Esophageal Acid Exposure Time Research Articles

234. EFFECTS OF TRANSCUTANEOUS ELECTRICAL STIMULATION SYSTEM ON HEARTBURN, REGURGITATION AND ESOPHAGEAL ACID EXPOSURE IN GERD PATIENTS

Abstract Background Chronic PPI treatment in GERD is associated with high failure rate and concerns regarding PPI's side effects. In a previously published proof of concept study, a non-pharmacological, non-invasive transcutaneous, electrical stimulation system, reduced esophageal acid exposure in GERD patients unresponsive to standard dose PPI. However, in that study, a symptomatic response to electrical stimulation was not assessed. Aim To determine the effect of a transcutaneous electrical stimulation system (TESS) on symptoms (heartburn and regurgitation) and the percentage of esophageal acid exposure time in GERD patients. Methods Patients suffering from heartburn and regurgitation were recruited into this multicenter study. The first phase of this study was a one week, run-in period, off-PPI's, during which, patients completed symptoms diaries and demographic questionnaires. Thereafter, all patients underwent upper endoscopy with subsequently wireless esophageal pH capsule placement (off PPI). Based on pH analysis in the first 24-hours, (day 0) only those with increased acid exposure time (percent total time pH <4 above 6%) continued to the next phase. During phase two of the study, patients were treated for two weeks with TESS and documented their symptoms. Primary end points included the reduction of baseline (pretreatment) number of heartburn and regurgitation episodes as well as 24-hour percent total time pH <4 and/or DeMeester score by at least 50%. Results 26 GERD patients (16 male, aged 47±15 years, mean BMI 25±3 kg/m2) completed the study. At baseline, mean number of daily heartburn and regurgitation events was 2.41±0.36 and 1.38±0.35, respectively. Following TESS, mean number of daily heartburn and regurgitation events dropped to 0.69±0.16 and 0.31±0.19, respectively (p=0.01). At baseline, mean percent total time pH < 4 was 11.8±0.9. Following TESS, mean percent total time pH < 4 dropped to 7.3±0.8, 7.8±1.0, 6.7±1.1 and 5.0±0.7 for day 1, 2, 3 and 4, respectively (p=0.01). At baseline, mean DeMeester score was 31.4±2.1. Following TESS, mean DeMeester score dropped to 20.1±2.0, 20.4±2.5, 17.3±2.6 and 14.3±2.0 for day 1, 2, 3 and 4, respectively (p=0.01). Conclusions TESS is effective in reducing both symptoms (heartburn and regurgitation) and esophageal acid exposure time in GERD patients.

Outcomes of Transoral Incisionless Fundoplication (TIF 2.0): A Prospective, Multicenter Cohort Study in Academic and Community Practices (with video)

BACKGROUND AND AIMSTransoral incisionless fundoplication (TIF) is an established safe endoscopic technique for the management of GERD but with variable efficacy. In the last decade, the TIF technology and technique have been optimized and more widely accepted but data on outcomes outside clinical trials are limited. We tracked patient-reported and clinical outcomes of GERD patients after TIF 2.0. METHODSPatients with BMI < 35, hiatal hernia < 2cm, and confirmed GERD with typical and/or atypical symptoms from 9 academic and community medical centers were enrolled in a prospective registry and underwent after TIF 2.0 performed by gastroenterologists and surgeons. The primary outcomes were safety and clinical success (response in >2 of 4 endpoints). Secondary endpoints were symptom improvement, acid exposure time (AET), esophagitis healing, proton pump inhibitor (PPI) use, and satisfaction. Outcomes were assessed at last follow-up within 12 months. RESULTS85 patients underwent TIF 2.0, 81 were included in the outcomes analysis. Clinical success was achieved in 94%, GERD-HRQL scores improved in 89%, and elevated RSI score normalized in 85% of patients with elevated baseline. Patient satisfaction improved from 8% to 79% (p <0.0001). At baseline, 81% were taking at least daily PPI, while 80% were on no or occasional PPI after TIF 2.0 (p<0.0001). Esophageal AET was normal in 72%, greater with an optimized TIF 2.0 valve >300 degree circumference, >3cm length (94% vs 57%, p=0.007). There were no TIF 2.0-related serious adverse events. CONCLUSIONTIF 2.0 is a safe and effective endoscopic outpatient treatment option for select patients with GERD.

