Esophageal baseline impedance levels in patients with pathophysiological characteristics of functional heartburn

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.

Topical Protection of Esophageal Mucosa as a New Treatment of GERD

Among the various factors implicated in the pathogenesis of gastroesophageal reflux disease (GERD), visceral hypersensitivity and mucosal resistance have been recently re-evaluated in relation to the increasing phenomenon of proton pump inhibitor failure, particularly in patients with nonerosive reflux disease (NERD). Intensive research has allowed us to understand that noxious substances contained in the refluxate are able to interact with esophageal epithelium and to induce the elicitation of symptoms. The frequent evidence of microscopic esophagitis able to increase the permeability of the mucosa, the proximity of sensory afferent nerve fibers to the esophageal lumen favoring the higher sensitivity to noxious substances and the possible activation of inflammatory pathways interacting with sensory nerve endings are pathophysiological alterations confirming that mucosal resistance is impaired in GERD patients. Accordingly, the reinforcement of protective mechanisms of esophageal mucosa by topical therapies has become a novel treatment target. Alginate, the combination of hyaluronic acid+chondroitin sulphate and Poliprotect have been shown to adhere to esophageal mucosa and to have good protective properties. Several placebo-controlled clinical trials have shown that these compounds, given alone or as add-on therapy for short periods, enable to relieve symptoms and to improve the quality of life in NERD patients. Further studies are needed to confirm the above results and to find new mucosal protectants in order to improve the management of NERD patients.

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.

Effect of Anti-reflux Mucosal Ablation on Esophageal Motility in Patients With Gastroesophageal Reflux Disease: A Study Based on High-resolution Impedance Manometry

Background/Aims

Anti-reflux mucosal ablation (ARMA) is a promising endoscopic intervention for proton pump inhibitor (PPI)-dependent gastroesophageal reflux disease (GERD). However, the effect of ARMA on esophageal motility remains unclear.

Methods

Twenty patients with PPI-dependent GERD receiving ARMA were prospectively enrolled. Comprehensive self-report symptom questionnaires, endoscopy, 24-hour impedance-pH monitoring, and high-resolution impedance manometry were performed and analyzed before and 3 months after ARMA.

Results

All ARMA procedures were performed successfully. Symptom scores, including GerdQ (11.16 ± 2.67 to 9.11 ± 2.64, P = 0.026) and reflux symptom index (11.63 ± 5.62 to 6.11 ± 3.86, P = 0.001), improved significantly, while 13 patients (65%) reported discontinuation of PPI. Total acid exposure time (5.84 ± 4.63% to 2.83 ± 3.41%, P = 0.024) and number of reflux episodes (73.05 ± 19.34 to 37.55 ± 22.71, P < 0.001) decreased significantly after ARMA. Improved esophagogastric junction (EGJ) barrier function, including increased lower esophageal sphincter resting pressure (13.89 ± 10.78 mmHg to 21.68 ± 11.5 mmHg, P = 0.034), 4-second integrated relaxation pressure (5.75 ± 6.42 mmHg to 9.99 ± 5.89 mmHg, P = 0.020), and EGJ-contractile integral (16.42 ± 16.93 mmHg·cm to 31.95 ± 21.25 mmHg·cm, P = 0.016), were observed. Esophageal body contractility also increased significantly (distal contractile integral, 966.85 ± 845.84 mmHg·s·cm to 1198.8 ± 811.74 mmHg·s·cm, P = 0.023). Patients with symptom improvement had better pre-AMRA esophageal body contractility.

Conclusions

ARMA effectively improves symptoms and reflux burden, EGJ barrier function, and esophageal body contractility in patients with PPIdependent GERD during short-term evaluation. Longer follow-up to clarify the sustainability of ARMA is needed.

Baseline Impedance via Manometry Predicts Pathological Mean Nocturnal Baseline Impedance in Isolated Laryngopharyngeal Reflux Symptoms

Background/Aims

Distal mean nocturnal baseline impedance (MNBI) measuring via pH-impedance may be valuable in diagnosing patients with suspected laryngopharyngeal reflux (LPR). However, its wide adoption is hindered by cost and invasiveness. This study investigates whether baseline impedance measured during high-resolution impedance manometry (HRIM-BI) can predict pathological MNBI.

Methods

A cross-sectional study in Taiwan included 74 subjects suspected of LPR, who underwent HRIM (MMS) and pH-impedance testing (Diversatek), after stopping proton pump inhibitors for more than 7 days. Subjects with grade C or D esophagitis or Barrett's esophagus were excluded. The cohort was divided into 2 groups: those with concomitant typical reflux symptoms (CTRS, n = 28) and those with isolated LPR symptoms (ILPRS, n = 46). HRIM-BI measurements focused on both distal and proximal esophagi. Pathological MNBI was identified as values below 2065 Ω, measured 3 cm above the lower esophageal sphincter.

Results

In all subjects, distal HRIM-BI values correlated weakly with distal MNBI(r = 0.34-0.39, P < 0.005). However, in patients with ILPRS, distal HRIM-BI corelated moderately with distal MNBI(r = 0.43-0.48, P < 0.005). The areas under the receiver operating characteristic curve was 0.78 (P = 0.001) with a sensitivity of 0.83 and a specificity of 0.68. No correlation exists between distal HRIM-BI and distal MNBI in patients with CTRS, and between proximal HRIM-BI and proximal MNBI in both groups.

Conclusions

Distal HRIM-BI from HRIM may potentially predict pathological MNBI in patients with ILPRS, but not in those with CTRS. Future outcome studies linked to the metric are warranted.

