Inter-reviewer Variability in Interpretation of pH-Impedance Studies: The Wingate Consensus

The Lyon Score: A Novel Reflux Scoring System Based on the Lyon Consensus 2.0 That Associates With Treatment Outcome From Antireflux Therapy

INTRODUCTION

We explored if a score derived from parameters from esophageal testing could increase confidence in diagnosing conclusive gastroesophageal reflux disease and in predicting outcome.

METHODS

A prediction score was developed using metrics based on Lyon Consensus 2.0 thresholds extracted from endoscopy and pH-impedance monitoring. The Lyon score was the sum of weighted scores derived from a logistic regression model. The outcome was response to antireflux therapy, defined as 50% reduction in global symptoms on validated questionnaires. An existing database of endoscopy-negative patients with typical reflux symptoms undergoing esophageal testing from 2 centers (Europe and the United States) constituted the developmental cohort, while 2 separate cohorts (Europe and Asia) served as validation cohorts. Receiver operating characteristics analysis determined performance of the Lyon score in predicting treatment response.

RESULTS

In 281 developmental cohort patients (median age 53 years, 57.7% female), the Lyon score demonstrated an area under the curve (AUC) of 0.819 in predicting 50% symptom improvement ( P < 0.001) on receiver operating characteristics, with an optimal threshold of 6.25 (sensitivity 81.2%, specificity 73.4%). Of the individual components, only acid exposure time (AUC 0.799, P < 0.001), mean nocturnal baseline impedance (AUC 0.785, P < 0.001), and reflux episodes (AUC 0.764, P < 0.001) approached the Lyon score performance. The Lyon score segregated treatment response in both the European (AUC 0.908, P < 0.001) and Asian validation cohorts (AUC 0.637, P < 0.001) and outperformed the DeMeester score in sensitivity for predicting outcome in the developmental and Asian validation cohorts.

DISCUSSION

The novel Lyon score segregates reflux phenotypes and identifies likelihood of symptom response from antireflux therapy.

Mucosal integrity and acid sensitivity predict proton pump inhibitor response in patients with heartburn and normal acid exposure

BACKGROUND

Patients with typical reflux symptoms and normal acid exposure time (AET) are classified as either reflux hypersensitivity (RH) or functional heartburn (FH), some of whom respond to proton pump inhibitors (PPIs). We determined if esophageal psychophysiological parameters predict PPI response in symptomatic RH and FH patients.

METHODS

We prospectively recruited adults with heartburn diagnosed with RH or FH on 24-h impedance-pH monitoring off PPI. Mucosal integrity was evaluated using mean nocturnal baseline impedance (MNBI). Symptom response required ≥50 % reduction in global symptom severity. Infusion of hydrochloric acid (0.1 N) into the mid-esophagus evaluated acid sensitivity, using time to initial typical symptom perception (lag time) and intensity rating. Factors influencing PPI response were identified using logistic regression.

RESULTS

Of 102 study participants (age 21-64 years, 69.6 % women, 54 RH, 48 FH), 37.3 % demonstrated PPI response (RH: 44.4 %, FH: 29.2 %, p = NS). On multivariable logistic regression, lower MNBI correlated with PPI response in both RH and FH, shorter lag time also correlated in RH. The optimal MNBI threshold for predicting PPI response was 2500 ohms.

CONCLUSIONS

Lower MNBI indicating mucosal acid damage, and esophageal acid sensitivity prompting early symptom reporting are physiomarkers of PPIs response in RH and FH patients.

Primary Peristalsis Is the Dominant Mechanism of Refluxate Clearance Following Gastroesophageal Reflux

BACKGROUND

Refluxate volume and pH drop following gastroesophageal reflux are mostly cleared by peristalsis. We evaluated the roles of primary volume clearing peristaltic wave (VCPW), secondary VCPW, post-reflux swallow-induced peristaltic wave (PSPW), and late primary peristaltic wave (LPPW) in refluxate clearance.

METHODS

We retrospectively analyzed pH-impedance studies performed off therapy in 40 patients with typical esophageal symptoms. Mechanism of refluxate clearance was evaluated for each reflux episode (primary VCPW vs. secondary VCPW vs. none), as well as presence of PSPW, LPPW when PSPW was absent, and pH recovery with each mechanism. Per-episode and per-patient analyses determined the dominant mechanism of refluxate clearance and pH recovery.

RESULTS

Of 958 reflux episodes, 88% were acidic. A primary VCPW was the dominant mechanism for volume clearance (48.4% acid, 47.8% non-acid reflux episodes), and ≥ 50% pH recovery (58.7%). Of reflux episodes lacking pH recovery, PSPW resulted in ≥ 50% pH recovery in 40.2%, and LPPW in 60.9%. In logistic regression models, primary peristaltic wave (primary VCPW, PSPW, or LPPW) had the highest likelihood of pH recovery in per-episode analysis (OR 2.1, CI 1.3-3.0, p < 0.001), and in per-patient analysis (OR 11.0, CI 1.5-20.5, p = 0.025), among which primary VCPW was the most effective (OR 3.4, CI 1.5-7.7, p = 0.003).

CONCLUSIONS

A primary peristaltic wave from a swallow, either in the form of a VCPW, PSPW, or LPPW, is the dominant mechanism of pH recovery after gastroesophageal reflux. When a primary VCPW does not correct pH drop, PSPW, and LPPW are equivalent salvage mechanisms for pH recovery.

Esophageal high-resolution manometry and 24 h pH-impedance monitoring normative values in patients with obesity candidate for bariatric and metabolic surgery

Obesity is linked to increased risk of gastroesophageal reflux disease (GERD) and esophageal motility disorders, both of which may impact outcomes in metabolic and bariatric surgery (MBS). GERD pathophysiology in obesity includes elevated intraabdominal pressure and altered esophagogastric junction (EGJ) function. High resolution manometry (HRM) and 24-h esophageal pH-impedance (MII-pH) monitoring are vital in evaluating GERD, yet normative values specific to populations with obesity are limited, risking misdiagnosis if lean data are used. This study establishes normative HRM and MII-pH values in asymptomatic individuals with obesity, compared to normal-weight controls, to guide accurate diagnosis and treatment. A retrospective analysis was conducted on asymptomatic patients with obesity (BMI ≥ 30) and normal-weight controls (BMI 20-25) who underwent HRM and MII-pH prior to MBS between 2015 and 2024. Exclusion criteria included GERD symptoms, esophagitis, and prior gastrointestinal surgery. Key HRM parameters (LES pressure, EGJ morphology) and MII-pH metrics (acid exposure time, reflux episodes) were recorded and analyzed. Of the 96 patients with obesity and 25 normal-weight participants, significant differences in HRM and MII-pH results were observed. Individuals with obesity showed increased intra-gastric pressure, gastroesophageal pressure gradient, and higher acid exposure time. While LES pressure and EGJ morphology were similar to controls, participants with obesity exhibited distinct reflux patterns, especially postprandial, suggesting obesity-specific physiological changes. This study establishes normative HRM and MII-pH values for asymptomatic individuals with obesity, highlighting critical differences from normal-weight controls. Obesity-specific diagnostic criteria are essential for accurate GERD diagnosis, particularly for MBS candidates, to improve management and predict potential postoperative complications.

Diagnosis and Treatment of Gastroesophageal Reflux Disease (Clinical Guidelines of the Russian Gastroenterological Association, Russian Scientific Medical Society of Internal Medicine, Russian Society for the Prevention of Noncommunicable Diseases, Scientific Community for Human Microbiome Research)

Aim. These recommendations are developed for practitioners in order to familiarize them with modern diagnostic methods, management features and pharmacotherapy of patients with gastroesophageal reflux disease (GERD).

General provisions. GERD is the most common reason for patients to visit clinics. There are esophageal and extraesophageal manifestations of GERD. Patients' complaints of heartburn and regurgitation remain the most sensitive and specific clinical manifestations of GERD. The diagnosis of GERD is established on the basis of anamnestic data, instrumental examination (detection of reflux esophagitis during upper gastrointestinal endoscopy, detection of pathological gastroesophageal reflux with 24-hour pH-metry or/and 24-hour pH-impedance monitoring). Patients with suspected GERD and the absence of erosive and ulcerative changes in the mucous membrane of the esophagus or the presence of erosive esophagitis of Grade A according to Los Angeles Classification of Gastroesophageal Reflux Disease are recommended to conduct 24-hour pH-metry on PPI off to exclude or confirm the diagnosis of GERD. Patients with extraesophageal manifestations of GERD without classic symptoms (heartburn, regurgitation) are recommended to undergo 24-hour pH-impedance monitoring with discontinuation of proton pump inhibitor therapy. When deciding on surgical treatment, all patients need to perform high-resolution esophageal manometry and 24-hour pH-impedance monitoring. Complications of GERD include bleeding, strictures, Barrett’s esophagus and esophageal adenocarcinoma. The main groups of medications used in the treatment of GERD are proton pump inhibitors (PPIs), potassium-competitive acid blockers (P-CABs), alginates, antacids, and prokinetics. PPIs are the drugs of choice in the treatment of both symptoms of gastroesophageal reflux disease and existing erosive esophagitis. Combination therapy Rebamipide with PPIs increases the effectiveness of relief of GERD symptoms, as well as reduces the frequency of relapses.

Conclusion. These clinical recommendations will improve the quality of medical care for patients with GERD.

