Interventional Endoscopic Ultrasound: Current Status and Future Directions.

The evolution of endoscopic ultrasound (EUS) from a diagnostic to a therapeutic procedure has resulted in a paradigm shift toward endoscopic management of disease states that previously required percutaneous or surgical approaches. The past few years have seen additional techniques and devices that have enabled endoscopists to expand its diagnostic and therapeutic capabilities. Some of these techniques initially were reported more than a decade ago; however, with further device development and refinement in techniques there is potential for expanding the application of these techniques and new technologies to a broader group of interventional gastroenterologists. Lack of formalized training, devices, and prospective data regarding their use in addition to a scarcity of guidelines on implementation of these technologies into clinical practice are contributing factors impeding the growth of the field of interventional EUS. In April 2019, the American Gastroenterological Association's Center for Gastrointestinal Innovation and Technology conducted its annual Tech Summit and a key session focused on interventional EUS. This article is a White Paper generated from the conference, discusses the published literature pertaining to the topic of interventional EUS, and outlines a proposed framework for the implementation of interventional EUS techniques into clinical practice. Three primary areas of interventional EUS are addressed: (1) EUS-guided access; (2) EUS-guided tumor ablation; and (3) endohepatology. There was general agreement among participants on several key components. The introduction of these novel interventions requires better tools, more data on safety/outcomes, and improved training for endoscopists. Participants also agreed that widespread implementation and use of these techniques will require support from Gastrointestinal Societies and other key stakeholders including payers. Continued work by the Gastrointestinal Societies and manufacturers to provide training programs, appropriate equipment/work environments, and policies that motivate endoscopists to adopt new techniques is essential for growing the field of interventional EUS.

Time Given to Trainees to Attempt Cannulation During Endoscopic Retrograde Cholangiopancreatography Varies by Training Program and Is Not Associated With Competence.

Advanced endoscopy training programs (AETPs) were developed as a result of the lack of comprehensive endoscopic retrograde cholangiopancreatography (ERCP) training during gastroenterology fellowships. There is no standardized curriculum for AETPs and the influence of program- and trainer-associated factors on trainee competence in ERCP has not been investigated adequately. In prior work, we showed that advanced endoscopy trainees (AETs) achieve ERCP competence at varying rates.1,2 The aims of this study were to measure the variability in time given to AETs to attempt cannulation between AETPs and throughout the 1-year training period, and to determine the association between AET cannulation time and AET competence at the end of training.

Setting minimum standards for training in EUS and ERCP: results from a prospective multicenter study evaluating learning curves and competence among advanced endoscopy trainees.

BACKGROUND AND AIMS: Minimum EUS and ERCP volumes that should be offered per trainee in "high quality" advanced endoscopy training programs (AETPs) are not established. We aimed to define the number of procedures required by an "average" advanced endoscopy trainee (AET) to achieve competence in technical and cognitive EUS and ERCP tasks to help structure AETPs. METHODS: American Society for Gastrointestinal Endoscopy (ASGE)-recognized AETPs were invited to participate; AETs were graded on every fifth EUS and ERCP examination using a validated tool. Grading for each skill was done using a 4-point scoring system, and learning curves using cumulative sum analysis for overall, technical, and cognitive components of EUS and ERCP were shared with AETs and trainers quarterly. Generalized linear mixed-effects models with a random intercept for each AET were used to generate aggregate learning curves, allowing us to use data from all AETs to estimate the average learning experience for trainees. RESULTS: Among 62 invited AETPs, 37 AETs from 32 AETPs participated. Most AETs reported hands-on EUS (52%, median 20 cases) and ERCP (68%, median 50 cases) experience before starting an AETP. The median number of EUS and ERCPs performed per AET was 400 (range, 200-750) and 361 (range, 250-650), respectively. Overall, 2616 examinations were graded (EUS, 1277; ERCP-biliary, 1143; pancreatic, 196). Most graded EUS examinations were performed for pancreatobiliary indications (69.9%) and ERCP examinations for ASGE biliary grade of difficulty 1 (72.1%). The average AET achieved competence in core EUS and ERCP skills at approximately 225 and 250 cases, respectively. However, overall technical competence was achieved for grade 2 ERCP at about 300 cases. CONCLUSION: The thresholds provided for an average AET to achieve competence in EUS and ERCP may be used by the ASGE and AETPs in establishing the minimal standards for case volume exposure for AETs during their training. (Clinical trial registration number: NCT02509416.).

