Normal values and regional differences in oesophageal impedance-pH metrics: a consensus analysis of impedance-pH studies from around the world

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.

Insight into global burden of gastroesophageal reflux disease: Understanding its reach and impact

The exact worldwide prevalence of gastroesophageal reflux disease (GERD) remains uncertain, despite its recognition as a common condition. This conundrum arises primarily from the lack of a standardized definition for GERD. The gold standard diagnostic tests for GERD, such as pH impedance testing and endoscopy, are cumbersome and impractical for assessing community prevalence. Consequently, most epidemiological studies rely on symptom-based screening tools. GERD symptoms can be both esophageal and extraesophageal, varying widely among individuals. This variability has led to multiple symptom-based definitions of GERD, with no consensus, resulting in prevalence estimates ranging from 5% to 25% worldwide. Most systematic reviews define GERD as experiencing heartburn and/or regurgitation at least once weekly, yielding a calculated prevalence of 13.98%. In 2017, the global age-standardized prevalence of GERD was estimated at 8819 per 100000 people (95% confidence interval: 7781-9863), a figure that has remained stable from 1990 to 2017. Prevalence increases with age, leading to more years lived with disability. GERD significantly impairs quality of life and can lead to multiple complications. Additionally, it imposes a severe economic burden, with the United States alone estimated to spend around 10 billion dollars annually on diagnosis and treatment. In summary, GERD prevalence varies greatly by region and even within different areas of the same province. Determining the exact prevalence is challenging due to inconsistent diagnostic criteria. However, it is well-documented that GERD poses a significant global burden, affecting the quality of life of individuals and creating a substantial healthcare cost.

Mean Nocturnal Baseline Impedance May Be Greater Than 2500 Ohms in Chinese Patients With GERD

BACKGROUND

According to the Lyon Consensus 2.0, mean nocturnal baseline impedance (MNBI) greater than 2500 Ω is considered evidence against gastroesophageal reflux disease (GERD). However, we have observed that a subset of GERD patients presents with MNBI exceeding 2500 Ω.

AIMS

To investigate MNBI characteristics in Chinese GERD patients, identify clinical features of those with normal MNBI, and examine factors influencing MNBI values.

METHODS

We retrospectively investigated 259 patients with typical reflux symptoms. Demographics, symptoms, proton pump inhibitor (PPI) response, esophageal motility parameters were compared between patients with different AET levels and MNBI levels.

RESULTS

Among the cohort, 38.2% had AET 4%-6%, and 37.5% had AET > 6%. Notably, 95.2% of patients with AET < 4%, 49.5% with AET 4%-6%, and 17.6% with AET > 6% had MNBI > 2500 Ω. Independent risk factors for MNBI > 2500 Ω included the number and duration of supine acid reflux and lower esophageal sphincter (LES) resting pressure. In GERD patients with heartburn, patients with MNBI ≤ 2500 Ω had higher PPI response than MNBI > 2500 Ω (81.1% vs. 55.6%, p = 0.009).

CONCLUSIONS

Approximately one-third of Chinese GERD patients have an MNBI > 2500 Ω. The thresholds of MNBI for supporting or ruling out GERD in the Chinese population should be adjusted. MNBI values are independently predicted by the severity of supine acid reflux and the LES resting pressure. GERD patients with mild supine acid reflux may still exhibit normal MNBI levels. Patients with lower MNBI values tend to show better responses to PPI therapy.

Distal contractile integral and other key predictors of mean nocturnal baseline impedance: The role of esophageal peristaltic vigor in mucosal permeability

BACKGROUND

Understanding the relationship between distal contractile integral (DCI) and mean nocturnal baseline impedance (MNBI) could shed light on new diagnostic and treatment strategies, specifically concerning nocturnal reflux. This study aimed to assess this relationship to enhance our comprehension of the interplay between esophageal contractility and mucosal permeability.

METHODS

We identified adult patients who had high resolution esophageal manometry and pH-impedance tests performed within a 30-day period between December 2018 and March 2022. A random forest model was used to identify significant predictors of MNBI, assisting with variable selection for a following regression analysis. Subsequently, both univariable and multivariable regression models were utilized to measure the association between predictors and MNBI.

KEY RESULTS

Our study included 188 patients, primarily referred for testing due to reflux. The most common motility diagnoses were normal (62%) followed by possible esophagogastric junction outflow obstruction (22%). The mean DCI was 2020 mmHg∙s∙cm and MNBI was 3.05 kΩ. The random forest model identified 12 significant predictors for MNBI, key variables being acid exposure time (AET), total proximal reflux events, intraabdominal lower esophageal sphincter length, hiatal hernia presence, and DCI. Subsequent multivariable regression analyses demonstrated log AET (β = -0.69, p = <0.001), total proximal reflux events (β = -0.16, p = 0.008), hiatal hernia presence (β = -0.82, p = 0.014), log DCI (β = 1.26, p < 0.001), and age (β = -0.13, p = 0.036) as being significantly associated with MNBI.

CONCLUSIONS AND INFERENCES

DCI is a key manometric predictor of MNBI emphasizing the role of manometry in detecting reflux risk and the need for its consideration in reflux management.

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.

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.

Utility of mean nocturnal baseline impedance and post-reflux swallow-induced peristaltic wave index in clinical pH-impedance reflux study

BACKGROUND AND AIMS

Analysis of mean nocturnal baseline impedance (MNBI) and post-reflux swallow-induced peristaltic wave index (PSPWi) have been proposed to increase the diagnostic yield of pH-impedance studies in reflux disease. However, routine use of these indices in clinical studies is yet to be established, particularly with PSPWi, which requires laborious manual analysis. Our study aimed to assess the utility of MNBI and PSPWi and their potential for future incorporation into clinical practice.