In vitro and in vivo evaluation of a novel wired transmission pH-combined photographic catheter for ambulatory gastroesophageal reflux monitoring (with videos)

Twenty-four-hour pH-impedance monitoring is an important diagnostic approach for gastroesophageal reflux disease (GERD). Reflux monitoring results cannot be synchronized with ambulatory motility imaging of the esophageal sphincter. We have designed a novel wired transmission pH-combined photographic catheter (WT-CPC) for the synchronous acquisition of reflux image and pH. Different patterns of reflux events were simulated to perform in a porcine gastroesophageal reflux model in vitro. The live porcine model of gastroesophageal reflux was established in three Bama pigs. Monitoring was conducted with the WT-CPC and pH-impedance catheter simultaneously. Measurements included the number and proportion of reflux events, as well as acid exposure time (AET). The detection rates of WT-CPC for distal and horizontal acid reflux events were significantly higher compared to those of pH-impedance catheters (100% vs. 14.29%, 100% vs. 57.14%, P < 0.05). There was no significant difference between the two methods in proximal acid reflux events (P = 0.217). Regarding mixed reflux events, WT-CPC exhibited higher detection rates for distal events than pH-impedance catheter (100% vs. 42.86%, P < 0.05). However, there was no significant difference between the two methods for proximal reflux events (P > 0.05). Both methods showed similar results for horizontal reflux events. A porcine gastroesophageal reflux model was successfully established and utilized for reflux monitoring. A total of 28 episodes of reflux were detected within 6.5 min. The detection rate achieved by WT-CPC for reflux events was significantly higher than that obtained by pH-impedance (100% vs. 78.57%, P = 0.023). The WT-CPC has demonstrated reflux monitoring capabilities in an isolated reflux organ model. It also showed good operability and performance in the porcine model. The WT-CPC holds promising potential to provide valuable diagnostic evidence for GERD.

Prevalence of Gastroesophageal Reflux Disease in Congenital Diaphragmatic Hernia Survivors From Infancy to Adulthood

BACKGROUND

Gastroesophageal reflux disease (GERD) is a common comorbidity associated with congenital diaphragmatic hernia (CDH), with reported cases of Barrett's esophagus (BE) and esophageal adenocarcinoma before the age of 25. The prevalence and natural course of GERD in CDH survivors remain uncertain due to variations in diagnostic methods. We aimed to analyse the GERD prevalence from infancy through young adulthood.

METHODS

We retrospectively analyzed pH-impedance measurements and endoscopic findings in 96 CDH survivors evaluated as routine care using well established clinical protocols. GERD was defined as an abnormal acid exposure time for pH-MII measurements and as presence of reflux esophagitis or BE at upper endoscopy. Clinical data including symptoms at time of follow-up and use of antireflux medication were collected.

RESULTS

GERD prevalence remained consistently low (≤10%) across all age groups, yet many patients experienced GER symptoms. Histological abnormalities were observed in 80% of adolescents and young adults, including microscopic esophagitis in 50%. BE was diagnosed in 7% before the age of 18, all had GER symptoms. CDH severity, anatomy at the time of CDH correction, alcohol usage, and smoking did not emerge as significant risk factors for GERD.

CONCLUSIONS

Given the low GERD prevalence in CDH survivors, a symptom-driven approach to diagnosis and follow-up is warranted. We advise long-term follow-up for all adult patients due to the early onset of BE and the limited evidence available. The longitudinal course and impact of GERD on other long-term CDH-related comorbidities should be explored in larger cohorts.

LEVEL OF EVIDENCE

Not applicable.

A prediction model of abnormal acid reflux in gastroesophageal reflux disease

BACKGROUND AND AIM

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.

METHODS

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).

RESULTS

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.

CONCLUSIONS

We derived and externally validated a prediction model for abnormal AET. This system could assist in guiding the appropriate treatment strategies for GERD.

Comparison of Esophageal Dysmotility and Reflux Burden in Patients with Different Metabolic Obesity Phenotypes Based on High-Resolution Impedance Manometry and 24-h Impedance-pH

INTRODUCTION

The relationship between the metabolically healthy obesity (MHO) phenotype and the occurrence of gastroesophageal reflux disease (GERD) and inefficient esophageal motility (IEM) is still unclear. Thus, we assessed the association between different metabolic obesity phenotypes and GERD and IEM using empirical data.

METHODS

We collected clinical and test data of 712 patients, including 24-h multichannel intraluminal impedance-pH (24-h MII-pH) monitoring, high-resolution manometry (HRM), and endoscopy. We divided 567 individuals into four categories according to their metabolic obesity phenotype: metabolically unhealthy non-obesity (MUNO), metabolically unhealthy obesity (MUO), metabolically healthy non-obesity (MHNO), and MHO. We compared differences in the 24-h MII-pH monitoring, HRM, and endoscopy findings among the four metabolic obesity phenotypes.

RESULTS

Patients with the MUNO, MHO, or MUO phenotype showed a greater risk of IEM and GERD (pathologic acid exposure time [AET] >6%) compared with patients with the MHNO phenotype. Regarding the HRM results, patients with the MHNO or MUNO phenotype had a lower integrated relaxation pressure, esophageal sphincter pressure, and esophagogastric junction contractile integral, and more ineffective swallows than patients with the MHO or MUO phenotype (p < 0.05). In terms of 24-h MII-pH, patients with the MHO or MUO phenotype had a higher total, upright, and supine AET; a higher total number of reflux episodes (TRs); and a lower mean nocturnal baseline impedance and post-reflux swallow-induced peristaltic wave index compared with those with the MHNO or MUNO phenotype (all p < 0.05). Considering the odds ratio of 19.086 (95% confidence interval 6.170-59.044) for pathologic AET and 3.659 (95% confidence interval 1.647-8.130) for IEM, patients with the MUO phenotype had the greatest risk after adjusting for all confounding variables.

CONCLUSION

Obesity and metabolic disorders increase the risk of GERD and IEM. Obesity has a greater impact on esophageal dysmotility and pathologic acid exposure than metabolic diseases.

Utility of the Post-Reflux Swallow-Induced Peristaltic Wave Index and Mean Nocturnal Baseline Impedance for the Diagnosis of Gastroesophageal Reflux Disease Phenotypes in Children

(1) Objectives: Assessment of novel impedance parameters such as the post-reflux swallow-induced peristaltic wave (PSPW) index and mean nocturnal baseline impedance (MNBI) have been proposed to enhance the accuracy of gastroesophageal reflux disease (GERD) diagnosis. We aimed to evaluate the clinical value of MNBI and the PSPW index in discerning different phenotypes of GERD in children. (2) Methods: We conducted a prospective, observational study that included 49 children aged 5-18 years, referred for MII-pH monitoring due to negative endoscopy and persisting gastroesophageal reflux symptoms despite acid-suppressant treatment. The PSPW index and MNBI were assessed along with conventional metrics. (3) Results: Using a receiver operating characteristic (ROC) curve analysis, MNBI (AUC 0.864) and the PSPW index (AUC 0.83) had very good performance in differentiating between non-erosive reflux disease (NERD) and functional phenotypes. The PSPW index (AUC 0.87) discriminated better between functional heartburn (FH) and reflux hypersensitivity (RH) compared to the MNBI (AUC 0.712). A PSPW cut-off value of 65% provided a sensitivity of 76.9% and a specificity of 90% in distinguishing FH and RH. The PSPW index (AUC 0.87) proved to have better performance than the MNBI (AUC 0.802) in differentiating between FH and non-FH patients. MNBI diagnosed FH with a sensitivity of 84% and a specificity of 80.6% at a cut-off value of 2563 Ω. (4) Conclusions: The PSPW index and MNBI are useful to distinguish between GERD phenotypes in pediatric patients.

Differences Between Patients with Heartburn Refractory to Vonoprazan and Those Refractory to Proton Pump Inhibitors

BACKGROUND

Vonoprazan, a potassium-competitive acid blocker, demonstrates more potent acid inhibition than proton pump inhibitors (PPIs). This study aimed to evaluate the effect of vonoprazan in patients with unproven gastroesophageal reflux disease (GERD) by comparing patients with vonoprazan-refractory heartburn with those with PPI-refractory heartburn.

METHODS

This study included 104 consecutive patients with vonoprazan- or PPI-refractory heartburn (52 patients each), no erosive esophagitis on endoscopy and who underwent combined multichannel intraluminal impedance-pH (MII-pH) testing with vonoprazan/PPI discontinuation. Patients' backgrounds, symptom scores from four questionnaires, MII-pH results and high-resolution manometry results were compared between the two groups.

RESULTS

The vonoprazan group demonstrated significantly higher GERD symptoms and scores of abdominal pain and diarrhea on the Gastrointestinal Symptom Rating Scale questionnaire. MII-pH results revealed that the vonoprazan group demonstrated 40.4%, 17.3%, and 42.3% and the PPIs group exhibited 26.9%, 17.3%, and 55.8% of abnormal acid reflux [true non-erosive reflux disease (NERD)], reflux hypersensitivity and functional heartburn, respectively. The vonoprazan group demonstrated higher true NERD rates but with no significant difference (p = 0.307). Among the vonoprazan group, eight patients with true NERD underwent another MII-pH test on vonoprazan, and all cases demonstrated normal acid exposure times (0.0% [0.0-0.3]).

CONCLUSION

Patients with unproven GERD with vonoprazan-refractory heartburn demonstrated more symptoms, including not only GERD symptoms but also functional dyspepsia and irritable bowel syndrome symptoms, than those with PPI-refractory heartburn.

