Use of direct, endoscopic-guided measurements of mucosal impedance in diagnosis of gastroesophageal reflux disease

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.

A Non-Invasive Technique for Long-Term Monitoring of Gastroesophageal Reflux-A Pilot Study

Many people suffer from gastric or gastroesophageal reflux disorder (GERD) due to a malfunction of the cardia, the valve between the esophagus and the stomach. GERD is a syndrome caused by the ascent of gastric juices and bile from the stomach. This article proposes a non-invasive impedance measurement method and demonstrates the correlation between GERD and impedance variation between appropriately chosen points on the patient's chest. This method is presented as an alternative to the most widely accepted diagnostic techniques for reflux, such as pH-metry, pH-impedance measurement, and esophageal manometry, which are invasive because they use a probe that is inserted through a nostril and reaches down to the esophagus.

Endoluminal Procedures and Devices for Esophageal Tract Investigation: A Critical Review

Diseases of the esophageal tract represent a heterogeneous class of pathological conditions for which diagnostic paradigms continue to emerge. In the last few decades, innovative diagnostic devices have been developed, and several attempts have been made to advance and standardize diagnostic algorithms to be compliant with medical procedures. To the best of our knowledge, a comprehensive review of the procedures and available technologies to investigate the esophageal tract was missing in the literature. Therefore, the proposed review aims to provide a comprehensive analysis of available endoluminal technologies and procedures to investigate esophagus health conditions. The proposed systematic review was performed using PubMed, Scopus, and Web of Science databases. Studies have been divided into categories based on the type of evaluation and measurement that the investigated technology provides. In detail, three main categories have been identified, i.e., endoluminal technologies for the (i) morphological, (ii) bio-mechanical, and (iii) electro-chemical evaluation of the esophagus.

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 Mucosal Admittance: A New Technique to Diagnose Gastroesophageal Reflux Disease - Is It Feasible?

Purpose

Esophageal mucosal admittance (MA) is a promising diagnostic method for gastroesophageal reflux disease (GERD). We conducted a study to describe the esophageal MA in patients with reflux symptoms and determine its diagnostic accuracy.

Patients and Methods

We recruited 92 patients with ambulatory pH-impedance monitoring, upper gastrointestinal endoscopy, and MA measured by the tissue conductance meter. MA was measured during endoscopy at 5cm (distal esophagus) and 15cm above the Z line (middle esophagus), repeated at least five times at each position, and median MA was obtained. Afterwards, two biopsies were taken 5cm above the Z line for histopathological evaluation using the Esohisto criteria. Patients were classified as GERD or non-GERD according to the 2018 Lyon consensus.

Results

The mean age was 43.2 years, and 42 patients were males. The most common symptoms were regurgitation (75.0%), belching (65.2%), and heartburn (46.7%). Twenty-three (32.3%) were diagnosed with GERD using the Lyon consensus, and 24 (26.1%) had esophagitis on histopathology. The median MA at the distal and middle esophagus was moderately correlated. The median MA at both positions was higher in the GERD group but only statistically significant in the middle esophagus. MA was not associated with pH-impedance parameters and esophagitis on histopathology. The diagnostic model developed using the logistic regression did not have good accuracy.

Conclusion

MA was not different between GERD and non-GERD patients.

Airway Impedance: A Novel Diagnostic Tool to Predict Extraesophageal Airway Inflammation

OBJECTIVE

To validate a novel biomarker, airway impedance for extraesophageal disease.

STUDY DESIGN

We prospectively recruited patients with respiratory symptoms undergoing combined endoscopy and direct laryngoscopy for the evaluation of symptoms. The direct laryngoscopy was performed and videotaped for blinded scoring by 3 otolaryngologists and an impedance catheter was placed onto the posterior larynx to obtain measurements. Following this, an endoscopy was performed and impedance measurements and biopsies were taken at 3 esophageal heights. Impedance values were compared within and between patients.

RESULTS

Eighty-eight patients were recruited, of which 73 had complete airway and endoscopic exams. There was no significant correlation between airway impedance values and mean reflux finding scores (r² = 0.45, P = .07). There was no significant positive correlation between airway impedance and esophageal impedance values (r² = 0.097-0.138, P > .2). Patients taking proton pump inhibitors had significantly lower mean airway impedance values (706 ± 450 Ω) than patients not taking them (1069 ± 809 Ω, P = .06). Patients who had evidence of aspiration on video fluoroscopic swallow studies had lower airway impedance (871 ± 615 Ω) than patients without aspiration (1247 ± 360 Ω, P = .008). Inhaled steroids did not impact airway impedance levels (P = .7).

CONCLUSIONS

Airway impedance may be an important diagnostic tool to diagnose gastroesophageal reflux or aspiration, eliminating the subjectivity of airway appearance alone.

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.

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.

The role of endoscopy in the management of gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is a common disease that may cause a huge economic burden. Endoscopy is performed not only to rule out other organic diseases but also to diagnose reflux esophagitis or Barrett's esophagus. Non‐erosive GERD (non‐erosive reflux disease [NERD]) is called endoscopy‐negative GERD; however, GERD‐related findings could be obtained through histological assessment, image‐enhanced endoscopy, and new endoscopic modalities in patients with NERD. Moreover, endoscopy is useful to stratify the risk for the development of GERD. In addition, endoscopic treatments have been developed. These techniques could significantly improve patients’ quality of life as well as symptoms.

The role of advanced endoscopy in the management of inflammatory digestive diseases (upper gastrointestinal tract)

The Japan Gastroenterological Endoscopy Society held four serial symposia between 2019 and 2020 on the state-of-the-art of issues related to upper GI inflammatory diseases. This review discusses some of the topics addressed in these symposia. The papers regarding nonerosive reflux disease, recent improvements in intraesophageal pH-impedance monitoring and endoscopic diagnosis using image-enhanced endoscopy have been published. Many publications have addressed its usefulness in endoscopic treatment of gastroesophageal reflux disease such as anti-reflux mucosectomy. In the management of eosinophilic esophagitis, since the symptoms are subjective, objective indicators have been sought, and ultrasonography and high-resolution manometry may be useful tools for evaluation. The natural course of this condition, especially of asymptomatic cases, is not well clarified. Some newly developed anti-acid or anti-inflammatory medicines are now under investigation. With regard to autoimmune gastritis, because of widespread medical examinations, diagnosis of asymptomatic cases has been increasing. Recently, its endoscopic characteristics have become clear and the natural history of these conditions is being elucidated. The Kyoto Classification of Gastritis has been reported to be useful not only for Helicobacter pylori diagnosis but also for identification of risks of gastric cancer. Its usefulness is now recognized in Asia and Europe.

Mucosal Integrity Testing Can Detect Differences in the Rectums of Patients with Inflammatory Bowel Disease Compared to Controls: A Pilot Study

BACKGROUND

While the pathogenesis of inflammatory bowel disease (IBD) is incompletely understood, disruption of epithelial integrity is suspected to play a prominent role in disease initiation and progression. Currently, there is no convenient way to measure this in vivo.

