Postreflux swallow-induced peristaltic wave index and nocturnal baseline impedance can link PPI-responsive heartburn to reflux better than acid exposure time

Bile reflux in patients with nerd is associated with more severe heartburn and lower values of mean nocturnal baseline impedance and chemical clearance

BACKGROUND

Mean nocturnal baseline impedance (MNBI) and postreflux swallow-induced peristaltic wave (PSPW) index are novel impedance-based markers of reflux, but the effect of bile reflux on these metrics is unknown. The aim of this study was to evaluate bile reflux, MNBI, and PSPW index in patients with endoscopy-negative GERD partially responsive to PPI therapy.

METHODS

All patients underwent off-PPI endoscopy, esophageal manometry, multichannel intraluminal impedance pH (MII-pH), and bile reflux monitoring. Abnormal esophageal acid exposure time (AET) was required for inclusion. Symptom intensity (using 10-cm visual analog scales), and conventional and novel MII-pH metrics were compared between patients with and without abnormal bile reflux.

KEY RESULTS

We evaluated 42 NERD patients (29 males, mean age: 53.4 ± 13. years), mean AET 6.1 ± 2%, of which 21 had abnormal bile reflux (Group A, 10.2 ± 4.9%), and 21 had normal bile reflux (Group B, 0.4 ± 0.1%, P < .05 compared with Group A). Heartburn reporting on PPI was higher in Group A (7.2 ± 2.1 vs 5.8 ± 0.9; P = .002), but AET, number of reflux events (acidic and weakly acidic), did not differ between the two groups. However, both PSPW index and MNBI were lower in Group A (P < .001). A strong inverse linear correlation was found between bile reflux and both MNBI (Pearson's test; R = -0.714; P < .001) and PSPW index (R = -0.722; P < .001).

CONCLUSIONS AND INFERENCES

Compared to acid reflux alone, the presence of bile in an acidic esophageal environment is associated with more severe heartburn, lesser relief from PPI therapy, higher impairment of esophageal mucosal integrity and less effective chemical clearance.

Reduced Esophageal Contractility Is Associated with Dysplasia Progression in Barrett's Esophagus: A Multicenter Cohort Study

BACKGROUND

The incidence of Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) continues to rise, and risk stratification of patients with BE is needed. Impaired esophageal motility is associated with gastroesophageal reflux disease; however, whether esophageal dysmotility is a risk factor for dysplasia progression in BE is incompletely understood. This study aimed to characterize esophageal motility patterns in patients with BE and identify physiologic factors associated with dysplasia progression in BE.

METHODS

This multicenter retrospective study assessed data from adult patients with histologically confirmed BE who underwent high-resolution esophageal manometry from 1/2014 to 1/2018 at four tertiary care centers. Longitudinal data were collected when available among patients with non-dysplastic BE (NDBE) and separated as: no dysplastic progression or positive dysplastic progression. Multivariable logistic regression assessed for independent predictors of dysplasia progression.

RESULTS

Among 193 patients, histology at index endoscopy identified 152 (79%) NDBE, 23 (12%) low-grade dysplasia, 14 (7%) high-grade dysplasia, and 4 (2%) EAC. Ninety-eight (51%) had abnormal esophageal motor function on manometry. Longitudinal data were available for 84 of 152 patients with initial NDBE. Twelve (14%) exhibited dysplastic progression to low-grade (6) or high-grade (6) dysplasia. Mean esophageal distal contractile integral was lower for patients that progressed [455 mmHg s cm (SD 515)] compared with patients who did not progress [987 mmHg s cm (SD 953); aOR 1.21 (95% CI 1.01, 1.44)].

CONCLUSION

In this retrospective study of 193 BE patients, the majority exhibited abnormal esophageal motor function. Reduced esophageal contractility was independently associated with dysplastic progression in BE. Characterizing esophageal physiology in BE may help to risk stratify patients.

Use of the Functional Lumen Imaging Probe in Clinical Esophagology

The functional lumen imaging probe (FLIP) measures luminal dimensions using impedance planimetry, performed most often during sedated upper endoscopy. Mechanical properties of the esophageal wall and opening dynamics of the esophagogastric junction (EGJ) can be objectively evaluated in esophageal motor disorders, eosinophilic esophagitis, esophageal strictures, during esophageal surgery and in postsurgical symptomatic states. Distensibility index, the ratio of EGJ cross sectional area to intraballoon pressure, is the most useful FLIP metric. Secondary peristalsis from balloon distension can be displayed topographically as repetitive anterograde or retrograde contractile activity in the esophageal body, similar to high-resolution manometry. Real-time interpretation and postprocessing of FLIP metadata can complement the identification of esophageal outflow obstruction and achalasia, especially when findings are inconclusive from alternate esophageal tests in symptomatic patients. FLIP can complement the diagnosis of achalasia when manometry and barium studies are inconclusive or negative in patients with typical symptoms. FLIP can direct adequacy of disruption of the EGJ in achalasia when used during and immediately after myotomy and pneumatic dilation. Lumen diameter measured using FLIP in eosinophilic esophagitis and in complex strictures can potentially guide management. An abbreviated modification of the Grading of Recommendations Assessment, Development, and Evaluation was used to determine the quality of available evidence and recommendations regarding FLIP utilization. FLIP metrics that are diagnostic or suggestive of an abnormal motor pattern and metrics that define normal esophageal physiology were developed by consensus and are described in this review.

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

OBJECTIVE

Limitations of existing impedance-pH thresholds include small sample size of normative studies, inclusion of artefactual pH drops and incorrect identification of impedance reflux events. We aimed to obtain new impedance-pH thresholds from expert consensus analysis of tracings from a large number of healthy subjects.

DESIGN

Of 541 studies performed worldwide using two different systems (Diversatek, USA, and Laborie, Netherlands), 150 tracings with oesophageal diagnoses, behavioural disorders and study-related artefacts were excluded. The remainder studies were subject to two reviewer consensus analysis, in-person or through video conference, consisting of editing meals and pH drops, identification of impedance reflux and postreflux swallow-induced peristaltic wave (PSPW) using strict pre-established criteria and measurement of distal mean nocturnal baseline impedance (MNBI).