Utility of Water Siphon Maneuver during Barium Esophagography in Diagnosis of Gastroesophageal Reflux

Background: The water siphon maneuver (WSM) is performed during barium swallow test (BST) to elicit gastroesophageal reflux (GERD) in patients without identifiable spontaneous reflux. The objective of this study was to measure the correlation between WSM-induced reflux with pathologic GERD as determined by gold standard ambulatory pH testing. Methods: A retrospective review of consecutive adult patients that underwent both BST with WSM and pH testing at our institution from 2015 to 2019 (n = 228). Pathologic GERD was defined as total esophageal acid exposure time &gt;6% on pH testing (Lyon consensus). Exclusion criteria included history of foregut procedures and pH testing on proton pump inhibitors. Correlation between WSM-induced reflux and GERD by pH testing was assessed using Fisher’s exact test. Results: A total of 116 patients were included. Pathologic GERD was diagnosed on 28.4% (n = 33) of pH tests while reflux was observed in 69.8% (n = 81) of WSM. There was no correlation between positive WSM and pH test-detected pathologic GERD ( P = .415). The sensitivity and specificity of WSM for GERD relative to pH testing were 63.6% and 27.7% while positive and negative predictive values were 25.9% and 65.7%, respectively. Accuracy of the WSM was consistently low across both wireless or impedance pH testing and for the entire cohort (n = 228). Conclusion: This is the largest study to date comparing WSM during BST to ambulatory pH testing in the evaluation of GERD. WSM has limited sensitivity and negative predictive value for pathologic GERD, and therefore cannot reliably confirm or discard this diagnosis.

A prediction model of abnormal acid reflux in gastroesophageal reflux disease.

The measurement of esophageal acid exposure time (AET) using combined multichannel intraluminal impedance-pH (MII-pH) tests is the gold standard for diagnosing gastroesophageal reflux disease (GERD). However, this catheter-based 24-h test can cause considerable patient discomfort. Our aim is to identify factors affecting AET and to develop a scoring model for predicting AET abnormalities before conducting the MII-pH test. Of the 366 patients who underwent MII-pH test at two facilities in Japan and Vietnam, 255 patients who also had esophagogastroduodenoscopy and high-resolution manometry were included in this study. Logistic regression analysis was conducted using risk factors for AET>6% identified from a derivation cohort (n=109). A scoring system predicting AET>6% was then constructed and externally validated with a separate cohort (n=146). Three variables were derived from the prediction model: male gender, Hill grades III-IV, and weak mean distal contractile integrals. Based on these scores, patients were classified into low (0 point), intermediate (1-3 points), and high (4 points) risk groups. The probabilities of having an AET>6% were 6%, 34%, and 100% for these groups, respectively. A score of <1 excluded patients with abnormal AET, with a negative predictive value of 93.8% in the derivation cohort and 80.0% in the validation cohort. We derived and externally validated a prediction model for abnormal AET. This system could assist in guiding the appropriate treatment strategies for GERD.

Manometric esophagogastric junction barrier metrics as predictors of gastroesophageal reflux.