Is reflux hypersensitivity truly a functional gastrointestinal disorder? A retrospective cross-sectional study

BACKGROUND

According to Rome IV, reflux hypersensitivity (RH) represents a novel form of functional esophageal disorder. This study was designed to compare the clinical features of three types of endoscopic-negative heartburn: RH, nonerosive reflux disease (NERD), and functional heartburn (FH).

METHODS

Patients with heartburn in a medical center from 01/01/2017 to 10/31/2021 were included. This article presented a blinded retrospective analysis of 24 h MII-pH and HRM tracings from patients with NERD, RH, and FH to compare their clinical characteristics.

RESULTS

A total of 118 patients were included in the study. There were no significant differences in age, sex, BMI, smoking status, or drinking history among RH, NERD and FH. Functional dyspepsia (FD) symptoms were more prone to exist in FH than in NERD (P < 0.05), whereas hiatal hernia was more prevalent in NERD and RH than in FH (P < 0.05). The incidence of anxiety and depression gradually increased in the NERD, RH, and FH groups (P >  0.05). The distal MNBI and PSPW index of the NERD and RH groups were lower than those of the FH group (P < 0.05). The distal MNBI showed good diagnostic potential.

CONCLUSIONS

Clear pathological alterations, which are distinct from those of other FGIDs, are observable in RH. It might be inappropriate to categorize RHs within FGIDs.

Association between laryngopharyngeal reflux clinical scores and esophageal multichannel intraluminal impedance pH monitoring interpretation according to Lyon Consensus 2.0

Laryngopharyngeal reflux remains a diagnostic challenge due to the lack of a definitive diagnostic tool. Esophageal multichannel intraluminal impedance (MII) pH monitoring has been proven reliable for detecting gastric reflux. This study aims to evaluate the association between clinical scores and MII/pH monitoring according to the Lyon Consensus 2.0. Patients with laryngo-pharyngeal symptoms (LPS) who had a reflux symptom index (RSI) ≥13 or reflux finding score (RFS) ≥7 underwent MII/pH monitoring. The findings were analyzed in comparison with clinical scores. A total of 100 patients meeting the inclusion criteria were recruited for this study. MII/pH monitoring revealed a median acid exposure time (AET) of 1.9% (interquartile range [IQR] = 0.2, 4.9), with 22% of patients recording an AET above 6%. The median number of reflux episodes was 29.5 episodes per day (IQR = 19.0, 43.8), with 7% experiencing more than 80 episodes per day. Gas reflux was identified as the most prevalent type. Based on the Lyon Consensus 2.0, 25 patients exhibited conclusive pathological reflux, while 75 patients showed no conclusive evidence of pathological reflux. No significant differences were found in RSI and RFS between these groups. Only gas reflux episodes showed a significant correlation with RSI (r = 0.255, P = 0.011). RSI and RFS among patients with LPS showed no statistically significant differences in identifying pathological reflux or no conclusive evidence of pathological reflux. This finding suggests that the pathophysiology underlying LPS may not be solely attributable to reflux.

How to distinguish PPI-refractory from PPI-responsive patients in gastro-oesophageal reflux-induced chronic cough: post-reflux swallow induced peristaltic wave index and mean nocturnal baseline impedance provide new predictive factors

Background

The results of empirical trials with proton pump inhibitors (PPIs) for management of gastro-oesophageal reflux-induced chronic cough (GERC) have resulted in considerable controversy, and the mechanism of PPI refractoriness remains unclear. Our study aims to identify the predictors of PPI refractoriness of GERC in a retrospective clinical study.

Methods

In total, 128 GERC patients were enrolled between March 2018 and October 2022. Regression analysis was utilised to create a model for predicting PPI-refractory of GERC using retrospective analysis of the general data and MII-pH indicators.

Results

The post-reflux swallow induced peristaltic wave index (PSPWI) was lower in the PPI-refractory group than the PPI-responsive group (33.89±7.38 versus 39.45±9.47, respectively, p<0.001), as were the mean nocturnal baseline impedance (MNBI) and proximal MNBI (2092.11 (IQR: 652.23)] versus 2426.52 (IQR: 917.39) Ω, respectively, p=0.012; 1599.50 (IQR: 1206.63) versus 2274.50 (IQR: 1775.29) Ω, respectively, p=0.001). Multivariate logistic regression analysis identified the PSPWI (odds ratio 0.919, p=0.001) as an independent predictor of PPI-refractory GERC.

Conclusions

The diagnostic value of both proximal MNBI ≤39.90% and MNBI ≤2233.58 Ω had moderate sensitivity (71.67%) and specificity (75.00%) to identify PPI-refractory GERC.

Post-reflux swallow-induced peristaltic wave index and mean nocturnal baseline impedance predict proton pump inhibitor response in patients with reflux hypersensitivity

BACKGROUND AND AIM

Post-reflux swallow-induced peristaltic wave (PSPW) index and mean nocturnal baseline impedance (MNBI) have been shown to influence proton pump inhibitor (PPI) response in GERD patients. However, currently, little data concerning these variables in patients with reflux hypersensitivity (RH) are available. In this study, we aimed to evaluate, in RH patients, the prevalence of PPI responders and nonresponders and investigate the predictive value of impedance-pH variables, including PSPW and MNBI, on responses to PPI.

METHODS

A total of 108 RH patients who met ROME IV criteria were prospectively recruited from June 2018 to December 2022. The prevalence of PPI responders/nonresponders was calculated, and impedance-pH variables were compared between the response and nonresponse groups. Multiple logistic regression was used to investigate predictors for PPI response.

RESULTS

Among 108 patients with RH, 60 patients (55.56%) were the PPI responders, and 48 (44.44%) were the nonresponders. Compared with the nonresponders, the PPI responders had a lower PSPW index (47.05 ± 4.43 vs 51.33 ± 3.50, P = 0.004) and a decreased value of MNBI (1866.68 ± 390.62 vs 2181.14 ± 338.42, P = 0.017). Multivariate logistic regression revealed that only the pathologic PSPW index (OR: 2.064) and MNBI (OR: 1.800) significantly influenced PPI response.