AIMS

Our aim is to determine whether a mucosal integrity (MI) testing device that has been used to measure MI in the esophagus can also be used to measure barrier function in the colon during colonoscopy.

METHODS

Mucosal integrity testing was measured in patients with IBD (n = 17) and controls (n = 7) during colonoscopy. During the procedure, an MI catheter was passed down the working channel of the colonoscope and placed along the mucosal wall to measure MI in the rectum, left, transverse, and right colon. In patients with IBD, MI measurements and biopsies were taken in areas which appeared inflamed when present. We then determined if there was a significant difference in MI between patients with IBD and controls.

RESULTS

MI was significantly higher in the rectum of patients with IBD (CD and UC combined) versus control colons [767 (618-991) vs. 531 (418-604) ohms, P < 0.01]. There were no significant differences in MI among patients with IBD versus controls in the right, transverse, or left colon. Within the IBD group, there were no significant differences in MI between inflamed versus non-inflamed rectums. There was no correlation between quality of life scores or endoscopic severity with MI, though this study was likely underpowered to detect these differences.

CONCLUSION

Rectal MI is significantly higher in patients with IBD versus controls. Future studies are needed to determine how this information can be used clinically.

Gastro-oesophageal reflux disease

Gastro-oesophageal reflux disease (GERD) is a common disorder in adults and children. The global prevalence of GERD is high and increasing. Non-erosive reflux disease is the most common phenotype of GERD. Heartburn and regurgitation are considered classic symptoms but GERD may present with various atypical and extra-oesophageal manifestations. The pathophysiology of GERD is multifactorial and different mechanisms may result in GERD symptoms, including gastric composition and motility, anti-reflux barrier, refluxate characteristics, clearance mechanisms, mucosal integrity and symptom perception. In clinical practice, the diagnosis of GERD is commonly established on the basis of response to anti-reflux treatment; however, a more accurate diagnosis requires testing that includes upper gastrointestinal tract endoscopy and reflux monitoring. New techniques and new reflux testing parameters help to better phenotype the condition. In children, the diagnosis of GERD is primarily based on history and physical examination and treatment vary with age. Treatment in adults includes a combination of lifestyle modifications with pharmacological, endoscopic or surgical intervention. In refractory GERD, optimization of proton-pump inhibitor treatment should be attempted before a series of diagnostic tests to assess the patient's phenotype.

The role of endoscopy in eosinophilic esophagitis: from diagnosis to therapy

Endoscopy plays an important role in the management of eosinophilic esophagitis (EoE), since it is involved in the diagnosis, follow-up and treatment of this condition. In patients presenting with food impaction, dysphagia and other symptoms of suspected EoE, esophago-gastric-duodenoscopy (EGD) with multiple esophageal biopsies should be performed to confirm or rule out the diagnosis of EoE. The EREFS system, a validated instrument for assessment of the endoscopically-identified esophageal features in EoE (edema, rings, exudates, longitudinal furrows and strictures), is currently used in the clinical practice for the evaluation of the macroscopic aspects of esophageal mucosa during EGD. Multiple esophageal biopsies are mandatory to further confirm EoE diagnosis and subsequent response to treatment, since symptoms reported by patients do not always correlate with histological activity, and considering the low sensitivity of endoscopic assessment; a cut-off of ≥15 eosinophils in at least one high power field is the density threshold considered the standard for diagnosis (sensitivity 100%, specificity 96%). Other histological features, included in the EoE histologic scoring system (EoEHSS), are supportive for the diagnosis and for the assessment of inflammatory activity during follow-up. Esophageal dilation, performed either with Savary dilators/bougie or hydrostatic balloon, is an effective and safe treatment in both adult and pediatric EoE patients with fibrostenotic features, mainly in association with other therapeutic strategies which can control eosinophilic inflammation.

Esophageal reflux hypersensitivity: Non-GERD or still GERD?

The most recent iteration of the classifications for functional esophageal disorders, Rome IV, proposed relevant modifications of the previous definitions for Rome III. They specifically considered increased esophageal acid exposure as the marker of gastroesophageal reflux disease (GERD), including the remaining part of non-erosive reflux disease patients with normal acid in the group with functional alterations, considering both reflux hypersensitivity and functional heartburn. However, recent pathophysiological and therapeutic data suggest the need for a return to including reflux hypersensitivity in the GERD spectrum. Indeed, physiologic alterations in esophageal mucosal integrity and chemical clearance, the presence of microscopic esophagitis, and strict symptom-reflux association support the concept that reflux hypersensitivity pertains to GERD. Surgical anti-reflux therapy has resulted in positive outcomes, even in the long term, in patients with reflux hypersensitivity and not in those with functional heartburn. Moreover, clinical trials using neuromodulators have been scarce and provided conflicting results. As a result, the real progress of the Rome IV classifications is in dispute. This article aims to summarize the most recent knowledge of non-erosive reflux disease and reflux hypersensitivity to discuss the utility of Rome IV criteria in the identification and management of functional esophageal disorders.

The esophageal mucosal barrier in health and disease: mucosal pathophysiology and protective mechanisms

Diseases of the esophagus, such as gastroesophageal reflux (GER), can result in changes to mucosal integrity, neurological function, and the microbiome. Although poorly understood, both age and GER can lead to changes to the enteric nervous system. In addition, the esophagus has a distinct microbiome that can be altered in GER. Mucosal integrity is also at risk due to persistent damage from acid. Diagnostic tools, such as ambulatory pH/impedance testing and esophageal mucosal impedance, can assess short-term and longitudinal GER burden, which can also assess the risk for mucosal compromise. The quality of the mucosal barrier is determined by its intercellular spaces, tight junctions, and tight junction proteins, which are represented by claudins, occludins, and adhesion molecules. Fortunately, there are protective factors for mucosal integrity that are secreted by the esophageal submucosal mucous glands and within saliva that are augmented by mastication. These protective factors have potential as therapeutic targets for GER. In this article, we aim to review diagnostic tools used to predict mucosal integrity, aging, and microbiome changes to the esophagus and esophageal mucosal defense mechanisms.

Baseline impedance via manometry and ambulatory reflux testing are not equivalent when utilized in the evaluation of potential extra-esophageal gastroesophageal reflux disease

Background

Esophageal baseline impedance (BI) shows promise for the diagnosis of gastroesophageal reflux disease (GERD), but means of acquisition and relevance to extra-esophageal manifestations of GERD (EE-GERD) remain unclear. In this study we aim to (I) evaluate concordance between BI as measured by 24-hour pH-impedance (pH-MII) and high-resolution impedance manometry (HRIM), and (II) assess relationship to potential EE-GERD symptoms.

