The CEA family comprises 18 genes and 11 pseudogenes located at chromosome 19q13.2 and is divided into two main groups: cell surface anchored CEA-related cell adhesion molecules (CEACAMs) and the secreted pregnancy-specific glycoproteins (PSGs). CEACAMs are highly glycosylated cell surface anchored, intracellular, and intercellular signaling molecules with diverse functions, from cell differentiation and transformation to modulating immune responses associated with infection, inflammation, and cancer. In this review, we explore current knowledge surrounding CEACAM1, CEACAM5, and CEACAM6, highlight their pathological significance in the areas of cancer biology, immunology, and inflammatory disease, and describe the utility of murine models in exploring questions related to these proteins.

The introduction of new technologies in endoscopy has been met with uncertainty, skepticism, and lack of standardization or training parameters, particularly when disruptive devices or techniques are involved. The widespread availability of a novel endoscopic suturing device (OverStitch™) for tissue apposition has enabled the development of applications of endoscopic suturing. The American Gastroenterological Association partnered with Apollo Endosurgery to develop a registry to capture in a pragmatic non-randomized study the safety, effectiveness, and durability of endoscopic suturing in approximating tissue in the setting of bariatric revision and fixation of endoprosthetic devices. We highlight the challenges of the adoption of novel techniques by examining the process of developing and executing this multicenter registry to assess real-world use of this endoscopic suturing device. We also present our preliminary data on the safety and effectiveness of the novel device as it is applied in the treatment of obesity. The Prospective Registry for Trans-Orifice Endoscopic Suturing Applications (ES Registry) was an effective Phase 4, postmarketing registry aimed at capturing pragmatic, real-world use of a novel device. These findings serve to solidify the role of endoscopic suturing in clinical practice.

Anil Vegesna: NO financial relationship with a commercial interest | Larry Miller: NO financial relationship with a commercial interest | Jamie Huot: NO financial relationship with a commercial interest | Anita Nguyen: NO financial relationship with a commercial interest | Daren Chen: NO financial relationship with a commercial interest | Joel Zachariah: NO financial relationship with a commercial interest

Background and study aims The rate of gastroesophageal reflux disease (GERD) after per oral endoscopic myotomy (POEM) is concerning. Endoscopic anti-reflux methods, such as Trans Oral Incisionless Fundoplication (TIF), are crucial for the long-term success of POEM, especially if they can be performed in the same session. Methods We completed a proof-of-concept canine pilot study (n = 6) to assess safety and feasibility of POEM and TIF in a single session (POEM-TIF). Subsequently, POEM-TIF was also performed in patients with achalasia (n = 5). Herein, we report on the safety, technical and clinical success of the first-in-human cases with symptom follow-up at 1, 3 and 6 months and pH testing at 6 months. Results POEM was completed successfully in six canines (3 anterior and 3 posterior myotomies), followed by TIF in the same session. Necropsy and extensive testing demonstrated no evidence of mucosal injury and no leaks. The reconstructed valve was 220 to 240 degrees, 3 to 4 cm in length, and resulted in concomitant esophageal lengthening (2–5 cm). Using similar principles, the first-in-human cases were performed without intraprocedural or delayed adverse events. pH testing at 6 months showed that four of five patients had no evidence of GERD (DeMeester > 14.72), and in one case, there was evidence of esophagitis. Conclusions Single session POEM-TIF appears to be safe and feasible. Early clinical human data suggests that it may be able to reduce post POEM GERD, however the additional secondary benefits such as lengthening and straightening of the esophagus, may prove to be equally important for the long-term success of POEM.

A) Photograph of an endoscope within the abdominal cavity with access to the intra-abdominal organs during transmural endoscopy. B) Photograph of a peripheral branch of the posterior Vagus nerve in a patient undergoing the POEM procedure