CONCLUSIONS

Nearly half of RH patients were PPI nonresponders. Impedance-pH monitoring was more valuable than pH-only monitoring in associating PPI response to reflux in RH patients owing to the appraisal of the PSPW index and MNBI.

Transoral Incisionless Fundoplication Leads to Esophageal Mucosa Healing in Responder Patients Followed up to 2 Years, as Documented by Esophageal Mean Nocturnal Baseline Impedance

Background/Aims

Decrease of esophageal mean nocturnal baseline impedance reflects loss of mucosal integrity. It can predict response to anti-reflux therapy. Mean nocturnal baseline impedance after transoral incisionless fundoplication for gastroesophageal reflux disease has never been assessed. The aim of the study is to investigate mean nocturnal baseline impedance and conventional pathophysiological parameters following transoral incisionless fundoplication.

Methods

Patients prospectively treated by transoral incisionless fundoplication in a single center were retrospectively reviewed regarding 1- and 2-year 24-hour pH-metry and multichannel intraluminal impedance with calculation of mean nocturnal baseline impedance, gastroesophageal reflux disease-health related quality of life and reflux symptom index scores.

Results

Thirty-eight and 17/38 patients with 1- and 2-year 24-hour pH-multichannel intraluminal impedance assessment and mean nocturnal baseline impedance's calculation after transoral incisionless fundoplication, respectively, were identified. Mean nocturnal baseline impedance significantly increased up to 2-year follow-up (P = 0.033), along with significant decrease in % of acid exposure time (P = 0.003), gastroesophageal reflux disease-health related quality of life score (P < 0.001), and reflux symptom index (P = 0.008), compared with baseline. The longest orthostatic reflux decreased too, approaching statistical significance (P = 0.054). These significant changes occurred in patients experiencing ≥ 50% reduction of symptom questionnaires' scores ("responders"). Conversely, mean nocturnal baseline impedance worsened and no significant changes of 24-hour pH-multichannel intraluminal impedance metrics were observed in "non-responder" patients (symptom questionnaires' scores decrease < 50%).ConclusionIn patients who responded a significant improvement of mean nocturnal baseline impedance and % acid exposure time was observed up to 2-year follow-up, suggesting that transoral incisionless fundoplication achieves an effective esophageal mucosa healing besides symptom improvement.

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.

Comparison between Conventional and Simple Measuring Methods of Mean Nocturnal Baseline Impedance in Pediatric Gastroesophageal Reflux Disease

(1) Background: Multichannel intraluminal impedance-pH (MII-pH) monitoring is commonly used to diagnose gastroesophageal reflux disease (GERD). The mean nocturnal baseline impedance (MNBI) is an important parameter, reflecting the esophageal mucosal integrity and improvement in GERD. This study aims to evaluate the correlation between conventionally measured MNBI and a recently described simple MNBI measurement method in diagnosing pediatric GERD. (2) Methods: This prospective observational study enrolled 64 children aged one month to 18 years who underwent 24 h MII-pH monitoring. Conventional MNBI was measured during stable 10 min intervals at night, while the simple MNBI method averaged impedance throughout the nocturnal supine period. (3) Results: Strong correlations were found between conventional and simple MNBI values across all impedance channels in both infants (r > 0.85) and older children (r > 0.9). Conventional and simple MNBIs in the most distal channel (Z6) effectively differentiated non-erosive reflux disease (NERD) from other phenotypes, with AUCs of 0.864 and 0.860, respectively. The simple MNBI demonstrated good diagnostic performance with similar sensitivity and specificity to the conventional MNBI. (4) Conclusions: Including MNBI measurements into routine MII-pH monitoring may enhance GERD diagnosis and reduce the need for more invasive procedures.

Gastroesophageal Reflux Disease: New Insights and Treatment Approaches

Gastroesophageal reflux disease (GERD) remains a significant global health concern, with increasing prevalence and a substantial impact on quality of life. This narrative review explores recent advances in our understanding of GERD pathophysiology, diagnosis, and management. The complex interplay of factors contributing to GERD, including lower esophageal sphincter dysfunction, transient sphincter relaxations, and esophageal motility disorders, is discussed. Emerging diagnostic techniques, such as high-resolution manometry and impedance-pH monitoring, have enhanced our ability to accurately identify and characterize GERD. The review highlights the evolving landscape of GERD treatment, from conventional approaches like lifestyle modifications and proton pump inhibitors to novel strategies including potassium-competitive acid blockers, endoscopic therapies, and minimally invasive surgical techniques. The potential role of the microbiome in GERD pathogenesis and as a therapeutic target is examined. The concept of personalized medicine in GERD management is explored, considering genetic factors, biomarkers, and individual patient profiles. Complications of GERD, including erosive esophagitis, Barrett's esophagus, and esophageal adenocarcinoma, are reviewed, emphasizing the importance of early detection and appropriate management. The economic burden and impact on the quality of due to GERD are also addressed. This comprehensive review underscores the multifaceted nature of GERD and the need for a personalized, multidisciplinary approach to its management. It highlights ongoing research efforts and emerging therapies that promise to improve outcomes for GERD patients, while also identifying areas requiring further investigation to optimize diagnosis and treatment strategies.