Methods

In this prospective open cohort study, patients presenting for outpatient HRIM and pH-MII studies were prospectively enrolled. All patients completed the GERD-HRQL, NOSE, and respiratory symptom index questionnaire (RSI), plus questions regarding wheezing and dental procedures. HRIM and pH-MII were evaluated with calculation of BI. Correlations were assessed using either Pearson’s correlation or Spearman’s rank coefficients.

Results

70 HRIM patients were enrolled, 35 of whom underwent pH-MII. There was no correlation between BI measurements as assessed by HRIM and pH-MII proximally, but there was moderate-weak correlation distally (r=0.34 to 0.5). Distal acid exposure time correlated with distal BI only for measurements by pH-MII (rho= −0.5 to −0.65), and not by HRIM. There was no relationship between proximal acid exposure time and proximal BI. There were no correlations when comparing proximal or distal BI measurements, acid exposure times, and impedance events to symptoms.

Conclusions

Concordance between BI as measured by HRIM and pH-MII is poor, especially proximally, suggesting that these two methods are not interchangeable. There is no correlation between BI both distally/proximally and symptoms of either GERD/EE-GERD, suggesting that many symptoms are unrelated to acid or that BI is not an adequate marker to assess EE-GERD symptoms.

The Usefulness of Esophageal Baseline Impedance Levels for the Diagnosis of Nonerosive Reflux Disease and the Proper Time for Measurement in Endoscopy-negative Korean Patients With Esophageal or Supraesophageal Symptoms

Background/Aims

Low baseline impedance levels (BILs) have been suggested to be evidence of GERD. The aim of this study is to investigate the usefulness of esophageal BILs for the diagnosis of nonerosive reflux disease (NERD) and the proper time for measurement in endoscopy-negative Korean patients with esophageal or supraesophageal symptoms.

Methods

Endoscopy-negative patients with esophageal or supraesophageal symptoms who underwent esophageal multichannel intraluminal impedance-pH monitoring were included. BILs were measured in the proximal and distal esophagus around 10 minutes before meals, 10 minutes and 30 minutes after meals, 30 minutes before the start of nighttime sleep, and 30 minutes and 60 minutes after the start of nighttime sleep.

Results

A total of 104 patients were included in the study. Distal and proximal esophageal BILs were decreased after meal ingestion. The BILs of the distal esophagus were significantly lower at all time points in the NERD group, but not in the reflux hypersensitivity (RH) group, compared with the functional group. The area under the receiver operating characteristic curve for the diagnosis of NERD was significant at all time points, but that for the diagnosis of RH was not. The cut-off value of 2375 Ω or 2125 Ω measured around 30 minutes before or 60 minutes after the start of nighttime sleep, respectively, were appropriate for the diagnosis of NERD.

Conclusion

The BILs of the distal esophagus measured at time points before or after the start of nighttime sleep appear to be useful for the diagnosis of NERD, but not for the diagnosis of RH, in endoscopy-negative Korean patients with esophageal or supraesophageal symptoms.

A SIGE-SINGEM-AIGO technical review on the clinical use of esophageal reflux monitoring

Patients with esophageal symptoms potentially associated with gastroesophageal reflux disease such as heartburn, regurgitation, chest pain, or cough represent one of the most frequent reasons for referral to gastroenterological evaluation. The utility of esophageal reflux monitoring in clinical practice is: (1) to accurately define reflux burden, (2) to segregate patients according to reflux monitoring results as true GERD, reflux hypersensitivity and functional heartburn, and (3) to establish a treatment plan. With this in mind, in the last decade, investigations and technical advances, with the introduction of impedance-pH monitoring and wireless pH capsule, have enhanced our understanding and management of GERD. The following recommendations were discussed and approved after a comprehensive review of the medical literature pertaining to reflux testing techniques and their recent application. This review created under the auspices of the Società Italiana di Gastroenterologia ed Endoscopia Digestiva (SIGE), Società Italiana di Neuro-Gastro-Enterologia e Motilità (SINGEM) and Associazione Italiana Gastroenterologi ed Endoscopisti Digestivi Ospedalieri (AIGO) is intended to help clinicians in applying reflux studies in the most fruitful manner within the context of their patients with esophageal symptoms.

Distal Esophageal Impedance Measured by High-resolution Esophageal Manometry With Impedance Suggests the Presence of Barrett's Esophagus

Background/Aims

Barrett's esophagus (BE) is characterized by intestinal metaplasia in the distal esophagus. The aims of this study are to: (1) Compare baseline distal esophageal impedance (DEI) using high-resolution esophageal manometry with impedance (HREMI) in patients with BE, esophagitis, and healthy volunteers and (2) Correlate length of low impedance on HREMI in patients with BE to the length of endoscopic BE.

Methods

Patients with BE or esophagitis who underwent HREMI were included. Ten volunteers had HREMI. Baseline DEI was calculated from HREMI using the landmark segment. In patients with BE, the impedance was plotted to measure the extent of plotted low impedance (PLI) and visual low impedance (VLI). Lengths of VLI and PLI were correlated to endoscopic length of BE by Prague score.

Results

Forty-five patients were included (16 BE; 19 esophagitis; 10 volunteers). BE patients had lower baseline DEI at the first, second, and third sensors above the lower esophageal sphincter (mean ± SEM: 1.37 ± 0.45, 0.97 ± 0.27, and 0.81 ± 0.20) compared to volunteers (8.73 ± 0.60, 8.20 ± 0.73, and 6.94 ± 0.99; P < 0.001). Baseline DEI was lower in BE than esophagitis patients (2.98 ± 0.65, 2.49 ± 0.56, and 2.01 ± 0.51) at the first, second, and third sensors (P < 0.052 for second and third sensors); ie, BE < esophagitis < controls. PLI and VLI had a stronger correlation to circumferential score (r² = 0.84 and 0.83) than maximal score (r² = 0.76 and 0.68).

Conclusions

Baseline DEI is lower in BE compared with esophagitis and healthy volunteers. The length of low impedance correlates to the endoscopic extent of BE. Thus, impedance values during HREMI may help suggest the presence and extent of BE or esophagitis.

Impedance and Histologic Characteristics of the Sub-Laryngeal Esophagus Distinguish Eosinophilic Esophagitis From Other Esophageal Disorders

BACKGROUND & AIMS

The region of the esophagus 15-17 cm below the incisors, called the sub-upper esophageal sphincter (sub-UES), has not been characterized in adults with eosinophilic esophagitis (EoE) but appears different during endoscopy. We investigated how the sub-UES differs from the remaining esophagus in patients with EoE and aimed to determine whether these differences be used to distinguish patients with EoE from those with lichen planus.

METHODS

We performed a prospective study of 14 patients with EoE, 7 patients with lichen planus (based on presence of Civatte bodies, dysphagia, and/or narrow esophagus with thin esophageal mucosa without signs of EoE), and 20 patients undergoing upper endoscopy for upper gastrointestinal or with dysphagia but without features of EoE (controls) at a single medical center from 2015 through 2018. Biopsies from the distal, middle, and sub-UES regions of the esophagus were analyzed by histology, quantitative PCR, and immunohistochemistry. We measured mucosal impedance (MI) in all subjects at the sub-UES and 2 cm, 5 cm, and 10 cm from the gastro-esophageal junction.