RESULTS

Consensus analysis was performed in 391 tracings (age 32.7 years, range 18-71, 54.2% female). Normative thresholds were significantly different between Diversatek and Laborie (total acid exposure time: 2.8% and 5%; reflux episodes: 55 and 78; MNBI at 3 cm: 1400 and 1500 ohms, at 5 cm: 1400 and 1800 ohms). Males had higher acid exposure, more reflux episodes and lower MNBI. Significant regional differences were identified, including higher PSPW scores in Western countries, and higher MNBI in Asia using Diversatek, and higher acid exposure in the Netherlands, higher MNBI in Asia and South Africa, and lower MNBI in Turkey using Laborie.

CONCLUSION

Normal impedance-pH monitoring thresholds have regional and system-related differences. Clinical interpretation needs to use normal thresholds valid for the system used and world region, following careful editing of the tracings.

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.

High-resolution Manometry Determinants of Refractoriness of Reflux Symptoms to Proton Pump Inhibitor Therapy

Background/Aims

Impaired esophageal motility and disrupted esophagogastric junction (EGJ) on high-resolution manometry (HRM) have been associated with increased reflux severity in gastroesophageal reflux disease (GERD) patients. However, there are limited data evaluating HRM parameters in proton pump inhibitors (PPI) non-responders.

Methods

Clinical and endoscopic data, HRM and multichannel intraluminal impedance-pH studies performed of PPI therapy in patients with typical GERD symptoms were reviewed from 3 international centers. Frequency of GERD symptoms was assessed on and off PPI therapy in both non-responders (< 50% symptom improvement on PPI therapy) and responders. Rome IV definitions identified non-erosive reflux disease, reflux hypersensitivity, and functional heartburn. Univariate and multivariate analyses were performed to determine predictors of non-response.

Results

Of 204 patients, 105 were PPI non-responders and 99 were responders. Non-responders showed higher EGJ contractile integral values, and a lower frequency of type II and III EGJ morphology (P ≤ 0.03 for each comparison). Esophageal body diagnoses on HRM (fragmented peristalsis, ineffective esophageal motility, or absent peristalsis) did not predict non-response. On multivariate analysis, non-pathological acid exposure time (OR, 2.5; 95% CI, 1.2-5.0; P < 0.001), normal mean nocturnal baseline impedance values (OR, 2.7-2.4; 95% CI, 1.0-6.1; P < 0.05), normal EGJ contractile integral values (OR, 3; 95% CI, 1.3-7.4; P = 0.012), and presence of type I EGJ morphology (OR, 1.9; 95% CI, 1.0-3.4; P = 0.044) were associated with an unfavorable response to PPIs.

Conclusions

Intact EGJ metrics on HRM complement normal reflux burden in predicting non-response to PPI therapy. HRM has value in the evaluation of PPI non-responders.

Gastroesophageal reflux disease in pediatric esophageal atresia: Assessment of clinical symptoms and pH-impedance data

BACKGROUND

Esophageal atresia (EA) is the most common congenital anomaly of the gastrointestinal tract. Gastroesophageal reflux disease (GERD) is a frequent and lifelong problem in these patients. GERD can be asymptomatic and the incidence of esophageal gastric and intestinal metaplasia (Barrett’s esophagus) is increased in adults with EA compared with the general population. Timely and accurate diagnosis of GERD is important to reduce long-term problems and this may be achieved by pH-impedance testing.

AIM

To assess symptoms and pH-impedance data in children after EA, in order to identify their specific features of GERD.

METHODS

This study was conducted from November 2017 to February 2020 and involved 37 children who had undergone EA via open surgical repair (51.35% boys, 48.65% girls; age range: 1-14 years, median: 4.99 years). GERD diagnosis was made based on multichannel intraluminal impedance/pH study and two groups were established: EA without GERD, n = 17; EA with GERD, n = 20. A control group was established with 66 children with proven GERD (68.18% boys, 31.82% girls; median age: 7.21 years), composed of a nonerosive reflux disease (referred to as NERD) group (n = 41) and a reflux esophagitis group (n = 25). Upper gastrointestinal endoscopy with a mucosal esophageal biopsy was performed on all patients.

RESULTS

The most frequently observed symptom in EA patients with GERD and without GERD was cough (70% and 76.5% respectively). The number of patients with positive symptom association probability in the EA groups was significantly larger in the EA without GERD group (P = 0.03). In the control reflux esophagitis group, prevalence of gastrointestinal symptoms was significantly higher than in the NERD group (P = 0.017). For both EA groups, there was strong correlation with index of proximal events (IPE) and total proximal events (EA with GERD: 0.96, P < 0.001; EA without GERD: 0.97, P < 0.001) but level of IPE was significantly lower than in GERD patients without any surgical treatment (P < 0.001). Data on distal mean nocturnal baseline impedance were significantly different between the EA with GERD group (P < 0.001) and the two control groups but not between EA without GERD and the two control groups.

CONCLUSION

Mean nocturnal baseline impedance may have diagnostic value for GERD in EA children after open surgical repair. IPE might be an additional parameter of pH-impedance monitoring.

Impact of ineffective esophageal motility on chemical clearance in patients with gastroesophageal reflux symptoms

Ineffective esophageal motility (IEM) is the most common manometric abnormality in gastroesophageal reflux disease (GERD). However, the impact of IEM on esophageal chemical clearance has not been fully investigated. This study aimed to determine the impact of IEM on esophageal chemical clearance in patients with GERD. A total of 369 patients with GERD symptoms who underwent upper endoscopy and high-resolution manometry (HRM) test were retrospectively analyzed. The relationship between IEM and erosive esophagitis was examined. In addition, the impact of IEM on chemical clearance was examined in patients who underwent an additional combined multichannel intraluminal impedance-pH (MII-pH) test. Esophageal chemical clearance capability was evaluated via postreflux swallow-induced peristaltic wave (PSPW) index and acid clearance time (ACT). Of 369 patients, 181 (49.1%) had esophageal motility disorders, of which 78 (21.1%) had IEM. The proportion of IEM patients in those with erosive esophagitis and those without were 16.2% and 21.7%, respectively, and no significant difference was observed (P = 0.53). After excluding patients other than those with IEM and normal esophageal motility, 64 subsequently underwent MII-pH test. The median values of the PSPW index in the IEM and normal esophageal motility group were 11.1% (4.2%-20.0%) and 17.1% (9.8%-30.6%), respectively. The PSPW index was significantly lower in the IEM group than in the normal esophageal motility group (P < 0.05). The median ACT values in the IEM group and normal esophageal motility group were 125.5 (54.0-183.5) seconds and 60.0 (27.2-105.7) seconds, respectively. The ACT was significantly longer in the IEM group than in the normal esophageal motility group (P < 0.05). In conclusion, IEM was found to be associated with chemical clearance dysfunction as measured against the PSPW index and ACT. As this condition could be a risk factor for GERD, future treatments should be developed with a focus on chemical clearance.