METHODS

pH-impedance recordings from consecutive patients referred to the Motility Laboratory at Royal Adelaide Hospital for evaluation of gastro-oesophageal reflux disease (GORD) were prospectively collected and manually analysed. Baseline demographic characteristics, symptoms, acid exposure time (AET), number of reflux episodes, and MNBI and PSPWi were collected.

RESULTS

Eighty-nine patients were included in the study (age 50 ± 17 years, 35 males). MNBI and PSPWi inversely correlated with AET (R = -0.678, P < 0.0001 and R = -0.460, P < 0.0001 respectively) and with reflux episodes (R = -0.391, P = 0.0002 and R = -0.305, P = 0.0037 respectively). In patients with a negative pH study, but with typical reflux symptoms, 4/30 (13%) had pathologic MNBI and PSPWi. There was a positive correlation between MNBI and PSPWi values (R = 0.525, P < 0.0001). Performing analysis of PSPWi was substantially more laborious than MNBI.

CONCLUSION

MNBI and PSPWi are both useful adjuncts in the diagnosis of reflux disease, although in our cohort MNBI showed stronger correlation with AET with less time to analyse. The role of these indices remains to be further explored, particularly in patients with inconclusive AET and in those with positive compared to negative symptom association.

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.

The Revised Reflux Symptom Index (R-RSI): Development, Internal and External Validation Study

INTRODUCTION

This study proposes a revised version of the Reflux Symptom Index (R-RSI), a seventeen-item questionnaire that was revised to increase the suspicion of laryngopharyngeal reflux disease (LPRD).

METHODS

Internal validation involved 213 participants, comprising 160 subjects without a previous LPRD diagnosis and 53 subjects with a self-reported previous diagnosis of LPRD with or without gastroesophageal reflux disease (GERD). Test-retest reliability and internal consistency were calculated. For the external validation, 56 patients (independent from the previous cohort) were enrolled to explore the R-RSI screening properties and determine a cutoff using 24-h MII-pH as the gold standard.

RESULTS

R-RSI test-retest reliability was high, both for the total score (ICC: 0.970) and for each item (ranging from 0.876 to 0.980). Cronbach's alpha was 0.910, indicating excellent internal consistency of the questionnaire. Participants with a previous self-reported diagnosis scored significantly higher (mean 24.94 ± 7.4; median 26, IQR 20-29) than those without a previous diagnosis (mean 4.66 ± 5.3; median 4, IQR 1-6) (p value <0.0001). Participants with both previous LPRD and GERD diagnoses had higher scores (27.20 ± 7.8) compared to those with only LPRD (21.77 ± 5.5) (p value = 0.003). Using 24-h MII-pH diagnosis as a gold standard, the optimal R-RSI cutoff point was determined to be 18, with a sensitivity of 84.5% and a specificity of 81.8%, positive predictive value of 95%, and negative predictive value of 60%.

CONCLUSIONS

Our results suggest that the R-RSI may be useful to suspect LPRD, with or without GERD. The R-RSI is a self-administered patient-reported outcome questionnaire that demonstrates excellent reliability and high screening properties. Employing a cutoff of ≥18 in the R-RSI can assist in diagnosing and monitoring LPRD.

Mean nocturnal baseline impedance in gastro-esophageal reflux disease diagnosis: Should we strictly follow the Lyon 2 Consensus?

Clinical practice guidelines drive clinical practice and clinicians rely to them when trying to answer their most common questions. One of the most important position papers in the field of gastro-esophageal reflux disease (GERD) is the one produced by the Lyon Consensus. Recently an updated second version has been released. Mean nocturnal baseline impedance (MNBI) was proposed by the first Consensus to act as supportive evidence for GERD diagnosis. Originally a cut-off of 2292 Ohms was proposed, a value revised in the second edition. The updated Consensus recommended that an MNBI < 1500 Ohms strongly suggests GERD while a value > 2500 Ohms can be used to refute GERD. The proposed cut-offs move in the correct direction by diminishing the original cut-off, nevertheless they arise from a study of normal subjects where cut-offs were provided by measuring the mean value ± 2SD and not in symptomatic patients. However, data exist that even symptomatic patients with inconclusive disease or reflux hypersensitivity (RH) show lower MNBI values in comparison to normal subjects or patients with functional heartburn (FH). Moreover, according to the data, MNBI, even among symptomatic patients, is affected by age and body mass index. Also, various studies have proposed different cut-offs by using receiver operating characteristic curve analysis even lower than the one proposed. Finally, no information is given for patients submitted to on-proton pump inhibitors pH-impedance studies even if new and extremely important data now exist. Therefore, even if MNBI is an extremely important tool when trying to approach patients with reflux symptoms and could distinguish conclusive GERD from RH or FH, its values should be interpreted with caution.

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.

Pathophysiology of gastro-oesophageal reflux disease: implications for diagnosis and management

Gastro-oesophageal reflux disease (GERD) is a common gastrointestinal disorder in which retrograde flow of gastric content into the oesophagus causes uncomfortable symptoms and/or complications. It has a multifactorial and partially understood pathophysiology. GERD starts in the stomach, where the refluxate material is produced. Following the trajectory of reflux, the failure of the antireflux barrier, primarily the lower oesophageal sphincter and the crural diaphragm, enables the refluxate to reach the oesophageal lumen, triggering oesophageal or extra-oesophageal symptoms. Reflux clearance mechanisms such as primary and secondary peristalsis and the arrival of bicarbonate-rich saliva are critical to prevent mucosal damage. Alterations of the oesophageal mucosal integrity, such as macroscopic oesophagitis or microscopic changes, determine the perception of symptoms. The intensity of the symptoms is affected by peripheral and central neural and psychological mechanisms. In this Review, we describe an updated understanding of the complex and multifactorial pathophysiology of GERD. It is now recognized that different GERD phenotypes have different degrees of reflux, severity of mucosal integrity damage and type, and severity of symptoms. These variations are probably due to the occurrence of a predominant pathophysiological mechanism in each patient. We also describe the main pathophysiological mechanisms of GERD and their implications for personalized diagnosis and management.