RESULTS

Patients with EoE had significantly fewer eosinophils (median, 2 eosinophils/high-powered field [HPF]; range, 0-8 eosinophils/HPF) in sub-UES tissues compared with distal esophagus (median, 50 eosinophils/HPF; range, 22.5-60.8 eosinophils/HPF; P < .0001) or middle esophagus (median, 32 eosinophils/HPF; range, 19.3-60; P < .0001). Sub-UES tissues from patients with EoE had significantly less basal cell hyperplasia (P < .01), papillary elongation (P < .01), and dilated intercellular spaces (P < .01) than middle or and distal esophagus. MI in the sub-UES did not differ significantly between patients with EoE vs controls (P = .24), but was significantly lower in patients with lichen planus (median, 1344 ohms; range, 1046-1488) than patients with EoE (median, 2880 ohms; range, 2149-4858) (P < .001). mRNA and protein expression patterns did not differ significantly in the sub-UES of patients with EoE vs controls, except for expression of desmoglein-1, which was increased in sub-UES tissues from patients with EoE.

CONCLUSIONS

Sub-UES tissues from patients with EoE differ in numbers of eosinophils, histologic features, and MI compared to controls or patients with lichen planus. These features might help to distinguish these 2 diseases.

Mucosal impedance for esophageal disease: evaluating the evidence

Impedance has traditionally been employed in esophageal disease as a means to assess bolus flow and reflux episodes. Recent and ongoing research has provided new and novel applications for this technology. Measurement of esophageal mucosal impedance, via either multichannel intraluminal impedance catheters or specially designed endoscopically deployed impedance catheters, provides a marker of mucosal integrity. Mucosal impedance has been shown to segregate gastroesophageal reflux disease (GERD) and eosinophilic esophagitis from non-GERD controls and may play a role in predicting response to reflux intervention. More data are needed with regard to other esophageal subgroups, outcome studies, and functional disease. Our paper reviews the history of impedance in esophageal disease, the means of assessing baseline and mucosal impedance, data with regard to the newly developed mucosal impedance probes, the clinical utility of mucosal impedance in specific clinical conditions, and limitations in our existing knowledge, along with suggestions for future studies.

Impedance in the evaluation of the esophagus

The aim of this paper is to review esophageal electrical impedance technologies and to discuss the use of these technologies for physiological measurements, diagnostics, and therapy of esophageal disease. In order to develop a better understanding of the pathophysiology of and improve the diagnosis of esophageal disorders, such as gastroesophageal reflux disease (GERD) and achalasia, several new diagnostic tests, including intraluminal impedance, esophageal mucosal impedance, and the functional luminal imaging probe, have been developed. These technologies have proven valuable for assessment of the esophagus in recent years. They provide information on esophageal flow properties, mucosal integrity, lumen shape, and distensibility in esophageal disorders, in particular for GERD and achalasia. Despite their promise and novel clinical studies, the potential of these technologies has been far from realized. New multidisciplinary approaches will contribute to our understanding and interpretation of esophageal impedance data and disease mechanisms.

New Developments in the Diagnosis and Management of Gastroesophageal Reflux

PURPOSE OF REVIEW

To examine recent key developments in the pathophysiology, diagnosis, and treatment of gastroesophageal reflux disease (GERD).

RECENT FINDINGS

Newer research has suggested cytokine-mediated inflammation may play a role in the physiology of GERD, implying that the underlying mechanism may not be entirely related to chemical damage due to acid. Aided by novel technologies, diagnostic testing is also moving toward elucidating individual mechanisms and better defining specific GERD phenotypes with the goal of providing directed therapy. This is especially important in current times given the increase in coverage of adverse events reportedly linked to long-term proton pump inhibitor use.

SUMMARY

As patients are looking for potential alternatives, we highlight the key recent updates in pathophysiology and understanding of GERD and current medical and endoscopic/surgical options and explore the exciting treatments in the pipeline.

Baseline Impedance Measured During High-resolution Esophageal Impedance Manometry in Patients With Rumination Syndrome is as Abnormal as in Patients With GERD

GOALS AND BACKGROUND

Baseline impedance measured during high-resolution impedance manometry (HRIM) can distinguish patients with gastroesophageal reflux disease (GERD) from controls, presumably due to differences in esophageal acid exposure. The characteristics of regurgitation and reflux in rumination syndrome and GERD are very different, and thus we investigated whether baseline esophageal impedance would differ in these 2 patient groups compared with controls.

STUDY

We compared 20 patients with rumination syndrome with 20 patients who had GERD and 40 controls. Baseline impedance was measured over 15 seconds during the landmark period of HRIM in all 18 impedance sensors on a HRIM catheter.

RESULTS

The mean distal baseline impedance measured in ohms during HRIM was 1336 Ω [95% confidence interval (CI)=799, 1873) in patients with GERD, 1536 Ω in rumination syndrome (95% CI=1012, 2061), and 3379 Ω in controls (95% CI=2999, 3759) (P<0.0001). Proximal impedance was significantly lower in the GERD and rumination groups compared with controls; rumination syndrome (2026; 95% CI=1493, 2559 Ω), GERD (2572; 95% CI=2027, 3118 Ω), and controls (3412; 95% CI=3026, 3798 Ω) (P<0.001).

CONCLUSIONS

Baseline impedance measured during HRIM in patients with rumination syndrome is significantly lower than controls and appears similar to patients with GERD both in the proximal and distal esophagus. These findings suggest that the postprandial regurgitation in rumination syndrome alters both the distal and proximal esophageal mucosal barrier.

Lower oesophageal sphincter identification for gastro-oesophageal reflux monitoring: The step-up method revisited with use of basal impedance

Background

Oesophageal manometry is the gold standard for accurate positioning of multichannel intraluminal impedance pH (MII-pH) monitoring. The pH step-up method is not as accurate as oesophageal manometry and needs patients to be off proton pump inhibitor (PPI) therapy.

Objective

This study aimed to evaluate the feasibility of the impedance step-up method for lower oesophageal sphincter (LOS) localisation.

Methods

A total of 100 patients who underwent 24-hour MII-pH monitoring were enrolled. High-resolution manometry (HRM) was performed before MII-pH monitoring in order to locate the LOS by a different operator. The impedance step-up was defined as an increase of ≥50% with respect to gastric baseline. Lin's concordance correlation coefficient (ρ_c ) with 95% Bland-Altman limits of agreement (LOA) and Spearman's rho correlation coefficient were used when appropriate.

Results

The median impedance step-up was on average 0.8 cm caudal to the manometric upper border of the LOS. Agreement between two step-up impedance performances and inter-observer agreement were excellent (ρ_c  = 0.98 and 0.95), although the LOA ranges were wide (-2.4 to 4.0 cm). Impedance step-up performances were similar between patients off and on PPI.