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.

ACG Clinical Guidelines: Clinical Use of Esophageal Physiologic Testing

Esophageal symptoms are common and may indicate the presence of gastroesophageal reflux disease (GERD), structural processes, motor dysfunction, behavioral conditions, or functional disorders. Esophageal physiologic tests are often performed when initial endoscopic evaluation is unrevealing, especially when symptoms persist despite empiric management. Commonly used esophageal physiologic tests include esophageal manometry, ambulatory reflux monitoring, and barium esophagram. Functional lumen imaging probe (FLIP) has recently been approved for the evaluation of esophageal pressure and dimensions using volumetric distension of a catheter-mounted balloon and as an adjunctive test for the evaluation of symptoms suggestive of motor dysfunction. Targeted utilization of esophageal physiologic tests can lead to definitive diagnosis of esophageal disorders but can also help rule out organic disorders while making a diagnosis of functional esophageal disorders. Esophageal physiologic tests can evaluate obstructive symptoms (dysphagia and regurgitation), typical and atypical GERD symptoms, and behavioral symptoms (belching and rumination). Certain parameters from esophageal physiologic tests can help guide the management of GERD and predict outcomes. In this ACG clinical guideline, we used the Grading of Recommendations Assessment, Development and Evaluation process to describe performance characteristics and clinical value of esophageal physiologic tests and provide recommendations for their utilization in routine clinical practice.

The Lyon Consensus: Does It Differ From the Previous Ones?

Gastroesophageal reflux disease (GERD) is a complex disorder with heterogeneous symptoms and a multifaceted pathogenetic basis, which prevent a simple diagnostic algorithm or any categorical classification. Clinical history, questionnaires and response to proton pump inhibitor (PPI) therapy are insufficient tools to make a conclusive diagnosis of GERD and further investigations are frequently required. The Lyon Consensus goes beyond the previous classifications and defines endoscopic and functional parameters able to establish the presence of GERD. Evidences for reflux include high-grade erosive esophagitis, Barrett’s esophagus, and peptic strictures at endoscopy as well as esophageal acid exposure time > 6% on pH-metry or combined pH-impedance monitoring. Even if a normal endoscopy does not exclude GERD, its combination with distal acid exposure time < 4% on off-PPI pH-impedance monitoring provides sufficient evidence refuting this diagnosis. Reflux-symptom association on pH-monitoring provides supportive evidence for reflux-triggered symptoms and may predict a better treatment outcome, when present. Also recommendations to perform pH-impedance “on” or “off” PPI are well depicted. When endoscopy and pH-metry or combined pH-impedance monitoring are inconclusive, adjunctive evidence from biopsy findings (eg, microscopic esophagitis), high-resolution manometry (ie, ineffective esophagogastric barrier and esophageal body hypomotility), and novel impedance metrics, such as mean nocturnal baseline impedance and post-reflux swallow-induced peristaltic wave index, can contribute to better identify patients with GERD. Definition of individual patient phenotype, based on the level of refluxate exposure, mechanism of reflux, efficacy of clearance, underlying anatomy of the esophagogastric junction, and clinical presentation, will lead to manage GERD patients with a tailored approach chosen among different types of therapy.

Factors of Reflux Episodes With Post-reflux Swallow-induced Peristaltic Wave in Gastroesophageal Reflux Disease

Background/Aims

It is known that post-reflux swallow-induced peristaltic wave (PSPW) index represents the chemical clearance of the esophagus. However, few studies have explored why some reflux episodes could induce PSPW while others in the same patient could not. The purpose of this study is to investigate the characteristics of reflux episodes which could elicit PSPW.

Methods

In this study, 269 reflux episodes were detected, of which 90 with a PSPW and 179 without a PSPW. Comparisons were made between the characteristics of reflux episodes with a PSPW and without a PSPW. The characteristics were including nadir pH, pH drop, proximal extent (cm, sec), ascending velocity (cm/sec), volume clearance time, acid clearance time, percentage acidic (%), 15 to 60-minute acid burden (seconds), and 15- to 60-minute volume burden (seconds). The characteristics between the 2 groups were compared through performing Wilcoxon signed rank test.

Results

Reflux episodes followed by a PSPW were significantly associated with a higher proximal extent than those without a PSPW. After the reflux episodes, higher volume clearance time and larger volume burden were more likely to trigger a PSPW. However, there were no significant differences between the 2 groups in nadir pH, pH drop, ascending velocity, acid clearance time, percentage acidic, or acid burden.

Conclusions

The role of acid seems to be less important in a reflux episode inducing a PSPW. Proximal reflux episodes are more likely to induce a PSPW. The depression of volume clearance may also be an important factor in eliciting a PSPW.

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.

Optimization of impedance-measured reflux events in GORD utilizing acid exposure time

Background

Combining impedance with pH monitoring improves the detection and characterization of gastro-oesophageal reflux (GOR), yet the two modalities frequently differ in GOR quantification. Ambulatory 24-h pH-impedance monitoring often reveals more significant oesophageal acid exposure than impedance-measured reflux activity in patients with symptomatic gastro-oesophageal reflux disease (GORD). The purpose of this study is to elucidate the discrepancies between these modalities by assessing the predictive accuracy of impedance compared to acid exposure standards.

Methods

A single-institution, retrospective review of sequential 24-h pH-impedance results of 72 patients with symptomatic GOR off anti-secretory therapy was conducted. Reflux events measured by impedance were stratified by patient position and compared to oesophageal acid exposure time (AET). Oesophageal AET limits for GORD detection were utilized as gold standards to generate serial receiver operator characteristics (ROC) curves to assess the sensitivity and specificity of current impedance GORD detection limits and identify optimized impedance standards based on area under the curve (AUC) analysis.

Results

Mean total AET time was 10.5% (± 9.9%), and 63.8% of patients had elevated AET. By impedance, median GOR frequency was 43 (IQR 21–68), and 22.2% exceeded conventional GOR frequency limits of normal. ROC curve analysis revealed the current impedance standard of > 73 GOR events has a sensitivity of 32.6% and specificity of 96.5% (AUC 0.74) for GORD detection. By AUC analysis, an impedance threshold of > 41 GOR events is optimal for GORD detection (sensitivity 69.6%, specificity 80.7%, AUC 0.83).

