT) is commonly treated with endoscopic retrograde cholangiopancreatography (ERCP); however, there are limited data regarding the optimal treatment strategy. OBJECTIVE: We aimed to examine the role of ERCP in LT recipients with bile leaks at two large institutions. METHODS: We reviewed all ERCPs performed in LT recipients with bile leak and duct-to-duct biliary anastomosis at two high-volume transplant centers. RESULTS: Eighty patients were included. Forty-seven (59%) patients underwent ERCP with plastic stent placement (with or without sphincterotomy) and 33 patients (41%) underwent sphincterotomy alone. Complete resolution was obtained in 94% of the stent group vs. 58% of the sphincterotomy group (p < 0.01). There was no difference in three-month survival among both groups. Percutaneous transhepatic therapy and surgery were required in 4% and 6% in the stent group vs. 12% and 42% in the sphincterotomy group, respectively (p = 0.22 and p < 0.001). The only predictive factor of bile leak resolution was stent placement. CONCLUSION: ERCP with plastic stent placement is highly successful and more effective than sphincterotomy alone for post-LT bile leak treatment. These results indicate that ERCP and plastic stent placement should be considered the standard of care for the treatment of bile leaks in LT.

Accuracy of Colon Capsule Endoscopy in Detecting Colorectal Polyps in Individuals with Familial Colorectal Cancer: Could We Avoid Colonoscopies?

Background. Individuals with a family history of colorectal cancer (CRC) have an increased risk of CRC. We evaluated the diagnostic yield of CCE in the detection of lesions and also two different colon preparations. Methods. A prospective multicenter study was designed to assess CCE diagnostic yield in a cohort of asymptomatic individuals with a family history of CRC. CCE and colonoscopy were performed on the same day by 2 endoscopists who were blinded to the results of the other procedure. Results. Fifty-three participants were enrolled. The sensitivity, specificity, PPV, and NPV of CCE for detecting advanced adenomas were 100%, 98%, 67%, and 100%. Sensitivity, specificity, PPV, and NPV of CCE for the diagnosis of individuals with polyps were 87%, 97%, 93%, and 88%, respectively. CCE identify 100% of individuals with significant or advanced lesions. Overall cleanliness was adequate by 60.7% of them. The PEG-ascorbic boost seems to improve colon cleanliness, with similar colonic transit time. Conclusion. CCE is a promising tool, but it has to be considered as an alternative technique in this population in order to reduce the number of colonoscopies performed. More studies are needed to understand appropriate screening follow-up intervals and optimize the bowel preparation regimen.

Exploring the clinical potential of an automatic colonic polyp detection method based on the creation of energy maps.

BACKGROUND AND AIMS: Polyp miss-rate is a drawback of colonoscopy that increases significantly for small polyps. We explored the efficacy of an automatic computer-vision method for polyp detection. METHODS: Our method relies on a model that defines polyp boundaries as valleys of image intensity. Valley information is integrated into energy maps that represent the likelihood of the presence of a polyp. RESULTS: In 24 videos containing polyps from routine colonoscopies, all polyps were detected in at least one frame. The mean of the maximum values on the energy map was higher for frames with polyps than without (P < 0.001). Performance improved in high quality frames (AUC = 0.79 [95 %CI 0.70 - 0.87] vs. 0.75 [95 %CI 0.66 - 0.83]). With 3.75 set as the maximum threshold value, sensitivity and specificity for the detection of polyps were 70.4 % (95 %CI 60.3 % - 80.8 %) and 72.4 % (95 %CI 61.6 % - 84.6 %), respectively. CONCLUSION: Energy maps performed well for colonic polyp detection, indicating their potential applicability in clinical practice.

Adverse events of EUS-guided FNA of pancreatic cystic and solid lesions by using the lexicon proposed in an ASGE workshop: a prospective and comparative study.