Conclusions

We have described an alternative new method for pH impedance probe positioning using impedance step-up. Although less accurate than HRM in locating the LOS, it has excellent intra- and inter-observer agreement.

Assessing different diagnostic tests for gastroesophageal reflux disease: a systematic review and network meta-analysis

BACKGROUND

The aim of the current systematic review and network meta-analysis (NMA) was to assess the diagnostic characteristics of the gastroesophageal reflux disease questionnaire (GERDQ), proton-pump inhibitor (PPI) test, baseline impedance, mucosal impedance, dilated intercellular spaces (DIS), salivary pepsin, esophageal pH/pH impedance monitoring and endoscopy for gastroesophageal reflux disease (GERD).

METHODS

We searched PubMed and the Cochrane Controlled Trial Register database (from inception to 10 April 2018) for studies assessing the diagnostic characteristics of the GERDQ, PPI test, baseline impedance, mucosal impedance, DIS, or salivary pepsin and esophageal pH/pH impedance monitoring/endoscopy in patients with GERD. Direct pairwise comparison and a NMA using Bayesian methods under random effects were performed. We also assessed the ranking probability.

RESULTS

A total of 40 studies were identified. The NMA found no significant difference among the baseline impedance, mucosal impedance, and esophageal pH/pH impedance monitoring and endoscopy in terms of both sensitivity and specificity. It was also demonstrated that the salivary pepsin detected by the Peptest device had comparable specificity to esophageal pH/pH impedance monitoring and endoscopy. Results of ranking probability indicated that esophageal pH/pH impedance monitoring and endoscopy had highest sensitivity and specificity, followed by mucosal impedance and baseline impedance, whereas GERDQ had the lowest sensitivity and PPI test had the lowest specificity.

CONCLUSIONS

In a systematic review and NMA of studies of patients with GERD, we found that baseline impedance and mucosal impedance have relatively high diagnostic performance, similar to esophageal pH/pH impedance monitoring and endoscopy.

The Altered Mucosal Barrier Function in the Duodenum Plays a Role in the Pathogenesis of Functional Dyspepsia

BACKGROUND

An altered gastrointestinal barrier function is reportedly associated with the pathogenesis of functional dyspepsia (FD); however, the pathogenesis of FD has not yet been fully elucidated.

AIMS

The objective of the present study was to determine whether the mucosal barrier function is impaired in patients with FD and to investigate the mechanisms underlying FD.

METHODS

The present study included patients with FD (FD group, n = 24), non-FD patients with abdominal symptoms (symptomatic control group, n = 14), and patients with no abdominal symptoms (asymptomatic control group, n = 20). The groups were compared regarding the mucosal electrical impedance (MI) values of the stomach and duodenum, which were measured using a tissue conductance meter during esophagogastroduodenoscopy.

RESULTS

There were no significant differences between the three groups in the MI of the stomach. In contrast, the duodenal MI of the FD group (17.8 ± 4.3 Ω) was significantly lower than those of the symptomatic control group (27.2 ± 6.4 Ω, p < 0.0001) and asymptomatic control group (23.0 ± 7.4 Ω, p = 0.016). The expression of zonula occludens-1 (ZO-1) was significantly lower in the FD group than in the symptomatic control group (p = 0.011), where ZO-1 was positively correlated with the duodenal MI (β = 0.513, p = 0.017). The interleukin (IL)-1β expression was significantly higher in the FD group than in the symptomatic control group (p = 0.041), where IL-1β was inversely correlated with the duodenal MI (β = - 0.600, p = 0.004).

CONCLUSIONS

The mucosal barrier function of the duodenum was altered in patients with FD. Both a decreased ZO-1 and increased IL-1β may play a role in the pathogenesis of FD.

Mucosal impedance testing: A new diagnostic testing in gastroesophageal reflux disease

Current diagnostic testing for gastroesophageal reflux disease (GERD) include endoscopy, ambulatory pH and intraluminal impedance monitoring. However, they are suboptimal and do not measure chronicity of reflux. Recently, a mucosal impedance (MI) device has been developed to measure esophageal epithelial conductivity changes, a marker of chronic GERD. The aim of this review is to summarize the use of MI testing (MIT) for the evaluation and management of esophageal disease. MIT is a minimally invasive and simple through-the-scope procedure performed during endoscopy. It allows for a rapid derivation of MI values within seconds without an uncomfortable overnight pH- impedance catheter. The MI values can correlate with histological findings of epithelial barrier dysfunction, normalize with effective treatment, and show promise for differentiating GERD from non-GERD conditions such as eosinophilic esophagitis (EoE). In conclusion, endoscopic MIT measurement can differentiate esophageal disorders instantly during endoscopy. It may not only serve as an important tool in diagnosing of GERD but also help guide therapy in clinically difficult situations as a surrogate to predict the treatment response.

Ineffective esophageal motility: Concepts, future directions, and conclusions from the Stanford 2018 symposium

BACKGROUND

Ineffective esophageal motility (IEM) is a heterogenous minor motility disorder diagnosed when ≥50% ineffective peristaltic sequences (distal contractile integral <450 mm Hg cm s) coexist with normal lower esophageal sphincter relaxation (integrated relaxation pressure < upper limit of normal) on esophageal high-resolution manometry (HRM). Ineffective esophageal motility is not consistently related to disease states or symptoms and may be seen in asymptomatic healthy individuals.

PURPOSE

A 1-day symposium of esophageal experts reviewed existing literature on IEM, and this review represents the conclusions from the symposium. Severe IEM (>70% ineffective sequences) is associated with higher esophageal reflux burden, particularly while supine, but milder variants do not progress over time or consistently impact quality of life. Ineffective esophageal motility can be further characterized using provocative maneuvers during HRM, especially multiple rapid swallows, where augmentation of smooth muscle contraction defines contraction reserve. The presence of contraction reserve may predict better prognosis, lesser reflux burden and confidence in a standard fundoplication for surgical management of reflux. Other provocative maneuvers (solid swallows, standardized test meal, rapid drink challenge) are useful to characterize bolus transit in IEM. No effective pharmacotherapy exists, and current managements target symptoms and concurrent reflux. Novel testing modalities (baseline and mucosal impedance, functional lumen imaging probe) show promise in elucidating pathophysiology and stratifying IEM phenotypes. Specific prokinetic agents targeting esophageal smooth muscle need to be developed for precision management.

Evaluation of Baseline Impedance During Water-perfused High Resolution Impedance Manometry in Patients With Symptomatic GERD

GOALS

We aimed to investigate the hypothesis whether baseline impedance measured during water-perfused high resolution impedance manometry (HRIM) can help discriminate patients with reflux symptoms from the controls and predict the response to the proton pump inhibitors (PPIs).

BACKGROUND/AIM

Baseline impedance measured during solid-state HRIM can reliably discriminate patients with gastroesophageal reflux disease (GERD) from controls.