Impact of Esophageal Motility on Microbiome Alterations in Symptomatic Gastroesophageal Reflux Disease Patients With Negative Endoscopy: Exploring the Role of Ineffective Esophageal Motility and Contraction Reserve

Background/Aims

Ineffective esophageal motility (IEM) is common in patients with gastroesophageal reflux disease (GERD) and can be associated with poor esophageal contraction reserve on multiple rapid swallows. Alterations in the esophageal microbiome have been reported in GERD, but the relationship to presence or absence of contraction reserve in IEM patients has not been evaluated. We aim to investigate whether contraction reserve influences esophageal microbiome alterations in patients with GERD and IEM.

Methods

We prospectively enrolled GERD patients with normal endoscopy and evaluated esophageal motility and contraction reserve with multiple rapid swallows during high-resolution manometry. The esophageal mucosa was biopsied for DNA extraction and 16S ribosomal RNA gene V3-V4 (Illumina)/full-length (Pacbio) amplicon sequencing analysis.

Results

Among the 56 recruited patients, 20 had normal motility (NM), 19 had IEM with contraction reserve (IEM-R), and 17 had IEM without contraction reserve (IEM-NR). Esophageal microbiome analysis showed a significant decrease in microbial richness in patients with IEM-NR when compared to NM. The beta diversity revealed different microbiome profiles between patients with NM or IEM-R and IEM-NR (P = 0.037). Several esophageal bacterial taxa were characteristic in patients with IEM-NR, including reduced Prevotella spp. and Veillonella dispar, and enriched Fusobacterium nucleatum. In a microbiome-based random forest model for predicting IEM-NR, an area under the receiver operating characteristic curve of 0.81 was yielded.

Conclusions

In symptomatic GERD patients with normal endoscopic findings, the esophageal microbiome differs based on contraction reserve among IEM. Absent contraction reserve appears to alter the physiology and microbiota of the esophagus.

Esophageal Mucosal Impedance Assessment for the Diagnosis of Gastroesophageal Reflux Disease

Background/Aims

Diagnosing gastroesophageal reflux disease (GERD) is sometimes challenging because the performance of available tests is not entirely satisfactory. This study aims to directly measure the esophageal mucosal impedance during upper gastrointestinal endoscopy for the diagnosis of GERD.

Methods

Sixty participants with typical symptoms of GERD underwent high-resolution esophageal manometry, 24-hour multichannel intraluminal impedance-pH monitoring, upper gastrointestinal endoscopy, and mucosal impedance measurement. Mucosal impedance measurement was performed at 2, 5, 10, and 18 cm above the esophagogastric junction during gastrointestinal endoscopy using a specific catheter developed based on devices described in the literature over the last decade. The patients were divided into groups A (acid exposure time < 4%) and B (acid exposure time ≥ 4%).

Results

The mucosal impedance was significantly lower in group B at 2 cm (2264.4 Ω ± 1099.0 vs 4575.0 Ω ± 1407.6 [group A]) and 5 cm above the esophagogastric junction (4221.2 Ω ± 2623.7 vs 5888.2 Ω ± 2529.4 [group A]). There was no significant difference in the mucosal impedance between the 2 groups at 10 cm and 18 cm above the esophagogastric junction. Mucosal impedance value at 2 cm > 2970 Ω resulted in a sensitivity of 96.4% and a specificity of 87.5% to exclude GERD.

Conclusions

Direct measurement of mucosal impedance during endoscopy is a simple and promising method for diagnosing GERD. Individuals with an abnormal acid exposure time have lower mucosal impedance measurements than those with a normal acid exposure time.

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.

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.

The Utility of Novel pH-Impedance Monitoring Parameters (PSPW Index and MNBI) in Pediatric Gastroesophageal Reflux Disease Phenotypes-A Systematic Review

Background/Objectives: Researchers have proposed two novel impedance-pH parameters, mean nocturnal baseline impedance (MNBI) and the post-reflux swallow-induced peristaltic wave (PSPW) index, to enhance the diagnosis of gastroesophageal reflux disease (GERD) and enable better predictions of the effectiveness of anti-reflux therapies. This systematic review aims to synthesize the available evidence on the utility of the PSPW index and MNBI as diagnostic tools for pediatric GERD. Methods: A systematic search of studies reporting PSPW index and MNBI values in patients with GERD was performed in PubMed, Embase, Clarivate, Scopus, Cochrane and Google Scholar databases from their beginning until April 2024. The following terms were used: GERD, children, pediatric, PSPW and MNBI. Results: Eight studies were included, describing 479 patients ranging from 2 months to 17 years old over an 8-year period in 12 pediatric centers. Four studies demonstrated that children with pathological acid exposure have a significantly lower MNBI, with a good discriminatory ability to diagnose GERD. The PSPW index showed lower values in patients with reflux hypersensitivity (RH) compared to those with functional heartburn (FH). Conclusions: Patients with pathological acid exposure tend to exhibit lower MNBI and PSPW index values compared to those with normal acid exposure. MNBI and the PSPW index show promise as diagnostic tools in distinguishing between different GERD phenotypes. Further research is needed to establish standardized diagnostic criteria and optimize the clinical applicability in GERD diagnosis and management.

How to diagnose GERC more effectively: reflections on post-reflux swallow-induced peristaltic wave index and mean nocturnal baseline impedance

INTRODUCTION

Post-reflux swallow-induced peristaltic wave index (PSPWI) and mean nocturnal baseline impedance (MNBI) are novel parameters reflect esophageal clearance capacity and mucosal integrity. They hold potential in aiding the recognition of gastroesophageal reflux-induced chronic cough (GERC). Our study aims to investigate their diagnostic value in GERC.

METHODS

This study included patients suspected GERC. General information and relevant laboratory examinations were collected, and final diagnosis were determined following guidelines for chronic cough. The parameters of multichannel intraluminal impedance-pH monitoring (MII-pH) in patients were analyzed and compared to explore their diagnostic value in GERC.