High-resolution manometry (HRM) tools, like esophagogastric junction contractile integral (EGJ-CI), assess EGJ barrier function. This study aimed to evaluate the relationships between manometric EGJ metrics with esophageal acid exposure. We conducted a retrospective review of 284 patients who underwent HRM and ambulatory reflux testing between 11/2017-1/2020. EGJ-CI and total-EGJ-CI were manually calculated. Pathologic acid exposure was defined as pH < 4 with esophageal acid exposure time (EAET) exceeding 6.0%. Pearson's correlation, univariable and multivariable regression models were utilized to assess the relationships between pathologic acid exposure and EGJ parameters. Sensitivity and specificity thresholds for EGJ-CI and total EGJ-CI were optimized with ROC analyses. On univariable analysis, patients with pathologic acid exposure had increased odds of having lower mean basal LES pressures, EGJ-CI, and total EGJ-CI than patients without pathologic acid exposure. On multivariable analysis, age, EGJ-CI and mean DCI were significant predictors of pathologic acid exposure. There were significant, though weak, correlations between EAET and EGJ-CI and total EGJ-CI (r = - 0.18, - 0.19, p < 0.01, respectively). An EGJ-CI cutoff of 44.16 as a predictor for pathologic acid exposure had a sensitivity of 46% and specificity of 42% (AUC 0.60). Total EGJ-CI cutoff of 11,461.3 for pathologic acid exposure had a sensitivity of 44% and a specificity of 43% (AUC 0.62). EGJ-CI can independently predict pathologic acid exposure. However, the poor correlation between EGJ-CI and acid exposure, as well as the low sensitivity and specificity of calculated thresholds, indicate that mechanisms other than EGJ barrier function may impact acid exposure.

Mucosal impedance as a diagnostic tool for gastroesophageal reflux disease: an update for clinicians.

Mucosal impedance is a marker of esophageal mucosal integrity and a novel technique for assessing esophageal function and pathology. This article highlights its development and clinical application for gastroesophageal reflux disease (GERD), Barrett's esophagus, and eosinophilic esophagitis. A narrative review of key publications describing the development and use of mucosal impedance in clinical practice was conducted. A low mean nocturnal baseline impedance (MNBI) has been shown to be an independent predictor of response to anti-reflux therapy. MNBI predicts medication-responsive heartburn better than distal esophageal acid exposure time. Patients with equivocal evidence of GERD using conventional methods, with a low MNBI, had an improvement in symptoms following the initiation of PPI therapy compared to those with a normal MNBI. A similar trend was seen in a post fundoplication cohort. Strong clinical utility for the use of mucosal impedance in assessing eosinophilic esophagitis has been repeatedly demonstrated; however, there is minimal direction for application in Barrett's esophagus. The authors conclude that mucosal impedance has potential clinical utility for the assessment and diagnosis of GERD, particularly when conventional investigations have yielded equivocal results.

Correlation of the Endoscopic Gastroesophageal Flap Valve with Pathologic Reflux.

The Hill classification characterizes the geometry of gastroesophageal junction and Hill grades (HGs) III and IV have a high association with pathologic reflux. This study aimed to understand the use of the Hill classification and correlate the prevalence of pathologic reflux across different HGs. A retrospective review of 477 patients who underwent upper endoscopy and BRAVO pH monitoring between August 2018 and October 2021 was performed. These charts were reviewed for endoscopic findings for hiatal hernia and association of HGs with pathologic reflux, defined as an abnormal esophageal acid exposure time (AET) of ≥4.9%. Of 477 patients, 252 (52.8%) had an HG documented on the endoscopy report. Of the 252 patients, 61 had HG I (24.2%), 100 had HG II (39.7%), 61 had HG III (24.2%), and 30 had HG IV (11.9%). The proportion of patients with abnormal AET increases with increasing HGs (p < 0.001) as follows: I (39.3%), II (52.5%), III (67.2%), and IV (79.3%). The mean overall AET is as follows: HG I (5.5 ± 6%), HG II (7.0 ± 5.9%), HG III (10.2 ± 10.3%), and HG IV (9.5 ± 5.5%). The proportion of patients with hiatal hernia was 18% for HG I, 28% for HG II, 39.3% for HG III, and 80% for HG IV. Use of the Hill classification in clinical practice is low. There is an association of increasing HGs with increasing proportion of patients with abnormal AET. There is a high proportion of patients within HGs I and II with documented pathologic reflux and the presence of a hiatal hernia as observed on endoscopic examination. Our study suggests that endoscopic grading of the gastroesophageal junction may not adequately differentiate between normal vs abnormal reflux status, particularly for HGs I and II.

Current Status of Anti-Reflux Surgery as a Treatment for GERD.