The Milan score: A novel manometric tool for a more efficient diagnosis of gastro-esophageal reflux disease

OBJECTIVE

A definitive diagnosis of gastroesophageal reflux disease (GERD) depends on endoscopic and/or pH-study criteria. However, high resolution manometry (HRM) can identify factors predicting GERD, such as ineffective esophageal motility (IEM), esophago-gastric junction contractile integral (EGJ-CI), evaluating esophagogastric junction (EGJ) type and straight leg raise (SLR) maneuver response. We aimed to build and externally validate a manometric score (Milan Score) to stratify the risk and severity of the disease in patients undergoing HRM for suspected GERD.

METHODS

A population of 295 consecutive patients undergoing HRM and pH-study for persistent typical or atypical GERD symptoms was prospectively enrolled to build a model and a nomogram that provides a risk score for AET > 6%. Collected HRM data included IEM, EGJ-CI, EGJ type and SLR. A supplemental cohort of patients undergoing HRM and pH-study was also prospectively enrolled in 13 high-volume esophageal function laboratories across the world in order to validate the model. Discrimination and calibration were used to assess model's accuracy. Gastroesophageal reflux disease was defined as acid exposure time >6%.

RESULTS

Out of the analyzed variables, SLR response and EGJ subtype 3 had the highest impact on the score (odd ratio 18.20 and 3.87, respectively). The external validation cohort consisted of 233 patients. In the validation model, the corrected Harrel c-index was 0.90. The model-fitting optimism adjusted calibration slope was 0.93 and the integrated calibration index was 0.07, indicating good calibration.

CONCLUSIONS

A novel HRM score for GERD diagnosis has been created and validated. The MS might be a useful screening tool to stratify the risk and the severity of GERD, allowing a more comprehensive pathophysiologic assessment of the anti-reflux barrier.

TRIAL REGISTRATION

ClinicalTrials.gov (Identifier: NCT05851482).

Saliva Production and Esophageal Motility Influence Esophageal Acid Clearance Related to Post-reflux Swallow-Induced Peristaltic Wave

BACKGROUND

The post-reflux swallow-induced peristaltic wave (PSPW) brings salivary bicarbonate to neutralize residual distal esophageal mucosal acidification.

AIMS

To determine if reduced saliva production and esophageal body hypomotility would compromise PSPW-induced pH recovery in the distal esophagus.

METHODS

In this multicenter retrospective cross-sectional study, patients with confirmed Sjogren's syndrome and scleroderma/mixed connective tissue disease (MCTD) who underwent high resolution manometry (HRM) and ambulatory pH-impedance monitoring off antisecretory therapy were retrospectively identified. Patients without these disorders undergoing HRM and pH-impedance monitoring for GERD symptoms were identified from the same time-period. Acid exposure time, numbers of reflux episodes and PSPW, pH recovery with PSPW, and HRM metrics were extracted. Univariate comparisons and multivariable analysis were performed to determine predictors of pH recovery with PSPW.

RESULTS

Among Sjogren's syndrome (n = 34), scleroderma/MCTD (n = 14), and comparison patients with reflux symptoms (n = 96), the scleroderma/MCTD group had significantly higher AET, higher prevalence of hypomotility, lower detected reflux episodes, and very low numbers of PSPW (p ≤ 0.004 compared to other groups). There was no difference in pH-impedance metrics between Sjogren's syndrome, and comparison patients (p ≥ 0.481). Proportions with complete pH recovery with PSPW was lower in Sjogren's patients compared to comparison reflux patients (p = 0.009), predominantly in subsets with hypomotility (p < 0.001). On multivariable analysis, diagnosis of Sjogren's syndrome, scleroderma/MCTD or neither (p = 0.014) and esophageal hypomotility (p = 0.024) independently predicted lack of complete pH recovery with PSPW, while higher total reflux episodes trended (p = 0.051).

CONCLUSIONS

Saliva production and motor function are both important in PSPW related pH recovery.

Evaluating acidic gastroesophageal reflux with wireless pH monitoring in French bulldogs with sliding hiatal herniation

BACKGROUND

Sliding hiatal herniation (SHH) and gastroesophageal reflux (GER) commonly occur in French bulldogs. Wireless pH monitoring can quantitatively assess acidic GER in dogs affected by SHH.

HYPOTHESIS/OBJECTIVES

Measure acidic GER in French bulldogs with SHH, pre- and post-brachycephalic obstructive airway syndrome (BOAS) surgery, utilizing a wireless pH capsule (Bravo Calibration-free, Medtronic, Minnesota), and correlate with owners' observations of regurgitation.

ANIMALS

Eleven French bulldogs diagnosed with SHH via swallowing fluoroscopy.

METHODS

Prospective cohort study. A pH capsule was endoscopically placed in the esophagus. Up to 96 hours of data were acquired as the owner logged clinical signs. Spearman's correlation and Wilcoxon rank-sum tests evaluated factors correlated with acid exposure time (AET), defined by the % time pH < 4. In 4/11 dogs, Bravo monitoring was repeated 2-4 months after BOAS surgery.

RESULTS

Medians (Q1-Q3) for age and weight were 21 months (17-35.5) and 10.0 kg (8.9-11.5). BOAS severity was mild (3), moderate (4), or severe (4). Medians (Q1-Q3) for AET and reflux events were 3.3% (2.6-6.4) and 70 (34-173). Clinical score (P = .82) and BOAS severity (P = .60) were not correlated with AET, but age was negatively correlated (rho = -.66, P = .03). Median probability (Q1-Q3) that regurgitation was associated with a reflux event was 72.5% (0-99). Percent AET numerically improved in all 4 dogs that underwent BOAS surgery although not statistically assessed.

CONCLUSIONS AND CLINICAL IMPORTANCE

Wireless pH monitoring documented acidic GER in French bulldogs with SHH, captured subclinical events, and showed improvements after BOAS surgery.

Refractory Gastroesophageal Reflux Disease: Diagnosis and Management

Gastroesophageal reflux disease (GERD) is common, with increasing worldwide disease prevalence and high economic burden. A significant number of patients will remain symptomatic following an empiric proton pump inhibitor (PPI) trial. Persistent symptoms despite PPI therapy are often mislabeled as refractory GERD. For patients with no prior GERD evidence (unproven GERD), testing is performed off antisecretory therapy to identify objective evidence of pathologic reflux using criteria outlined by the Lyon consensus. In proven GERD, differentiation between refractory symptoms (persisting symptoms despite optimized antisecretory therapy) and refractory GERD (abnormal reflux metrics on ambulatory pH impedance monitoring and/or persistent erosive esophagitis on endoscopy while on optimized PPI therapy) can direct subsequent management. While refractory symptoms may arise from esophageal hypersensitivity or functional heartburn, proven refractory GERD requires personalization of the management approach, tapping from an array of non-pharmacologic, pharmacologic, endoscopic, and surgical interventions. Proper diagnosis and management of refractory GERD is critical to mitigate undesirable long-term complications such as strictures, Barrett's esophagus, and esophageal adenocarcinoma. This review outlines the diagnostic workup of patients presenting with refractory GERD symptoms, describes the distinction between unproven and proven GERD, and provides a comprehensive review of the current treatment strategies available for the management of refractory GERD.

Updates to the modern diagnosis of GERD: Lyon consensus 2.0

The Lyon Consensus provides conclusive criteria for and against the diagnosis of gastro-oesophageal reflux disease (GERD), and adjunctive metrics that consolidate or refute GERD diagnosis when primary criteria are borderline or inconclusive. An international core and working group was assembled to evaluate research since publication of the original Lyon Consensus, and to vote on statements collaboratively developed to update criteria. The Lyon Consensus 2.0 provides a modern definition of actionable GERD, where evidence from oesophageal testing supports revising, escalating or personalising GERD management for the symptomatic patient. Symptoms that have a high versus low likelihood of relationship to reflux episodes are described. Unproven versus proven GERD define diagnostic strategies and testing options. Patients with no prior GERD evidence (unproven GERD) are studied using prolonged wireless pH monitoring or catheter-based pH or pH-monitoring off antisecretory medication, while patients with conclusive GERD evidence (proven GERD) and persisting symptoms are evaluated using pH-impedance monitoring while on optimised antisecretory therapy. The major changes from the original Lyon Consensus criteria include establishment of Los Angeles grade B oesophagitis as conclusive GERD evidence, description of metrics and thresholds to be used with prolonged wireless pH monitoring, and inclusion of parameters useful in diagnosis of refractory GERD when testing is performed on antisecretory therapy in proven GERD. Criteria that have not performed well in the diagnosis of actionable GERD have been retired. Personalisation of investigation and management to each patient's unique presentation will optimise GERD diagnosis and management.

Optimizing ambulatory reflux monitoring: current findings and future directions

INTRODUCTION

Gastroesophageal reflux disease (GERD) is the most common diagnosis seen in outpatient gastroenterology clinics. The diagnosis is made by a variable combination of symptoms, response to acid suppressive therapy, endoscopic evaluation, and pH testing. In this review, we evaluate how to utilize various reflux testing in clinical practice based on current evidence.

AREAS COVERED

Ambulatory reflux monitoring is a recognized diagnostic tool for clinical decision making in patients with/without established GERD, persistent reflux symptoms, and lack of response to proton pump inhibitor (PPI) therapy. Standard evaluation approaches include 24-hour pH or impedance monitoring via transnasal catheter, prolonged (48 to 96 hour) wireless pH monitoring, and the recently developed mucosal integrity testing. Testing using one of these methods allows for measurement of acid exposure, frequency of reflux, and to phenotype patients to personalize treatment recommendations.

EXPERT OPINION

The primary goal of future studies should be to simplify ambulatory reflux monitoring, reduce diagnostic latency, improve patient tolerance, and to obtain clinical outcomes-based studies. The current paradigm of reflux testing is vastly complex with multiple modalities and shifting cutoffs of pH abnormality that lead to high economic burden on the society.