Conclusion

Conventional impedance standards for abnormal GOR frequency are weakly sensitive for the detection of GORD, providing a possible explanation to discrepancies in AET and impedance interpretation. Lowering impedance-measured GOR frequency limits to > 41 optimizes sensitivity and specificity while increasing congruence between pH and impedance metrics.

Measurement of Esophageal Nocturnal Baseline Impedance: A Simplified Method

Background/Aims

Mean nocturnal baseline impedance (MNBI) during multichannel intraluminal impedance pH-monitoring (MII-pH) reflects the status of esophageal mucosal integrity. MNBI is suggested as an adjunctive method to distinguish patients with true gastroesophageal reflux disease (GERD) from functional heartburn (FH) and might predict outcomes for anti-reflux treatment. However, current methodology for calculation of MNBI is time-consuming and subject to operator-dependent selection bias. We aim to simplify and provide a more objective method to calculate MNBI.

Methods

We retrospectively analyzed 100 MII-pH tracings from 20 patients with erosive reflux disease, 20 with non-erosive reflux disease (NERD), 20 with reflux hypersensitivity, 20 with functional heartburn (FH), and 20 healthy asymptomatic volunteers. We compared the current “conventional” MNBI analysis with our “simple” MNBI analysis measured by selecting the whole supine period using the impedance average calculation function in the MII-pH software.

Results

Absolute values were very similar and there was a strong correlation between conventional and simple MNBI values in the most distal channel in all groups (r ≥ 0.8, P < 0.001) including patients with increased supine acid reflux. Distal esophageal simple MNBI negatively correlated with acid exposure time (r = –0.695, P < 0.001). Patients with erosive reflux disease and NERD had lower simple MNBI values in the most distal channel compared to other groups (P < 0.001). With a cutoff value of 1785 ohms, simple MNBI can discriminate patients with GERD from those with reflux hypersensitivity and FH (sensitivity 80.0% and specificity 89.7%).

Conclusion

Simple MNBI analysis provides very similar values and has an excellent correlation with conventional MNBI analysis.

Pathophysiology, diagnosis, and pharmacological treatment of gastro-esophageal reflux disease

INTRODUCTION

Gastro-esophageal reflux disease (GERD) is a highly prevalent, chronic, relapsing disorder, whose knowledge has increased in last years thanks to the advent of new sophisticated techniques, such as 24-h impedance-pH monitoring and high-resolution manometry, for the study of esophageal functions.

AREAS COVERED

This review provides an overview of our advancements in understanding the complex pathophysiology, improving the diagnosis and defining the modern pharmacological therapeutic approach to GERD.

EXPERT OPINION

The growing clinical application of impedance-pH testing has allowed us to know the diversity of patients with non-erosive reflux disease (NERD), who nowadays represent about 70% of the whole population with reflux symptoms. We have realized that NERD has to be considered as an umbrella term covering various subgroups with different pathophysiologies. The development of new impedance metrics, in particular mean nocturnal baseline impedance, seems to be promising in the improvement of the diagnostic process of this disease. There are no particularly innovative features in the pharmacological therapy of GERD, unless the interest toward drugs is able to increase the defense properties of esophageal mucosa and/or its protection. These compounds can be of help in combination with proton pump inhibitors in NERD patients with partial response to antisecretory drugs alone.

Mean Nocturnal Baseline Impedance Correlates With Symptom Outcome When Acid Exposure Time Is Inconclusive on Esophageal Reflux Monitoring

BACKGROUND & AIMS

Abnormal acid exposure time (AET) is associated with good outcomes of symptoms from antireflux therapy. Low esophageal mean nocturnal baseline impedance (MNBI) is an additional marker of reflux disease. We aimed to evaluate the value of MNBI when analysis of AET produces borderline or inconclusive results.

METHODS

We studied a retrospective cohort of 371 patients (mean age, 54.5 ± 0.7 y; 60.0% female) who had persistent reflux symptoms after treatment and underwent ambulatory pH-impedance monitoring off antisecretory therapy at 1 tertiary center in Europe or 1 in the United States. Total AET was determined from pH impedance studies (pathologic, >6%; physiologic, <4%; borderline or inconclusive, 4%-6%). Baseline impedance values were calculated at the 5-cm impedance channel at 3 nocturnal 10-minute periods and averaged to yield MNBI (abnormal, <2292 ohms). The primary outcome was response to antireflux therapy, defined as global symptom improvement of 50% or greater on patients' answers on standardized visual analog scales.

RESULTS

Among the 371 patients, 107 (28.8%) had pathologic AET and 234 (63.1%) had abnormal MNBI. Low MNBI was concordant in 99.1% of patients with pathologic AET, in 91.2% with borderline AET, and in 33.7% with physiologic AET. During 38.7 ± 0.8 months of follow-up evaluation, 43.0% of patients had improved symptoms with medical therapy and 76.2% had improved symptoms with surgical antireflux therapy (P < .0001). When MNBI was low, response to medical therapy did not differ significantly between patients with borderline AET and patients with pathologic AET (P = .44), but did differ significantly when each group was compared with patients with physiologic AET, regardless of whether MNBI was normal or low (P < .0001 for each comparison).

CONCLUSIONS

When low, MNBI identifies patients with pathologic and borderline AET who respond to antireflux therapy. MNBI analysis complements AET in defining esophageal reflux burden. MNBI correlates with response of symptoms to antireflux therapy.

Correlation between reflux burden, peristaltic function, and mucosal integrity in GERD patients

BACKGROUND

Mean nocturnal baseline impedance (MNBI) augments the diagnostic yield of multichannel intraluminal impedance-pH (MII-pH) monitoring. While acid exposure time (AET) correlates with MNBI, it remains unclear whether esophageal motility affects MNBI values. The present study was aimed at evaluating the respective roles of esophageal motor function and AET on MNBI.

METHODS

High-resolution manometry (HRM) studies and ambulatory 24-hour MII-pH monitoring tracings were retrospectively analyzed from consecutive endoscopy-negative GERD patients with typical symptoms responsive to previous acid-suppressive therapy from three tertiary care centers. Univariate and multivariate analyses were performed to determine predictors of pathologic MNBI values at 3 cm and 5 cm above the lower esophageal sphincter (LES).