We previously reported the preliminary short-term outcomes of our prospective trial on gastric per-oral endoscopic myotomy (G-POEM) with promising results. To prospectively 1) evaluate the efficacy and safety of G-POEM and 2) assess factors associated with clinical success of G-POEM. In this prospective multicenter (4 US, 1 South America) study, patients with refractory gastroparesis - defined as symptoms refractory to standard medical therapy - underwent G-POEM between 11/2015 and 11/2018, and were followed for one year. Clinical symptoms (measured by Gastroparesis Cardinal Symptom Index [GCSI]) and quality of life (measured by Short Form 36 [SF-36]) were evaluated before and at 1-, 3-, 6-, and 12-month followups. Clinical success was defined as one score decrease in average GCSI with >25% decrease in at least 2 sub-scales. Gastric emptying study (GES) was performed before and 3 months after the G-POEM. Pylorus characteristics were measured by endoscopic functional luminal imaging probe (EndoFLIP) device pre and post G-POEM. A total of 80 patients (F 71%, mean age: 49yr) were enrolled. The most common etiology was idiopathic (41.3%), followed by postsurgical (35%) and diabetes (23.8%). All procedures were technically successful (technical success 100%). A total of 67 (84%) patients were followed up to one year with clinical success rate of 59.7%. GCSI and its subscales improved significantly following G-POEM (p<0.05) (Figure 1). Furthermore, 5 out of 8 domains of SF-36 including physical functioning, physical role, energy, emotional well-being, social functioning, general health, and health change improved significantly after G-POEM (p<0.05). A total of 5 adverse events, all rated as mild, were reported and included 3 symptomatic capnoperitoneum (treated by needle decompression), 1 mucosotomy (treated with stent replacement), and 1 thermal mucosal injury (treated with clipping). Pre and 3-month post G-POEM GES were performed in 53 (66.3%) patients. GES improvement and normalization were achieved in 34/53 (64.2%) and 25/53 (47.2%) patients, respectively. Following G-POEM, pylorus distensibility index (DI), measured with EndoFLIP, increased from 4.99 ± 2.57 to 6.74 ± 4.34 mm2/mmHg, and from 4.97 ± 3.02 to 6.99 ± 3.92 mm2/mmHg using 40- and 50-ml volume bags, respectively (p<0.05). Lower pre G-POEM DI using 40 ml bag was significantly associated with pre G-POEM disease severity (p=0.039). Baseline disease severity and increase in pylorus DI following G-POEM were significantly associated with clinical success (Table 1). G-POEM is safe and improves clinical symptoms and pylorus characteristics of patients with refractory gastroparesis. Disease severity predicts the one-year clinical success; thus, the procedure may be considered for patients with more severe gastroparesis symptoms.Table 1association between disease characteristics and one-year clinical success of G-POEMView Large Image Figure ViewerDownload Hi-res image Download (PPT)

Background A significant proportion of duodenoscope-transmitted infections have resulted from errors related to reprocessing. Remote video auditing (RVA) is a tool that can monitor reprocessing compliance but it has not been previously evaluated in a tertiary care setting. The aims of this study were to evaluate: 1) RVA feasibility in a tertiary care setting (defined as the ability to audit every step of duodenoscope reprocessing without delaying the next procedure due to unavailability of duodenoscopes); and 2) the use of RVA as a compliance monitoring tool. Methods This was a prospective study at a tertiary care center. A video camera with offsite monitoring was installed in March 2018. Auditors delivered a compliance score after each procedure. The duodenoscope was not used until it passed the audit. Feasibility and compliance data were collected from April 2018 to August 2019 after a 1-month run-in phase. Both per-step compliance and overall 100 % compliance rates were measured. Results Of 743 duodenoscope reprocessing procedures, 32 666 individual steps were audited and 99.9 % of the steps were fully viewable. The mean time per audit was 38.3 minutes, the mean duodenoscope turnover time was 76.1 minutes, and there were no delays to the next procedure due to unavailability of duodenoscopes. The per-step compliance rate was 99.5 % but the overall 100 % compliance rate was 90.3 %. Conclusions The use of RVA in duodenoscope reprocessing was feasible and promoted sustained high-level compliance in a tertiary care center.