BACKGROUND AND AIMS: Pancreatic cysts and solid lesions are routinely examined by EUS-guided FNA (EUS-FNA). The aim of this study was to compare the incidence of adverse events (AEs) of this procedure by using the lexicon recommended by the American Society for Gastrointestinal Endoscopy (ASGE). METHODS: This was a prospective and comparative study of patients who underwent EUS-FNA in which a 22-gauge needle was used. In the pancreatic cystic lesions group (group I), complete fluid evacuation in a single needle pass was attempted, and ciprofloxacin was given during the procedure and for 3 days after. In the pancreatic solid lesions group (group II), the number of passes was determined by the on-site evaluation of the sample. AEs were defined and graded according to the lexicon recommended by the ASGE. Patients were followed for 48 hours, 1 week, and 1 month after the procedure. RESULTS: A total of 146 patients were included, 73 in group I and 73 in group II. Potential factors influencing the incidence of AEs (ie, access route for FNA) were similar in both groups. AEs occurred in 5 of 146 patients (3.4%; 95% confidence interval [CI], 1.3%-8%): 4 in group I (5.5%; 95% CI, 1.7%-13.7%) and 1 in group II (1.4%; 95% CI, -0.5% to 8.1%) (P = .03). Severity was mild in 1 of 5 patients (20%) and moderate in 3 of 5 patients (60%). One patient with a solid mass in the head of the pancreas had a duodenal perforation after EUS and died after surgery. All other AEs occurred in the first 48 hours and resolved with medical therapy. There were 3 incidents of transient hypoxia and self-limited abdominal pain in 1 and 2 patients, respectively. No patients were lost to follow-up. CONCLUSION: EUS-FNA of pancreatic cysts has an AEs rate similar to that of solid pancreatic masses, which is small enough to consider this procedure a safe and effective method for managing patients with both types of lesions. AEs occurred early after EUS-FNA, and patients should be closely followed during the first 2 days after the procedure.

Adverse events of NOTES mediastinoscopy compared to conventional video-assisted mediastinoscopy: a randomized survival study in a porcine model.

BACKGROUND: Safety is a concern in natural orifice transluminal endoscopic surgery (NOTES) mediastinoscopy. The objective of this study was to compare the safety of NOTES mediastinoscopy with video-assisted mediastinoscopy (VAM). METHODS: Twenty-four pigs were randomly assigned to NOTES or VAM. Thirty-minute mediastinoscopies were performed with the identification of seven predetermined structures. The animals were euthanized after 7 days and necropsy was performed. RESULTS: Mediastinoscopy was not possible in one animal in each group. There were more intraoperative adverse events with NOTES than VAM (7 vs. 2, P = 0.04); hemorrhage was the most frequent adverse event (4 and 1, respectively). At necropsy, pathological findings were observed in 13 animals (9 NOTES and 4 VAM; P = 0.03). Inflammatory parameters were not different between groups and were not related to adverse events. CONCLUSION: Systematic NOTES mediastinoscopy is possible and comparable to VAM in terms of number of organs identified and inflammatory impact. However, the safety profile of NOTES mediastinoscopy has to be improved before it can be adopted in a clinical setting.

Accuracy of advanced endoscopy and fecal calprotectin for prediction of relapse in ulcerative colitis: a prospective study.

BACKGROUND: The aim of this study was to determine the accuracy of advanced endoscopy for prediction of relapse in ulcerative colitis, in comparison with serum and fecal biomarkers. METHODS: Patients with ulcerative colitis with sustained clinical remission defined as absence of blood in stool for a minimum of 3 months and Mayo endoscopic subscore of 0 were included. High-resolution rectosigmoidoscopy was performed at baseline and at the end of study (week 52 or relapse), assessing mucosal pit pattern by chromoendoscopy and narrow band imaging as well as vascular pattern by narrow band imaging. Histology was evaluated at baseline and at the end of the study. Follow-up for 1 year or until relapse with clinical evaluations and serum and fecal biomarkers every 3 months was established. Relapse was defined as presence of blood in stool and a Mayo endoscopic subscore ≥1 with histologic confirmation. RESULTS: Seventeen out of 64 patients (27%) relapsed during the follow-up period. Baseline clinical characteristics in patients who relapsed and those who did not were similar. Neither pit or vascular pattern nor histology was significantly different between relapsers and nonrelapsers. Among serum biomarkers, high platelet count was significantly associated with higher relapse rates. Fecal calprotectin was predictor of relapse within 3- and 12-month period with high specificity but low sensitivity. CONCLUSIONS: Advanced endoscopy and histology do not predict relapse over 1-year period in patients with ulcerative colitis. Fecal calprotectin can predict relapse in 3- and 12-month period with low accuracy.