KEY RESULTS

Patients with pathological AET displayed lower MNBI values at 3 cm and 5 cm (P < .01) compared to patients with non-pathological AET. Similarly, significantly lower MNBI values were also noted at both sites with type 3 EGJ compared to type 1 EGJ (P ≤ .02 for each comparison), and with absent contractility compared to normal peristalsis (P ≤ .02 for each comparison). On multivariate analysis, the presence of type 2 or 3 EGJ and absent contractility were associated with a significantly higher probability of pathological MNBI values at 3 cm and 5 cm above the LES.

CONCLUSIONS AND INFERENCES

Disruption of the EGJ and absent contractility on HRM are both associated with lower MNBI values. HRM findings complement reflux testing using MII-pH monitoring.

Minor esophageal functional disorders: are they relevant?

PURPOSE OF REVIEW

High resolution esophageal manometry (HRM) has expanded understanding of esophageal motor function. The Chicago Classification scheme has allowed systematic categorization of the myriad of manometric parameters identified during HRM. Multichannel intraluminal impedance pH has enhanced ambulatory reflux monitoring through complete assessment of esophageal content transit. However, the clinical implications of identified minor esophageal functional disorders remain unclear.

RECENT FINDINGS

Esophagogastric junction outlet obstruction is defined by esophagogastric junction obstruction with preserved peristalsis and may be managed expectantly, or in a manner similar to achalasia. Hypercontractile esophagus has been associated with dysphagia and non-cardiac chest pain, but the clinical significance is unclear as a majority of patients will improve without specific therapy. Additionally, these findings may be confounded by chronic opiate use. Ineffective esophageal motility is characterized by diminished esophageal contraction amplitude, potentially causing dysphagia and GERD. However, this is commonly identified in asymptomatic volunteers and may represent a normal variant. The multiple rapid swallow sequence can assess esophageal contraction reserve, which may predict post fundoplication dysphagia. The post-swallow induced peristaltic wave can serve as a surrogate of gastric refluxate clearance, providing important prognostic value. However, the associated time burden and lack of alternative therapeutic options limit its clinical utility.

SUMMARY

Minor esophageal functional disorders provide new therapeutic targets for symptomatic patients. However, these findings have inconsistent associations with symptoms and poorly defined therapeutic options. Minor esophageal function disorders should not be interpreted in isolation, with management decisions accounting for clinical, endoscopic, and radiographic factors in addition.

Fragmented and failed swallows on esophageal high-resolution manometry associate with abnormal reflux burden better than weak swallows

BACKGROUND

Association between proportions of hypomotile swallows on esophageal high-resolution manometry (HRM) and esophageal reflux burden remains incompletely understood. We investigated relationships between hypomotility, acid exposure time (AET), and mean nocturnal baseline impedance (MNBI) on ambulatory reflux monitoring.

METHODS

Clinical data, HRM, and ambulatory pH-impedance studies (performed off acid suppression) from patients with persisting reflux symptoms were reviewed from five international centers. AET (abnormal > 6%) and MNBI (abnormal < 2292 ohms) were extracted from pH-impedance studies. Distal contractile integral (DCI) designated esophageal peristalsis into normal (DCI > 450 mmHg.cm.s), fragmented (DCI > 450 mmHg.cm.s with breaks > 5 cm), weak (DCI 100-450 mmHg.cm.s), and failed (DCI < 100 mm mmHg.cm.s) sequences. Univariate and multivariate analyses were performed to identify motor associations of abnormal reflux burden.

KEY RESULTS

Of 351 patients (52.1 ± 0.8 years, 67%F), 29.3% had AET > 6% and 61.8% had MNBI < 2292 ohms. On univariate analysis, both fragmented peristalsis and IEM associated with abnormal AET (P ≤ .01) and MNBI (P ≤ .03); reflux burden was more profound with >70% fragmented as well as ineffective sequences compared to ≤70% for each (P < .05 for each comparison). When weak and failed sequences within IEM were separately analyzed, ≥50% failed sequences predicted abnormal AET (P ≤ .009), and ≥50% weak sequences did not (P = .14). On multivariate regression, ≥50% failed sequences predicted abnormal AET (P = .02), and >70% ineffective sequences trended strongly (P = .069); >70% ineffective sequences predicted abnormal MNBI (P = .046), and >70% fragmented sequences trended strongly (P = .076).

CONCLUSIONS AND INFERENCES

Breaks in esophageal peristaltic integrity seen with fragmented and failed sequences are more relevant to abnormal esophageal acid burden than weak sequences.

Post-reflux swallow-induced peristaltic wave index and mean nocturnal baseline impedance predict PPI response in GERD patients with extra esophageal symptoms

BACKGROUND

Mean nocturnal baseline impedance (MNBI) and post-reflux swallow-induced peristaltic wave (PSPW) index are able to increase the diagnostic yield of impedance-pH and are associated to proton pump inhibitor (PPI) response. Few data concerning these variables in patients with extra-esophageal symptoms (EES) are available.

AIMS

To evaluate, in EES patients, the role of the conventional and new impedance-pH variables in diagnosing GERD and the predictive value of impedance-pH variables for PPI response.

METHODS

Consecutive patients presenting suspected GERD-related EES underwent impedance-pH. Patients treated in the last six months with double dose PPI therapy were enrolled. The presence of concomitant typical symptoms was assessed.

RESULTS

239 EES patients were studied; 102 responders and 137 non-responders. Eighty-one (34%) were affected by non-erosive reflux disease (NERD), 61 (26%) presented reflux hypersensitivity (RH) and 97 (40%) were non-GERD. In NERD and RH groups, a significantly higher proportion of patients with pathological PSPW index or MNBI values compared to non-GERD group was observed. 24 (25%) non-GERD patients presented a pathological PSPW index and/or MNBI. Pathological PSPW index, MNBI and presence of typical symptoms were associated to PPI response.

CONCLUSIONS

MNBI and PSPW index measurement increases the diagnostic yield of impedance-pH; abnormal values are associated with a satisfactory response to acid-suppressive therapy in EES patients.

Post-reflux swallow-induced peristaltic wave (PSPW): physiology, triggering factors and role in reflux clearance in healthy subjects

BACKGROUND AND AIMS

The underlying physiology of post-reflux swallow-induced peristaltic wave (PSPW) is unclear. We aimed to: 1) calculate the probability of a random association between reflux and PSPW; 2) characterize factors that could underlie triggering of PSPW and 3) assess the chemical clearance effect of PSPW in healthy asymptomatic subjects.

METHODS

A total of 251 impedance-pH tracings from healthy asymptomatic subjects were analysed. Twenty consecutive tracings from this pool with 20-40 reflux episodes/24 h and a PSPW index higher than 50% were separately analyzed to evaluate the probability of a random association between reflux and PSPW. The characteristics of reflux episodes followed by a PSPW were compared with those not associated with PSPW.