Gastric peroral endoscopic myotomy (G-POEM) is a promising therapy for patients with gastroparesis because of its safety and efficacy. Most prospective studies suggest up to 75% of patients may see an improvement in symptoms and gastric emptying. Recent meta-analyses also suggest that results may be comparable to laparoscopic pyloroplasty (LP); however, LP continues to have a more robust improvement in gastric emptying and higher rates of complete normalization. A single tunnel double myotomy may offer an incremental advantage to help bridge the gap with LP. We performed an analysis of 30 patients that underwent G-POEM for refractory gastroparesis using a single tunnel double myotomy technique. Data is from consecutive patients at two centers from January 2019 to the present. A submucosal tunnel was initiated and extended to the pylorus along the greater curvature of the gastric antrum. After identification and exposure of the pyloric ring (6 o'clock), the first myotomy was performed at 7 o'clock followed by a second myotomy at 5 o'clock, both within the same tunnel (Fig 1). EndoFLIP® impedance planimetry was performed with measurements taken before the submucosal incision, and after each myotomy. Gastric emptying studies (GES-4Hr), and Gastroparesis Cardinal Symptom Index (GCSI) scores were recorded at baseline, 1-month and 3-months. A total of 30 patients (23 Females) with refractory gastroparesis (9 diabetic, 10 post-surgical, 11 idiopathic) successfully underwent a G-POEM using the single tunnel double myotomy approach. There was 1 mild procedural adverse event (AE), and no AEs at 48 hours or 30 days. The total procedure time was 37.2+/-7.2 minutes. The addition of a second myotomy added 2.2+/-2 minutes overall. A second myotomy was associated with a significant incremental increase in diameter, especially at 40 and 50ml (Table 1). The average final improvement in diameter was 4.2mm (range 1.2 to 9mm). In addition, there was a significant change in distensibility, which was noted only after the second myotomy (Table 1). At 3-months (n=21), 85.7% of the patients had an objective improvement in gastric emptying with an absolute reduction of 30.1+/-16.8%. This correlated with an improvement in GCSI from 1.8 at baseline to 1.1 at 1-month and 0.9 at 3-months. None of the patients reported any symptoms of dumping syndrome. A single tunnel double myotomy is both safe and feasible and can be performed with minimal incremental effort when compared to a conventional G-POEM. It results in a significant improvement in final diameter and distensibility which correlates to significant clinical improvement and objective response in gastric emptying.Table 1Incremental Increase in diameter and distensibility of pylorus following first and second myotomyView Large Image Figure ViewerDownload Hi-res image Download (PPT)

Studies have suggested that dysplasia in Barrett’s Esophagus (BE) has a predilection for the right hemisphere of the esophagus in patients who are ablation naive. However, these studies were limited by only including dysplasia detected in visible lesions on high-definition white light endoscopy (HDWLE). Advanced imaging such as volumetric laser endomicroscopy (VLE) allows for visualization of lesions that cannot always be detected on HDWLE and for precise targeting/lesion location with laser marking. Thus, the aim of this study was to further describe the circumferential distribution of dysplasia found in visible lesions on HDWLE and invisible lesions (detected only by VLE) in a prospective fashion. This is an analysis of patients treated at one tertiary care center from three separate prospective studies (VLE IRIS Study NCT03814824, VLE Dysplasia Detection Pilot NCT02864043, and the VLE National Registry NCT02215291) who underwent evaluation for BE with HDWLE and VLE with laser marking (for the first two mentioned studies) between 9/2016 and 10/2019. Only visible lesions were recorded from patients for the national registry study, as laser marking was not available during this study. Patients were included if they were over the age of 18 with confirmed dysplasia on biopsy. The location of lesions was recorded prospectively with the gastroscope in the neutral position. Orientation of VLE laser marked targeted lesions were recorded based on the endoscope in the neutral position. Quadrant 1 was defined as 12-3 o’clock, quadrant 2 was 3-6 o’clock, quadrant 3 was 6-9 o’clock, and quadrant 4 was 9-12 o’clock. Visible versus invisible lesion characteristics were compared. Data was prospectively collected on 149 dysplastic lesions in 102 patients. 35.6% of the lesions were IMCA, 38.8% were HGD, and 25.5% were LGD on surgical pathology. There was an approximately equal distribution of each type of dysplastic lesion within each the 4 quadrants and between the left and right hemispheres. 73.8% of the lesions were visible on HDWLE; the rest were discovered only by VLE examination. The majority of visible lesions were IMCA (43.6%), whereas the majority of invisible lesions were LGD (46.2%). There was no significant difference in the distribution of visible and invisible lesions within the 4 quadrants or hemispheres, and furthermore, when stratified by class of dysplasia, the distribution again remained relatively uniform. In contrast to previously retrospective published data on clock-face orientation showing dysplasia predilection in the right hemisphere, we found no difference in the clock-face distribution of dysplasia when examined with HDWLE and advanced imaging in a prospective fashion. Dysplasia can be found throughout the whole clock-face and thus a careful, 360-degree evaluation is necessary.Table 1Details of clock-face orientation of dysplasia for the pooled analysis of three prospective studies.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