Cardiorespiratory impact of transesophageal endoscopic mediastinoscopy compared with cervical mediastinoscopy: a randomized experimental study.

BACKGROUND: Transesophageal natural-orifice transluminal endoscopic surgery (NOTES) mediastinoscopy has been described as a feasible, less-invasive alternative to video-assisted mediastinoscopy (VAM). We aimed to investigate hemodynamic and respiratory effects during transesophageal NOTES mediastinoscopy compared with VAM. PATIENTS AND METHODS: This was a short-survival experiment in 20 female pigs randomized to NOTES (n = 10) or VAM (n = 10) mediastinoscopy. In the NOTES group, an endoscopist accessed the mediastinum through a 5-cm submucosal tunnel in the esophageal wall, and CO2 was used to create the pneumomediastinum. Conventional VAM was carried out by thoracic surgeons. A 30-minute systematic exploration of the mediastinum was then performed, including invasive monitoring for hemodynamic and respiratory data. Blood samples were drawn for gas analyses. RESULTS: All experiments except 2 in the NOTES group (one because of technical difficulties, the other because of thoracic lymphatic duct lesion) were completed as planned, and animals survived 24 hours. Also, 3 animals in the NOTES group presented a tension pneumothorax that was immediately recognized and percutaneously drained. VAM and NOTES animals showed similar pulmonary and systemic hemodynamic behavior during mediastinoscopy. Pulmonary gas exchange pattern was mildly impaired during the NOTES procedure, showing lower partial arterial oxygen pressure associated with higher airway pressures (more important in animals that presented with pneumothorax). CONCLUSIONS: NOTES mediastinoscopy induces minimal deleterious respiratory effects and hemodynamic changes similar to conventional cervical VAM and could be feasible when performed under strict hemodynamic and respiratory surveillance. Notably, serious complications caused by the injury of pleura are more frequent in NOTES, which mandates an improvement in technique and suitable equipment.

Comparative study of NOTES alone versus NOTES guided by a new image registration system for navigation in the mediastinum: a study in a porcine model.

BACKGROUND: Natural orifice transluminal endoscopic surgery (NOTES) mediastinoscopy (MED) through the esophagus has proved to be feasible in the animal model. However, injury of the adjacent pleura and pneumothorax has been reported as a frequent adverse event when using a blind access. OBJECTIVE: To assess the utility and safety of a CT-based image registration system (IRS) for navigation in the mediastinum. DESIGN: Prospective, randomized, controlled trial in 30 Yorkshire pigs. Thirty-minute MEDs were performed: 15 MEDs were performed with IRS guidance (MED-IRS), and 15 MEDs were performed with a blind access. SETTING: Animal research laboratory. INTERVENTIONS: In both groups, the mediastinum was accessed through a 10-cm submucosal tunnel in the esophageal wall. Timed exploration was performed with identification of 8 mediastinal structures. MAIN OUTCOME MEASUREMENTS: Technical feasibility, adverse events, and the number of mediastinal structures identified. RESULTS: Thirty animals weighing 31.5 ± 3.5 kg were included in this study. MED was not possible in 2 animals in the "MED with blind access" group but was possible in all MEDs performed with IRS. The mean number of identified organs was slightly higher in "with IRS-MED" (6.13 ± 1.3) than with MED with blind access (4.7 ± 2.3; P = .066). Moreover, the right atrium and vena cava were identified in more cases with IRS-MED than in MED with blind access (13 vs 3 and 15 vs 11, P = .000 and P = .03, respectively). There were 3 (23%) adverse events with IRS-MED and 4 (27%) with "MED with blind access" (P = not significant), with pneumothorax being the most frequent (2 and 3, respectively). LIMITATIONS: Nonsurvival animal study. CONCLUSIONS: This study demonstrates that the IRS system appears feasible in natural orifice transluminal endoscopic surgery MED and suggests that IRS guidance might be useful for selected procedures.