RESULTS

A total of 186 patients were enrolled in this study. The diagnostic value of PSPWI for GERC was significant, with the area under the working curve (AUC) of 0.757 and a cutoff value of 39.4%, which was not statistically different from that of acid exposure time (AET) (p > 0.05). The combined diagnostic value of AET > 4.4% and PSPWI < 39.4% was superior to using AET > 4.4% alone (p < 0.05). Additionally, MNBI and distal MNBI also contributed to the diagnosis of GERC, with AUC values of 0.639 and 0.624, respectively. AET > 4.4% or PSPWI < 39.4% is associated with a 44% reduction in missed diagnoses of non-acid GERC compared to AET > 6.0% or symptom association probability (SAP) ≥ 95%, and may be more favorable for identifying GERC.

CONCLUSION

The diagnostic value of PSPWI for GERC is comparable to that of AET. Combining PSPWI < 39.4% or AET > 4.4% can improve the diagnostic efficiency by reducing the risk of missed diagnoses in cases where non-acid reflux is predominant. Distal MNBI and MNBI can serve as secondary reference indices in the diagnosis of GERC.

The impact of lung transplantation on esophageal motility and inter-relationships with reflux and lung mechanics in patients with restrictive and obstructive respiratory disease

BACKGROUND

For many patients with lung disease the only proven intervention to improve survival and quality of life is lung transplantation (LTx). Esophageal dysmotility and gastroesophageal reflux (GER) are common in patients with respiratory disease, and often associate with worse prognosis following LTx. Which, if any patients, should be excluded from LTx based on esophageal concerns remains unclear. Our aim was to understand the effect of LTx on esophageal motility diagnosis and examine how this and the other physiological and mechanical factors relate to GER and clearance of boluses swallowed.

METHODS

We prospectively recruited 62 patients with restrictive (RLD) and obstructive (OLD) lung disease (aged 33-75 years; 42 men) who underwent high resolution impedance manometry and 24-h pH-impedance before and after LTx.

KEY RESULTS

RLD patients with normal motility were more likely to remain normal (p = 0.02), or if having abnormal motility to change to normal (p = 0.07) post-LTx than OLD patients. Esophageal length (EL) was greater in OLD than RLD patients' pre-LTx (p < 0.001), reducing only in OLD patients' post-LTx (p = 0.02). Reduced EL post-LTx associated with greater contractile reserve (r = 0.735; p = 0.01) and increased likelihood of motility normalization (p = 0.10). Clearance of reflux improved (p = 0.01) and associated with increased mean nocturnal baseline impedance (p < 0.001) in RLD but not OLD. Peristaltic breaks and thoraco-abdominal pressure gradient impact both esophageal clearance of reflux and boluses swallowed (p < 0.05).

CONCLUSIONS AND INFERENCES

RLD patients are more likely to show improvement in esophageal motility than OLD patients post-LTx. However, the effect on GER is more difficult to predict and requires other GI, anatomical and pulmonary factors to be taken into consideration.

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.

How safe are heartburn medications and who should use them?

INTRODUCTION

Heartburn is a frequent symptom occurring in daily clinical practice and is mainly associated with gastroesophageal reflux disease (GERD). However, it can be stimulated by various factors and diseases other than GERD can present with heartburn. Therefore, physicians must be very careful in distinguishing GERD from non-GERD conditions in their patients, particularly when heartburn is refractory to anti-reflux medications.

AREAS COVERED

The aim of this narrative review was to analyze the medical literature regarding the prevalence of heartburn and the various clinical disorders which can be present with this symptom. The type of medications usually adopted for treating heartburn and their grade of safety have been reviewed using an extensive computerized (Medline/PubMed) search with particular focus on the last 20 years.

EXPERT OPINION

Many drugs can be used for relieving heartburn in patients with GERD, although PPIs are the pharmacological agents with the greatest efficacy. However, it must be highlighted that many non-GERD conditions may present clinically with this symptom whose intensity does not differ between GERD and functional esophageal disorders, which represent about 50% of all patients with suspected GERD. It is very important to identify these functional conditions because their treatment differs completely from that of GERD.

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.

Diagnosis of Laryngopharyngeal Reflux: Past, Present, and Future-A Mini-Review

Laryngopharyngeal reflux (LPR) is a variant of gastroesophageal reflux disease (GERD) in which gastric refluxate irritates the lining of the aerodigestive tract and causes troublesome airway symptoms or complications. LPR is a prevalent disease that creates a significant socioeconomic burden due to its negative impact on quality of life, tremendous medical expense, and possible cancer risk. Although treatment modalities are similar between LPR and GERD, the diagnosis of LPR is more challenging than GERD due to its non-specific symptoms/signs. Due to the lack of pathognomonic features of endoscopy, mounting evidence focused on physiological diagnostic testing. Two decades ago, a dual pH probe was considered the gold standard for detecting pharyngeal acidic reflux episodes. Despite an association with LPR, the dual pH was unable to predict the treatment response in clinical practice, presumably due to frequently encountered artifacts. Currently, hypopharygneal multichannel intraluminal impedance-pH catheters incorporating two trans-upper esophageal sphincter impedance sensors enable to differentiate pharyngeal refluxes from swallows. The validation of pharyngeal acid reflux episodes that are relevant to anti-reflux treatment is, therefore, crucial. Given no diagnostic gold standard of LPR, this review article aimed to discuss the evolution of objective diagnostic testing and its predictive role of treatment response.

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

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

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.

Ambulatory pH-Impedance Findings Confirm That Grade B Esophagitis Provides Objective Diagnosis of Gastroesophageal Reflux Disease

INTRODUCTION

The Lyon Consensus designates Los Angeles (LA) grade C/D esophagitis or acid exposure time (AET) >6% on impedance-pH monitoring (MII-pH) as conclusive for gastroesophageal reflux disease (GERD). We aimed to evaluate proportions with objective GERD among symptomatic patients with LA grade A, B, and C esophagitis on endoscopy.