STUDY

We enrolled consecutive patients with typical reflux symptoms and healthy controls for the measurement of baseline impedance during the landmark period of HRIM. All patients were given PPIs and PPI response was assessed after 8 weeks of the treatment.

RESULTS

Baseline mucosa impedance measured during HRIM was lower in GERD patients than the controls (1861±183 vs. 3371±250 Ω; P<0.001). Baseline impedance during water-perfused HRIM had moderate diagnostic accuracy for differentiating symptomatic GERD with an area under the curve of 0.853 on receiver operating characteristics analysis. A threshold of 2530 Ω for baseline impedance had a sensitivity of 88.3% and specificity of 82.4% for GERD with a positive predictive value of 83.4% and negative predictive value of 87.6%. Among symptomatic GERD patients, poor PPI responders had higher baseline impedance than those without it (2340±260 vs. 1479±189 Ω; P=0.02). BMI negatively correlated to base impedance in either controls (r=-0.59; P=0.012) or GERD patients (r=-0.47; P=0.047).

CONCLUSIONS

Baseline impedance measurement during water-perfused HRIM helps differentiate patients with typical reflux symptoms from controls and also serves as a potential utility in predicting PPI response.

Evaluation of Esophageal Mucosal Integrity in Patients with Gastroesophageal Reflux Disease

BACKGROUND

Impaired esophageal mucosal integrity plays a role in causing symptoms of gastroesophageal reflux disease (GERD). Recently, the assessment of esophageal baseline impedance (BI) using the multichannel intraluminal impedance-pH (MII-pH) test was suggested as a surrogate technique for the study of esophageal mucosal integrity and was reported to be useful in distinguishing GERD from non-GERD. However, measuring BI requires a 24-h testing period, is complicated, and causes considerable patient discomfort.

SUMMARY

Recently, endoscopy-guided catheters that can measure mucosal impedance (MI) and mucosal admittance (MA), which is the inverse of impedance, were developed, and their usefulness in measuring MI and MA for the diagnosis of GERD has been reported. In these studies, esophageal MI values were significantly lower in patients with GERD than in those without GERD. In contrast, esophageal MA was significantly higher in patients with GERD than in those without. Furthermore, we reported that MA is inversely correlated with BI and correlated with acid exposure time. Key Messages: Endoscopy-guided real-time measurement of MI and MA may allow the estimation of mucosal integrity and may be a useful diagnostic tool for patients with GERD in a manner similar to 24-h MII-pH monitoring.

Modern diagnosis of GERD: the Lyon Consensus

Clinical history, questionnaire data and response to antisecretory therapy are insufficient to make a conclusive diagnosis of GERD in isolation, but are of value in determining need for further investigation. Conclusive evidence for reflux on oesophageal testing include advanced grade erosive oesophagitis (LA grades C and D), long-segment Barrett's mucosa or peptic strictures on endoscopy or distal oesophageal acid exposure time (AET) >6% on ambulatory pH or pH-impedance monitoring. A normal endoscopy does not exclude GERD, but provides supportive evidence refuting GERD in conjunction with distal AET <4% and <40 reflux episodes on pH-impedance monitoring off proton pump inhibitors. Reflux-symptom association on ambulatory reflux monitoring provides supportive evidence for reflux triggered symptoms, and may predict a better treatment outcome when present. When endoscopy and pH or pH-impedance monitoring are inconclusive, adjunctive evidence from biopsy findings (histopathology scores, dilated intercellular spaces), motor evaluation (hypotensive lower oesophageal sphincter, hiatus hernia and oesophageal body hypomotility on high-resolution manometry) and novel impedance metrics (baseline impedance, postreflux swallow-induced peristaltic wave index) can add confidence for a GERD diagnosis; however, diagnosis cannot be based on these findings alone. An assessment of anatomy, motor function, reflux burden and symptomatic phenotype will therefore help direct management. Future GERD management strategies should focus on defining individual patient phenotypes based on the level of refluxate exposure, mechanism of reflux, efficacy of clearance, underlying anatomy of the oesophagogastric junction and psychometrics defining symptomatic presentations.

Mucosal Impedance: a New Approach to Diagnosing Gastroesophageal Reflux Disease and Eosinophilic Esophagitis

PURPOSE OF REVIEW

In this review, we discuss current diagnostic testing modalities for both gastroesophageal reflux disease (GERD) and eosinophilic esophagitis (EoE) and then introduce mucosal impedance (MI), a novel technology that measures epithelial integrity in real time during endoscopy. We describe the advantages and disadvantages of MI as compared with traditional diagnostic testing.

RECENT FINDINGS

We review studies that demonstrate that GERD and EoE have distinct MI patterns, and that physicians can accurately diagnose and distinguish the two during endoscopy with minimal time added to the procedure. We also review studies showing that MI has the capability to assess treatment response in both GERD and EoE and that it can be used to diagnose GERD in patients with extraesophageal reflux symptoms. Mucosal impedance testing is a major advancement in the diagnosis of GERD and EoE. Future studies are planned to assess whether MI can be used as a treatment endpoint in EoE and whether it can be used to predict response to anti-reflux surgery.

Esophageal Mucosal Impedance Patterns Discriminate Patients With Eosinophilic Esophagitis From Patients With GERD

BACKGROUND & AIMS

It is a challenge to make a diagnosis of eosinophilic esophagitis (EoE) because its symptoms and histologic features overlap with those of gastroesophageal reflux disease (GERD). A minimally invasive device was recently developed to detect mucosal impedance (MI) that measures epithelial integrity during upper endoscopy. We aimed to quantify MI along the esophagus and identify patterns that differentiated patients with and without GERD from those with EoE, and determine whether MI values and patterns are sufficient to identify patients with EoE using histologic findings as a reference.

METHODS

We performed a retrospective analysis of 91 patients with upper gastrointestinal symptoms referred for diagnostic testing for GERD and EoE from 2012 through 2014 (discovery set). During the first endoscopy, MI measurements were obtained at 2, 5, and 10 cm from the squamocolumnar junction. GERD was confirmed by ambulatory pH tests, and histologic analyses of biopsies were used to confirm EoE. We then used statistical modeling to identify MI patterns along the esophagus (at 10 cm, 5 cm, and 2 cm) that associated with GERD vs EoE. We validated our findings in a prospective cohort of 49 patients undergoing elective upper endoscopy for dysphagia, from 2015 through 2016, testing the ability of MI patterns to identify patients with vs. without EoE.

RESULTS

We found patients with EoE to have a unique MI pattern, with low values along the esophageal axis. MI measurements at 5 cm could discern patients with normal vs abnormal mucosa with 83% sensitivity and 79% specificity, and patients with EoE vs GERD with 84% sensitivity and 70% specificity; these measurements differentiated the patient populations with the highest level of accuracy of any of the 6 measurements tested. In the validation study, a rater using the esophageal MI pattern identified patients with EoE with 100% sensitivity and 96% specificity.