RESULTS

A mean time interval of 29.3 s between a reflux episode and the first swallow captured 71% of total reflux episodes, and 67% of accompanying swallows were non-random. Compared to reflux without PSPW, reflux episodes with PSPW were more frequently acidic (P = 0.048), mixed with gas (P < 0.0001), of high proximal extent (P < 0.0001), while awake (P < 0.0001), and with shorter chemical clearance time (P = 0.040). High proximal extent, gas presence and occurring while awake were independent factors associated with PSPW (P < 0.0001).

CONCLUSION

Using a time window between reflux and PSPW of around 30 s, the probability of a chance association is around 30%. Reflux episodes with high proximal extent, containing gas and occurring while awake are important factors associated with PSPW in healthy subjects. Reflux episodes with PSPW have a shorter chemical clearance time.

Esophageal physiologic profiles within erosive esophagitis in China: Predominantly low-grade esophagitis with low reflux burden

BACKGROUND & AIMS

The Lyon Consensus defines LA grades C&D erosive esophagitis (EE) or acid exposure time (AET) >6% as the conclusive evidence for gastro-esophageal reflux disease (GERD). However, most of EE is LA grade A&B and the rate of AET exceeding 6% is low in China. We aimed to evaluate patients with EE in the Chinese population based on the Lyon Criteria.

METHODS

A retrospective study was performed among patients with EE who had esophageal function tests performed in a tertiary hospital from 2013 to 2017. Erosive esophagitis was staged according to the Los Angeles classification. Their motor profiles from high-resolution manometry (HRM), reflux profiles from multichannel intraluminal impedance-pH (MII-pH) monitoring and proton pump inhibitor (PPI) efficacy were analyzed. Patients were categorized as conclusive or inconclusive GERD.

RESULTS

Among 112 patients with EE who underwent esophageal function tests, EE of LA grade C&D was found in only 4.46% (N = 5). Almost 35% (N = 37) of patients with LA grade A&B EE had AET exceeded 6%, who had good PPI response similar to those with LA grade C&D EE (77.42% vs 100%, P = .559). The remaining 70 patients (62.50%) were inconclusive GERD, of whom 56.25% responded to PPI. Inconclusive GERD patients had a wide range (7.14%-97.14%) of positive adjunctive evidences from HRM and MII-pH monitoring without significant correlation to PPI response rate.

CONCLUSIONS

The reflux burden within patients with EE is predominantly low in China, and adjunctive HRM and MII-pH profiles from Lyon criteria do not segregate PPI response.

Role of Esophageal Mean Nocturnal Baseline Impedance and Post-reflux Swallow-induced Peristaltic Wave Index in Discriminating Chinese Patients With Heartburn

Background/Aims

Recently, esophageal mean nocturnal baseline impedance (MNBI) and post-reflux swallow-induced peristaltic wave (PSPW) index have been proposed, which can increase the diagnostic role of multichannel intraluminal impedance and pH recording (MII/pH) for differentiating patients with heartburn. Therefore, our aim is to investigate the role of esophageal proximal MNBI, distal MNBI, and PSPW index in differentiating Chinese patients with heartburn.

Methods

Patients with heartburn from the Beijing Anzhen Hospital, who underwent upper gastrointestinal endoscopy and 24-hour MII/pH, were enrolled in this study.

Results

In all, 24 erosive esophagitis (EE), 46 non-erosive reflux disease (NERD), 52 reflux hypersensitivity (RH), and 78 functional heartburn (FH) patients were recruited. The respective median values for the EE, NERD, RH, and FH groups were as follows: proximal MNBI 1858.0, 2147.5, 2374.3, and 2329.0 Ω (P = 0.053); distal MNBI 1243.4, 1506.5, 2451.2, and 2477.3 Ω (P < 0.001); and PSPWI 15.0%, 25.0%, 25.0%, and 45.0% (P < 0.001). Spearman correlation analysis showed that distal MNBI and PSPW index were significantly negatively correlated with acid and bolus exposure time and acid reflux events. Receiver operating characteristic analyses showed that distal MNBI and PSPW index significantly discriminated FH from EE, NERD, and RH (P < 0.001), with cut-off values of 1890.6 Ω and 27.5% and areas under the curve of 0.721 and 0.779, respectively.

Conclusion

Esophageal distal MNBI and PSPW index could increase the diagnostic role of MII/pH, especially for differentiating Chinese patients with heartburn.

Role of Reflux in the Pathogenesis of Eosinophilic Esophagitis: Comprehensive Appraisal With Off- and On PPI Impedance-pH Monitoring

OBJECTIVES

Role of reflux and mechanisms of response to proton pump inhibitor (PPI) therapy in eosinophilic esophagitis (EoE) have not yet been fully elucidated. Comprehensive assessment by impedance-pH monitoring could clarify these issues.

METHODS

Prospective multicenter study comparing EoE patients with healthy controls and gastroesophageal reflux disease cases. Patients with EoE were evaluated off- and on PPI; responsiveness was assessed by histology. Impedance-pH appraisal included chemical clearance, assessed with the postreflux swallow-induced peristaltic wave (PSPW) index, and mucosal integrity measured with mean nocturnal baseline impedance (MNBI).

RESULTS

Sixty consecutive patients with EoE were compared with 60 age- and sex-matched healthy controls and 60 subjects with gastroesophageal reflux disease. The number of total refluxes was higher, while the PSPW index was lower in patients with EoE than in healthy controls. Off PPI, a lower MNBI gradient between the mid and distal esophagus distinguished 20 patients with PPI-refractory EoE from 40 patients with PPI-responsive EoE and was a predictor of PPI failure. On PPI, a lower PSPW index was the sole reflux parameter distinguishing PPI-refractory from PPI-responsive EoE; all reflux parameters improved in PPI-responsive patients, whereas the PSPW index was not modified in PPI-refractory cases and was independently associated with PPI-responsiveness. MNBI in the distal and mid esophagus improved much more in PPI-responsive than in PPI-refractory EoE.

DISCUSSION

Reflux plays a role in the pathogenesis of EoE, more relevant in PPI-responsive cases. Low impedance gradient between the mid and distal esophagus may be useful to predict PPI refractoriness. PPIs mainly act by improving chemical clearance, i.e., by an antireflux action supporting long-term prescription in PPI-responsive EoE.