Anti-reflux surgery (ARS) is an efficient treatment option for gastroesophageal reflux disease (GERD). Despite growing evidence of the efficacy and safety of ARS, medications including proton pump inhibitors (PPIs) remain the most commonly administered treatments for GERD. Meanwhile, ARS can be an effective treatment option for patients who need medications continuously or for those who are refractory to PPI treatment, if proper candidates are selected. However, in practice, ARS is often regarded as a last resort for patients who are unresponsive to PPIs. Accumulating ARS-related studies indicate that surgery is equivalent to or better than medical treatment for controlling typical and atypical GERD symptoms. Furthermore, because of overall reduced medication expenses, ARS may be more cost-effective than PPI. Patients are selected for ARS based on endoscopic findings, esophageal acid exposure time, and PPI responsiveness. Although there is limited evidence, ARS may be expanded to include patients with normal acid exposure, such as those with reflux hypersensitivity. Additionally, other factors such as age, body mass index, and comorbidities are known to affect ARS outcomes; and such factors should be considered. Nissen fundoplication or partial fundoplication including Dor fundoplication and Toupet fundoplication can be chosen, depending on whether the patient prioritizes symptom improvement or minimizing postoperative symptoms such as dysphagia. Furthermore, efforts to reduce and manage postoperative complications and create awareness of the long-term efficacy and safety of the ARS are recommended, as well as adequate training programs for new surgeons.

The Efficacy of Dietary Interventions in Patients with Gastroesophageal Reflux Disease: A Systematic Review and Meta-Analysis of Intervention Studies.

International guidelines recommend dietary interventions as one of the most important treatments for patients with gastroesophageal reflux disease (GERD). Evidence to confirm the efficacy of these treatment modalities is lacking. The present study aims to evaluate the efficacy of dietary interventions on GERD-related outcomes evaluated in intervention studies on GERD patients. A systematic review and meta-analysis was performed according to PRISMA. The PubMed/MEDLINE, Web of Sciences, and Scopus databases were utilized for the literature search. Two independent researchers searched for relevant publications published up until June 2023. Intervention studies evaluating the efficacy of dietary interventions in patients with GERD were included. A total of 577 articles were identified during the initial literature search. After reviewing, 21 studies with 16 different types of dietary interventions were included in the analysis. The interventions were divided into low-carbohydrate diets (3 studies), high-fat diets (2 studies), speed of eating studies (3 studies), low-FODMAP diets (2 studies), and other interventions (12 studies). A meta-analysis could be performed for low-carbohydrate diets and speed of eating interventions. Low-carbohydrate diets resulted in a significant reduction in esophageal acid exposure time (mean difference = -2.834%, 95% confidence interval (CI): -4.554 to -1.114), while a slow speed of eating did not lead to a lower percentage of reflux events compared to fast eating (risk ratio = 1.044, 95% CI: 0.543-2.004). Most other interventions showed positive effects in only a single study. Low-carbohydrate diets showed a significant improvement in GERD-related outcomes, while a slow eating speed did not result in a reduction in reflux events. The overall evidence regarding dietary interventions in GERD remains scarce. High-quality, long-term RCTs are still required to confirm the effects of dietary interventions in GERD patients.

Latin American consensus on diagnosis of gastroesophageal reflux disease.

Diagnosing gastroesophageal reflux disease (GERD) can be challenging given varying symptom presentations, and complex multifactorial pathophysiology. The gold standard for GERD diagnosis is esophageal acid exposure time (AET) measured by pH-metry. A variety of additional diagnostic tools are available. The goal of this consensus was to assess the individual merits of GERD diagnostic tools based on current evidence, and provide consensus recommendations following discussion and voting by experts. This consensus was developed by 15 experts from nine countries, based on a systematic search of the literature, using GRADE (grading of recommendations, assessment, development and evaluation) methodology to assess the quality and strength of the evidence, and provide recommendations regarding the diagnostic utility of different GERD diagnosis tools, using AET as the reference standard. A proton pump inhibitor (PPI) trial is appropriate for patients with heartburn and no alarm symptoms, but nor for patients with regurgitation, chest pain, or extraesophageal presentations. Severe erosive esophagitis and abnormal reflux monitoring off PPI are clearly indicative of GERD. Esophagram, esophageal biopsies, laryngoscopy, and pharyngeal pH monitoring are not recommended to diagnose GERD. Patients with PPI-refractory symptoms and normal endoscopy require reflux monitoring by pH or pH-impedance to confirm or exclude GERD, and identify treatment failure mechanisms. GERD confounders need to be considered in some patients, pH-impedance can identify supragrastric belching, impedance-manometry can diagnose rumination. Erosive esophagitis on endoscopy and abnormal pH or pH-impedance monitoring are the most appropriate methods to establish a diagnosis of GERD. Other tools may add useful complementary information.