Latin American consensus on diagnosis of gastroesophageal reflux disease

BACKGROUND

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.

METHODS

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.

KEY RESULTS

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.

CONCLUSIONS

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.

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.

Association between Mean Nocturnal Baseline Impedance (MNBI) and Post-Reflux Swallow-Induced Peristaltic Wave Index (PSPW) in GERD Patients

Gastroesophageal reflux disease (GERD) is one of the most common gastrointestinal disorders in the world. Two parameters, mean nocturnal baseline impedance (MNBI) and post-reflux swallow-induced peristaltic wave index (PSPW), have been recently proposed to help differentiate GERD phenotypes. Our study aimed to assess whether there is any correlation between the two parameters, while also taking a look at their ability to distinguish between GERD phenotypes. We recruited 81 patients who were divided into 4 groups based on their GERD phenotype: erosive reflux disease (ERD), non-erosive reflux disease (NERD), reflux hypersensitivity (RH), and functional heartburn (FH). Both MNBI (AUROC 0.855) and PSPW (AUROC 0.835) had very good performances in separating ERD patients from non-ERD patients. PSPW (AUROC 0.784) was superior to MNBI (AUROC 0.703) in distinguishing NERD patients from patients with RH or FH. The PSPW index (AUROC 0.762) was more effective than MNBI (AUROC 0.668) in separating RH from FH. We found that PSPW and MNBI have a strong statistical correlation (Pearson correlation coefficient, r = 0.722, p < 0.001). Furthermore, PSPW predicted pathological MNBI (<2292 Ω) with good performance (AUROC 0.807). MNBI and PSPW are useful in distinguishing GERD phenotypes, with a strong correlation between the two parameters.

Barrier Dysfunction in Eosinophilic Esophagitis

PURPOSE OF REVIEW

Compelling evidence over the past decade supports the central role of epithelial barrier dysfunction in the pathophysiology of eosinophilic esophagitis (EoE). The purpose of this review is to summarize the genetic, environmental, and immunologic factors driving epithelial barrier dysfunction, and how this impaired barrier can further promote the inflammatory response in EoE.

RECENT FINDINGS

Common environmental exposures, such as detergents, may have a direct impact on the esophageal epithelial barrier. In addition, the effects of IL-13 on barrier dysfunction may be reduced by 17β-estradiol, Vitamin D, and the short chain fatty acids butyrate and propionate, suggesting novel therapeutic targets. There are many genetic, environmental, and immunologic factors that contribute to epithelial barrier dysfunction in EoE. This leads to further skewing of the immune response to a "Th2" phenotype, alterations in the esophageal microbiome, and penetration of relevant antigens into the esophageal mucosa, which are central to the pathophysiology of EoE.

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.

Esophageal Reflux Hypersensitivity: A Comprehensive Review

Reflux hypersensitivity (RH) is one of the phenotypes of gastroesophageal reflux disease. The latest Rome IV defines RH as a condition with typical reflux symptoms and positive reflux-symptom association despite normal acid exposure. Subsequently, the Lyon consensus proposed detailed cutoff values for the criteria on the basis of experts' consensus. Rome IV brought a clear-cut perspective into the pathophysiology of gastroesophageal reflux disease and the importance of esophageal hypersensitivity. This perspective can be supported by the fact that other functional gastrointestinal disorders such as irritable bowel syndrome and functional dyspepsia often overlap with RH. Although several possible pathophysiological mechanisms of esophageal hypersensitivity have been identified, there is still unmet medical needs in terms of treatment for this condition. This review summarizes the current knowledge regarding RH.

A perspective on the clinical relevance of weak or nonacid reflux

BACKGROUND

Advances in ambulatory esophageal reflux monitoring that incorporated impedance electrodes to pH catheters have resulted in better characterization of retrograde bolus flow in the esophagus. With pH-impedance monitoring, in addition to acid reflux episodes identified by pH drops below 4.0, weakly acid reflux (WAR, pH 4-7) and nonacid reflux (NAR, pH >7.0) are also recognized, although both may be included under the umbrella term NAR. However, despite identification of ambulatory pH-impedance monitoring, data on clinical relevance and prognostic value of NAR are limited. The Lyon Consensus, an international expert review that defines conclusive metrics for gastroesophageal reflux disease (GERD), identifies NAR as "supportive" but not conclusive for GERD.

PURPOSE

This review provides perspectives on whether NAR fulfills three criteria for clinical relevance: whether NAR sufficiently explains pathogenesis of symptoms, whether it is associated with meaningful manifestations of GERD, and whether it can predict treatment efficacy.

Revisiting the Role of Esophageal Mucosal Dilated Intercellular Spaces in the Diagnosis and Pathophysiology of Heartburn

Background/Aims

Dilated intercellular spaces (DISs) facilitate the diffusion of noxious agents into the deep layers of the esophageal epithelium. The role of DIS in heartburn pathogenesis is still controversial. Therefore, we aim to reinvestigate DIS in an extensively evaluated group of patients and healthy controls (HCs).

