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Background Larger caliber lumen-apposing stents (LAMSs) have been increasingly used in the management of pancreatic fluid collections, specifically when solid debris is present; however, their advantages over smaller caliber plastic stents in the management of pancreatic pseudocysts are unclear. The aim of this study was to investigate the safety and efficacy of LAMS specifically in the management of pancreatic pseudocysts compared with double-pigtail plastic stents (DPPSs). Methods We performed a multicenter, international, retrospective study between January 2012 and August 2016. A total of 205 patients with a diagnosis of pancreatic pseudocysts were included, 80 patients received LAMSs and 125 received DPPSs. Measured outcomes included clinical success, technical success, adverse events, stent dysfunction, pancreatic pseudocyst recurrence, and need for surgery. Results Technical success was similar between the LAMS and the DPPS groups (97.5 % vs. 99.2 %; P = 0.32). Clinical success was higher for LAMSs than for DPPSs (96.3 % vs. 87.2 %; P = 0.03). While the need for surgery was similar between the two groups (1.3 % vs. 4.9 %, respectively; P = 0.17), the use of percutaneous drainage was significantly lower in the LAMS group (1.3 % vs. 8.8 %; P = 0.03). At 6-month follow-up, the recurrence rate was similar between the groups (6.7 % vs 18.8 %, respectively; P = 0.12). The rate of adverse events was significantly higher in the DPPS group (7.5 % vs. 17.6 %; P = 0.04). There was no difference in post-procedure mean length of hospital stay (6.3 days [standard deviation 27.9] vs. 3.7 days [5.7]; P = 0.31). Conclusion When compared to DPPSs, LAMSs are a safe, feasible, and effective modality for the treatment of pancreatic pseudocysts and are associated with a higher rate of clinical success, shorter procedure time, less need for percutaneous interventions, and a lower overall rate of adverse events.

Background and study aim Standard endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) procedures involve use of no-suction or suction aspiration techniques. A new aspiration method, the stylet slow-pull technique, involves slow withdrawal of the needle stylet to create minimum negative pressure. The aim of this study was to compare the sensitivity of EUS-FNA using stylet slow-pull or suction techniques for malignant solid pancreatic lesions using a standard 22-gauge needle. Patients and methods Consecutive patients presenting for EUS-FNA of pancreatic mass lesions were randomized to the stylet slow-pull or suction techniques using a 22-gauge needle. Both techniques were standardized for each pass until an adequate specimen was obtained, as determined by rapid on-site cytology examination. Patients were crossed over to the alternative technique after four nondiagnostic passes. Results Of 147 patients screened, 121 (mean age 64 ± 13.8 years) met inclusion criteria and were randomized to the stylet slow-pull technique (n = 61) or the suction technique (n = 60). Technical success rates were 96.7 % and 98.3 % in the slow-pull and suction groups, respectively (P > 0.99). The sensitivity for malignancy of EUS-FNA was 82 % in the slow-pull group and 69 % in the suction group (P = 0.10). The first-pass diagnostic rate (42.6 % vs. 38.3 %; P = 0.71), acquisition of core tissue (60.6 % vs. 46.7 %; P = 0.14), and the median (range) number of passes to diagnosis (2 1 2 3 vs. 1 1 2; P = 0.71) were similar in the slow-pull and suction groups, respectively. Conclusions The stylet slow-pull and suction techniques both offered high and comparable diagnostic sensitivity with a mean of 2 passes required for diagnosis of solid pancreatic lesions. The endosonographer may choose either technique during FNA.