Radiofrequency ablation for the treatment of weight regain after Roux-en-Y gastric bypass surgery.

BACKGROUND AND AIMS: Roux-en-Y gastric bypass (RYGB) surgery is an established modality for the treatment of morbid obesity. However, approximately one-quarter of patients experience weight regain after initially successful weight loss. Endoscopic therapy targeting the gastric remnant pouch represents a novel potential strategy to re-induce weight loss in this population. We performed a pilot trial of radiofrequency ablation (RFA) of the gastric remnant pouch after RYGB to determine feasibility, safety, and efficacy for weight loss. METHODS: We identified patients who had undergone RYGB, achieved >40% excess body weight loss (EBWL), and then regained >25% of lost weight. RFA was applied to the gastrojejunal anastomosis and the entire surface area of the gastric remnant pouch. Treatment was repeated at 4 and 8 months if patients did not meet specified weight loss targets. Weekly weights were obtained for 12 months. The primary efficacy outcome was percent EBWL at 12 months, compared with baseline. RESULTS: Twenty-five patients were enrolled at 4 centers. Mean (± standard deviation [SD]) age was 45.4 ± 9.1 years, and 84% (21/25) were female. Mean (± SD) baseline body mass index was 40.2 ± 7.8. Twenty-two of 25 patients completed 12 months of follow-up. At 12 months, median (± SD) EBWL was 18.4% (interquartile ratio 10.8, 33.7; P < .0001). Significant weight loss was seen at 3.5 months (P < .0001) and at 7.5 months (P < .0001), with a significant trend for continued weight loss over the 12-month period (P = .013). Two patients had serious adverse events requiring hospitalization. CONCLUSIONS: RFA of the gastric remnant pouch in patients with weight regain after RYGB resulted in significant reductions in excess body weight with an acceptable safety profile. Continued weight loss was observed after each RFA treatment. Further clinical trials in well-selected populations are warranted to determine the optimal number and frequency of RFA treatments and to assess durability of weight loss. (Clinical trial registration number: NCT01910688.).

A Survey of Expert Practice and Attitudes Regarding Advanced Imaging Modalities in Surveillance of Barrett's Esophagus.

BACKGROUND: Published guidelines do not address what the minimum incremental diagnostic yield (IDY) for detection of dysplasia/cancer is required over the standard Seattle protocol for an advanced imaging modality (AIM) to be implemented in routine surveillance of Barrett's esophagus (BE) patients. We aimed to report expert practice patterns and attitudes, specifically addressing the minimum IDY in the use of AIMs in BE surveillance. METHODS: An international group of BE experts completed an anonymous electronic survey of domains relevant to surveillance practice patterns and use of AIMs. The evaluated AIMs were conventional chromoendoscopy (CC), virtual chromoendoscopy (VC), volumetric laser endomicroscopy (VLE), confocal laser endomicroscopy (CLE), and wide-area transepithelial sampling (WATS3D). Responses were recorded using five-point balanced Likert items and analyzed as continuous variables. RESULTS: The survey response rate was 84% (61/73)-41 US and 20 non-US. Experts were most comfortable with and routinely use VC and CC, and least comfortable with and rarely use VLE, CLE, and WATS3D. Experts rated data from randomized controlled trials (1.4 ± 0.9) and guidelines (2.6 ± 1.2) as the two most influential factors for implementing AIMs in clinical practice. The minimum IDY of AIMs over standard biopsies to be considered of clinical benefit was lowest for VC (15%, IQR 10-29%) and highest for VLE (30%, IQR 20-50%). Compared to US experts, non-US experts reported higher use of CC for BE surveillance (p < 0.001). CONCLUSION: These results should inform benchmarks that need to be met for guidelines to recommend the routine use of AIMs in the surveillance of BE patients.

Endoscopic ultrasound-guided biliary access versus precut papillotomy in patients with failed biliary cannulation: a retrospective study.