Methods

We classified 149 subjects into the following groups: 15 HC, 58 mild erosive reflux disease (ERD), 17 severe ERD, 25 nonerosive reflux disease (NERD), 15 reflux hypersensitivity (RH), and 19 functional heartburn (FH). A total of 100 length measurements were performed for each patient's biopsy.

Results

The overall intercellular spaces (ISs) value of gastroesophageal reflux disease (GERD) patients was higher than that of HC (P = 0.020). In phenotypes, mild ERD (vs HC [P = 0.036], NERD [P = 0.004], RH [P = 0.014]) and severe ERD (vs HC [P = 0.002], NERD [P < 0.001], RH [P = 0.001], FH [P = 0.004]) showed significantly higher IS. There was no significant difference between the HC, NERD, RH, and FH groups. The 1.12 μm DIS cutoff value had 63.5% sensitivity and 66.7% specificity in the diagnosis of GERD. There was a weak correlation (r = 0.302) between the IS value and acid exposure time, and a weak correlation (r = -0.359) between the IS value and baseline impedance. A strong correlation was shown between acid exposure time and baseline impedance (r = -0.783).

Conclusions

Since the IS length measurement had better discrimination power only in erosive groups, it is not feasible to use in daily routine to discriminate other nonerosive phenotypes and FH. The role of DIS in heartburn in nonerosive patients should be reconsidered.

Effect of aging and obesity on esophageal mucosal integrity as measured by baseline impedance

AIM

Low mean nocturnal baseline impedance (MNBI) values support gastroesophageal reflux disease (GERD) diagnosis. Recent data denote that age and obesity may affect MNBI. We aimed to evaluate diagnostic MNBI cutoffs as also the effect of aging and body mass index (BMI) on MNBI.

METHODS

In total 311 patients (M/F: 139/172, mean age: 47 ± 13) referred for typical GERD symptoms that have undertaken both high-resolution manometry (HRM) and pH-Impedance studies off PPI were evaluated. MNBI at 3, 5, and 17 cm over lower esophageal sphincter (LES) were evaluated. GERD was diagnosed if acid exposure time (AET) >6%.

RESULTS

Mean BMI was 26.6 ± 5.9 kg/cm2 . GERD was diagnosed in 39.2% and 13.5% had inconclusive GERD. MNBI was correlated to patients' age, BMI, AET, and the length of LES-CD separation and at 3 cm also to the total number of reflux and LES hypotension. In the multivariate analysis MNBI at 3 and 5 cm was independently correlated only to age, BMI, and AET. Patients with definite GERD showed lower MNBI at 3 cm compared with inconclusive GERD though both showed lower values when compared with GERD absence. At 3 cm MNBI ability for diagnosing GERD was good (0.815, p < 0.001 95% CI: 0.766-0.863) with an optimal cutoff point of 1281 Ohm.

CONCLUSION

According to our study findings age and BMI affect independently lower esophageal MNBI values in patients evaluated for GERD. MNBI significantly aids toward GERD diagnosis though in a real-life setting MNBI values much lower than the one previously proposed should be used.

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.

Positive and negative impact of anti-reflux mucosal intervention on gastroesophageal reflux disease

BACKGROUND

Anti-reflux mucosal intervention (ARMI), including anti-reflux mucosectomy (ARMS) and anti-reflux mucosal ablation (ARMA), is a promising endoscopic treatment for gastroesophageal reflux disease (GERD). Few studies reported a detailed analysis of the objective reflux parameters.

METHODS

Patients with chronic PPI-dependent GERD and receiving ARMI were prospectively enrolled. Comprehensive clinical symptom profiles, endoscopy results, and 24-h multichannel intraluminal impedance-pH (MII-pH) monitoring were collected and analyzed before and 3 months after ARMI.

RESULTS

Twenty-three patients undergoing ARMI (11 ARMS and 12 ARMA) were enrolled. The median (IQR) operative time and post-procedure stays were 50 (46-56) min and 2 (2-2) days without major complications. 73.9% of patients reported subjective global improvement. A significant decrease in the total reflux symptom index score was noted from 12 (5-19) to 8 (4-12) (P = 0.010). The esophageal acid exposure time (AET) significantly decreased from 4.6 (2.8-6.9) to 2.1 (1.1-5.6) (P = 0.013), and the number of acid refluxes and DeMeester score were significantly reduced. Three patients (13%) had increased AET (3.4% to 6.1%, 6.3% to 15.4%, and 3.2% to 5.6%); however, all reported global improvement and two patients could discontinue PPI subjectively. One patient (4.3%) had worsened erosive esophagitis and reflux symptoms. 56.5% of patients stopped PPI.

CONCLUSIONS

ARMI is generally effective and safe in PPI-dependent patients. However, possible negative effects of ARMI exist in some patients; further application of MII-pH is necessitated to evaluate the treatment response after ARMI and avoid the detrimental effect of PPI discontinuation. Graph.