Manual censoring of impedance tracings by the Wingate consensus reduces the number of impedance episodes, impacting on reflux categorization

BACKGROUND

The Lyon consensus classifies the evidence of gastroesophageal reflux (GERD) based on endoscopic features and results of pH/impedance monitoring (pH-MII) including the post-reflux swallow-induced peristaltic wave index (PSPWI) and mean nocturnal baseline impedance (MNBI). The Wingate consensus established criteria to reduce inter-reviewer variability when assessing reflux episodes and PSPWI by impedance. This study aims to assess the influence of the Wingate criteria on the different pH-MII parameters obtained by automated analysis.

METHODS

Thirty consecutive pH-MII off PPI were reviewed according to Wingate criteria. Number of impedance episodes and PSPWI were compared before and after censoring from automatic analysis. Reflux categorization according to Lyon consensus between censored and uncensored data was compared. Pearson correlations between impedance parameters and censored episodes were calculated.

KEY RESULTS

Censoring the tracings significantly reduced the number of reflux episodes (66 [42-90.25] vs. 44.5 [21.5-61.5], p = 0.0105). Reasons for censoring were as follows: 1/ anterograde episode: 9.5 [6-13], 2/ impedance drop <50%: 1 [0-3], 3/ duration <4 s: 1 [0-2], 4/ <2 distal channels: 2.5 [1-4], and 5/ artifacts: 2 [1-5]. Censored episodes were in majority non-acid (16.5 [13-26.5] vs. 2 [0-4], p < 0.00001). Censoring altered the categorization of impedance episodes (<40 episodes, 6 vs. 13 for resp. uncensored vs. censored tracings, 40-80 episodes: 13 vs. 13, and >80 episodes: 11 vs. 4, p = 0.0264), but not the symptom index, the symptom association probability, or the categorization according to the Lyon consensus. Nevertheless, individual tracings were affected. The percentage of censored episodes was inversely correlated with the number of acidic impedance episodes (r = -0.62, p = 0.0002).

CONCLUSION AND INFERENCES

Manual interpretation of impedance tracings based on the Wingate consensus reduces the number of impedance episodes, impacting on reflux categorization. Acidic reflux episodes are less likely to be censored, harboring a potential at improving automatic pH-MII analysis.

Improved diagnosis of reflux hypersensitivity

BACKGROUND

Reflux hypersensitivity (RH) is characterized by normal esophageal exposure to acid and positive correlation of symptoms to reflux episodes. Positivity of Symptomatic Index (SI) and/or Symptom Association Probability (SAP) is used diagnostically, though experts support that concordance of both is needed. We evaluated differences among patients with RH and concordance of SI/SAP or not.

METHODS

Patients with typical reflux symptoms without previous GERD diagnosis, submitted simultaneously to Ph-Impedance off PPI and high resolution manometry were included. Self-response to PPI was evaluated. Patients showing SI and/or SAP positivity were considered having RH and further classified to definite RH if both SI/SAP were positive or indefinite if only one positive.

KEY RESULTS

Totally 2659 patients (M/F: 35.6%/64.7%, mean age: 45 ± 14) were included. Final diagnosis was; FH: 21.8%, RH: 29.3% (definite: 14.3%/indefinite: 15%), GERD: 36% and inconclusive GERD: 12.9%. Patients with definite RH showed increased total reflux time, total number of reflux episodes and length of hiatus hernia, and also numerically but not statistically significant increased rates of PPI responsiveness versus indefinite RH and decreased mean nocturnal baseline impedance. Moreover, they showed significantly increased rate of PPI response versus patients with functional heartburn (FH).

CONCLUSION & INFERENCES

Some PPI responsiveness is frequent among patients with RH as also with FH, and cannot discriminate those entities clinically when diagnosing RH using SI and/or SAP positive criterion. Patients with RH and SI/SAP concordance differ from patients without. Implementation of a strict RH definition (both SI and SAP positive) can better distinguish RH from FH and should be used in the future.

Proximal Gastric Pressurization After Sleeve Gastrectomy Associates With Gastroesophageal Reflux

INTRODUCTION

Sleeve gastrectomy (SG) results in persistent or de novo reflux more often than Roux-en-Y gastric bypass (RYGB). We investigated pressurization patterns in the proximal stomach on high-resolution manometry (HRM) to determine associations with reflux after SG.

METHODS

Patients undergoing HRM and ambulatory pH-impedance monitoring after SG and RYGB over a 2-year period (2019-2020) were included. For each included patient, 2 symptomatic control patients with HRM and pH-impedance monitoring for reflux symptoms were identified within the same time frame; 15 asymptomatic healthy controls with HRM studies were also studied. Concurrent myotomy and preoperative diagnosis of obstructive motor disorders were exclusions. Conventional HRM metrics, esophagogastric junction (EGJ) pressures, contractile integral (EGJ-CI), acid exposure time (AET), and reflux episode numbers were extracted. Intragastric pressure was sampled at baseline, during swallows, and with straight leg raise maneuver, and compared with intraesophageal pressure and reflux burden.

RESULTS

Patient cohorts included 36 SG patients, 23 RYGB patients, 113 symptomatic controls, and 15 asymptomatic controls. While both SG and RYGB patients pressurized the stomach during swallows and straight leg raise, SG patients had higher AET (median 6.0% vs 0.2%), reflux episode numbers (median 63.0 vs 37.5), and baseline intragastric pressure (median 17.3 mm Hg vs 13.1 mm Hg) ( P < 0.001). SG patients also had lower trans-EGJ pressure gradients when reflux episodes were >80 or AET was >6.0% ( P = 0.018 and 0.08, respectively, compared with no pathologic reflux). On multivariable analysis, SG status and low EGJ-CI independently associated with AET and reflux episode numbers ( P ≤ 0.04).

DISCUSSION

Impaired EGJ barrier function and proximal gastric pressurization after SG are associated with gastroesophageal reflux, especially during strain maneuvers.

Study of gastroesophageal reflux. Interpretation of functional tests in the obese patient

Overweight and obesity are a public health problem and in 1997 obesity was recognized as a global epidemic by the World Health Organization (WHO). Overweight and obesity affect almost 60% of adults and one in three children in Europe according to the most recent WHO report. Objectively, gastroesophageal reflux disease (GERD) is defined as the presence of characteristic esophageal mucosal damage assessed by endoscopy and/or the demonstra-tion of pathological acid exposure by reflux monitoring studies. The prevalence of GERD is increased in obese patients In overweight and obese patients, the clinical symptoms of GERD are especially present in the supine position and this correlates with more frequent episodes of nocturnal reflux in the 24-h pH monitoring, there is also an increase in the number of refluxes with content acid. In the population with symptoms, digestive endoscopy detects data of erosive esophagitis in 50% of patients, while 24-h pH-impedanciometry diagnoses 92% of patients with non-erosive reflux disease (NERD) The presence of persistent GERD in the mucosa affects esophageal motility and patients may develop ineffective esophageal motility-type disorders, so we will review the interpre-tation of the functional tests that determine motility, which is esophageal manometry, and those that determine reflux gastroesophageal, acid and non-acid, which is the pH measure-ment with or without 24-h impedanciometry.

Clinical relevance of salivary pepsin detection in diagnosing gastroesophageal reflux disease subtypes

Background

Gastroesophageal reflux disease (GERD) is heterogeneous with a varied symptom spectrum and reflux profiles. Its definite diagnosis often requires invasive tools including endoscopy or reflux monitoring. The aim of this study was to investigate the clinical relevance of salivary pepsin detection as a non-invasive screening tool to diagnose GERD of different subtypes.

Methods

A total of 77 patients with suspected GERD symptoms and 12 asymptomatic controls were analysed. All participants performed symptom evaluation, upper endoscopy, esophageal manometry, and 24-hour multichannel intraluminal impedance-dual pH probe monitoring. Saliva was self-collected across three different time points: at early fasting, postprandially, and at symptom occurrence. Salivary pepsin levels were measured via Peptest. The optimal threshold of salivary pepsin for diagnosing distal or proximal reflux was determined according to a receiver-operating characteristic curve.

Results

The average salivary pepsin concentration of suspected GERD patients was significantly higher than that of controls (100.63 [68.46, 141.38] vs 67.90 [31.60, 115.06] ng/mL, P = 0.044), although no difference was found among patients with different symptom spectrums. The distal reflux group had a higher average pepsin concentration than non-reflux patients (170.54 [106.31, 262.76] vs 91.13 [63.35, 127.63] ng/mL, P = 0.043), while no difference was observed between the distal reflux group and the proximal reflux group. The optimal cut-off value of salivary pepsin concentration for diagnosing pathological distal reflux was 157.10 ng/mL, which was higher than that for diagnosing pathological proximal reflux (122.65 ng/mL). The salivary pepsin concentration was significantly correlated with distal and proximal reflux parameters.

Conclusions

Salivary pepsin measurement can help in identifying true GERD with pathological distal reflux or proximal reflux, regardless of different symptom spectrums. A higher threshold should be applied for diagnosing distal reflux than for proximal reflux.

Lemborexant Attenuates Regurgitation without Worsening Objective Parameters on Reflux Monitoring in Patients with Gastroesophageal Reflux Disease and Insomnia: A Single-Arm Proof-of-Concept Study

INTRODUCTION

Esophageal hypersensitivity is associated with gastroesophageal reflux disease (GERD). Since sleep disturbance causes esophageal hypersensitivity, hypnotics may ameliorate GERD. However, zolpidem prolongs esophageal acid clearance. Lemborexant is a new hypnotic with higher efficacy and fewer adverse events than zolpidem. Therefore, the present study investigated the effects of lemborexant on GERD.