On-demand endoscopic CO2 insufflation with feedback pressure regulation during natural orifice transluminal endoscopic surgery (NOTES) peritoneoscopy induces minimal hemodynamic and respiratory changes.

BACKGROUND: Endoscopic insufflation has been associated with marked increase in intra-abdominal pressure (IAP) and hemodynamic and respiratory changes during transgastric surgery. OBJECTIVE: To investigate the hemodynamic and respiratory effects during intraperitoneal cavity exploration through 3 different natural orifice transluminal endoscopic surgery (NOTES) access locations compared with laparoscopy. DESIGN AND SETTING: Survival experiments using 40 female pigs randomized to transgastric, transcolonic, transvaginal, and laparoscopic peritoneoscopy. INTERVENTIONS: On-demand endoscopic insufflation of CO(2) with feedback pressure regulation was used in NOTES with a maximum pressure of 14 mm Hg. In the laparoscopy group, the IAP was maintained at 14 mm Hg. NOTES procedures were performed by an endoscopist (with the assistance of a gynecologist in the transvaginal group and a second endoscopist in the transgastric and transrectal groups) and laparoscopy by 2 surgeons. MAIN OUTCOME MEASUREMENTS: Invasive hemodynamic and respiratory data. Blood samples were drawn for gas analyses. RESULTS: All experiments except one in the transrectal group were completed. The IAP was significantly lower in all NOTES groups compared with the laparoscopy group. A significant increase in mean systemic arterial blood pressure was observed in the laparoscopy group at 15 and 30 minutes of intraperitoneal cavity exploration, but it remained unchanged during all NOTES procedures. An increase in airway pressures was observed at 15 and 30 minutes of peritoneoscopy in the animals undergoing laparoscopy, whereas those parameters remained unchanged in the NOTES groups. The laparoscopy group showed a significant impairment in pulmonary gas exchange (decrease in Pao(2), increase in Paco(2), and decrease in arterial pH) after 30 minutes of peritoneoscopy, whereas only a slight increase in Paco(2) was observed in the transrectal and transvaginal groups. LIMITATIONS: Healthy animal model. CONCLUSION: On-demand endoscopic insufflation of CO(2) with feedback pressure regulation can minimize the risk of hemodynamic and respiratory compromise caused by acute changes in IAP.

[Timing of polyethylene glycol administration is a key factor in the tolerability and efficacy of colon preparation in colorectal cancer screening]. / La hora de ingesta del polietilenglicol es un factor clave en la tolerancia y eficacia de la preparación del colon en individuos de un programa poblacional de cribado de cáncer colorrectal.

INTRODUCTION: The quality and tolerability of antegrade gut lavage bowel preparation are key elements in the success of population-based colorectal cancer screening. OBJECTIVES: To evaluate cleansing quality and tolerability according to the timing of polyethylene glycol administration in persons undergoing colorectal cancer screening. METHOD: Participants in colorectal cancer screening were randomized to two groups: a) control group (colonoscopy scheduled at 9-12 h); preparation with polyethylene glycol on the previous afternoon; b) study group (colonoscopy scheduled at 12-15 h): preparation with polyethylene glycol on the morning of the colonoscopy, with the option of a split dose. The quality of cleansing was evaluated with the Boston scale and tolerability through a questionnaire. RESULTS: A total of 282 participants were included: preparation was carried out the day before the procedure in 134 and on the same day in 148, of which 26 received a split dose. Cleansing was adequate in 95% (n=268) of the participants. The quality of cleansing was higher in the study group (P=.045). The interval between the end of administration and the beginning of the procedure was inversely correlated with the Boston scale score (P=.036; r=-0.125). Tolerability was unrelated to the time of administration (P>.2). Acceptance of the timing of administration was lower in the study group than in the control group (26% vs 10%, respectively; P=.001). CONCLUSIONS: Preparation as close as possible to the colonoscopy improves the quality of cleansing with no detrimental effects on tolerability, although this option is less comfortable.