We present a wireless recording system designed for high-resolution mapping of gastric slow-wave signals. The system is composed of an implantable unit (IU), a wearable unit (WU), and a stationary unit (SU) connected to a computer. Two independent wireless data communication links consisting of IU-WU and IU-SU were developed based on near-field and far-field communication, respectively. Furthermore, the WU is capable to wirelessly recharge the IU's battery through an inductive link. For the IU-WU near-field communication, a differential pulse position data encoding algorithm with only 6.25% duty cycle, with load shift keying (LSK) modulation is developed to guarantee continuous power transmission and high data transfer rate, simultaneously. The IU sends the encoded data to the WU, and the WU can either store the data locally on a memory card or transmit them to the SU for real-time monitoring. In addition, the IU-SU far-field data communication was developed based on a RF transceiver in which the IU transmits the data directly to the SU. The benchtop validation of the system demonstrated successful IU-WU and WU-SU data transmission, while sample signals were recorded successfully at IU through saline solution and received by SU.

Benign and malignant biliary obstructions are commonly treated with ERCP and placement of self-expandable metallic stents (SEMS) or polyethylene stents (PS). With an estimated incidence of up to 5-8% in therapeutic ERCP, pancreatitis is known to be the most common complication. Years ago, SEMS were almost exclusively utilized for malignant strictures, but they are now routinely used in benign lesions as well. Studies have suggested a higher risk of post-ERCP pancreatitis (PEP) with SEMS, however they have been relatively small and exclusively focused on malignant obstructions. Our goal was to compare PEP rates in patients who underwent ERCP for malignant and benign strictures with placement of SEMS or PS.

INTRODUCTION: Little is known about the additive yield of wide-area transepithelial sampling with computer-assisted three-dimensional analysis (WATS-3D) after a thorough examination with advanced imaging. The aim was to evaluate the adjunctive yield of WATS-3D after advanced imaging. METHODS: This is an observational cohort study from January 2017 to December 2018 for consecutive patients who underwent an examination that consists of high-definition white light endoscopy (HDWLE), narrow-band imaging (NBI), volumetric laser endomicroscopy (VLE), and Seattle protocol (SP) biopsies (collectively termed HDWLE-NBI-VLE-SP examination). Raised lesions were removed by endoscopic resection. Areas suspicious for dysplasia on NBI and VLE were biopsied. This was followed by random biopsies and WATS-3D brush biopsies. RESULTS: One hundred thirty-eight cases were included in this study. Thirty-five cases (25% of the total) were identified as some degree of dysplasia on the HDWLE-NBI-VLE-SP examination. Adjunctive use of WATS-3D yielded an additional 12 new cases of dysplasia (9 with crypt dysplasia and 3 with low-grade dysplasia [LGD]), for added yield of 34.3% (=12/35, 95% confidence interval 14.6%–62.2%). When restricting the analysis to LGD and higher, 21 dysplastic cases (15% of the total cases) were identified by HDWLE-NBI-VLE-SP, while WATS-3D found 4 additional new cases (3 with LGD and 1 with high-grade dysplasia) for an added yield of 19% (=4/21, 95% confidence interval 0.6%–45.7%). DISCUSSION: The addition of WATS-3D to an already thorough examination with HDWLE-NBI-VLE-SP may increase the yield of dysplasia detection.

Background and study aims After stone removal in endoscopic retrograde cholangiopancreatography (ERCP), an occlusion cholangiogram (OC) is performed to confirm bile duct clearance. OC can miss residual stones that can lead to recurrent biliary symptoms. The aim of this study was to assess if digital peroral cholangioscopy (POC) increased the diagnostic yield of residual biliary stones that are missed with OC. Patients and methods Patients having ERCP performed for choledocholithiasis were enrolled into the study only if they had one of the following criteria: dilated bile duct ≥ 12 mm and/or if lithotripsy was being performed. An OC was performed to confirm duct clearance after removal of stones followed by POC, based on inclusion criteria. The incremental yield of biliary stones missed by OC but confirmed by POC was then measured. A total of 96 POC procedures were performed on 93 patients in two tertiary care centers. Results Residual biliary stones were found in 34 % of cases. The average bile duct size in cases with residual stones was 15.1 mm ± 0.7 mm. One- to three-mm stones were found in 41 % of cases, 4- to 7-mm stones in 45 % of cases, and ≥ 8-mm stones in 14 % of cases. Lithotripsy was performed in 13 % of cases and was significantly associated with residual stones (30 % vs. 3 %, P < 0.001). Conclusions Occlusion cholangiogram can miss residual stones in patients with dilated bile ducts and those receiving lithotripsy. Digital POC can increase the yield of residual stone detection in these patients and should be considered to confirm clearance of stones. (ClinicalTrials.gov-NCT03482375).