METHODS

Patients with heartburn and/or regurgitation and insomnia who did not take acid suppressants or hypnotics in the last month were recruited. Symptom assessments using GerdQ and reflux monitoring were performed before and after a 28-day treatment with 5 mg lemborexant at bedtime. The primary outcome was a change in the total GerdQ score, excluding the score for insomnia. Secondary outcomes were changes in each GerdQ score and the following parameters on reflux monitoring: the acid exposure time (AET), number of reflux events (RE), acid clearance time (ACT), and post-reflux swallow-induced peristaltic wave (PSPW) index.

RESULTS

Sixteen patients (age 45.0 [33.3-56.0], 11 females [68.8%]) completed the intervention (1 patient did not tolerate the second reflux monitoring). The total GerdQ score, excluding the score for insomnia, did not significantly change (8.0 [6.0-9.0] before vs. 7.0 [6.3-9.0] after p = 0.16). GerdQ showed the significant attenuation of regurgitation (2.0 [2.0-3.0] vs. 1.0 [0-2.8] p = 0.0054) but not heartburn (2.5 [1.0-3.0] vs. 1.0 [0.3-2.0] p = 0.175). No significant differences were observed in AET, RE, ACT, or PSPW index before and after the intervention.

CONCLUSION

Lemborexant attenuated regurgitation without the worsening of objective reflux parameters. A randomized placebo-controlled study is warranted in the future.

Encouraging appropriate use of proton pump inhibitors: existing initiatives and proposals for the future

INTRODUCTION

Proton pump inhibitors (PPIs) have revolutionized the management of acid-related disorders, representing today the mainstay treatment of these conditions. However, despite their large range of indications and usefulness, the remarkable expansion of their use in the last two decades cannot be explained by the increasing prevalence of acid-related diseases only. An inappropriate prescription for clinical conditions in which the pathogenetic role of acid has not been documented has been described, with the natural consequence of increasing the costs and the potential risk of iatrogenic harm due to adverse events and complications recently emerged.

AREAS COVERED

In this review, we summarize current indications of PPIs administration, potential adverse events associated with their chronic utilization, and misuse of PPIs. Moreover, we describe existing and possible initiatives for improving the use of PPIs, and some proposals for the future.

EXPERT OPINION

PPI deprescribing is the preferred and most effective approach to reduce the use of PPIs, rather than adopting sharp discontinuation, probably due to fewer withdrawal symptoms. Nonetheless, large knowledge gaps still exist in clinical practice regarding the optimal approach of PPI deprescribing in various clinical scenarios. Further prospective well-designed international studies are eagerly warranted to improve our perspectives on controlling global PPI inappropriate use.

Esophageal secondary peristalsis following acid infusion and chemical clearance correlate with mucosal integrity and acid sensitivity in GERD patients

Background

Acid sensitivity can be altered in patients with gastroesophageal reflux disease (GERD). Secondary peristalsis helps clear gastro-esophageal refluxate and residual ingested food bolus.

Objectives

The aim of this study was to investigate the associations among acid sensitivity, esophageal mucosal integrity, chemical clearance, and secondary peristalsis before and after esophageal acid infusion.

Design

This was an investigator-initiated, prospective, cross-sectional study.

Methods

Adult reflux patients underwent high resolution manometry and 24 h impedance-pH monitoring off acid suppression to identify GERD phenotypes, including non-erosive reflux disease (NERD), reflux hypersensitivity (RH), and functional heartburn (FH). Secondary peristalsis was assessed using five rapid 20 mL air injections into the esophagus before and after infusion of hydrochloric acid (0.1 N) into the mid-esophagus. Conventional acid infusion parameters recorded included lag time, intensity rating, and sensitivity score. Chemical clearance was evaluated using the post-reflux swallow-induced peristaltic wave (PSPW), and mucosal integrity was assessed by the mean nocturnal baseline impedance (MNBI) derived from impedance-pH monitoring.

Results

A total of 88 patients (age 21-64 years, 62.5% women) completed the study including 12 patients with NERD, 45 with RH, and 31 with FH. There was no significant difference in acid infusion parameters between patients with NERD, RH, and FH. Upon acid infusion, patients who exhibited successful secondary peristalsis had longer lag time, higher MNBI, and shorter bolus contact time than those without secondary peristalsis. Meanwhile, patients with intact PSPW demonstrated significantly higher intensity ratings in response to acid perfusion and higher MNBI than those with impaired PSPW. The lag time correlated positively with MNBI (r = 0.285; p = 0.007).

Conclusion

In conclusion, the protective effect of esophageal secondary peristalsis and chemical clearance on esophageal mucosal integrity was demonstrated. Concerning acid sensitivity, longer lag time in patients with intact secondary peristalsis may be attributed to better esophageal mucosal integrity, while stronger intensity ratings may have a greater tendency to induce PSPW and protect esophageal mucosal integrity.

Relevance of Excessive Air Swallowing in GERD Patients With Concomitant Functional Dyspepsia and Poor Response to PPI Therapy

GOALS

The present study was aimed at evaluating the possible role of air swallowing in the association between gastroesophageal reflux disease (GERD) symptoms and concomitant functional dyspepsia (FD) and their role in GERD symptom persistence despite proton pump inhibitor (PPI) therapy.

BACKGROUND

It has been shown that individuals with excessive air swallowing experience FD. It has been also demonstrated that a consistent group of GERD patients not responding to PPI therapy swallow more air during mealtime and also have more mixed refluxes.

MATERIALS AND METHODS

Multichannel intraluminal impedance-pH tracings from consecutive patients were retrospectively evaluated. A validated structured questionnaire was used to evaluate GERD and concomitant FD symptoms. All patients were treated, within the previous year, with at least 8 weeks of standard-dose PPI therapy.

RESULTS

A total of 35 patients with conclusive GERD, 35 patients with reflux hypersensitivity, and 35 with functional heartburn were studied. A direct relationship was observed between the number of air swallows and of mixed refluxes ( R =0.64). At receiver operating characteristic curve analysis, air swallows and mixed refluxes were significantly associated to the presence of FD and PPI refractoriness. An air swallow cutoff of 107 episodes/24 hours was identified to discriminate patients with and without FD (sensitivity: 87%, specificity: 82.8%). A mixed reflux cutoff of 34 episodes/24 hours was identified to discriminate PPI responders from nonresponders (sensitivity: 84.8%, specificity: 69%). At multivariate analysis, an abnormal number of air swallows and of mixed refluxes were significantly associated to FD and PPI refractoriness.

CONCLUSION

Our study highlights the relevant role of excessive air swallowing in eliciting both dyspepsia and refractoriness of typical GERD symptoms to PPI therapy.

Esophagogastric junction contractile integral (EGJ-CI) complements reflux disease severity and provides insight into the pathophysiology of reflux disease

BACKGROUND

Esophagogastric junction contractile integral (EGJ-CI) has not come into routine use due to methodological discrepancies and its unclear clinical utility. We aimed to determine which method of calculating EGJ-CI was best at discriminating between common reflux disease states.

METHODS

High-resolution manometry (HRM) and pH-Impedance measurements were acquired for 100 patients; 25 Barrett's esophagus (>3 cm/acid exposure time (AET) > 6), 25 endoscopy-negative reflux disease (ENRD; AET >6), 25 borderline reflux (AET 4-6), 25 functional heartburn (FH; AET <4), constituting the developmental cohort. EGJ-CI was calculated at 20 mmHg, 2 mmHg, and 0 mmHg isobaric contour. Empirical associations, univariable, multivariable and ROC analyses were performed between EGJ-CI and manometric/pH-impedance metrics. A validation cohort (n = 25) was used to test the new EGJ-CI cutoff.

KEY RESULTS

Significant correlations with AET were observed when EGJ-CI was calculated with an isobaric threshold of 20 mmHg (p < 0.001). Significant differences in EGJ-CI were observed between patients with FH and Barrett's esophagus (p = 0.004) and with ENRD (p = 0.01); however, LES basal pressure was unable to differentiate between these disease states (p = 0.09, p = 0.25, respectively). ROC analysis on the developmental cohort found that EGJ-CI 21.2 mmHg.cm demonstrated sensitivity 72% and specificity 72% between patients with reflux (Barrett's esophagus/ENRD) and FH. In the validation cohort, 92.8% with a low EGJ-CI had good/moderate improvement in symptoms following therapy compared to 54.5% with raised EGJ-CI (p = 0.026).

CONCLUSIONS AND INFERENCES

This study re-affirms EGJ-CI as a reliable discriminator between reflux disease (Barrett's esophagus/ENRD) and FH. In borderline reflux patients, patients with a lower EGJ-CI score (<21.2 mmHg) appear to respond better to anti-reflux therapies compared to those with a higher value.

Esophageal chemical clearance and mucosa integrity values in refractory gastroesophageal reflux disease patients with different esophageal dynamics

OBJECTIVES

Esophageal post-reflux swallow-induced peristaltic wave index (PSPWI) and mean nocturnal baseline impedance (MNBI), novel impedance-based markers of reflux burden, are associated with esophageal dynamics. We aim to investigate the characteristics of PSPWI and MNBI in Chinese refractory gastroesophageal reflux disease (RGERD) patients with different esophageal dynamic changes.