Background and study aims: Endoscopic cryotherapy has been used successfully for the ablation of Barrett’s esophagus but outcome data are limited. The aim of this study was to assess the long-term safety and efficacy of carbon dioxide (CO2) cryotherapy as primary or rescue treatment for Barrett’s esophagus with high grade dysplasia (HGD) or neoplasia. Patients and methods: This was a retrospective, single-center, nonrandomized study carried out in an academic, tertiary care center and affiliated community hospital. A total of 78 patients with neoplastic Barrett’s esophagus who had not undergone previous ablation (treatment-naive group) or who had persistent or recurrent neoplasia despite previous treatment (rescue treatment group) were enrolled. Visible Barrett’s lesions, when present, were removed by endoscopic mucosal resection, which was followed by CO2 cryotherapy until neoplasia had been eradicated, or intervening therapy was necessary, or treatment was considered to have failed. Surveillance biopsies were obtained at standard intervals. Rates of complete response for cancer, HGD, and intestinal metaplasia were calculated. Treatment failure, recurrence, adverse events, progression, and mortality were also recorded. Results: Between 2006 and 2013, 64 evaluable patients (20 treatment naive, 44 rescue treatment) were treated and followed up (median time 4.2 years). At 1 year, the overall complete response rates were 77 % for cancer (10/13), 89 % for dysplasia 57/64), 94 % for HGD (60/64; 100 % for treatment naive, 91 % for rescue treatment), and 55 % for intestinal metaplasia (35/64). Long-term complete response for neoplasia with rescue therapy was 87 % (56/64). Disease-specific mortality was 1/68 (2 %). Treatment failed to eradicate neoplasia in four patients (6 %) (all in the rescue group). Recurrent or new intestinal metaplasia was detected in 20/64 (31 %) after two negative follow-up procedures. Serious adverse events were noted in two patients (3 %). Post-cryotherapy pain occurred in four patients (6 %; only two needed analgesics). No bleeding or new strictures were noted. Buried Barrett’s was detected in 5/68 patients (7 %). Conclusions: CO2 cryotherapy was a safe and effective primary curative or rescue therapy for Barrett’s neoplasia.

Background and study aims: A new on-demand enteroscopy (ODE) device has been designed to allow deep enteroscopy using a standard adult colonoscope with the aid of a novel through-the-scope balloon. The aims of the current study were to establish the feasibility, efficacy, and safety of ODE in performing anterograde and retrograde enteroscopy. Patients and methods: A retrospective, single-center study of 28 consecutive deep ODE procedures (11 anterograde and 17 retrograde) was performed. Diagnostic yield, therapeutic yield, technical success, procedure time, depth of maximal insertion (DMI), time to DMI, and adverse events were recorded. Results: The mean diagnostic and therapeutic yields were 45 % and 36 % for anterograde enteroscopy and 59 % and 47 % for retrograde enteroscopy, respectively. Technical success was achieved in 100 %. For anterograde enteroscopy, the mean total procedure time was 24 minutes, with a mean DMI of 1.2 m. For retrograde enteroscopy, the mean total procedure time was 31 minutes, with a mean DMI of 1.1 m. No adverse events were recorded. Conclusion: Deep enteroscopy using a novel through-the-scope balloon and standard endoscope appeared to be feasible and safe, with rapid procedures times.

Background and study aim: Endoscopic therapy of brisk upper gastrointestinal bleeding remains challenging. A proprietary nanopowder (TC-325) has been proven to be effective in high pressure bleeding from external wounds. The efficacy and safety of TC-325 were assessed in a survival gastrointestinal bleeding animal model. Method: 10 animals were randomized to treatment or sham. All animals received intravenous antibiotics, H2-blockers and heparin (activated clotting time 2 × normal). In a sterile laparotomy the gastroepiploic vessels were dissected, inserted through a 1-cm gastrotomy, and freely exposed in the gastric lumen, and the exposed vessel lacerated by needle knife. The treatment group received TC-325 by a modified delivery catheter while the sham group received no endoscopic treatment. Time to hemostasis, and mortality at 60 minutes, 24 hours, 48 hours, and 7 days were noted. Necropsy was performed in all animals. Results: Spurting arterial bleeding was achieved in all animals. No control animal showed hemostasis within the first hour compared with 100 % (5 / 5) in the treatment arm (mean 13.8 minutes, P < 0.0079). Durable hemostasis was achieved with no evidence of rebleeding after 1 and 24 hours in 80 % (4 / 5) of the treated animals compared with none in the control group ( P < 0.0098). None of the control animals survived more than 6 hours. Necropsy at 1 week in treated animals revealed healed gastrotomy without foreign body granuloma or embolization to the lung or brain. Conclusion: TC-325 is safe and highly effective in achieving hemostasis in an anticoagulated severe arterial gastrointestinal bleeding animal model.