Background and aims Precut papillotomy is widely used after failed biliary cannulation. Endoscopic ultrasound (EUS)-guided biliary access techniques are newer methods to facilitate access and therapy in failed cannulation. We evaluated the impact of EUS-guided biliary access on endoscopic retrograde cholangiopancreatography (ERCP) success and compared these techniques to precut papillotomy. Patients and methods We retrospectively compared two ERCP cohorts. One cohort consisted of biliary ERCPs (n = 1053) attempted in patients with native papillae and surgically unaltered anatomy in whom precut papillotomy and/or EUS-guided biliary access were routinely performed immediately after failed cannulation. This cohort was compared with a similar ERCP cohort (n = 1062) in which only precut papillotomy was available for failed cannulation. The following outcomes were compared: conventional cannulation success, rates of attempted advanced access techniques (precut or EUS), precut success, EUS-guided biliary access success, and ERCP failure rates. Results Although conventional cannulation success, rates of attempted advanced access technique (precut or EUS), and precut success were similar, the ERCP failure rate was lower when both EUS-guided biliary access and precut were available (1.0 % [95 % confidence interval (CI) 0.4 - 1.6]), compared with when only precut was possible for failed access (3.6 % [95 %CI 2.5 - 4.7]; P < 0.001). Success for EUS-guided biliary access (95.1 % [95 %CI 89.7 - 100]) was significantly higher than for precut (75.3 % [95 %CI 68.2 - 82.4]; P < 0.001), and mainly due to superiority in malignant obstruction (93.5 % vs. 64 %; P < 0.001). Conclusions EUS-guided biliary access decreases the rate of therapeutic biliary ERCP failure. Our results support the use of EUS-guided biliary access to optimize single-session ERCP success. In experienced hands, these techniques appear as effective, if not more so, than precut papillotomy.

Adverse events after surgery for nonmalignant colon polyps are common and associated with increased length of stay and costs.

BACKGROUND AND AIMS: Endoscopic resection (ER) is a safe and effective treatment for nonmalignant complex colorectal polyps (complex polyps). Surgical resection (SR) remains prevalent despite limited outcomes data. We aimed to evaluate SR outcomes for complex polyps and compare SR outcomes to those of ER. METHODS: We performed a single-center, retrospective, cohort study of all patients undergoing SR (2003-2013) and ER (2011-2013) for complex polyps. We excluded patients with invasive carcinoma from the SR cohort. Primary outcomes were 12-month adverse event (AE) rate, length of stay (LOS), and costs. SR outcomes over a 3-year period (2011-2013) were compared with the overlapping ER cohort. RESULTS: Over the 11-year period, 359 patients (mean [± SD] age 64 ± 11 years) underwent SR (58% laparoscopic) for complex polyps. In total, 17% experienced an AE, and 3% required additional surgery; 12-month mortality was 1%. Including readmissions, median LOS was 5 days (IQR 4-7 days), and costs were $14,528. When an AE occurred, costs ($25,557 vs $14,029; P < .0001) and LOS (11 vs 5 days; P < .0001) significantly increased. From 2011 to 2013, 198 patients were referred for ER, and 73 underwent primary SR (70% laparoscopic). There was a lower AE rate for ER versus primary SR (10% vs 18%; P = .09). ER costs (including rescue SR, when required) were lower than those of primary SR ($2152 vs $15,264; P < .0001). CONCLUSIONS: AEs occur in approximately one-sixth of patients after SR for complex polyps. ER-accounting for rescue SR caused by malignancy, AEs, or incomplete resection-is associated with markedly lower costs than SR. These data should be used when counseling patients about treatment options for complex polyps.

ASGE Technology Committee systematic review and meta-analysis assessing the ASGE Preservation and Incorporation of Valuable Endoscopic Innovations thresholds for adopting real-time imaging-assisted endoscopic targeted biopsy during endoscopic surveillance of Barrett's esophagus.