MATERIALS AND METHODS

201 RGERD and 76 functional heartburn patients, undergone off-PPI endoscopy, esophageal manometry and impedance-pH monitoring, were included. Comparisons of conventional and novel impedance-pH metrics were made among different esophageal dynamics groups. Receiver operating-characteristic analyses were utilized to evaluate the diagnostic efficacy of PSPWI and MNBI in differentiating abnormal esophageal dynamics. Correlations were used to investigate their associated factors.

RESULTS

PSPWI and MNBI of RGERD with esophagogastric junction (EGJ) injury and esophageal dysmotility were lower than EGJ injury alone or normal dynamics (p < 0.05 for both comparisons). PSPWI with esophageal peristalsis abnormality was lower than EGJ injury (p = 0.049), while MNBI showed no statistical difference. PSPWI, MNBI and their combination have auxiliary diagnostic values for esophageal peristalsis [area under the curves (AUCs): 0.683, 0.656, 0.708)] while only their combination for EGJ injury (AUC: 0.610). And they positively correlated with esophageal motility while negatively correlated with ineffective swallows and acid reflux events.

CONCLUSIONS

PSPWI and MNBI, indicating impairment of esophageal chemical clearance and mucosa integrity, were lower in RGERD patients with multiple esophageal dynamic injuries than single injuries or normal dynamics. Moreover, they provided useful contributing information for potential dynamic injuries if manometry has already been found normal or marginal.

Application of Artificial Intelligence in Measuring Novel pH-Impedance Metrics for Optimal Diagnosis of GERD

Novel metrics extracted from pH-impedance monitoring can augment the diagnosis of gastroesophageal reflux disease (GERD). Artificial intelligence (AI) is being widely used to improve the diagnostic capabilities of various diseases. In this review, we update the current literature regarding applications of artificial intelligence in measuring novel pH-impedance metrics. AI demonstrates high performance in the measurement of impedance metrics, including numbers of reflux episodes and post-reflux swallow-induced peristaltic wave index and, furthermore, extracts baseline impedance from the entire pH-impedance study. AI is expected to play a reliable role in facilitating measuring novel impedance metrics in patients with GERD in the near future.

Artificial intelligence facilitates measuring reflux episodes and postreflux swallow-induced peristaltic wave index from impedance-pH studies in patients with reflux disease

BACKGROUND/AIM

Reflux episodes and postreflux swallow-induced peristaltic wave (PSPW) index are useful impedance parameters that can augment the diagnosis of gastroesophageal reflux disease (GERD). However, manual analysis of pH-impedance tracings is time consuming, resulting in limited use of these novel impedance metrics. This study aims to evaluate whether a supervised learning artificial intelligence (AI) model is useful to identify reflux episodes and PSPW index.

METHODS

Consecutive patients underwent 24-h impedance-pH monitoring were enrolled for analysis. Multiple AI and machine learning with a deep residual net model for image recognition were explored based on manual interpretation of reflux episodes and PSPW according to criteria from the Wingate Consensus. Intraclass correlation coefficients (ICCs) were used to measure the strength of inter-rater agreement of data between manual and AI interpretations.

RESULTS

We analyzed 106 eligible patients with 7939 impedance events, of whom 38 patients with pathological acid exposure time (AET) and 68 patients with physiological AET. On the manual interpretation, patients with pathological AET had more reflux episodes and lower PSPW index than those with physiological AET. Overall accuracy of AI identification for reflux episodes and PSPW achieved 87% and 82%, respectively. Inter-rater agreements between AI and manual interpretations achieved excellent for individual numbers of reflux episodes and PSPW index (ICC = 0.965 and ICC = 0.921).

CONCLUSIONS

AI has the potential to accurately and efficiently measure impedance metrics including reflux episodes and PSPW index. AI can be a reliable adjunct for measuring novel impedance metrics for GERD in the near future.

On-therapy impedance-pH monitoring can efficiently characterize PPI-refractory GERD and support treatment escalation

BACKGROUND

On-therapy impedance-pH monitoring is recommended in patients with documented GERD and PPI-refractory heartburn in order to establish whether the unremitting symptom is reflux-related or not.

AIMS

To define on-PPI cut-offs of impedance-pH metrics allowing proper interpretation of on-therapy impedance-pH monitoring.

METHODS

Blinded expert review of impedance-pH tracings performed during double-dosage PPI, prospectively collected from 150 GERD patients with PPI-refractory heartburn and 45 GERD patients with PPI-responsive heartburn but persisting extra-esophageal symptoms. Acid exposure time (AET), number of total refluxes (TRs), post-reflux swallow-induced peristaltic wave (PSPW) index, and mean nocturnal baseline impedance (MNBI) were assessed. On-PPI cut-offs were defined and evaluated with ROC analysis and the area under curve (AUC).

RESULTS

All the four impedance-pH metrics significantly differed between PPI-refractory and PPI-responsive heartburn cases. At ROC analysis, AUC was 0.73 for AET, 0.75 for TRs, 0.81 for PSPW index, and 0.71 for MNBI; best cut-offs were ≥1.7% for AET, ≥45 for TRs, ≤36% for PSPW index, and ≤ 1847 Ω for MNBI; AUC of such cut-offs was 0.66, 0.71, 0.73, and 0.68, respectively. Analysis of PSPW index and MNBI added to assessment of AET and TRs significantly increased the yield of on-therapy impedance-pH monitoring in the PPI-refractory cohort (97% vs. 83%, p < 0.0001). Notably, suboptimal acid suppression as shown by AET ≥1.7% was detected in 43% of 150 PPI-refractory cases.

CONCLUSIONS

We have defined on-PPI cut-offs of impedance-pH metrics by which comprehensive assessment of impedance-pH tracings, including analysis of PSPW index and MNBI can efficiently characterize PPI-refractory GERD and support treatment escalation.

Esophageal hypervigilance and visceral anxiety contribute to symptom severity of laryngopharyngeal reflux

OBJECTIVES

Laryngopharyngeal reflux (LPR) is a clinical conundrum without a diagnostic gold standard. The esophageal hypervigilance and anxiety scale (EHAS) is a questionnaire designed for cognitive-affective evaluation of visceral sensitivity. We hypothesized that esophageal hypervigilance and symptom-specific anxiety have an etiopathological role in generation of LPR symptoms, especially when gastroesophageal reflux disease (GERD) cannot explain these symptoms.

METHODS

Consecutive patients with LPR and/or GERD symptoms lasting >3 months were prospectively enrolled and characterized using the reflux symptom index (RSI), GERD questionnaire (GERDQ), and EHAS. Eligible patients with negative endoscopy underwent 24-hour impedance-pH monitoring off acid suppression for phenotyping GERD, and assessment of reflux burden, using conventional metrics [acid exposure time (AET) and number of reflux episodes] as well as novel metrics [mean nocturnal baseline impedance (MNBI) and post-reflux swallow induced peristaltic wave (PSPW) index].

RESULTS

Of 269 enrolled patients (mean age 47.1 years, 21-65 years, 60.6% female), 90 patients with concomitant GERD and LPR symptoms, 32 patients with dominant LPR symptoms, 102 patients with dominant GERD symptoms, and 45 controls. Patients with concomitant GERD and LPR symptoms had higher EHAS than those with dominant GERD symptoms and controls. ( P ≤ 0.001); patients with dominant LPR symptoms had higher EHAS than controls. ( P = 0.007). On Pearson's correlation, EHAS positively correlated with RSI.

CONCLUSIONS

Esophageal hypervigilance symptom-specific anxiety may be more important than reflux burden in LPR symptom perception.

Effect of hiatus hernia on reflux patterns and mucosal integrity in patients with non-erosive reflux disease

BACKGROUND

Hiatus hernia (HH) contributes to development of gastroesophageal reflux disease, Barrett's esophagus and esophageal adenocarcinoma. This study was aimed to investigate the influence of HH on reflux patterns and distal esophageal mucosal integrity in non-erosive reflux disease (NERD).

METHODS

We retrospectively analyzed PPI-refractory NERD patients referred to three tertiary referral centers who underwent high-resolution manometry and off-PPI 24-h impedance-pH monitoring (with or without bile spectrophotometry). Patients with HH ≥2 cm (HH group, n = 42) or no HH (non-HH group, n = 40) with similar esophageal acid exposure time (AET 6%-12%) were included.

KEY RESULTS

Age, gender, BMI, esophageal motility, AET, and esophageal clearance were similar between the two groups. The HH group had higher numbers of total reflux episodes (p = 0.015) with similar proportion of acid/non-acid reflux compared with the non-HH group. Mean nocturnal baseline impedance (MNBI) in the distal esophagus was significantly lower in the HH group than the non-HH group at both 5 cm (p = 0.002) and 3 cm (p = 0.015) above the lower esophageal sphincter. Multivariable regression analysis showed that HH, less non-acid reflux and lower post-reflux swallow-induced peristaltic wave index (PSPWI) were independently associated with lower MNBI. Among 31 patients tested with bile spectrophotometry, the HH group had significantly longer bile exposure time than the non-HH group (p = 0.011), and bile reflux inversely and significantly correlated with MNBI (rho = -0.75, p &lt; 0.001).

CONCLUSIONS AND INFERENCES

Hiatus hernia, less non-acid reflux and lower PSPWI were associated with lower MNBI. HH impairs distal esophageal mucosal integrity, the mechanism of which we speculate to be through excessive bile reflux.