Transoral incisionless fundoplication with or without hiatal hernia repair for gastroesophageal reflux disease after peroral endoscopic myotomy.

Background and study aims Gastroesophageal reflux disease (GERD) following peroral endoscopic myotomy (POEM) occurs in 40% to 60% of patients. There are limited data evaluating antireflux surgery or transoral incisionless fundoplication (TIF) for refractory post-POEM GERD. Patients and methods In a single-center prospective cohort study, consecutive patients with medically refractory post-POEM regurgitation and/or GERD treated with TIF or combined laparoscopic hernia repair and TIF (cTIF) were evaluated. Baseline evaluation: GERD-Health Related Quality of Life (GERD-HQRL) and Reflux Symptom Questionnaire 7-day recall (RESQ-7) questionnaires, EGD, high-resolution manometry (HRM), 48-hour pH test off proton pump inhibitors (PPIs) and impedance planimetry of the esophagogastric junction (EGJ) to calculate the diameter distensibility index (EGJ-DI). A PPI was taken twice daily for 2 weeks after TIF and restarted later if required. Patients returned 9 to 12 months after treatment when all preoperative studies were repeated. Quality of life, pH studies and EGJ metrics before and after antireflux surgery were compared. Results Seventeen patients underwent TIF (n=2, 12%) or cTIF (n=15, 88%) a mean 25±15 months after POEM. At follow-up a mean of 9±1 months after TIF/cTIF, patients required less frequent daily PPIs (n=0.001), were more satisfied (P=0.008), had improved GERD-HQRL (P=0.001), less intensity and frequency of GERD (P=0.001) and fewer reflux episodes (P=0.04) by pH testing. There was no change in EGJ-DI, EGJ diameter, integrated relaxation pressure, % total time pH <4, or DeMeester score. Conclusions TIF and cTIF for difficult-to-control post-POEM GERD appear safe, decrease PPI use and reflux episodes, and improve QOL without significant change in IRP, EGJ compliance, diameter or esophageal acid exposure time.

Contraction reserve in high resolution manometry is correlated with lower esophageal acid exposure time in patients with normal esophageal motility: A retrospective observational study.

In high resolution manometry (HRM), distal contractile integral post multiple rapid swallow augmentation is considered as contraction reserve. The relationship between contraction reserve and esophageal acid reflux remains unclear. The aim of this study was to explore the correlation between contraction reserve and esophageal acid exposure in ineffective esophageal motility (IEM) and normal HRM. Patients who underwent HRM and ambulatory reflux monitoring were retrospectively screened. Those with diagnosis of normal HRM or IEM were included in the analysis. The proportion of patients with abnormal acid exposure time (AET) was compared between patients with and without contraction reserve. Multivariate regression analysis was performed to determine the predictors of abnormal AET and contraction reserve. A total of 338 patients, including 264 normal HRM and 74 IEM, were included in the analysis. In patients with normal HRM, proportion of abnormal total AET (AET > 6.0%) was significantly lower in patients with supine contraction reserve than patients without contraction reserve (13.85% vs. 24.63%, p = 0.027). Multivariate regression analysis showed that supine contraction reserve could independently predict abnormal total AET (OR = 0.468, 95% CI: 0.249-0.948, p = 0.034), while upright contraction reserve trended strongly (OR = 0.558, 95% CI: 0.290-1.071, p = 0.079). Subgroup analysis showed that upright contraction reserve was an independent predictor of abnormal total AET in patients with 50-70% infective swallows (OR = 0.205, 95% CI: 0.051-0.821, p = 0.025), whereas supine contraction reserve did not have predictive value (p = 0.359). Supine contraction reserve correlates with esophageal acid reflux in patients with normal HRM, while only upright contraction reserve correlates with esophageal acid reflux in patients with infective swallows of 50-70%.