Introduction: Chronic intestinal pseudo-obstruction (CIPO) is defined by signs of obstruction without clear anatomical lesion or cause (volvulus, etc).Functional etiology varies between patients.Exams detailing motility aberrations are central to individualized treatment, while ghrelin and motilin agonists are under investigation for treatment of peristaltic paralysis.Little is known about gastrointestinal (GI) motility or changes in ghrelin or motilin in CIPO during a meal.The SmartPill ® wireless motility capsule (WMC) was used together with blood sampling during a meal to determine transit times through the GI tract as well as ghrelin and motilin levels during the first 4 hours of a meal.Aims: To characterize motility defects using WMC as well as ghrelin and motilin changes during a meal in CIPO.Methods: WMC recordings were performed in 13 CIPO patients.They arrived fasted and ingested a 2 6 0 k c a l m i x e d m e a l a n d t h e W M C .B l o o d w a s t a p p e d a t -10,0,10,20,30,40,50,60,90,120,180 and 240 min into the meal.Recordings were analyzed for gastric emptying (GET), small bowel transit (SBTT), colon transit (CTT), small+large bowel transit (SLBTT) and whole gut transit (WGTT) times.WMC results were compared to a healthy reference group (n=73, ref 1).Motilin was analyzed in parallel with 8 healthy subjects by RIA.Ghrelin was analyzed by ELISA and compared to a reference group of 41 healthy subjects.Results: In CIPO, GET averaged ~4 times longer than controls with 7 CIPO patients above the 95% percentile of reference GET.SBTT findings were more varied with 2 patients below and 5 above the 5-95% percentile.CTT and SLBTT were also more varied, with 2 below and 9 above 5-95% percentile of reference CTT and 2 patients below and 11 above 5-95% percentile interval of reference SLBTT.WGTT was above 95% percentile of reference in 11 of the 13 CIPO patients.All patients had abnormal findings in at least 2 transit time parameters.On average, 4 transit parameters were outside 5-95% percentile.Due to the diversity in WMC findings in CIPO, ghrelin and motilin levels were evaluated as coefficients of variation (CV%) across the 12 blood sampling times for each subject (Figure 1).Ghrelin CV% averaged 1.7-fold higher (51.9±7.3 vs 30.7±1.6, mean±SEM, P=0.002); motilin CV% averaged 1.2-fold higher in CIPO, but did not reach significance (15.2±1.1 vs 12.6±1.9).Conclusions: SLBTT was the only transit parameter out of range in all 13 CIPO patients.Altered SLBTT might potentially serve as a proxy for pathological manometry of the small intestine for diagnosis of CIPO.Derangements of the two upper GI hormones ghrelin and motilin may be tied to abnormal SLBTT.This implies that ghrelin and motilin agonists may be an option to mitigate peristaltic paralysis in some CIPO patients.References 1.