Novel Impedance-pH Parameters in Pre-Bariatric Assessment of Patients: A Pilot Study

Novel impedance-pH parameters, Mean Nocturnal Baseline Impedance (MNBI) and Post-Reflux Swallow-Induced Peristaltic Wave (PSPW) index, have been proposed to improve the gastro-esophageal reflux disease (GERD) diagnostic yield. This study aims to determine the integrity of the esophageal epithelial barrier and chemical clearance using these novel parameters and to correlate them with acid exposure time (AET) and acid clearance time (ACT) in obese patients who are candidates for bariatric surgery (BS). Twenty impedance-pHmetry tracings of patients prior to BS were reviewed. Nine (45%) patients with a conclusive diagnosis of GERD had significantly higher ACT, lower MNBI in the distal esophagus and lower PSPW indexes compared to obese patients without GERD. Moreover, 100% of obese patients with GERD had a pathological ACT compared to obese patients without GERD (p = 0.003). However, the percentage of pathological MNBI and PSPW index did not differ between obese patients with and without GERD. The PSPW index and MNBI of the distal channel significantly correlated with ACT and AET. Further studies are needed to assess the role of time-consuming novel parameters in the routine evaluation of morbidly obese patients candidates for BS. The value of acid clearance time is confirmed as a relevant impedance-pH parameter in these patients.

Mean nocturnal baseline impedance and endoscopic mucosal impedance measurements in patients with eosinophilic esophagitis: a new tool for follow up and management?

Eosinophilic esophagitis (EoE) is the second most common cause of chronic esophageal inflammation after GERD, with increasing incidence and prevalence across all age groups. Since current diagnosis and follow up of EoE require endoscopy with biopsies, there is an increased interest in non or less invasive tests for its diagnosis and follow up. Baseline mucosal impedance measurement allows evaluation of mucosal barrier properties and is widely accepted as an adjunct method in GERD diagnosis. As EoE is associated with increased mucosal permeability, the use of baseline impedance to evaluate mucosal integrity has been investigated in several studies. It was found that baseline mucosal impedance, measured either during 24 h reflux monitoring or during endoscopy, was significantly lower in all parts of the esophagus in EoE patients. Impedance measurement correlated with eosinophil counts on biopsies, offering a tool to monitor treatment response. Additionally, baseline impedance patterns differed between those responding to proton pump inhibitor (PPI) treatment and those resistant to PPI, potentially allowing to tailor future treatment to the individual patient. In summary, baseline impedance measurement offers a potential tool for diagnosis and follow up in EoE. Its exact place in EoE treatment is yet to be determined and requires further future studies.

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.

Mean Nocturnal Baseline Impedance and Post-reflux Swallow-induced Peristaltic Wave Index Could Identify Gastroesophageal Reflux Disease but pH-Impedance Metrics Alone Might Not Correlate With Proton Pump Inhibitor Response in Chinese Patients With Typical Reflux Symptoms

Background/Aims

Lyon consensus differentiates acid exposure time (AET) as physiological, borderline, and pathological. Mean nocturnal baseline impedance (MNBI) and post-reflux swallow-induced peristaltic wave index (PSPWi) are believed to increase diagnostic yield of gastroesophageal reflux disease (GERD) and correlate with symptom outcome of proton pump inhibitor (PPI) treatment. We aim to explore the clinical characteristics and the correlation of pH-impedance parameters with PPI response in Chinese patients with different AET levels.

Methods

We retrospectively investigated 177 patients with typical reflux symptoms who received esophageal function tests. The demographics, GERD questionnaire scores, the proportion of esophagitis and PPI responders, and manometric and pH-impedance parameters were compared among patients with AET < 4%, 4-6%, and > 6%. In patients with AET ≥ 4%, manometric and pH-impedance parameters were compared between PPI responders and non-responders.

Results

Among 177 patients, 69 (39.0%) had AET 4-6%, and 53 (29.9%) had AET > 6%. The demographics, esophagogastric junction type, and occurrence of ineffective esophageal motility were similar between patients with AET 4-6% and > 6%, but different from AET < 4%. MNBI and PSPWi were different among different AET levels, but similar between PPI responders and non-responders in patients with AET ≥ 4%.

Conclusions

It is reasonable to set 4% as a threshold to define pathological AET in Chinese patients. MNBI and PSPWi could identify GERD patients, but may not correlate with PPI response of Chinese GERD patients.

The efficacy and safety of keverprazan, a novel potassium-competitive acid blocker, in treating erosive oesophagitis: a phase III, randomised, double-blind multicentre study

BACKGROUND

Keverprazan is a novel potassium-competitive acid blocker (P-CAB) with a strong acid-suppressive capacity that may provide clinical benefit in acid-related diseases.

AIMS

This study aimed to explore the non-inferior efficacy and safety of keverprazan to lansoprazole in treating erosive oesophagitis (EO).

METHODS

This was a phase III, randomised, double-blind multicentre study. Patients were randomised to receive keverprazan 20 mg once daily or lansoprazole 30 mg once daily for 4-8 weeks. EO healing rates and adverse events (AEs) were compared between the keverprazan group and the lansoprazole group.

RESULTS

A total of 238 patients comprised the full analysis set (FAS) while 221 patients comprised the per-protocol set (PPS). For FAS analysis, the EO healing rates at week 8 were 95.8% (114/119) and 89.9% (107/119) for keverprazan and lansoprazole respectively. For PPS analysis, the EO healing rates at week 8 were 99.1% (110/111) and 92.7% (102/110) for keverprazan and lansoprazole respectively. Non-inferiority of keverprazan compared with lansoprazole according to EO healing rates at 8 weeks was demonstrated in both FAS (difference: 5.8% [95% CI: -0.6% to 12.3%]; p = 0.081) and PPS (difference: 6.1% [95% CI: 1.1%-11.2%]; p = 0.018) analysis. Drug-related AEs were reported in 34.5% (41/119) patients of the keverprazan group and 25.2% (30/119) patients of the lansoprazole group with no significant difference (p = 0.156). No severe AE happened in the keverprazan group.

CONCLUSIONS

This study demonstrated the non-inferior efficacy of keverprazan to lansoprazole in treating EO. The incidences of drug-related AEs were comparable between keverprazan and lansoprazole.