BACKGROUND AND AIMS: Endoscopic real-time imaging of Barrett's esophagus (BE) with advanced imaging technologies enables targeted biopsies and may eliminate the need for random biopsies to detect dysplasia during endoscopic surveillance of BE. This systematic review and meta-analysis was performed by the American Society for Gastrointestinal Endoscopy (ASGE) Technology Committee to specifically assess whether acceptable performance thresholds outlined by the ASGE Preservation and Incorporation of Valuable Endoscopic Innovations (PIVI) document for clinical adoption of these technologies have been met. METHODS: We conducted meta-analyses calculating the pooled sensitivity, negative predictive value (NPV), and specificity for chromoendoscopy by using acetic acid and methylene blue, electronic chromoendoscopy by using narrow-band imaging, and confocal laser endomicroscopy (CLE) for the detection of dysplasia. Random effects meta-analysis models were used. Statistical heterogeneity was evaluated by means of I(2) statistics. RESULTS: The pooled sensitivity, NPV, and specificity for acetic acid chromoendoscopy were 96.6% (95% confidence interval [CI], 95-98), 98.3% (95% CI, 94.8-99.4), and 84.6% (95% CI, 68.5-93.2), respectively. The pooled sensitivity, NPV, and specificity for electronic chromoendoscopy by using narrow-band imaging were 94.2% (95% CI, 82.6-98.2), 97.5% (95% CI, 95.1-98.7), and 94.4% (95% CI, 80.5-98.6), respectively. The pooled sensitivity, NPV, and specificity for endoscope-based CLE were 90.4% (95% CI, 71.9-97.2), 98.3% (95% CI, 94.2-99.5), and 92.7% (95% CI, 87-96), respectively. CONCLUSIONS: Our meta-analysis indicates that targeted biopsies with acetic acid chromoendoscopy, electronic chromoendoscopy by using narrow-band imaging, and endoscope-based CLE meet the thresholds set by the ASGE PIVI, at least when performed by endoscopists with expertise in advanced imaging techniques. The ASGE Technology Committee therefore endorses using these advanced imaging modalities to guide targeted biopsies for the detection of dysplasia during surveillance of patients with previously nondysplastic BE, thereby replacing the currently used random biopsy protocols.

The Clinical Utility of Evaluating the Luminal Upper Gastrointestinal Tract During Linear Endoscopic Ultrasonography.

BACKGROUND: The clinical utility of performing esophagogastroduodenoscopy (EGD) before linear endoscopic ultrasonography (L-EUS) to evaluate the luminal upper gastrointestinal (GI) tract is not well established. GOALS: The study was aimed to determine the prevalence of clinically meaningful luminal abnormalities (any luminal finding requiring further evaluation with mucosal biopsy or initiation of treatment) in patients undergoing L-EUS. The study also sought to compare the ability of the gastroscope and the linear echoendoscope in identifying these lesions. STUDY: A prospective, multicenter cohort study enrolled patients undergoing L-EUS for nonluminal indications. All patients underwent EGD followed by L-EUS by 2 different endoscopists. The second endoscopist was blinded to the results of the initial EGD. The identification of clinically meaningful luminal lesions and quality of endoscopic visualization of the upper GI tract were measured. RESULTS: In the cohort of 175 patients, 52 (29.7%) patients had clinically meaningful luminal findings seen in the upper GI tract. There was no significant difference in the number of clinically meaningful lesions identified on EGD and L-EUS (25.1% vs. 22.9%, P=0.39). No significant difference was found in the miss rate of clinically meaningful lesions between the 2 modalities (EGD: 4.5% vs. EUS: 6.9%, P=0.39). CONCLUSIONS: A substantial minority of patients undergoing L-EUS for nonluminal indications will have clinically meaningful luminal findings. The endoscopic evaluation of the luminal upper GI tract can be adequately achieved using the linear echoendoscope.

Enteroscopy.

Noninvasive imaging with CT and magnetic resonance enterography or direct visualization with wireless capsule endoscopy can provide valuable diagnostic information and direct therapy. Enteroscopy technology and techniques have evolved significantly and allow diagnosis and therapy deep within the small bowel, previously attainable only with intraoperative enteroscopy. Push enteroscopy, readily available in most endoscopy units, plays an important role in the evaluation and management of lesions located up to the proximal jejunum. Currently available device-assisted enteroscopy systems, DBE, SBE, and spiral enteroscopy each have their technical nuances, clinical advantages, and limitations. Newer, on-demand enteroscopy systems appear promising, but further studies are needed. Despite slight differences in parameters such as procedural times, depths of insertion, and rates of complete enteroscopy, the overall clinical outcomes with all overtube-assisted systems appear to be similar. Endoscopists should therefore master the enteroscopy technology based on institutional availability and their level of technical expertise.

Electronic chromoendoscopy.