Endoscopic mucosal resection (EMR) of large colon polyps is technically challenging and therefore often performed by endoscopists with significant experience in this procedure. It is not known if endoscopist fatigue influences the success of colon EMR for large colon polyps. The primary objective of our study is to assess whether procedural success of colon EMR is affected by endoscopist fatigue or time of day when colon EMR is performed. We conducted a retrospective review of all colon EMR procedures performed by four therapeutic endoscopists at two academic tertiary care hospitals between 1/1/2015 – 12/31/2016. Patients included for this review had colon polyps > 20 mm that were removed with injection-lift EMR technique. Technical success was defined as endoscopist assessment of complete resection of the polyp. All patients for whom follow-up information was available were assessed for residual neoplasia on follow-up colonoscopy. We assessed whether endoscopist fatigue as measured by: afternoon versus morning, number of endoscopic procedures performed before the procedure under consideration, including adjustment for procedure complexity and the total procedure related RVUs had an impact on the technical success of the procedure or the rate of residual neoplasia. In order to examine these fatigue measures we stratified the cases under review into quartiles. Quartile 1 represents the colon EMR cases with fewest preceding cases, while quartile 4 represents colon EMR cases with the largest number of preceding cases. A total of 154 patients underwent colonoscopy to resect 170 large colon polyps by EMR technique. Overall, 87.7% of the lesions were removed successfully. 21 lesions could not be removed endoscopically. Follow-up information was available for 68.3% of patients. 28 patients underwent surgery (14 for invasive carcinoma, 3 for high grade dysplasia, 11 for unresectable lesions). Of 75 patients who underwent successful colon EMR and had follow-up colonoscopy, 80% had no evidence of residual neoplasia. When assessing endoscopist fatigue by total number of procedures, number of procedures adjusted for complexity and total procedure-related RVUs prior to performing colon EMR, no effect was found in relation to technical success or rates of residual neoplasia on follow-up. There appeared to be a trend towards lower rate of technical success and a higher rate of residual neoplasia for colon EMR procedures performed in the afternoon versus the morning, however this difference was not statistically significant. We conducted similar analysis for each endoscopist individually with the same findings. Endoscopist fatigue did not have a significant effect on the technical success of colon EMR, nor did it adversely impact the rate of residual neoplasia on follow-up colonoscopy.Tabled 1Association between endoscopist fatigue and colon EMR outcome measuresFatigue measureTechnical successResidual neoplasia rateStart timeMorning exam89.5% (referant)20.4% (referent)Afternoon exam83.0% (p=0.25)34.8% (p=0.18)Raw fatigue scoreQuartile 192.7% (referent)25.0% (referent)Quartile 284.4% (p = 0.27)32.1% (p=0.62)Quartile 381.6% (p= 0.14)30.8% (p=0.73)Quartile 490.2% (p=0.69)15.8 % (p=0.50)Consensus fatigue scoreQuartile 192.7% (referent)25.0% (referent)Quartile 281.6% (p=0.15)26.3% (p=0.93)Quartile 382.5% (p =0.18)30.0% (p=0.74)Quartile 490.9% (p=0.77)13.6% (p=0.38)RVU fatigue scoreQuartile 192.7% (referent)25.0% (referent)Quartile 280.5% (p=0.12)26.3% (p=0.93)Quartile 380.5% (p=0.12)36.8% (p=0.43)Quartile 495.0% (p=0.67)15.8% (p=0.48) Open table in a new tab

Background: Distensibility of the gastroesophageal junction high-pressure zone (GEJHPZ) has been shown to be greater in GERD patients than in non-GERD patients by using functional luminal imaging (FLIP) and yield pressures.In GERD patients, the pressure generated by the clasp and sling muscle fibers of the esophagus are lower, and the pressure of the lower esophageal circular smooth muscle (LEC) is attenuated.Aim: The aim of this project is to evaluate the distensibility of the GEJHPZ by using FLIP in GERD subjects, and non-GERD subjects before and after muscarinic blockade with atropine.Methods: Following anesthesia, a FLIP probe was passed trans-orally into the stomach and positioned across the GEJHPZ in 7 GERD subjects, and 8 non-GERD subjects before and after atropine administration.Each balloon contained 16 impedance sensors spaced 5 mm apart.The balloon was positioned so that at least one distal sensor was in the stomach and at least one proximal sensor was in the esophagus.Minimum cross sectional area (CSA) at each impedance sensor and the pressure within the FLIP balloon were recorded as the balloon was sequentially filled to 40 ml by 10 ml increments.Key Results: CSA and pressures at 20, 30, and 40 ml were collected and analyzed.The distensibility plot was located significantly to the left in non-GERD post-atropine subjects and in GERD subjects when compared to non-GERD pre-atropine subjects.The GERD subjects' distensibility plot was further to the left than the non-GERD post-atropine subjects' plot (Fig. 1).The slopes of the distensibility plots from 20 to 40 ml of non-GERD pre-atropine, post-atropine, and GERD subjects were 1.2, 2.0, and 4.8 mm 2 /mmHg respectively (Fig. 1).Distensibility of the GEJHPZ was significantly less in the GERD patients compared to the non-GERD subjects both pre-and post-atropine at 40 ml (Table 1).Both GERD patients and non-GERD post-atropine subjects show significantly lower balloon pressures at all balloon volumes.Conclusions: Atropine increased the distensibility of the GEJHPZ in non-GERD subjects suggesting that tone and distensibity are influenced by vagal innervation in addition to passive tone.The increased distensibility in GERD subjects compared to the non-GERD subjects both pre-and post atropine suggests that there are other factors, in addition to loss of muscarinic tone, that contribute to increased distensibility in GERD patients.Average narrowest CSA in Non-GERD subjects and GERD patients