Idiopathic pulmonary fibrosis and GERD: links and risks

Gastroesophageal reflux disease (GERD) and idiopathic pulmonary fibrosis (IPF) are two pathological conditions often strictly related, even if a clear relationship of causality has not been demonstrated. GERD is a frequent comorbidity in IPF patients, as demonstrated using combined multichannel intraluminal impedance-pH, despite being mostly clinically silent. According to that, it has been hypothesized that microaspiration of gastric material may play a fundamental role in the fibrotic transformation of pulmonary parenchyma. In contrast, it cannot be excluded that IPF may favor GERD by increasing the negative intrathoracic pressure. Therefore, this relationship is uncertain as well as not univocal. Nevertheless, the latest international guidelines recommend the use of proton pump inhibitors (PPIs) in IPF based on several data showing that PPIs can stabilize lung function, reduce disease flares and hospitalizations. On the contrary, recent studies not only question the relevance of these results, but also associate the use of PPIs with an increased risk of lung infections and a negative prognostic outcome. The aim of this review is to analyze the possible links between GERD and IPF and their possible therapeutic implications, trying to translate this scientific evidence into useful information for clinical practice.

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.

Updates in the field of non-esophageal gastroesophageal reflux disorder

Introduction: Gastroesophageal reflux disease (GERD) is one of the most prevalent conditions in Western Countries, normally presenting with heartburn and regurgitation. Extra-esophageal (EE) GERD manifestations, such as asthma, laryngitis, chronic cough and dental erosion, represent the most challenging aspects from diagnostic and therapeutic points of view because of their multifactorial pathogenesis and low response to proton pump inhibitors (PPIs). In fact, in the case of EE, other causes must by preventively excluded, but instrumental methods, such as upper gastrointestinal endoscopy and laryngoscopy, have low specificity and sensitivity as diagnostic tools. In the absence of alarm signs and symptoms, empirical therapy with a double-dose of PPIs is recommended as a first diagnostic approach. Subsequently, impedance-pH monitoring could help to define whether the symptoms are GERD-related. Areas covered: This article reviews the current literature regarding established and proposed EE-GERD, reporting on all available options for its correct diagnosis and therapeutic management. Expert opinion: MII-pH could help to identify a hidden GERD that causes EE. Unfortunately, standard MII-pH analysis results are often unable to define this association. New parameters such as the mean nocturnal baseline impedance and post-reflux swallow-induced peristaltic wave index may have an improved diagnostic yield, but prospective studies using impedance-pH are needed.

New classifications of gastroesophageal reflux disease: an improvement for patient management?

Introduction: Gastroesophageal reflux disease (GERD) is a very common and often debilitating disease. In the broad spectrum of GERD phenotypes, three main groups may be traditionally distinguished: 1) patients only affected by esophageal and/or extra-esophageal symptoms; 2) patients with erosive esophagitis and 3) patients with further complications. Areas covered: This review provides an overview on the current classifications of GERD patients, and their impact on their management. Expert opinion: In 2017, the GERD Consensus Working Group focused the attention on patients unresponsive to PPIs. In this scenario, a diagnosis of GERD might be confirmed by evident signs of erosive esophagitis and the finding of pH or multichannel intraluminal impedance-pH tests, such as more than 6%. The 'Lyon Consensus' panel of experts confirmed that positive indices of reflux-symptom association, without other altered parameters, represent reflux hypersensitivity. GERD requires a customized management; it is crucial to assess frequency and severity of symptoms and their response to an optimal course of therapy as well as to explore the endoscopic alterations and consider other diagnoses responsible for persistent symptoms.

The Utility of Esophageal Motility Testing in Gastroesophageal Reflux Disease (GERD)

PURPOSE OF REVIEW

Here, we discuss how esophageal motor testing plays important roles in patients with suspected gastroesophageal reflux disease (GERD). In addition to guiding appropriate placement of catheters for ambulatory reflux monitoring, esophageal high-resolution manometry (HRM) rules out confounding diagnoses, such as achalasia spectrum disorders, that can present with symptoms similar to that of GERD, but are managed very differently.

RECENT FINDINGS

HRM performed with impedance in the post-prandial setting (PP-HRIM) can assess for rumination syndrome or supragastric belching, which should be directed towards behavioral interventions. The recent GERD Classification of Motor Function recommends a hierarchical approach, focusing on (1) the esophagogastric junction (EGJ), (2) the esophageal body, and (3) esophageal contraction reserve, which can be assessed with provocative maneuvers at HRM, such as multiple rapid swallows (MRS). This approach can inform the appropriate tailoring of antireflux surgery. Novel esophageal motility metrics, such as the EGJ-contractile integral from HRM, or post-reflux swallow-induced peristaltic wave indices from 24-h pH-impedance monitoring, may also assist with GERD diagnosis. Assessment of esophageal motor function can contribute in a significant manner to the care of patients with suspected GERD, particularly when esophageal symptoms do not improve with antisecretory therapy, and/or when surgical or endoscopic antireflux therapies are under consideration.

Diagnosis of GERD in typical and atypical manifestations

The manifestations of gastroesophageal reflux disease (GERD) have been recently classified into either esophageal or extra-esophageal syndromes. Clinical history, questionnaire data and response to antisecretory therapy are insufficient to make a conclusive diagnosis of GERD. Endoscopy had a low sensitivity. Recently, the availability of multichannel intraluminal impedance and pH-monitoring (MII-pH) has modified the diagnostic approach towards atypical manifestations of GERD. There is a rising consensus that this technique should be considered as the gold standard for GERD diagnosis. Gastrin 17 (G-17) has been proposed as a non-invasive marker of GERD, due to the negative feedback between acid and the hormone. G17 levels seem able to identify patients with acid and non-acid reflux. (www.actabiomedica.it)

Gastroesophageal reflux disease, functional dyspepsia and irritable bowel syndrome: common overlapping gastrointestinal disorders

Several studies have indicated an overlap between gastroesophageal reflux disease (GERD) and various functional gastrointestinal disorders (FGIDs). The overlapping conditions reported have mainly been functional dyspepsia (FD) and irritable bowel syndrome (IBS). The available literature is frequently based on symptomatic questionnaires or endoscopic procedures to diagnose GERD. Rarely, among patients with heartburn, pathophysiological evaluations have been considered to differentiate those with proven GERD from those without. Moreover, both GERD and IBS or FD showed enormous heterogeneity in terms of the criteria and diagnostic procedures used. The GERD-IBS overlap ranges from 3-79% in questionnaire-based studies and from 10-74% when GERD has been diagnosed endoscopically. The prevalence of functional dyspepsia (after normal upper endoscopy) is 12-15% and an overlap with GERD has been reported frequently. Only a few studies have considered a potential overlap between functional heartburn (FH) and IBS using a 24-h pH-metry or impedance-pH evaluation. Similar data has been reported for an overlap between FH and FD. Recently, a revision of the Rome criteria for esophageal FGIDs identified both FH and hypersensitive esophagus (HE) as potential functional esophageal disorders. This might increase the potential overlap between different FGIDs, with FH and HE rather than with GERD. The aim of the present review article was to appraise and discuss the current evidence supporting the possible concomitance of GERD with IBS and FD in the same patients and to evaluate how various GERD treatments could impact on the quality of life of these patients.