METHODS

Demographics, clinical data, endoscopy findings, and objective proton-pump inhibitor response were collected from symptomatic prospectively enrolled patients from 2 referral centers. Off-therapy MII-pH parameters included AET, number of reflux episodes, mean nocturnal baseline impedance, and postreflux swallow-induced peristaltic wave index. Objective GERD evidence was compared between LA grades.

RESULTS

Of 155 patients (LA grade A: 74 patients, B: 61 patients, and C: 20 patients), demographics and presentation were similar across LA grades. AET >6% was seen in 1.4%, 52.5%, and 75%, respectively, in LA grades A, B, and C. Using additional MII-pH metrics, an additional 16.2% with LA grade A and 47.5% with LA grade B esophagitis had AET 4%-6% with low mean nocturnal baseline impedance and postreflux swallow-induced peristaltic wave index; there were no additional gains using the number of reflux episodes or symptom-reflux association metrics. Compared with LA grade C (100% conclusive GERD based on endoscopic findings), 100% of LA grade B esophagitis also had objective GERD but only 17.6% with LA grade A esophagitis ( P < 0.001 compared with each). Proton-pump inhibitor response was comparable between LA grades B and C (74% and 70%, respectively) but low in LA grade A (39%, P < 0.001).

DISCUSSION

Grade B esophagitis indicates an objective diagnosis of GERD.

Randomised clinical trial: the use of alginates during preinvestigation proton pump inhibitor wash-out and their impact on compliance and symptom burden

BACKGROUND/AIMS

Investigation of gastro-oesophageal reflux disease is usually performed off proton pump inhibitors (PPIs). This can exacerbate symptoms, potentially impacting investigation accuracy if patients circumvent the preinvestigation instructions. There are no standard recommendations on how to manage PPI withdrawal. We aimed to assess the impact of structured alginate use on symptom burden.

METHODS

Participants were already established on ≥4 weeks of PPI therapy and being referred for manometry and 24-hour pH/impedance testing. Preinvestigation instructions involved stopping PPIs and H2 receptor antagonists for 1 week, but antacids and alginates were allowed until the night before. Participants were randomised to follow these standard instructions (control group), or the same instructions with the provision of Gaviscon Advance to be taken four times daily (treatment group). The primary outcome assessed change in Gastro-Oesophageal Reflux Disease Health-Related Quality of Life Score.

KEY RESULTS

Data for 48 patients were available for primary outcome assessment. While patients in the control group had a significant increase in symptoms (median difference 6.5, 95% CI (1 to 7), p=0.04), no change occurred in the treatment arm (median difference -1.5, 95% CI (-2, 3.5), p=0.54). There were no serious adverse events.

CONCLUSIONS

Structured alginate use prevents symptom exacerbation during preinvestigation PPI wash-out. These findings are limited to the 1-week wash-out period but can benefit thousands of patients undergoing investigation for gastro-oesophageal reflux each year. Further research is required to assess this effect in other settings, such as sustained PPI deprescription. The trial was funded by Reckitt Benckiser.

TRIAL REGISTRATION NUMBER

EudraCT registration 2019-004561-41.

Association between post-reflux swallow-induced peristaltic wave index and esophageal mucosal integrity in patients with GERD symptoms

BACKGROUND

Impedance-pH monitoring allows evaluation of esophageal chemical clearance, a response to reflux elicited by the esophago-salivary reflex, by means of the post-reflux swallow-induced peristaltic wave (PSPW) index; mucosal integrity can be evaluated by means of mean nocturnal baseline impedance (MNBI) and is regarded as a GERD marker. Currently, the relationship between PSPW index and MNBI has not yet been fully investigated and represents the aim of the present study.

METHODS

Impedance-pH tracings from consecutive patients were reviewed. ROC analysis and multivariate regression models were generated to evaluate the association between acid exposure time (AET), total refluxes (TRs), PSPW index, and MNBI. Patients were classified by means of AET thresholds and symptom-reflux association indexes into conclusive and inconclusive GERD, reflux hypersensitivity (RH), and functional heartburn (FH). Pathologic MNBI <2292 Ω was defined according to published outcome studies.

KEY RESULTS

Two hundred and thirty patients constituted the study cohort. Overall, a significant direct correlation was observed between PSPW index and MNBI (0.759, p < 0.001). At ROC analysis, a PSPW index cut-off value of 53% was the best discriminator between normal from pathologic MNBI values (sensitivity 88%, specificity 86.4%). Considering AET cut-off of 4% or 6%, a sensitivity of 80.7% and 46% and a specificity of 62.5% and 93.2% were found, respectively. According to multivariate analysis, AET >4% and PSPW index value <53% or <61% were significantly associated with pathologic MNBI values.

CONCLUSIONS AND INFERENCES

Esophageal chemical clearance is a major defense mechanism against reflux and its impairment represents a major determinant of reflux-associated mucosal damage.

Mean nocturnal baseline impedance: Influencing factors and diagnostic value in gastroesophageal reflux disease

BACKGROUND

At present, there are few studies related to mean nocturnal baseline impedance (MNBI), esophageal dynamic reflux monitoring, high-resolution esophageal manometry (HRM) parameter indexes, and its diagnostic value in gastroesophageal reflux disease (GERD).

OBJECTIVE

To analyze the factors influencing MNBI and examine the diagnostic value of MNBI in GERD.