Application of Lyon Consensus criteria for GORD diagnosis: evaluation of conventional and new impedance-pH parameters

OBJECTIVE

To validate Lyon Consensus criteria for diagnosing gastro-oesophageal reflux disease (GORD) by reflux monitoring.

DESIGN

Manual review of impedance-pH tracings from patients with proton pump inhibitor (PPI)-dependent heartburn, evaluated off PPI. Acid exposure time (AET) thresholds defined by the Lyon Consensus and impedance parameters were investigated, namely, total refluxes (TRs), postreflux swallow-induced peristaltic wave (PSPW) index and mean nocturnal baseline impedance (MNBI).

RESULTS

The study included 488 patients, 178 (36%) with normal (<4%) AET, 89 (18%) with inconclusive (4%-6%) AET and 221 (45%) with abnormal (>6%) AET, alongside with 70 healthy controls. At receiver operating characteristic analysis, area under curve was 0.89, 0.95 and 0.89 for TRs, PSPW index and MNBI, respectively, and threshold values were 40, 50% and 2000 Ω; the 4% physiological AET threshold defined by the Lyon Consensus showed 100% specificity but 63% sensitivity. The thresholds defined for impedance parameters were validated against AET by means of ordered logistic regression, being in concordance with the 4% AET threshold (OR 2.5 for TRs, 18.9 for PSPW index and 5.7 for MNBI). TRs positivity and concordant PSPW index/MNBI positivity were found in 80%-90% of patients in the abnormal AET group, in 73%-74% of cases in the inconclusive AET group and in 28%-40% of cases in the group with normal AET.

CONCLUSIONS

Our results show the overall validity of the Lyon Consensus approach to GORD diagnosis. Adding evaluation of impedance parameters, namely, TRs, PSPW index and MNBI to AET appraisal, substantially improves the diagnostic yield of reflux monitoring.

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

Complex Gastroesophageal Reflux Disease

Gastroesophageal reflux disease (GERD) is the most prevalent gastrointestinal disorder posing diagnostic and therapeutic challenges. Diagnosis should be objectively defined with endoscopy and pH testing, while novel metrics may augment diagnosis for inconclusive GERD cases, including the postreflux swallow-induced peristaltic wave index and esophageal mucosal impedance. Conditions that overlap with or mimic GERD should be considered such as achalasia, rumination, and eosinophilic esophagitis. Genetic testing for proton pump inhibitor metabolism is an option for precision therapy in complex persistent GERD. Proton pump inhibitor refractory GERD may require medical, surgical, or endoscopic therapies. The presence of GERD should be objectively evaluated in achalasia patients treated with peroral endoscopic myotomy, and further studies are needed to determine timing of this evaluation. Patients with scleroderma are at a high risk for GERD owing to abnormal esophageal motility and should be managed with aggressive medical therapy and lifestyle changes given the high prevalence of esophagitis and Barrett's esophagus in this population. Further studies are needed to understand the complex mechanisms of GERD in idiopathic pulmonary fibrosis and lung transplantation.

Gastroesophageal reflux disease: When East meets West

Gastroesophageal reflux disease (GERD) is common worldwide and poses a huge challenge to health. Consensuses and guidelines on the diagnosis and management of GERD in China and the USA have recently been updated. The divergence between these guidelines indicates the differences in the conception of this disease by experts in different countries, and is influenced by available medications and interventional procedures. Prompt endoscopy has been advocated in China due to a high prevalence of upper gastrointestinal (GI) cancer, while endoscopy has been reserved for those who are at a risk of malignancy or who are reisitant to proton pump inhibitors (PPIs) in the USA. A potassium channel acid-blocker is widely used in Asian countries and has proven efficacy. Moreover, it has been recommended, together with PPIs, as a primary therapy for GERD in China; while PPI alone is recommended as a first-line treatment in the USA. Although more prokinetics are available in China than in the USA and can alleviate GERD symptoms when combined with PPI, the choice of prokinetics is limited in the USA, leading to completely opposite attitudes to prokinetics in the two countries. Novel anti-reflux procedures have been introduced in both countries. Transoral incisionless fundoplication (TIF) is recommended as an endoscopic anti-reflux procedure, and magnetic sphincter augmentation (MSA) is recognized as equivocal to conventional laparoscopic fundoplication in the USA. However, radiofrequency ablation is more popular in China, and clinical trials on TIF and MSA are not complete, which results in diverse opinions about suitable anti-reflux procedures in China. A comparison of the guidelines may therefore shed light on the multiple dimensions of GERD and thus deepen our understanding of the disease.

Pathophysiology of Pediatric Gastroesophageal Reflux Disease: Similarities and Differences With Adults

Gastroesophageal reflux (GOR) is defined as "the passage of gastric contents into the esophagus with or without regurgitation and vomiting" and gastroesophageal reflux disease (GORD) is defined "when GOR leads to troublesome symptoms affecting the daily functioning and/or complications." This definition was first developed in 2006 by the Montreal consensus group (1) and later on adopted by pediatric gastroenterology societies such as ESPGHAN and NASPGHAN in 2009 (2). The definition of gastroesophageal reflux reveals little about its pathophysiology and is focused on symptomatology. In this way, it acts as an umbrella term for the multifactorial causes of the disease and the various phenotypes encountered; from functional heartburn to hypersensitive esophagus and nonerosive reflux disease, to erosive esophagitis and Barrett's esophagus. This article is devoted to the pathophysiology of pediatric GORD in comparison to adult GORD and is divided in 2 parts. In the first part, we will systematically describe the different mechanisms for the generation and clearance of reflux events, while on the second part we will discuss the mechanisms involved in symptoms generation. Finally, we will discuss the similarities and differences between pediatric and adult GORD.