CONCLUSION

We identified and validated a pattern of MI along the esophagus that can identify patients with EoE vs normal mucosa or GERD with high levels of sensitivity.

Assessing Old and New Diagnostic Tests for Gastroesophageal Reflux Disease

A detailed critique of objective measurements of gastroesophageal reflux disease (GERD) would improve management of patients suspecting of having reflux, leading to rational selection of treatment and better outcomes. Many diagnostic tests for GERD have been developed over the past decades. We analyze their development, positive- and negative-predictive values, and ability to predict response to treatment. These features are important for development of medical, surgical, and endoscopic therapies for GERD. We discuss the value of available diagnostic tests and review their role in management of patients with persistent reflux symptoms despite adequate medical or surgical treatment. This is becoming a significant health economic problem, due to the widespread use of proton pump inhibitors. GERD is believed to cause nonesophageal symptoms, such as those provoked by ear, nose, throat, or respiratory disorders. We analyze the value of GERD diagnostic tests in evaluation of these troublesome, nonesophageal symptoms.

Utility of esophageal mucosal impedance as a diagnostic test for esophageal disease

PURPOSE OF REVIEW

The aim of this review is to summarize the use of direct mucosal impedance (MI) for the evaluation and management of esophageal diseases.

RECENT FINDINGS

Esophageal multichannel intraluminal impedance with pH (MII-pH) monitoring has been considered the most sensitive test for gastroesophageal reflux disease (GERD), but recent studies have failed to establish impedance parameters that reliably predict treatment response to medical and surgical GERD therapies. MII-pH uses a catheter passed through the nose, which is uncomfortable for patients, and the test is compromised by the day-to-day variability of reflux patterns. Recently, an MI device has been developed that can be passed through the working channel of an endoscope to measure esophageal epithelial conductivity as a marker of chronic GERD. The MI values so obtained are available within seconds, correlate with histological findings of epithelial barrier dysfunction, normalize with effective treatment, and show promise for diagnosing eosinophilic esophagitis and for distinguishing it from GERD.

SUMMARY

MI can differentiate esophageal disorders instantly during endoscopy, and can monitor treatment responses in GERD and eosinophilic esophagitis.

In vivo measurement of vocal fold surface resistance

OBJECTIVES/HYPOTHESIS

A custom-designed probe was developed to measure vocal fold surface resistance in vivo. The purpose of this study was to demonstrate proof of concept of using vocal fold surface resistance as a proxy of functional tissue integrity after acute phonotrauma using an animal model.

STUDY DESIGN

Prospective animal study.

METHODS

New Zealand White breeder rabbits received 120 minutes of airflow without vocal fold approximation (control) or 120 minutes of raised intensity phonation (experimental). The probe was inserted via laryngoscope and placed on the left vocal fold under endoscopic visualization. Vocal fold surface resistance of the middle one-third of the vocal fold was measured after 0 (baseline), 60, and 120 minutes of phonation. After the phonation procedure, the larynx was harvested and prepared for transmission electron microscopy.

RESULTS

In the control group, vocal fold surface resistance values remained stable across time points. In the experimental group, surface resistance (X% ± Y% relative to baseline) was significantly decreased after 120 minutes of raised intensity phonation. This was associated with structural changes using transmission electron microscopy, which revealed damage to the vocal fold epithelium after phonotrauma, including disruption of the epithelium and basement membrane, dilated paracellular spaces, and alterations to epithelial microprojections. In contrast, control vocal fold specimens showed well-preserved stratified squamous epithelia.

CONCLUSIONS

These data demonstrate the feasibility of measuring vocal fold surface resistance in vivo as a means of evaluating functional vocal fold epithelial barrier integrity. Device prototypes are in development for additional testing, validation, and for clinical applications in laryngology.

LEVEL OF EVIDENCE

NA Laryngoscope, 127:E364-E370, 2017.

A baseline impedance analysis in neurologically impaired children: A potent parameter for estimating the condition of the esophageal mucosa

BACKGROUND

The aim of the present study was to investigate whether the baseline impedance (BI) value is a useful parameter to evaluate the condition of the esophageal mucosa in neurologically impaired (NI) children undergoing multichannel intraluminal impedance pH measurements (pH/MII).

METHODS

The retrospective study included 55 NI patients ≤15 years. The patients were divided into acid gastroesophageal reflux disease (GERD), non-acid GERD and GERD (-) groups. Furthermore, the patients in the acid GERD group were subdivided into erosive reflux disease (ERD) and non-erosive reflux disease (NERD) groups. pH/MII parameters and BI values (Z1-6) were compared among three groups or between two groups, respectively. A Spearman's correlation analysis was used for the correlation analysis of pH/MII parameters and BI values. A receiver operator characteristic curve analysis was used to evaluate the optimum cut-off values of BI to discriminate ERD patients.

KEY RESULTS

The BI values of the proximal and the distal channels in ERD group were significantly lower than those in NERD group. The BI values of the distal channels demonstrated significant negative correlations with acid exposure related pH/MII parameters. The optimal cut off value of BI in the most distal channel was determined to be 1500 Ω.

CONCLUSIONS & INFERENCES

The present study suggested that NI children with reflux esophagitis were likely to suffer mucosal damage up to the proximal esophagus and cut-off BI values may help estimate the presence of reflux esophagitis. Baseline impedance is a potent parameter, reflecting the esophageal mucosal damage in NI children who have difficulty in undergoing endoscopic examinations.

Endoscopic-Guided Measurement of Mucosal Admittance can Discriminate Gastroesophageal Reflux Disease from Functional Heartburn

Objectives:

A novel catheter that can measure mucosal admittance (MA), the inverse of impedance, was developed recently. In this pilot study, we aimed to clarify the usefulness of measuring MA for diagnosing gastroesophageal reflux disease (GERD).

Methods:

We conducted two prospective studies. In the first study, esophageal MA was evaluated in 120 participants (24 with erosive esophagitis, 82 with heartburn but non-erosive esophagitis, and 14 healthy volunteers) and compared with the endoscopic findings. In the second study, multichannel intraluminal impedance combined with pH (MII-pH) tests was conducted followed by an MA measurement in 33 patients with non-erosive esophagitis and proton pump inhibitor (PPI)-refractory heartburn. Based on the MII-pH test results, patients were divided into GERD or functional heartburn (FH). MA was compared between the GERD and FH groups and also compared with the baseline impedance (BI) and acid exposure time (AET).

Results:

Median MA at the distal esophagus was significantly higher in patients with erosive esophagitis compared with that in patients with non-erosive esophagitis and healthy volunteers (46.8, 13.1 and 6.5, respectively, P<0.01). In patients with PPI-refractory heartburn, the median MA at the distal esophagus was significantly higher in patients with GERD than those with FH (19.3 vs. 7.2, P<0.05). There was a negative correlation between MA and BI, and a positive correlation between MA and AET at the distal esophagus (r=−0.46 and r=0.53, P<0.05).