METHODS

A retrospective analysis on 434 patients with typical reflux symptoms who underwent gastroscopy, 24-hour multichannel intraluminal impedance and pH monitoring (MII/pH) and HRM. They were divided into the conclusive evidence group (103 cases), borderline evidence group (229 cases), and exclusion evidence group (102 cases) according to the level of diagnostic evidence of GERD based on the Lyon Consensus. We analyzed the differences in MNBI, esophagitis grade, MII/pH and HRM index among the groups; the correlation between MNBI and the above indexes and its influence on MNBI; and to evaluate the diagnostic value of MNBI in GERD.

RESULTS

There were significant differences in MNBI, Acid Exposure Time (AET) 4%, DeMeester score, and total reflux episodes among the three groups (P< 0.001). EGJ contractile integral (EGJ-CI) of the conclusive evidence group and the borderline evidence group was significantly lower than that in the exclusion evidence group (P< 0.001). MNBI was significantly and negatively correlated with age, BMI, AET 4%, DeMeester score, total reflux episodes, EGJ classification, esophageal motility abnormalities, and esophagitis grade (all P< 0.05), and significantly and positively correlated with EGJ-CI (P< 0.001). Age, BMI, AET 4%, EGJ classification, EGJ-CI, and esophagitis grade had significant effects on MNBI (P< 0.05); MNBI was used to diagnose GERD with a diagnostic cutoff of 2061 Ω, and AUC was 0.792 (sensitivity 74.9%, specificity 67.4%); MNBI was used to diagnose exclusion evidence group with a diagnostic cutoff of 2432 Ω, AUC was 0.774 (sensitivity 67.6%, specificity 72%).

CONCLUSION

AET, EGJ-CI, and esophagitis grade are the most important influence factors of MNBI. MNBI has good diagnostic value in identifying conclusive GERD.

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.

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.

Difference in meal-related esophageal intraluminal impedance change between gastroesophageal reflux disease and functional disorders

OBJECTIVES

Gastroesophageal reflux disease (GERD) has overlapping symptoms with functional disorders such as functional heart burn. Twenty-four-hour pH with impedance monitoring is useful for differentiation. The intraluminal impedance change with meal in distal esophagus is not investigated.

METHODS

We performed a retrospective investigation of clinical files, 24-hour pH with intraluminal impedance monitoring in patients with GERD and functional disorders. The post-reflux swallow induced peristaltic wave (PSPW) index as well as the impedance in distal esophagus before the first meal and 30 min and 60 min after the meal were measured and analyzed.

RESULTS

A significant decrease of intraluminal impedance in distal esophagus was noted at 30 min (ΔI_30min -301.5 [747.5] Ω, p = 0.018) and recovered at 60 min (ΔI_60min -194.6 [766.0] Ω, p = 0.126) after meals in GERD patients. On the other hand, there was no significant change of impedance in patients with functional disorders. There were positive correlations between ΔI_30min and PSPW index (correlation = 0.232, p = 0.038). Comparing GERD to functional disorders, the best cut-off value for ΔI_30min was -212Ω with 74.4% sensitivity and 60.5% specificity.

CONCLUSIONS

The intraluminal impedance in distal esophagus was lowered after meals in GERD patients other than functional disorders. This impedance change was correlated with PSPW index and could help differentiate GERD from functional disorders.

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.

GERD-related chronic cough: Possible mechanism, diagnosis and treatment

GERD, or gastroesophageal reflux disease, is a prevalent medical condition that affects millions of individuals throughout the world. Chronic cough is often caused by GERD, and chronic cough caused by GER is defined as GERD-related chronic cough (GERC). It is still unclear what the underlying molecular mechanism behind GERC is. Reflux theory, reflex theory, airway allergies, and the novel mechanism of esophageal motility disorders are all assumed to be linked to GERC. Multichannel intraluminal impedance combined with pH monitoring remains the gold standard for the diagnosis of GERC, but is not well tolerated by patients due to its invasive nature. Recent discoveries of new impedance markers and new techniques (mucosal impedance testing, salivary pepsin, real-time MRI and narrow band imaging) show promises in the diagnosis of GERD, but the role in GERC needs further investigation. Advances in pharmacological treatment include potassium-competitive acid blockers and neuromodulators (such as Baclofen and Gabapentin), prokinetics and herbal medicines, as well as non-pharmacological treatments (such as lifestyle changes and respiratory exercises). More options have been provided for the treatment of GERC other than acid suppression therapy and anti-reflux surgery. In this review, we attempt to review recent advances in GERC mechanism, diagnosis, and subsequent treatment options, so as to provide guidance for management of GERC.

Correlation of Esophageal Mean Nocturnal Baseline Impedance With Markers of Laryngopharyngeal Reflux

OBJECTIVES

Mean nocturnal baseline impedance (MNBI) is a measure of the esophageal epithelial barrier function calculated via high-resolution impedance manometry and can be used as a diagnostic tool and treatment response predictor for gastroesophageal reflux disease (GERD). However, its utility for laryngopharyngeal reflux (LPR) has been minimally studied. We aimed to investigate the relationship of MNBI between patients with suspected LPR, healthy controls, and their 24-h multichannel intraluminal impedance-pH (MII-pH) study results.

METHODS

Retrospective patient series analysis was performed of patients with suspected LPR and healthy controls who underwent 24-h MII-pH monitoring. MNBI values were calculated from impedance channels at the level of the hypopharynx, proximal esophagus, and distal esophagus. We compared these MNBI values between the subject groups with secondary analysis on MII-pH results, reflux symptom index, reflux findings score, DeMeester score, and salivary pepsin levels.

RESULTS

Twenty-three patients with suspected LPR and 14 healthy controls were enrolled. Decreased distal esophageal MNBI was found to be significantly decreased in patients with suspected LPR compared with healthy controls (p < 0.01) and in subjects with positive MII-pH studies compared to negative MII-pH studies (p < 0.01). There were no significant correlations of MNBI at the hypopharynx or proximal esophagus.