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.

Ineffective esophageal motility in Chicago Classification version 4.0 better predicts abnormal acid exposure

BACKGROUND

The updated Chicago Classification version 4.0 (CCv4.0) establishes a more stringent criteria to diagnose ineffective esophageal motility (IEM). This study aims to investigate the clinical significance of IEM in CCv4.0 in the context of gastroesophageal reflux disease (GERD).

METHODS

A retrospective study was conducted among suspected GERD patients who had heartburn and/or regurgitation as their chief complaints and completed esophageal function tests in our center from 2017 to 2019. Patients were further grouped as "CCv3.0 IEM" and normal motility according to Chicago Classification version 3.0 (CCv3.0), and as "CCv4.0 IEM" and normal motility according to CCv4.0. The clinical characteristics, high-resolution manometry, esophageal reflux monitoring, and proton pump inhibitor (PPI) efficacy were compared between different groups. Multivariate analyses were performed to identify esophageal motility parameters associated with reflux burden and symptom outcome.

RESULTS

Of 172 subjects included, 93 patients were identified as CCv3.0 IEM, 69 as CCv4.0 IEM. IEM in either version was concomitant with elevated acid burden and impaired esophageal clearance as compared to normal motility in corresponding diagnostic criteria, while the only presence of IEM in CCv4.0 was predictive to abnormal acid exposure (AET > 6%: OR = 2.66, 95% CI [1.27-5.56], p < 0.01). The presence of "CCv3.0 IEM" and low EGJ-CI (EGJ-CI < 39.1 mmHg·cm) had no added value in predicting increased reflux burden. No interaction effect was found between the presence of IEM and a weakened EGJ. None of the manometric variables was capable of predicting PPI response.

CONCLUSIONS

Stringent criteria of IEM in CCv4.0 can better predict abnormal acid exposure as compared to CCv3.0.

Value of pH Impedance Monitoring While on Twice-Daily Proton Pump Inhibitor Therapy to Identify Need for Escalation of Reflux Management

BACKGROUND AND AIMS

Acid exposure time (AET) and reflux episode thresholds from the Lyon Consensus may not apply for pH impedance studies performed while on proton pump inhibitor (PPI) therapy. We aimed to determine metrics from "on PPI" pH impedance studies predicting need for escalation of therapy.

METHODS

De-identified pH impedance studies performed while on twice-daily PPI (Diversatek, Boulder, CO) in healthy volunteers (n = 66, median age 37.5 years, 43.9% female), and patients with proven gastroesophageal reflux disease (GERD) (European heartburn-predominant cohort: n = 43, median age 57.0 years, 55.8% female; North American regurgitation-predominant cohort: n = 42, median age 41.6 years, 42.9% female) were analyzed. Median values and interquartile ranges for pH impedance metrics in healthy volunteers were compared with proven GERD patients with and without 50% symptom improvement on validated measures. Receiver operating characteristic (ROC) analyses identified optimal thresholds predicting symptom response.

RESULTS

Both conventional and novel reflux metrics were similar between PPI responders and nonresponders (P ≥ .1 for each) despite differences from healthy volunteers. Combinations of metrics associated with conclusively abnormal reflux burden (AET >4%, >80 reflux episodes) were seen in 32.6% and 40.5% of heartburn and regurgitation-predominant patients, respectively, 57.1% and 82.4% of whom reported nonresponse; and 85% with these metrics improved with invasive GERD management. On ROC analysis, AET threshold of 0.5% modestly predicted nonresponse (sensitivity, 0.62; specificity, 0.51; P = .22), and 40 reflux episodes had better performance characteristics (sensitivity, 0.80; specificity, 0.51; P = .002); 79% with these metrics improved with invasive GERD management.

CONCLUSION

Combinations of abnormal "on PPI" pH impedance metrics are associated with PPI nonresponse in proven GERD patients, and can be targeted for treatment escalation, including surgery, particularly in regurgitation-predominant GERD.

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.

Esophageal pH increments associated with post-reflux swallow-induced peristaltic waves show the occurrence and relevance of esophago-salivary reflex in clinical setting

BACKGROUND

Following acid perfusion, esophageal pH is restored by swallowed bicarbonate-containing saliva secreted in response to a vagal esophago-salivary reflex. At impedance-pH monitoring, the post-reflux swallow-induced peristaltic wave (PSPW) index puts into relationship timely post-reflux swallows with the number of reflux events: Low values typify reflux-related heartburn (RRH) and lack of on-therapy improvement characterizes proton pump inhibitor (PPI) failure. Considerable esophageal pH increments associated with PSPWs could demonstrate the occurrence of esophago-salivary reflex in clinical setting, while its relevance could be shown by lower esophageal pH increments in PPI-refractory RRH.

METHODS

Prospective multicenter study in patients with PPI-refractory or PPI-responsive RRH evaluated with off-PPI impedance-pH monitoring. Increments in pH associated with PSPWs were measured and the mean calculated to obtain the PSPW-associated ∆pH.

KEY RESULTS

The mean PSPW-associated ∆pH in 294 RRH patients was 1.2 ± 0.7 and was lower in 137 PPI-refractory (1.0 ± 0.6) than in 157 PPI-responsive (1.5 ± 0.6) cases (p < 0.0001). Lower PSPW-associated ∆pH was independently related to PPI failure at multivariable logistic regression analysis (OR 0.16, 95% CI 0.09-0.26). At ROC analysis, comparing PPI-refractory to PPI-responsive cases the AUC for PSPW-associated ∆pH was 0.76 (95% CI 0.71-0.82), the best cutoff value being 1.2.