BACKGROUND AND STUDY AIMS Changes in portal pressure during endoscopy have not been previously evaluated. The aims of this study were to assess the effect of esophagogastroduodenoscopy (EGD), colonoscopy, and endoscopic retrograde cholangiopancreatography (ERCP) on portal vein, inferior vena cava (IVC), and systemic pressures. PATIENTS AND METHODS Five acute experiments were performed on 50-kg pigs utilizing endoscopic ultrasound (EUS)-guided catheterization of the portal vein and IVC. Systemic, intra-abdominal, IVC, and portal vein pressures were monitored during colonoscopy, EGD, and ERCP with endoscopic sphincterotomy. After endoscopy the animals were sacrificed for necropsy. The main outcome measure was pressure change during each type of endoscopic procedure. RESULTS There were no significant changes in heart rate or systemic pressure during all endoscopic procedures. Intra-abdominal pressure increased during colonoscopy ( P = 0.02) and ERCP ( P = 0.007). However, mean portal venous pressure was significantly elevated only after the injection of contrast into the common bile duct, reaching its peak value at the time of biliary sphincterotomy (39.0 +/- 15.2 mm Hg vs. 13.4 +/- 3.6 mm Hg at baseline, P = 0.006). Mean peak IVC pressure was also elevated during ERCP, but it did not reach statistical significance (24.0 +/- 10.7 mm Hg vs. 12.6 +/- 4.1 mm Hg at baseline, P = 0.06). CONCLUSION EGD and colonoscopy did not cause significant changes in portal vein, IVC, or systemic pressures. ERCP with biliary sphincterotomy increased portal pressure with only limited effect on IVC and systemic pressures. These new data indicate a possible connection between ERCP with sphincterotomy and portal pressure, and may be clinically important for patients with liver disease and other causes of portal hypertension who undergo this procedure.

BACKGROUND AND STUDY AIMS: Pancreatitis complicates 1 % - 22 % of endoscopic retrograde cholangiopancreatography procedures. The study aims were to develop a reproducible animal model of post-ERCP pancreatitis (PEP), and investigate the impact of endoscopic technique on severity of PEP. PATIENTS AND METHODS: ERCP was carried out in six male hound dogs. Pancreatitis was induced by one of three escalating methods: 1) pancreatic acinarization with 20 - 30 mL of contrast; 2) acinarization + ductal balloon occlusion + sphincterotomy; 3) acinarization + intraductal synthetic bile injection + ductal balloon occlusion + sphincterotomy. Dogs 5 and 6 received a pancreatic stent. Necropsy was performed on postoperative day 5. All pancreatic specimens were graded by two blinded pathologists according to a validated scoring system. All dogs were compared with three control dogs. RESULTS: Dogs 1 - 4 developed clinical pancreatitis and hyperamylasemia (11 736 vs. 722 U/L, P = 0.02). Total injury scores were significantly elevated compared with controls (6.85 vs. 1.06, P = 0.004). There was significant increase in acinar cell necrosis (0.86 vs. 0.06, P = < 0.001), and all other categories (except fibrosis) demonstrated elevated injury scores . Dogs 5 and 6 developed clinical pancreatitis without significant hyperamylasemia; total injury scores were elevated compared with controls (4.83 vs. 1.06, P = 0.01), but lower than in Dogs 1 - 4 (4.83 vs. 6.85, P = 0.25). There was escalating severity of pancreatic injury from Dogs 1 to 4 correlating with the method of endoscopic injury used. CONCLUSION: Severity of PEP is directly proportional to invasiveness of endoscopic intervention. Pancreatic acinarization, even without balloon occlusion and sphincterotomy, can be used as a reliable animal model for future studies investigating therapy and prevention of disease.