Conclusions:

Real-time measurement of MA is useful to distinguish GERD from non-GERD.

Recent advances in diagnostic testing for gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) has a large economic burden with important complications that include esophagitis, Barrett's esophagus, and adenocarcinoma. Despite endoscopy, validated patient questionnaires, and traditional ambulatory pH monitoring, the diagnosis of GERD continues to be challenging. Areas covered: This review will explore the difficulties in diagnosing GERD with a focus on new developments, ranging from basic fundamental changes (histology and immunohistochemistry) to direct patient care (narrow-band imaging, impedance, and response to anti-reflux surgery). We searched PubMed using the noted keywords. We included data from full-text articles published in English. Further relevant articles were identified from the reference lists of review articles. Expert commentary: Important advances in novel parameters in intraluminal impedance monitoring such as baseline impedance monitoring has created some insight into alternative diagnostic strategies in GERD. Recent advances in endoscopic assessment of esophageal epithelial integrity via mucosal impedance measurement is questioning the paradigm of prolonged ambulatory testing for GERD. The future of reflux diagnosis may very well be without the need for currently employed technologies and could be as simple as assessing changes in epithelia integrity as a surrogate marker for GERD. However, future studies must validate such an approach.

Baseline impedance measured during high-resolution esophageal impedance manometry reliably discriminates GERD patients

BACKGROUND

Baseline impedance measured with ambulatory impedance pH monitoring (MII-pH) and a mucosal impedance catheter detects gastroesophageal reflux disease (GERD). However, these tools are limited by cost or patient tolerance. We investigated whether baseline impedance measured during high-resolution impedance manometry (HRIM) distinguishes GERD patients from controls.

METHODS

Consecutive patients with clinical HRIM and MII-pH testing were identified. Gastroesophageal reflux disease was defined by esophageal pH <4 for ≥5% of both the supine and total study time, whereas controls had an esophageal pH <4 for ≤3% of the study performed off PPI. Baseline impedance was measured over 15 seconds during the landmark period of HRIM and over three 10 minute intervals during the overnight period of MII-pH.

KEY RESULTS

Among 29 GERD patients and 26 controls, GERD patients had a mean esophageal acid exposure time of 22.7% compared to 1.2% in controls (P<.0001). Mean baseline impedance during HRIM was lower in GERD (1061 Ω) than controls (2814 Ω) (P<.0001). Baseline mucosal impedance measured during HRIM and MII-pH correlated (r=0.59, P<.0001). High-resolution esophageal manometry baseline impedance had high diagnostic accuracy for GERD, with an area under the curve (AUC) of 0.931 on receiver operating characteristics (ROC) analysis. A HRIM baseline impedance threshold of 1582 Ω had a sensitivity of 86.2% and specificity of 88.5% for GERD, with a positive predictive value of 89.3% and negative predictive value of 85.2%.

CONCLUSIONS & INFERENCES

Baseline impedance measured during HRIM can reliably discriminate GERD patients with at least moderate esophageal acid exposure from controls. This diagnostic tool may represent an accurate, cost-effective, and less invasive test for GERD.

Does my patient still have reflux when ppi therapy does not work?

Gastroesophageal reflux disease (GERD) is a common condition around the world. The management of this disease is less than satisfying given complexity of patient presentation and suboptimal diagnostic testing when employed for those poorly responsive to acid suppressive therapy. In this mini review, we discuss some new strategies employed for patients with suspected GERD to better understand disease pathophysiology. We compare the strategies and outline a clinically relevant approach in this difficult group of patients.

Recent Advances in Non-invasive Esophageal Tissue Sampling

PURPOSE OF REVIEW

The costs to society and accuracy of screening for esophageal cancer and other esophageal diseases with standard endoscopy are formidable. As a result, the applicability of endoscopy as a general screening tool has been challenged.

RECENT FINDINGS

To maintain accuracy but reduce the price of endoscopy on society, multiple adjunct or replacement technologies are being developed that are less expensive and more easily applied. These devices include image-enhancing techniques that more reliably identify dysplasia and cancer reducing the need for extensive biopsy sampling during standard endoscopy. They also include ambulatory forms for procuring esophageal imaging including smaller endoscopes and capsule endoscopy. Finally, some of the newer methods either obtain samples of esophageal tissue through bedside maneuvers not requiring endoscopy or retrieve information about mucosal inflammation and function without the need to procure esophageal tissue. There is an exciting future for esophageal diagnosis with tools that will save cost and/or provide greater accuracy and safety for some of the most common esophageal disorders.

The diagnostic value of 24-hour ambulatory intraesophageal pH-impedance in patients with laryngopharyngeal reflux symptoms comparable with typical symptoms

BACKGROUND

The diagnosis of laryngopharyngeal reflux is currently based on a combination of the patient history of multichannel intraluminal impedance and ambulatory pH (MII-pH); however, none of these findings alone is specific for the diagnosis of laryngopharyngeal reflux. We aimed to compare the baseline characteristics and esophageal baseline impedance values between patients with and without laryngopharyngeal reflux symptoms.

METHODS

We retrospectively analyzed data from two groups of patients with laryngopharyngeal reflux according to their reflux finding score (RFS) as scored by ENTs. Control patients were nonerosive reflux disease patients without laryngopharyngeal reflux. All MII-pH parameters and baseline impedance were analyzed from six levels and the proximal and distal baseline impedance and the ratio of the proximal to distal baseline impedance levels was calculated.

RESULTS

Altogether 123 patients with laryngopharyngeal reflux and 49 control patients were included. A total of 81 of 123 patients had RFS ≥ 7, and 42 of 123 patients had RFS < 7. Baseline impedance analysis showed that patients with laryngopharyngeal reflux symptoms had significantly lower proximal baseline impedance values (1997 ± 51 vs 2245 ± 109, p < 0.05) than the control group. Additionally, patients with laryngopharyngeal reflux symptoms had a significantly lower proximal-to-distal ratio (1.28 ± 0.05 vs 1.53 ± 0.09, p < 0.05). In the subgroup analysis, patients with RFS < 7 were found to have a significantly lower acid exposure time than either the patients with RFS ≥ 7 (3.85 ± 0.65 vs 8.2 ± 1.52, p < 0.05) or the control group (3.85 ± 0.65 vs 6.1 ± 0.81, p < 0.05). Additionally, patients with RFS ≥ 7 had significantly lower proximal baseline impedance levels than the control group (1970 ± 63 vs 2245 ± 109, p < 0.05).

CONCLUSIONS

Patients with pathologic laryngopharyngeal reflux symptom scores had lower proximal baseline impedance levels and lower proximal-to-distal ratios, which may reflect the proximal mucosal noxious effect of the refluxate. These results may indicate that laryngopharyngeal reflux symptoms may be due to chronic acid exposure in the proximal segments of the esophagus, and the proximal-to-distal ratio may be used as a new metric for diagnosis.