CONCLUSIONS AND INFERENCES

Considerable PSPW-associated pH increments demonstrate the occurrence of esophago-salivary reflex in clinical setting. Lower increments in PPI-refractory RRH cases show the clinical relevance of esophago-salivary reflex, confirming that PSPW represents a defense mechanism against reflux. PSPW-associated ∆pH can efficiently predict PPI response in patients undergoing off-therapy impedance-pH monitoring.

Response of eosinophilic oesophagitis to proton pump inhibitors is associated with impedance-pH parameters implying anti-reflux mechanism of action

BACKGROUND

Proton pump inhibitors (PPIs) are effective therapies for eosinophilic oesophagitis (EoE), but the mechanism of action is uncertain. At on-PPI impedance-pH monitoring, improvement in oesophageal chemical clearance assessed with post-reflux swallow-induced peristaltic wave (PSPW) index characterises PPI-responsive EoE and reflux disease. Off-PPI, higher efficacy of the oesophago-salivary reflex as measured with PSPW-associated pH increments characterises PPI-responsive reflux disease and could typify PPI-responsive EoE as well.

AIM

To establish whether PPI responsiveness in EoE is associated with higher efficacy of the oesophago-salivary reflex.

METHODS

Prospective multicentre study in EoE patients investigated with impedance-pH monitoring before starting PPI. Impedance-pH parameters in PPI-responsive and PPI-refractory cases were compared. PPI response was defined histologically.

RESULTS

Considerable PSPW-associated pH increments (median 1.4 units) were found in 80 EoE patients, with significantly higher values in 48 PPI-responsive than in 32 PPI-refractory cases (1.8 vs 1.0, P = 0.02). Mucosal integrity, as measured with mean nocturnal baseline impedance was more severely impaired in the distal oesophagus in PPI-responsive cases, the gradient between mid and distal oesophagus being significantly higher (546 vs 137 Ω, P = 0.0002). PSPW-associated pH increments and the baseline impedance gradient between mid and distal oesophagus were independently associated with histological response at multivariable logistic regression; at receiver operating characteristic analysis, the area under the curve of PPI response calculated by combined assessment was 0.88.

CONCLUSION

Higher efficacy of oesophago-salivary reflex and more severe mucosal damage in the distal oesophagus are associated with EoE response to PPIs, implying an anti-reflux mechanism of action as most likely.

Patients With Definite and Inconclusive Evidence of Reflux According to Lyon Consensus Display Similar Motility and Esophagogastric Junction Characteristics

Background/Aims

The role of esophageal high-resolution manometry (HRM) within Lyon consensus phenotypes, especially patients with inconclusive gastroesophageal reflux disease (GERD) evidence, has not been fully investigated. In this multicenter, observational study we aim to compare HRM parameters in patients with GERD stratified according to the Lyon consensus.

Methods

Clinical and endoscopic data, HRM and multichannel intraluminal impedance-pH (MII-pH) studies performed off proton pump inhibitor therapy in patients with esophageal GERD symptoms were reviewed. Lyon consensus criteria identified pathological GERD, reflux hypersensitivity, functional heartburn, and inconclusive GERD. Patients, with inconclusive GERD were further subdivided into 2 groups based on total reflux numbers (≤ 80 or > 80 reflux episodes) during the MII-pH recording time.

Results

A total of 264 patients formed the study cohort. Pathological GERD and inconclusive GERD patients were associated with higher numbers of reflux episodes, lower mean nocturnal baseline impedance (MNBI) values, and a higher proportion of patients with pathologic MNBI compared to functional heartburn (P < 0.05 for each comparison). On multivariate analysis, pathological GERD and inconclusive GERD patients, both with ≤ 80 or > 80 reflux episodes, were significantly associated with pathologic esophagogastric junction contractile integral values and with presence of hiatus hernia (type 2/3 esophagogastric junction). Patients with inconclusive GERD and > 80 reflux episodes were significantly associated with fragmented peristalsis and ineffective esophageal motility whilst inconclusive GERD with ≤ 80 reflux episodes were significantly associated with fragmented peristalsis.

Conclusion

Esophageal motor parameters on HRM are similar between pathologic and inconclusive GERD according to the Lyon consensus.

ESNM/ANMS consensus paper: Diagnosis and management of refractory gastro-esophageal reflux disease

Up to 40% of patients with symptoms suspicious of gastroesophageal reflux disease (GERD) do not respond completely to proton pump inhibitor (PPI) therapy. The term "refractory GERD" has been used loosely in the literature. A distinction should be made between refractory symptoms (ie, symptoms may or may not be GERD-related), refractory GERD symptoms (ie, persisting symptoms in patients with proven GERD, regardless of relationship to ongoing reflux), and refractory GERD (ie, objective evidence of GERD despite adequate medical management). The present ESNM/ANMS consensus paper proposes use the term "refractory GERD symptoms" only in patients with persisting symptoms and previously proven GERD by either endoscopy or esophageal pH monitoring. Even in this context, symptoms may or may not be reflux related. Objective evaluation, including endoscopy and esophageal physiologic testing, is requisite to provide insights into mechanisms of symptom generation and evidence of true refractory GERD. Some patients may have true ongoing refractory acid or weakly acidic reflux despite PPIs, while others have no evidence of ongoing reflux, and yet others have functional esophageal disorders (overlapping with proven GERD confirmed off therapy). In this context, attention should also be paid to supragastric belching and rumination syndrome, which may be important contributors to refractory symptoms.