Esophageal Inlet Patch: Association with Barrett's Esophagus.

Esophageal inlet patch (IP) with heterotopic gastric mucosa is an incidental finding on esophagogastroduodenoscopy (EGD). Although IP is thought to be embryologic in nature, IP has been associated with Barrett's esophagus (BE). The aim of this study was to compare prevalence, symptoms, demographic factors, and esophageal testing in patients with IP and BE. We retrospectively analyzed endoscopic findings of EGDs, high-resolution esophageal manometry and esophageal pH impedance studies from January 2010 to January 2021 at a single academic medical center. Patients were grouped by presence or absence of IP and BE. Of 27,498 patients evaluated, 1.3% had endoscopic evidence of IP and 4.9% had BE. Of 362 patients with IP, 17.1% had BE; of 1356 patients with BE, 4.6% had IP. Both IP and BE patients presented primarily with heartburn and/or regurgitation. Patients with BE and/or IP were older and had higher BMI than those without (p < 0.001). Mean lower esophageal sphincter pressure was lower and mean acid exposure time (AET) was higher in patients with IP and/or BE than those without (p < 0.05). Our study reports an IP prevalence of 1.3%, with 17.1% patients having concomitant BE; and a BE prevalence of 4.9%, with 4.6% also having IP. Patients with IP alone presented with similar symptoms to patients with concomitant BE. Esophageal function testing showed that patients with either IP or BE had decreased LES pressures and increased esophageal AET. During endoscopy, patients found to have one of these findings should be carefully examined for the other.

Effect of Proton Pump Inhibitors on the Management of GERD in the Department of Gastroenterology HMC Peshawar

Background: In this trial, patients treated at the Department of Gastroenterology, Hayatabad Medical Complex in Peshawar, would have their gastroesophageal reflux disease (GERD) managed with proton pump inhibitor (PPI) medication. The treatment of omeprazole (40 mg once daily) or famotidine (40 mg O.D. daily) for 12 months was randomly allocated to 100 patients with GERD. The primary outcome measure was the mean change in oesophageal acid exposure time from baseline to twelve months. The frequency of GERD-related symptoms and general health-related quality of life over time were considered secondary objectives. Endoscopic results were also documented at the beginning and after a year. The study's adverse occurrences were kept under observation. The findings demonstrated that from baseline to twelve months, the mean oesophageal acid exposure duration significantly decreased in both PPI groups (mean S.E., 18.9 1.7 minutes for omeprazole group against 16.4 2.1 minutes for famotidine group, p0.001). Additionally, the treatment groups substantially outperformed the control groups at twelve months compared to baseline regarding the mean Frequency of GERD-related symptoms and overall health-related quality of life (p 0.001). There were no documented severe adverse events. GERD may be effectively and safely treated with PPI medication, and there are no clinically significant differences between omeprazole and famotidine.

The effect of sleep positional therapy on nocturnal gastroesophageal reflux measured by esophageal pH-impedance monitoring.

The aim of the study was to evaluate the effect of an electronic positional therapy wearable device on nocturnal gastroesophageal reflux measured by pH-impedance reflux monitoring. We performed a single-center, prospective, interventional study in 30 patients with nocturnal reflux symptoms and a nocturnal esophageal acid exposure time (AET) ≥1.5% measured off acid-suppressive medication by ambulatory pH-impedance reflux monitoring. Patients were treated with an electronic positional therapy wearable device for 2 weeks. The device vibrates in the right lateral decubitus position so it conditions patients to avoid that sleep position. After 2 weeks treatment, the pH-impedance study was repeated. Primary outcome was the change in nocturnal AET. Secondary outcomes include change in number of reflux episodes and reflux symptoms. Complete data were available for 27 patients (13 females, mean age 49.8 years). The median nocturnal AET decreased from 6.0% (IQR, 2.3-15.3) to 3.1% (0.1-10.8) after 2 weeks of treatment (p = 0.079). The number of reflux episodes was significantly reduced after 2 weeks of treatment (baseline: 8.0 (3.0-12.3) vs. end: 3.0 (1.0-8.0); p = 0.041). Treatment led to a statistically significant decrease in time spent in right lateral decubitus position (baseline: mean 36.9% ± 15.2% vs. end: 2.7% ± 8.2%; p = <0.001) and an increase in the left lateral decubitus position (baseline 29.2% ± 14.8% vs. end: 63.3% ± 21.9%; p = <0.001). Symptom improvement was reported by 70.4% of the patients. Sleep positional therapy using an electronic wearable device promotes sleeping in the left lateral decubitus position and improves reflux parameters measured by pH-impedance reflux monitoring.