The Lyon Consensus Criteria for GERD Diagnosis in a Greek Population: The Clinical Impact and Changes in GERD Diagnosis in a Real-World, Retrospective Study

(1) Introduction/aim: Gastroesophageal reflux disease (GERD) affects 8−33% globally. The gold standard examination technique in diagnosing GERD is 24 h pHmetry ± impedance. Recently, new diagnostic criteria were introduced by the Lyon Consensus for GERD diagnosis. Our aim was to investigate the diagnostic yield of pHmetry + impedance using the Lyon Consensus criteria in a real-world study. (2) Patients and methods: Our study included 249 consecutive patients (M/F: 120/129, mean age 50 ± 15 years) who underwent 24 h pH+ impedance monitoring in our department, during a 5-year period. Epidemiological, endoscopic, clinical, and 24 h pH+ impedance data were retrospectively collected. (3) Results: Typical GERD symptoms were reported by 140/249 (56.2%) patients, whereas 99/249 (39.6%) patients reported various extraesophageal symptoms. Endoscopic findings supportive of GERD based on the Lyon Consensus were present in 42/185 (22.7%). An AET value of >6% was observed in 60/249 (24.1%). GERD diagnosis according to the Lyon Consensus criteria was set in 63/249 (25.3%) patients; a rate significantly lower than that observed by implementing the older criteria (32.1%), p < 0.001. In the multivariate analysis, the existence of endoscopic findings supportive of GERD diagnosis as defined by the Lyon Consensus (p = 0.036), a De Meester score of over 14.7, and the presence of typical GERD symptoms were correlated to GERD diagnosis (p < 0.001, respectively) using the criteria defined for pH−impedance monitoring. (4) Conclusions: Changes in the diagnostic criteria concerning the 24 h pH−impedance monitoring of GERD based on the Lyon Consensus led to a conclusive GERD diagnosis in approximately 25% of the patients. This rate of GERD diagnosis is reduced in comparison to the one confirmed with the use of previously established criteria.

Diagnostic value of reflux episodes in gastroesophageal reflux-induced chronic cough: a novel predictive indicator

Background

Multichannel intraluminal impedance and pH-monitoring (MII-pH) is an essential testing modality for gastroesophageal reflux-induced chronic cough (GERC), while the existing diagnostic criteria still have some inherent defects. This study aimed to explore the diagnostic value of a direct and objective index, reflux episodes, and related parameters in MII-pH in different types of GERC.

Methods

Patients with chronic cough suspected of gastroesophageal reflux disease who successfully received MII-pH were enrolled. The differences in MII-pH parameters were analyzed among patients with different etiologies and the predictive diagnostic value of reflux episodes and related parameters were analyzed in patients with GERC, acid GERC, and non-acid GERC, and compared with existing diagnostic criteria.

Results

A total of 190 patients with suspected GERC who underwent MII-pH were enrolled; 131 of these patients were finally diagnosed with GERC. When the reflux episodes were used to diagnose GERC, the area under the curve (AUC) was 0.684; when the acid reflux episodes and the ratio of acid reflux episodes were used to diagnose acid GERC, the AUCs were 0.769 and 0.854; when the non-acid reflux episodes and the ratio of non-acid reflux episodes were used to diagnose non-acid GERC, the AUCs were 0.735 and 0.705, respectively. When the non-acid reflux episodes > 58 and the proportion of non-acid reflux episodes > 68.18% were used alone or in combination to diagnose non-acid GERC, their diagnostic value was significantly better than SAP or SI (all ps < 0.05).

Conclusion

The number of reflux episodes has a good diagnostic value for GERC, especially in the diagnosis of non-acid GERC.

Applying Lyon Consensus criteria in the work-up of patients with proton pump inhibitory-refractory heartburn

BACKGROUND

A hierarchical approach for gastro-oesophageal reflux disease (GERD) diagnosis by impedance-pH monitoring was proposed by the Lyon Consensus, based on acid exposure time (AET) and supportive impedance metrics.

AIMS

To establish the clinical value of Lyon Consensus criteria in the work-up of patients with proton pump inhibitory (PPI)-refractory heartburn.

METHODS

Expert review of off-therapy impedance-pH tracings from unproven GERD patients with PPI-refractory heartburn prospectively evaluated at referral centers. Impedance metrics, namely total reflux episodes, postreflux swallow-induced peristaltic wave index, and mean nocturnal baseline impedance, were assessed. Expert review of on-therapy preoperative impedance-pH tracings from a separate cohort of surgically treated erosive/nonerosive GERD cases.

RESULTS

Off-therapy, normal, inconclusive, and abnormal AET was found in 59%, 17%, and 23% of 317 cases. Supportive evidence of GERD was provided by abnormal impedance metrics in up to 22% and 62% of cases in the normal and inconclusive AET groups, respectively. Adding the cases with inconclusive AET and abnormal impedance metrics to the abnormal AET group, a significant increase in GERD evidence was observed (from 23% to 37% of cases, p < 0.0002). At the on-therapy presurgical evaluation, abnormal/inconclusive AET and supraphysiological values of impedance metrics showed ongoing reflux in 21% and 90% of 96 cases, respectively (p < 0.00001); a relationship between on-therapy ongoing reflux and PPI-refractory heartburn was confirmed by the favorable surgical outcome at 3-year follow-up, 88% of cases being in persistent off-PPI heartburn remission.

CONCLUSIONS

Impedance-pH monitoring, off- and on-therapy, is of high clinical value in the work-up of patients with PPI-refractory heartburn.

AGA Clinical Practice Update on the Personalized Approach to the Evaluation and Management of GERD: Expert Review

BACKGROUND & AIMS

As many as one-half of all patients with suspected gastroesophageal reflux disease (GERD) do not derive benefit from acid suppression. This review outlines a personalized diagnostic and therapeutic approach to GERD symptoms.

METHODS

The Best Practice Advice statements presented here were developed from expert review of existing literature combined with extensive discussion and expert opinion to provide practical advice. Formal rating of the quality of evidence or strength of recommendations was not the intent of this clinical practice update. BEST PRACTICE ADVICE 1: Clinicians should develop a care plan for investigation of symptoms suggestive of GERD, selection of therapy (with explanation of potential risks and benefits), and long-term management, including possible de-escalation, in a shared-decision making model with the patient. BEST PRACTICE ADVICE 2: Clinicians should provide standardized educational material on GERD mechanisms, weight management, lifestyle and dietary behaviors, relaxation strategies, and awareness about the brain-gut axis relationship to patients with reflux symptoms. BEST PRACTICE ADVICE 3: Clinicians should emphasize safety of proton pump inhibitors (PPIs) for the treatment of GERD. BEST PRACTICE ADVICE 4: Clinicians should provide patients presenting with troublesome heartburn, regurgitation, and/or non-cardiac chest pain without alarm symptoms a 4- to 8-week trial of single-dose PPI therapy. With inadequate response, dosing can be increased to twice a day or switched to a more effective acid suppressive agent once a day. When there is adequate response, PPI should be tapered to the lowest effective dose. BEST PRACTICE ADVICE 5: If PPI therapy is continued in a patient with unproven GERD, clinicians should evaluate the appropriateness and dosing within 12 months after initiation, and offer endoscopy with prolonged wireless reflux monitoring off PPI therapy to establish appropriateness of long-term PPI therapy. BEST PRACTICE ADVICE 6: If troublesome heartburn, regurgitation, and/or non-cardiac chest pain do not respond adequately to a PPI trial or when alarm symptoms exist, clinicians should investigate with endoscopy and, in the absence of erosive reflux disease (Los Angeles B or greater) or long-segment (≥3 cm) Barrett's esophagus, perform prolonged wireless pH monitoring off medication (96-hour preferred if available) to confirm and phenotype GERD or to rule out GERD. BEST PRACTICE ADVICE 7: Complete endoscopic evaluation of GERD symptoms includes inspection for erosive esophagitis (graded according to the Los Angeles classification when present), diaphragmatic hiatus (Hill grade of flap valve), axial hiatus hernia length, and inspection for Barrett's esophagus (graded according to the Prague classification and biopsied when present). BEST PRACTICE ADVICE 8: Clinicians should perform upfront objective reflux testing off medication (rather than an empiric PPI trial) in patients with isolated extra-esophageal symptoms and suspicion for reflux etiology. BEST PRACTICE ADVICE 9: In symptomatic patients with proven GERD, clinicians should consider ambulatory 24-hour pH-impedance monitoring on PPI as an option to determine the mechanism of persisting esophageal symptoms despite therapy (if adequate expertise exists for interpretation). BEST PRACTICE ADVICE 10: Clinicians should personalize adjunctive pharmacotherapy to the GERD phenotype, in contrast to empiric use of these agents. Adjunctive agents include alginate antacids for breakthrough symptoms, nighttime H2 receptor antagonists for nocturnal symptoms, baclofen for regurgitation or belch predominant symptoms, and prokinetics for coexistent gastroparesis. BEST PRACTICE ADVICE 11: Clinicians should provide pharmacologic neuromodulation, and/or referral to a behavioral therapist for hypnotherapy, cognitive behavioral therapy, diaphragmatic breathing, and relaxation strategies in patients with functional heartburn or reflux disease associated with esophageal hypervigilance reflux hypersensitivity and/or behavioral disorders. BEST PRACTICE ADVICE 12: In patients with proven GERD, laparoscopic fundoplication and magnetic sphincter augmentation are effective surgical options, and transoral incisionless fundoplication is an effective endoscopic option in carefully selected patients. BEST PRACTICE ADVICE 13: In patients with proven GERD, Roux-en-Y gastric bypass is an effective primary anti-reflux intervention in obese patients, and a salvage option in non-obese patients, whereas sleeve gastrectomy has potential to worsen GERD. BEST PRACTICE ADVICE 14: Candidacy for invasive anti-reflux procedures includes confirmatory evidence of pathologic GERD, exclusion of achalasia, and assessment of esophageal peristaltic function.