BACKGROUND AND STUDY AIMS: Pancreatic ablation is gaining popularity for the treatment of focal pancreatic lesions. The aim of our study was to evaluate local effects of intrapancreatic alcohol injection and the utility of contrast-enhanced endoscopic ultrasound (EUS) for its monitoring in a porcine model. METHODS: We performed four survival experiments on 50-kg pigs. Under linear EUS guidance, 0.5mL of 50 % ethanol plus purified carbon particle solution (GI Spot®) was injected into the pancreatic body to create a focal area of pancreatic necrosis. The animals survived for 24 - 48 hours (pigs # 1, # 2, and # 3) and 7 days (pig # 4). EUS was then repeated with and without perflutren lipid microspheres (Definity®) administration through the peripheral vein. Standard and microsphere-enhanced images of the pancreas were compared. Afterwards the animals were euthanized for necropsy. RESULTS: Alcohol injection caused focal pancreatic necrosis, which was barely seen by standard EUS as a subtle hypoechoic lesion 1 cm in diameter. Color and power Doppler EUS of this region did not reveal any blood flow. After intravenous injection of microspheres, color Doppler EUS revealed marked contrast enhancement of normal pancreatic parenchyma with a clearly delineated avascular alcohol-treated area, which on postmortem examination corresponded to the discrete necrotic area marked with carbon particles. CONCLUSIONS: EUS-guided alcohol injection consistently causes focal areas of pancreatic necrosis. Contrast-enhanced EUS with microspheres improves visualization of altered pancreatic vascular perfusion and can be used to facilitate detection of small pancreatic lesions and its follow-up post-ablation.

BACKGROUND AND STUDY AIMS: Safe entrance into the peritoneal cavity through the gastric wall is paramount for the successful clinical introduction of natural orifice transluminal endoscopic surgery (NOTES). The aim of the study was to develop alternative safe transgastric access to the peritoneal cavity. PATIENTS AND METHODS: We performed 11 survival experiments on 50-kg pigs. In sterile conditions, the abdominal wall was punctured with a Veress needle. The peritoneal cavity was insufflated with 2 L carbon dioxide (CO 2 ). A sterile endoscope was introduced into the stomach through a sterile overtube; the gastric wall was punctured with a needle-knife; after balloon dilation of the puncture site, the endoscope was advanced into the peritoneal cavity. Peritoneoscopy with biopsies from abdominal wall, liver and omentum, was performed. The endoscope was withdrawn into the stomach. The animals were kept alive for 2 weeks and repeat endoscopy was followed by necropsy. RESULTS: The pneumoperitoneum, easily created with the Veress needle, lifted the abdominal wall and made a CO 2 -filled space between the stomach and adjacent organs, facilitating gastric wall puncture and advancement of the endoscope into the peritoneal cavity. There were no hemodynamic changes or immediate or delayed complications related to pneumoperitoneum, transgastric access, or intraperitoneal manipulations. Follow-up endoscopy and necropsy revealed no problems or complications inside the stomach or peritoneal cavity. CONCLUSIONS: Creation of a preliminary pneumoperitoneum with a Veress needle facilitates gastric wall puncture and entrance into the peritoneal cavity without injury to adjacent organs, and can improve the safety of NOTES.

BACKGROUND AND STUDY AIMS Creation of a submucosal cushion before endoscopic mucosal resection (EMR) significantly reduces perforation risk. We evaluated six solutions as cushioning agents in live pigs. MATERIAL AND METHODS 5 ml of normal saline, normal saline plus epinephrine, albumin 12.5 %, albumin 25 %, hydroxypropyl methylcellulose, and the pig's own whole blood were endoscopically injected into the porcine esophageal submucosa. Blood was obtained from a peripheral vein immediately before injection. Injections were made every 4 cm from the gastroesophageal junction. The time from completion of the injection to disappearance of the cushion was recorded. Endoscopy was repeated at 48 hours post injection. Two EMRs were performed after blood injection. Statistical analysis employed one-way analysis of variance followed by pairwise T test comparisons using the Bonferroni correction. RESULTS Five animal experiments were completed. The mean time to dissipation of the submucosal cushion was shortest for saline plus epinephrine sites (2.87 minutes, SD 2.21) followed by the saline (4.8 minutes, SD 1.56), albumin 12.5 % (5.68 minutes, SD 3.48), albumin 25 % (7.83 minutes, SD 2.02), hydroxypropyl methylcellulose (9.77 minutes, SD 1.55), and blood sites (38.6 minutes, SD 6.07). Injection of blood resulted in significantly longer mucosal elevation than any other solution ( P < 0.0007). Blood from the cushion did not hamper visualization and facilitated EMR. CONCLUSION Blood produces the most durable cushion compared with standard agents, also having the advantages of being readily available and without cost. Albumin 25 % provides as durable a cushion as hydroxypropyl methylcellulose.