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.

Lack of improvement of impaired chemical clearance characterizes PPI-refractory reflux-related heartburn

OBJECTIVE

Heartburn is the most specific symptom of reflux disease and is highly responsive to proton pump inhibitor (PPI) therapy. Some patients do not respond to PPIs, but mechanisms of refractoriness have not yet been fully elucidated. Impedance-pH monitoring, allowing comprehensive on-therapy assessment of reflux, represents a valuable test to investigate PPI refractoriness.

METHODS

Prospective multicenter study comparing endoscopy-negative patients with PPI-refractory and PPI-responsive heartburn. Reflux disease was demonstrated by off-PPI impedance-pH monitoring and mechanisms of refractoriness were studied with on-PPI impedance-pH monitoring. Assessment of impedance-pH tracings comprised conventional parameters, post-reflux swallow-induced peristaltic wave (PSPW) index, and mean nocturnal baseline impedance (MNBI).

RESULTS

Sixty-four patients entered the study, 32 with PPI-refractory and 32 with PPI-responsive heartburn. On PPI, median percentage gastric and esophageal acid exposure time and number of acid refluxes did not differ between the two groups; conversely, number of total and weakly acidic refluxes and percentage bolus exposure were significantly higher while PSPW index and MNBI were significantly lower in PPI-refractory cases. At multivariate logistic regression analysis, PSPW index was the sole independent risk factor for PPI refractoriness (OR 1.082, 95% CI 1.022-1.146, P = 0.007). Comparing off- and on-PPI parameters, median PSPW index did not change in PPI-refractory patients (24% vs. 26%, P = 0.327) but increased significantly in PPI-responsive cases (29% vs. 46%, P < 0.001).

CONCLUSIONS

Lack of improvement of impaired chemical clearance is a major determinant of PPI refractoriness. Timely post-reflux salivary swallowing represents a key defensive mechanism and a potential target for future treatment modalities in PPI-refractory reflux-related heartburn.

Differences in salivary secretory function between patients with erosive esophagitis and those with nonerosive reflux disease

BACKGROUND AND AIM

It has been speculated that impaired salivary flow contributes to abnormal acid clearance in patients with erosive esophagitis (EE). For easy and objective assessment of salivary function, we developed a salivary gland blood flow measurement technique using continuous-wave Doppler sonography. In the present study, we evaluated the salivary secretory function in patients with EE and those with nonerosive reflux disease (NERD) using this method.

METHODS

Doppler waveform analysis was performed on the facial artery to assess blood inflow to the submandibular gland of 30 healthy subjects (HS). Blood flow was compared before and after secretory stimulation with 1 mL of lemon juice. Saliva was simultaneously collected and weighed before and after stimulation. Continuous-wave Doppler sonography was also performed in patients with EE and NERD. The size of the submandibular gland was compared in 26 patients with EE, 41 patients with NERD, and 86 HS.

RESULTS

The submandibular gland blood flow increased after stimulation in all HS. Both within-day and day-to-day reproducibility were good. There was a significant correlation between the percent increase in the maximum velocity and the percent increase in salivary secretion. Although the size of the submandibular gland was not significantly different among the three groups, the percent increase in the maximum velocity in patients with EE was significantly smaller than that in HS.

CONCLUSIONS

We have established an easy method of assessing salivary function in daily practice. This study revealed that a decrease in salivary secretory function is involved in the pathology of EE.

Critical appraisal of Rome IV criteria: hypersensitive esophagus does belong to gastroesophageal reflux disease spectrum

The Rome IV Committee introduced a major change in the classification of functional gastrointestinal disorders, proposing a more restrictive definition of gastroesophageal reflux disease (GERD). It was suggested that hypersensitive esophagus (HE) may sit more firmly within the functional realm. It was suggested that GERD diagnosis should be based upon abnormal acid exposure time (AET) only, implying no advantage of impedance-pH over pH monitoring. Symptom association probability (SAP), symptom index (SI) and heartburn relief with proton pump inhibitor (PPI) therapy were regarded as unreliable, whereas a lack of response to PPI was considered as evidence of functional heartburn. These assumptions are contradicted by numerous studies showing the clinical relevance of weakly acidic refluxes and the diagnostic utility of SAP, SI and new impedance parameters, namely the post-reflux swallow-induced peristaltic wave (PSPW) index and the mean nocturnal baseline impedance (MNBI). The PSPW index and MNBI provide significant diagnostic advantage, particularly in patients with normal AET who can be classified as HE when both parameters are abnormal, even though SAP and SI are negative. Visceral pain modulators are recommended by the Rome IV Committee despite scanty evidence of efficacy, but a positive outcome with medical or surgical anti-reflux treatment has been reported by several studies of HE patients. Therefore, we believe that patients with endoscopy-negative heartburn should be investigated by means of impedance-pH monitoring with analysis of PSPW index and MNBI: such an approach provides accurate identification of HE cases, who remain, in our opinion, within the realm of GERD and should be treated accordingly.

Pathophysiology of Gastroesophageal Reflux Disease

The pathogenesis of gastroesophageal reflux disease (GERD) is complex and involves changes in reflux exposure, epithelial resistance, and visceral sensitivity. The gastric refluxate is a noxious material that injures the esophagus and elicits symptoms. Esophageal exposure to gastric refluxate is the primary determinant of disease severity. This exposure arises via compromise of the anti-reflux barrier and reduced ability of the esophagus to clear and buffer the refluxate, leading to reflux disease. However, complications and symptoms also occur in the context of normal reflux burden, when there is either poor epithelial resistance or increased visceral sensitivity. Reflux therefore develops via alterations in the balance of aggressive and defensive forces.