Novel Diagnostic Techniques in the Evaluation of Gastroesophageal Reflux Disease (GERD).

In our present clinical paradigm, patient symptoms and presentation in the setting of traditional findings from endoscopy (erosive esophagitis, Barrett's esophagus, reflux-mediated stenosis), esophageal high-resolution manometry, and/or ambulatory reflux monitoring (distal esophageal acid exposure time, numbers of reflux events, reflux-symptom association) guide the care of patients with suspected GERD. However, novel metrics and techniques acquired from or performed at endoscopy, manometry, or pH-impedance monitoring, beyond conventional evaluation, are of great interest to the gastroenterology community given the frequent (and sometimes challenging) presentation of suspected GERD. These novel and evolving diagnostic approaches have the potential to enhance the evaluation of these patients and optimize their management. In this invited review, we discuss the present evidence and potential clinical utility of selected GERD metrics and techniques of interest at endoscopy (dilated intercellular spaces, mucosal impedance), manometry (contractile integral, impedance analysis, straight leg raise, multiple rapid swallow maneuvers), and reflux monitoring (mean nocturnal baseline impedance, post-reflux swallow-induced peristaltic wave indices), and how these tools may be most optimally adopted and utilized for clinical care (Fig.1).

Value of 96-hour ambulatory esophageal pH monitoring in the assessment of patients with refractory acid reflux symptoms and their response to anti-reflux diet.

Ambulatory esophageal pH monitoring is a diagnostic tool in patients with heartburn and regurgitation. The aim of this study is to evaluate 96-hour esophageal pH monitoring in patients with gastroesophageal reflux disease (GERD), at baseline and under diet that impedes GER. We hypothesized that diet would potentially reduce pathologic acid exposure time (AET). Retrospective series of 88 patients with GERD undergoing wireless 96-hour pH monitoring. Two-day (48hours) tandem periods, one on liberal, followed by another on restricted diet assessed esophageal AET. Primary end point was >30% reduction in AET while on anti-GER diet. Of the 88 patients, 16 were excluded because of probe migration. Endoscopy and biopsies assessed erosive esophagitis (EE) and Barrett's esophagus (BE), or normal esophagus. Abnormal AET (% pH < 4.0 ≥ 6) further defined nonerosive reflux disease (NERD), whereas normal AET (% pH < 4.0 < 6) with normal endoscopy defined patients as functional heartburn (FH). There were 6 patients with EE (n = 5) and BE (n = 1), 23 with NERD and 43 with FH. Anti-GER diet led to >30% reduction in AET in EE and NERD patients, but not in those with FH. Most patients (n = 43/72; 60%) had FH and could have avoided acid suppression. Furthermore, (14/23; 61%) of patients with NERD completely normalized AET with diet, potentially negating acid suppression. Ninety-six-hour esophageal pH distinguishes GERD patients from those with FH. Fifty percent of EE/BE patients and 61% of those with NERD completely normalize AET with diet. If pathologic AET occurs despite diet, acid suppression is indicated.