Electronic chromoendoscopy technologies provide image enhancement and may improve the diagnosis of mucosal lesions. Although strides have been made in standardization of image characterization, especially with NBI, further image-to-pathology correlation and validation are required. There is promise for the development of a resect and discard policy for diminutive adenomas by using electronic chromoendoscopy; however, before this can be adopted, further community-based studies are needed. Further validated training tools for NBI, FICE, and i-SCAN will also be required for the use of these techniques to become widespread.

Endoscopic mucosal resection.

EMR has become an established therapeutic option for premalignant and early-stage GI malignancies, particularly in the esophagus and colon. EMR can also aid in the diagnosis and therapy of subepithelial lesions localized to the muscularis mucosa or submucosa. Several dedicated EMR devices are available to facilitate these procedures. Adverse event rates, particularly bleeding and perforation, are higher after EMR relative to other basic endoscopic interventions but lower than adverse event rates for ESD. Endoscopists performing EMR should be knowledgeable and skilled in managing potential adverse events resulting from EMR.

Echoendoscopes.

Advances in echoendoscopes and their processors have significantly expanded the role of EUS and its clinical applications.The diagnostic and therapeutic capabilities of EUS continue to evolve and improve. EUS has made a large impact on patient care but comes with significant startup and maintenance costs. As improved technology continues to enhance image resolution while decreasing the size of EUS processors, use of endosonography will become more widespread. EUS will continue to be a vital part of patient care and complement currently available cross-sectional imaging.

ASGE Technology Committee systematic review and meta-analysis assessing the ASGE PIVI thresholds for adopting real-time endoscopic assessment of the histology of diminutive colorectal polyps.

In vivo real-time assessment of the histology of diminutive (≤5 mm) colorectal polyps detected at colonoscopy can be achieved by means of an "optical biopsy" by using currently available endoscopic technologies. This systematic review and meta-analysis was performed by the American Society for Gastrointestinal Endoscopy (ASGE) Technology Committee to specifically assess whether acceptable performance thresholds outlined by an ASGE Preservation and Incorporation of Valuable endoscopic Innovations (PIVI) document for clinical adoption of these technologies have been met. We conducted direct meta-analyses calculating the pooled negative predictive value (NPV) for narrow-band imaging (NBI), i-SCAN, and Fujinon Intelligent Color Enhancement (FICE)-assisted optical biopsy for predicting adenomatous polyp histology of small/diminutive colorectal polyps. We also calculated the pooled percentage agreement with histopathology when assigning postpolypectomy surveillance intervals based on combining real-time optical biopsy of colorectal polyps 5 mm or smaller with histopathologic assessment of polyps larger than 5 mm. Random-effects meta-analysis models were used. Statistical heterogeneity was evaluated by means of I(2) statistics. Our meta-analyses indicate that optical biopsy with NBI, exceeds the NPV threshold for adenomatous polyp histology, supporting a "diagnose-and-leave" strategy for diminutive predicted nonneoplastic polyps in the rectosigmoid colon. The pooled NPV of NBI for adenomatous polyp histology by using the random-effects model was 91% (95% confidence interval [CI], 88-94). This finding was associated with a high degree of heterogeneity (I(2) = 89%). Subgroup analysis indicated that the pooled NPV was greater than 90% for academic medical centers (91.8%; 95% CI, 89-94), for experts (93%; 95% CI, 91-96), and when the optical biopsy assessment was made with high confidence (93%; 95% CI, 90-96). Our meta-analyses also indicate that the agreement in assignment of postpolypectomy surveillance intervals based on optical biopsy with NBI of diminutive colorectal polyps is 90% or greater in academic settings (91%; 95% CI, 86-95), with experienced endoscopists (92%; 95% CI, 88-96) and when optical biopsy assessments are made with high confidence (91%; 95% CI, 88-95). Our systematic review and meta-analysis confirms that the thresholds established by the ASGE PIVI for real-time endoscopic assessment of the histology of diminutive polyps have been met, at least with NBI optical biopsy, with endoscopists who are expert in using this advanced imaging technology and when assessments are made with high confidence.

Endoscopic submucosal dissection.