Editorial: Lyon consensus metrics-towards personalised diagnosis of non-erosive reflux disease

This article is linked to Frazzoni et al papers. To view these articles, visit https://doi.org/10.1111/apt.16838 and https://doi.org/10.1111/apt.16911

Editorial: Lyon consensus metrics-towards personalised diagnosis of non-erosive reflux disease: Authors' reply

This article is linked to Frazzoni et al papers. To view these articles, visit https://doi.org/10.1111/apt.16838 and https://doi.org/10.1111/apt.16899

Reflux characteristics triggering post-reflux swallow-induced peristaltic wave (PSPW) in patients with GERD symptoms

BACKGROUND

Esophageal chemical clearance has been evaluated with the post-reflux swallow-induced peristaltic wave (PSPW) index. The factors triggering PSPW in Gastro-esophageal reflux disease (GERD) have not yet been investigated. This multicenter study was aimed at evaluating the characteristics of reflux episodes associated with PSPW occurrence in patients with typical GERD symptoms.

METHODS

Impedance-pH tracings from patients with typical reflux symptoms were analyzed. Sixteen healthy subjects were included for comparison. Multivariate analysis was performed to determine predictors of PSPW events.

KEY RESULTS

Impedance-pH tracings from 60 patients and 16 healthy subjects were evaluated. A total of 3454 refluxes were recorded. In patients, comparing reflux episodes followed with those not followed by a PSPW, significantly higher proportions of acid (79% vs. 74%, p: 0.02), mixed (47% vs. 32%, p: 0.0001) and proximal refluxes (34% vs. 20%, p: 0.0001) were observed. A multivariate analysis, acid (OR: 1.3, 95% CI: 1.05-1.6), mixed (OR: 2, 95% CI: 1.6-2.3), and proximal (OR: 2.1, 95% CI: 1.7-2.5) refluxes were independently associated with PSPWs. Reflux episodes followed by a PSPW were characterized by a significantly higher bolus clearing time [(mean ± SD) 41 s ± 6 s vs. 30 s ± 5 s, p < 0.05] whereas nadir pH value of reflux events preceding PSPWs was tangentially but not significantly lower [(mean ± SD) 2.61 ± 1.22 vs. 2.74 ± 1.26, p: 0.057].

CONCLUSIONS AND INFERENCES

Acid, mixed and proximal refluxes, and their duration are key factors in eliciting PSPWs. PSPW represents a response to reflux directly related to the potential harmfulness of reflux contents.

Episode-level reflux characteristics: How experienced reviewers differentiate true reflux from artifact on pH-impedance studies

BACKGROUND

Accurate reflux episode identification is crucial for pH-impedance interpretation. Individual reflux episode characteristics associated with inter-reviewer concordance are incompletely understood.

METHODS

Ambulatory pH-impedance studies from 19 GERD patients (median age 52 years, 78.9% F) were analyzed by 5 reviewers. Metadata from pH-impedance studies were exported to a dedicated software tool designed to compare episode-by-episode identification between reviewers within a ±7.5 s window. Patient position, acidic vs. nonacidic episodes, acid clearance time (ACT), bolus clearance time (BCT), and proximal extent of reflux episodes were compared between episodes identified by all reviewers against those identified by automated analysis, and one to four reviewers, respectively.

RESULTS

Automated analysis identified 1644 episodes (median 78 episodes per patient, IQR 64-108), of which 84.9% were identified by ≥3 reviewers and 57.1% by all reviewers; 339 unique episodes were added by at least 1 reviewer. Characteristics defining 5 reviewer concordance included acid reflux episodes (88.9%), upright episodes (88.4%), high proximal extent (median 17 cm, IQR 15-17 cm), and longer acid clearance times (67.0 s, IQR 29.0-146.0 s) (P < 0.001 compared to 1-4 reviewer concordance for each). In contrast, 1 reviewer-identified episodes were 69.8% acidic, 76.9% upright, and limited to the distal esophagus. Using 5-reviewer concordance, designation of GERD evidence changed from automated analysis in 16%-19% of patients.

CONCLUSIONS

Acidic episodes with high proximal extent in the upright position and longer acid clearance times on pH-impedance studies have the highest concordance for identification by expert reviewers. Reflux episode identification may be influenced by reviewer opinion despite availability of established criteria.

Clinical use of mean nocturnal baseline impedance and post-reflux swallow-induced peristaltic wave index for the diagnosis of gastro-esophageal reflux disease

The clinical diagnosis of gastro-esophageal reflux disease (GERD) is based on the presence of typical esophageal troublesome symptoms. In clinical practice, heartburn relief following a proton pump inhibitor (PPI) trial or endoscopy can confirm a diagnosis of GERD. In cases of diagnostic uncertainty or before anti-reflux interventions, combined impedance-pH monitoring (MII-pH) provides a comprehensive assessment of both physical and chemical properties of the refluxate, allowing to achieve a conclusive diagnosis of GERD. Recently, the Lyon Consensus proposed the use of mean nocturnal baseline impedance (MNBI) and post-reflux swallow-induced peristaltic wave index (PSPW-I) as novel MII-pH metrics to support the diagnosis of GERD. The calculation of MNBI and PSPW-I currently needs to be performed manually, but artificial intelligence systems for the automated analysis of MII-pH tracings are being developed. Several studies demonstrated the increased diagnostic yield MNBI and PSPW-I for the categorization of patients with GERD at both on- and off-PPI MII-pH monitoring. Accordingly, we performed a narrative review on the clinical use and diagnostic yield of MNBI and PSPW-I when the diagnosis of GERD is uncertain. Based on currently available evidence, we strongly support the evaluation of PSPW-I and MNBI as part of the standard assessment of MII-pH tracings for the evaluation of GERD, especially in patients with endoscopy-negative heartburn.

Novel impedance-pH parameters are associated with proton pump inhibitor response in patients with inconclusive diagnosis of gastro-oesophageal reflux disease according to Lyon Consensus

BACKGROUND

The Lyon Consensus delineates impedance-pH parameters that can demonstrate/exclude gastro-oesophageal reflux disease (GERD). In patients with acid exposure time between 4% and 6%, GERD diagnosis has been considered inconclusive. In these cases, mean nocturnal baseline impedance (MNBI) and post-reflux swallow-induced peristaltic wave (PSPW) index may either confirm or refute GERD diagnosis and represent predictors of proton pump inhibitor (PPI) response.

AIMS

To investigate the diagnostic yield of MNBI and PSPW index and their relationship with PPI response in patients with inconclusive GERD diagnosis.

METHODS

Review of impedance-pH tracings from PPI responder/non-responder patients with typical reflux symptoms. Multivariate regression analysis was performed to determine the association of MNBI and PSPW index to PPI response.

RESULTS

Among 233 patients evaluated, 145/233 (62.2%) were PPI responders; 62 had conclusive and 65 inconclusive evidence of GERD, 46 had reflux hypersensitivity, and 60 functional heartburn. Abnormal MNBI and PSPW index were significantly more frequent in inconclusive GERD as compared to the functional heartburn group (P < 0.001). Within the inconclusive GERD group, 35/65 (54%) patients were PPI responders and displayed a significantly higher proportion of cases with pathological MNBI or PSPW index as compared to non-responders (32/35 [91.4%] and 30/35 [85.7%] vs 9/30 [30%] and 7/30 [23.3%], P < 0.001). By multivariate analysis, pathological PSPW index and/or MNBI values were significantly associated with PPI response in all groups.

CONCLUSIONS

The present study highlights the value of MNBI and PSPW index as adjunctive metrics in characterising patients with inconclusive evidence of GERD and identifying those responsive to PPI treatment.

Artificial intelligence automates and augments baseline impedance measurements from pH-impedance studies in gastroesophageal reflux disease

BACKGROUND

Artificial intelligence (AI) has potential to streamline interpretation of pH-impedance studies. In this exploratory observational cohort study, we determined feasibility of automated AI extraction of baseline impedance (AIBI) and evaluated clinical value of novel AI metrics.

METHODS

pH-impedance data from a convenience sample of symptomatic patients studied off (n = 117, 53.1 ± 1.2 years, 66% F) and on (n = 93, 53.8 ± 1.3 years, 74% F) anti-secretory therapy and from asymptomatic volunteers (n = 115, 29.3 ± 0.8 years, 47% F) were uploaded into dedicated prototypical AI software designed to automatically extract AIBI. Acid exposure time (AET) and manually extracted mean nocturnal baseline impedance (MNBI) were compared to corresponding total, upright, and recumbent AIBI and upright:recumbent AIBI ratio. AI metrics were compared to AET and MNBI in predicting  ≥ 50% symptom improvement in GERD patients.

RESULTS

Recumbent, but not upright AIBI, correlated with MNBI. Upright:recumbent AIBI ratio was higher when AET  > 6% (median 1.18, IQR 1.0-1.5), compared to  < 4% (0.95, IQR 0.84-1.1), 4-6% (0.89, IQR 0.72-0.98), and controls (0.93, IQR 0.80-1.09, p ≤ 0.04). While MNBI, total AIBI, and the AIBI ratio off PPI were significantly different between those with and without symptom improvement (p < 0.05 for each comparison), only AIBI ratio segregated management responders from other cohorts. On ROC analysis, off therapy AIBI ratio outperformed AET in predicting GERD symptom improvement when AET was  > 6% (AUC 0.766 vs. 0.606) and 4-6% (AUC 0.563 vs. 0.516) and outperformed MNBI overall (AUC 0.661 vs. 0.313).

CONCLUSIONS

BI calculation can be automated using AI. Novel AI metrics show potential in predicting GERD treatment outcome.