Improving the Diagnostic Yield of High-Resolution Esophageal Manometry for GERD: The “Straight Leg-Raise” International Study

The straight leg raise (SLR) maneuver during high-resolution manometry (HRM) can assess esophagogastric junction (EGJ) barrier function by measuring changes in intraesophageal pressure (IEP) when intra-abdominal pressure is increased. We aimed to determine whether increased esophageal pressure during SLR predicts pathologic esophageal acid exposure time (AET). Adult patients with persistent gastroesophageal reflux disease (GERD) symptoms undergoing HRM and pH-impedance or wireless pH study off proton pump inhibitor were prospectively studied between July 2021 and March 2022. After the HRM Chicago 4.0 protocol, patients were requested to elevate 1 leg at 45º for 5 seconds while supine. The SLR maneuver was considered effective when intra-abdominal pressure increased by 50%. IEPs were recorded 5 cm above the lower esophageal sphincter at baseline and during SLR. GERD was defined as AET greater than 6%. The SLR was effective in 295 patients (81%), 115 (39%) of whom had an AET greater than 6%. Hiatal hernia (EGJ type 2 or 3) was seen in 135 (46%) patients. Compared with patients with an AET less than 6%, peak IEP during SLR was significantly higher in the GERD group (29.7 vs 13.9 mm Hg; P < .001). Using receiver operating characteristic analysis, an increase of 11 mm Hg of peak IEP from baseline during SLR was the optimal cut-off value to predict an AET greater than 6% (area under the receiver operating characteristic curve, 0.84; sensitivity, 79%; and specificity, 85%), regardless of the presence of hiatal hernia. On multivariable analysis, an IEP pressure increase during the SLR maneuver, EGJ contractile integral, EGJ subtype 2, and EGJ subtype 3, were found to be significant predictors of AET greater than 6% CONCLUSIONS: The SLR maneuver can predict abnormal an AET, thereby increasing the diagnostic value of HRM when GERD is suspected. gov ID: NCT04813029.

S471 Does Lower Esophageal Sphincter Distensibility Measured by the Functional Lumen Imaging Probe Relate to Total Esophageal Acid Exposure Time?

S471 Does Lower Esophageal Sphincter Distensibility Measured by the Functional Lumen Imaging Probe Relate to Total Esophageal Acid Exposure Time?

S423 Association Between Defective Secondary Peristalsis Detected by Functional Lumen Imaging Probe Topography (FLIP) and GERD

Introduction: Esophageal secondary peristalsis is a defense mechanism against GERD by clearance of refluxate. When absent or defective, it may lead to increased esophageal acid exposure time (AET). Functional lumen imaging probe topography (FLIP) allows assessment of secondary peristalsis induced by volumetric distension. Aim: evaluate the association between secondary peristalsis and GERD. Methods: We included patients with esophageal symptoms who underwent FLIP topography and reflux monitoring (wireless pH or catheter-based pH-impedance) while off PPI ≥7 days, high-resolution esophageal manometry (HRM) findings (LES pressure, ineffective esophageal motility , absent contractility) were added for secondary analysis when available. Exclusion criteria: achalasia, prior gastroesophageal surgery, Botox injection within 6 months of FLIP and reflux study. Abnormal AET on reflux monitoring was defined as % time pH< 4 greater than 4%. FLIP was performed with a 16 cm balloon during propofol-sedated endoscopy; peristaltic response was assessed at 30-40-50-60 ml and classified as repetitive antegrade contractions (RACs), borderline contractile response, repetitive retrograde contractions (RRCs), impaired, absent, and spastic reactive. EGJ distensibility index (DI) was calculated at 60ml. Secondary peristalsis was considered intact if RACs seen at any volume, impaired otherwise. Those with borderline contractility but no RACs were excluded from analysis.. We assessed the association between FLIP and HRM findings and GERD by t test and chi square. Results: 37 patients included (23, 62% female), mean age 58.45 years, mean BMI 25.7. GERD present in 15 (40.5%). Mean esophageal AET was lower in patients with versus without intact peristalsis but significance not reached (5.8% vs 3.0%, p=0.058). The proportion of patients with GERD was lower in patients with peristalsis versus without intact peristalsis but significance not reached (25% vs 40%, p=0.18). There was no association between GERD and DI or any HRM measures. Conclusion: Our data suggests that defective secondary peristalsis is more frequent in GERD patients and is thus and important contributing factor to reflux. Lack of significance may be due to small sample size and type II error, but a larger number of patients is needed to clarify this and data collection is ongoing.