ESD is an established effective treatment modality for premalignant and early-stage malignant lesions of the stomach, esophagus, and colorectum. Compared with EMR, ESD is generally associated with higher rates of en bloc, R0, and curative resections and a lower rate of local recurrence. Oncologic outcomes with ESD compare favorably with competing surgical interventions, and ESD also serves as an excellent T-staging tool to identify noncurative resections that will require further treatment. ESD is technically demanding and has a higher rate of adverse events than most endoscopic procedures including EMR. As such,sufficient training is critical to ensure safe conduct and high-quality resections. A standardized training model for Western endoscopists has not been clearly established,but will be self-directed and include courses, animal model training, and optimally an observership at an expert center.Numerous dedicated ESD devices are now available in the United States from different manufacturers. Although the use of ESD in the United States is increasing, issues related to technical difficulty, limited training opportunities and mentors, risk of adverse events, long procedure duration,and suboptimal reimbursement may limit ESD adoption in the United States to a modest number of academic referral centers for the foreseeable future.

Use of a pancreatic duct stent or guidewire facilitates bile duct access with low rates of precut sphincterotomy: a randomized clinical trial.

BACKGROUND AND STUDY AIMS: Among cases of difficult biliary cannulation, alternatives include use of a pancreatic duct stent (PDS) or guidewire (PDW) to facilitate access. We compared the effectiveness of a PDS versus a PDW to facilitate common bile duct (CBD) cannulation. PATIENTS AND METHODS: We conducted a randomized, crossover trial at two endoscopy referral centers, limited to patients undergoing ERCP without a history of biliary sphincterotomy. After meeting predefined criteria for difficult cannulation, patients were randomized to using a PDS or PDW to facilitate CBD cannulation. Outcomes included cannulation rate within 6 min, overall cannulation rate, frequency of precut, and complication rates. RESULTS: Among 442 eligible patients, 87 (19.7 %) met criteria for difficult cannulation. Forty two were randomized to PDW, 54 to PDS (including 9 PDW patients crossed over to PDS). The rate of CBD cannulation within 6 min was similar in the PDW (38.1 %) and PDS (51.9 %) groups (p = 0.18). In a secondary analysis limited to patients who successfully underwent PDW or PDS deployment, the rate was also comparable (PDW 59.3 %, PDS 65.1 %; p = 0.62). The overall frequency of CBD cannulation was 66.7 % in PDW and 90.7 % in PDS patients. Precut was required in 9.5 % of PDW and 25.9 % of PDS patients. Complication rates were similar, with 4 (4.6 %) patients having post-ERCP pancreatitis and 1 (1.1 %) having post-ERCP pain without confirmation of pancreatitis. CONCLUSIONS: Use of a PDS or PDW facilitates CBD cannulation while maintaining a low complication rate and reducing the need for precut sphincterotomy in the majority of cases.

Post-embolization outcomes of splenic artery pseudoaneurysms: A single-center experience.

PURPOSE: Splenic artery pseudoaneurysms (PSA) are relatively rare but associated with high mortality/morbidity when presenting acutely. Embolization has emerged as the treatment of choice. We aim to evaluate the outcomes of embolization for the treatment of splenic artery PSAs. METHODS: From 2007 to 2019, all patients that underwent embolization for splenic artery PSAs were included in this IRB-approved review. Evaluated outcomes included complications, morbidity/mortality rates, and 30-day white blood cell count. Student t-tests were performed to compare laboratory values before and after embolization. 5-year survival rates were estimated using Kaplan Meier methodology. RESULTS: A retrospective analysis of 24 patients (14 males, mean age 51 ± 19 years) who underwent splenic artery PSA embolization was performed. Fifteen PSA embolizations were performed in an emergent setting. There was technical success in 23/24 patients. Etiologies included trauma (10), pancreatitis (9), post-surgical (3), and malignancy (2). Post-embolization patients had a mean length of stay of 19 days and within 30 days, 9 patients developed leukocytosis (median of 14,800/µl). The 5-year survival rate of these patients was 89% [95% CI 75% - 100%]. Post-procedure, 4 patients developed grade 2 complications. Grade 3 complications were observed in 5 patients. One (4.2%) splenic abscess was identified. Of the 19 patients with follow-up imaging, 14 patients had splenic infarcts (5 infarcts were >50% of splenic volume). CONCLUSIONS: Splenic artery PSAs are encountered in the emergent setting and are most frequently secondary to trauma or pancreatitis. Embolization can be life-saving in these critically ill patients.