CONCLUSION

Distal esophageal MNBI has significant correlations with many phenotypic and biological markers of LPR. These findings indicate that MNBI has the potential to be applied to LPR, similar to its emerging use as a diagnostic tool and treatment response predictor for GERD.

LEVEL OF EVIDENCE

3 Laryngoscope, 2022.

Trends in gastroesophageal reflux disease research: A bibliometric and visualized study

Background

Gastroesophageal reflux disease (GERD), a disorder resulting from the retrograde flow of gastric contents into the esophagus, affects an estimated 10-30% of the Western population, which is characterized by multifactorial pathogenesis. Over the past few decades, there have been many aspects of uncertainty regarding GERD leading to an ongoing interest in the field as reflected by a large number of publications, whose heterogeneity and variable quality may present a challenge for researchers to measure their scientific impact, identify scientific collaborations, and to grasp actively researched themes in the GERD field. Accordingly, we aim to evaluate the knowledge structure, evolution of research themes, and emerging topics of GERD research between 2012 and 2022 with the help of bibliometric approaches.

Methods

The literature focusing on GERD from 2012 to 2022 was retrieved from the Science Citation Index Expanded of the Web of Science Core Collection. The overall publication performance, the most prolific countries or regions, authors, journals and resources-, knowledge- and intellectual-networking, as well as the co-citation analysis of references and keywords, were analyzed through Microsoft Office Excel 2019, CiteSpace, and VOSviewer.

Results

A total of 8,964 publications were included in the study. The USA published the most articles (3,204, 35.74%). Mayo Clin ranked first in the number of articles published (201, 2.24%). EDOARDO SAVARINO was the most productive author (86, 0.96%). The most productive journal in this field was SURGICAL ENDOSCOPY AND OTHER INTERVENTIONAL TECHNIQUES (304, 3.39%). AMERICAN JOURNAL OF GASTROENTEROLOGY had the most co-citations (4,953, 3.30%). Keywords with the ongoing strong citation bursts were transoral incision less fundoplication, eosinophilic esophagitis, baseline impedance, and functional heartburn.

Conclusion

For the first time, we obtained deep insights into GERD research through bibliometric analysis. Findings in this study will be helpful for scholars seeking to understand essential information in this field and identify research frontiers.

Mean nocturnal baseline impedance, a novel metric of multichannel intraluminal impedance-pH monitoring in diagnosing gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is a common disease with increasing prevalence worldwide. However, the diagnosis of GERD is challenging because there are no definite gold standard criteria. Recently, a novel impedance parameter, namely mean nocturnal baseline impedance (MNBI), has been proposed, which reflects the burden of longitudinal reflux and the integrity of esophageal mucosa. MNBI has shown an immense promise for increasing the diagnostic rate of multichannel intraluminal impedance-pH (MII-pH) monitoring and predicting the response to proton pump inhibitor (PPI) or anti-reflux intervention in patients with reflux symptoms. The present paper reviews the association between baseline impedance and esophageal mucosal integrity, the acquisition of MNBI in 24-h MII-pH monitoring, the clinical utilization of MNBI in improving the diagnosis rate of GERD in patients with typical reflux symptoms, predicting the response to PPI or anti-reflux treatment in these patients, the utilization of MNBI in diagnosing patients with atypical symptoms or extra-esophageal symptoms, and the correlation between reflux burden and MNBI. MNBI should be routinely assessed using MII-pH monitoring.

Recent insights on functional heartburn and reflux hypersensitivity

PURPOSE OF REVIEW

Rome IV experts have proposed that gastroesophageal reflux disease (GERD) should be diagnosed only in patients with abnormal esophageal acid exposure, and that reflux hypersensitivity (RH) and functional heartburn (FH) both should be considered functional conditions separate from GERD. Although past and recent evidence support that FH can be completely distinguished from GERD, the concept that RH is not GERD is highly questionable. This review attempts to provide current data on these issues.

RECENT FINDINGS

Many recent investigations have provided new data on the different pathophysiological features characterizing RH and FH. Major differences have emerged from analyses of impedance-pH monitoring studies using the novel impedance metrics of baseline impedance (an index of mucosal integrity) and the rate of postreflux swallow-induced peristaltic waves (a reflection of the integrity of esophageal chemical clearance).

SUMMARY

The better ability to interpret impedance-pH tracings together with earlier data on the different prevalence of microscopic esophagitis in RH and FH patients, and recent studies documenting poor therapeutic efficacy of pain modulators and good results of antireflux surgery for RH support recategorization of RH within the GERD world. Further research is needed to correctly phenotype patients who have heartburn without mucosal breaks, and to guide their effective management.

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.

Current advances in the diagnosis and management of gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is very common and defined as troublesome symptoms owing to excessive acid reflux. The spectrum of GERD is broad, including not only erosive esophagitis and Barrett's esophagus but also nonerosive reflux disease (NERD), reflux hypersensitivity, and functional heartburn. Patients with reflux symptoms despite normal endoscopy remain common clinical presentation, can be heterogeneous overlapping with functional gastrointestinal disorders. Ambulatory esophageal pH monitoring with and without impedance helps the diagnosis of NERD. Metrics such as baseline impedance and postreflux swallow induced peristaltic wave enhance diagnostic accuracy in patients with inconclusive diagnoses. The major treatment of all manifestations of GERD is acid suppression with proton pump inhibitors, while other therapies, such as reflux-reducing agents and adjunctive medications, can be individualized where the response to traditional management is incomplete. GERD patients often need long-term treatment due to frequent relapses. Anti-reflux surgery can be effective too. Endoscopic therapies have some promising results, but long-term outcomes remain to be determined.