Relationship between baseline impedance levels and esophageal mucosal integrity in children with erosive and non-erosive reflux disease

Characteristics of esophageal refluxate and symptoms in infants compared between pre-treatment and on treatment with proton pump inhibitors

OBJECTIVE

To examine longitudinal pH-impedance characteristics from those infants who remained on proton pump inhibitors therapy for gastroesophageal reflux disease (GERD) as parents/providers refused to discontinue therapy after 4 weeks.

STUDY DESIGN

Eighteen infants with acid reflux index >3% underwent treatment, and pH-impedance data were compared prior to and on proton pump inhibitors at 42 ± 1 and 46 ± 1 weeks' postmenstrual age, respectively. Esophageal acid and bolus exposure, symptoms and swallowing characteristics were examined.

RESULTS

Proton pump inhibitors reduces the acid-mediated effects of reflux but modifies impedance and clearance mechanisms (P < 0.05). Prolonged therapy did not reduce symptoms (P > 0.05). Infants evaluated while on proton pump inhibitors were 1.8 times more likely to have swallows before and after reflux.

CONCLUSIONS

Prescription of proton pump inhibitors for objectively determined GERD should have time limits, as prolonged treatment can result in prolonged esophageal bolus clearance time without relieving symptoms.

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.

Impact of esophageal mucosal permeability markers on provocation-induced esophageal reflexes in high-risk infants

Esophageal distal baseline impedance (DBI) is an indicator of mucosal integrity; lower values suggest increased permeability. Aims were to characterize the (1) effect of DBI category (<900 Ω, 900-2000 Ω, and >2000 Ω) on sensory-motor characteristics of mid-esophageal provocation-induced motility reflexes, and (2) clinical outcomes among high-risk human infants evaluated for gastroesophageal reflux disease. Symptomatic infants (N = 49, 41 ± 3 weeks postmenstrual age) underwent pH-impedance testing to characterize acid reflux index (ARI) and DBI, and pharyngo-esophageal manometry to examine upper esophageal sphincter (UES), peristaltic, and lower esophageal sphincter (LES) functions. Sensory-motor response characteristics included response threshold (ml), occurrence (%), latency (s), duration (s), and magnitude (mmHg) upon mid-esophageal stimulations (0.1-2.0 ml of air, water, and apple juice). Motility and clinical outcomes were compared among DBI groups. In infants with DBI <900 Ω and 900-2000 Ω (vs. >2000 Ω): (a) Long-term feeding milestones did not differ (p > 0.05); (b) complete peristaltic propagation decreased in 900-2000 Ω (p < 0.05), polymorphic waveforms increased in <900 Ω and 900-2000 Ω (p < 0.05); (c) media effects were noted with liquids (vs. air) wherein UES and esophageal contractility were prolonged in <900 Ω and 900-2000 Ω (p < 0.05), and esophageal sensitivity heightened for <900 Ω with water and for 900-2000 Ω with air (both p < 0.05). ARI was not correlated with DBI in infants with chronic lung disease (r = 0.05, p = 0.82). We conclude that pharyngo-esophageal motility sensory-motor characteristics in infants are modified by DBI category. These preliminary findings pave-the-way for further physiological testing in convalescing high-risk infants to ascertain potential mechanisms of airway-digestive reflex interactions and symptom generation, which may lead to targeted therapies.

Nonachalasic esophageal motor disorders, from diagnosis to therapy

INTRODUCTION

Investigations conducted using conventional manometry and, recently, using high-resolution manometry (HRM), allowed us to explore the field of esophageal motility and understand the potential link between motor features and gastroesophageal reflux disease (GERD) pathogenesis. The management of patients with nonachalasic esophageal motor disorders is often challenging, due to the clinical heterogeneous presentation and the multifactorial nature of the mechanisms underlying symptoms.

AREAS COVERED

Several studies, carried out using HRM, have better interpreted the esophageal motor function in patients with esophagogastric junction outflow obstruction (EGJOO), distal esophageal spasm (DES), hypertensive esophagus, and hypomotility disorders. Moreover, HRM studies have shown a direct correlation between reduced esophageal motility, disruption of the esophagogastric junction, and gastroesophageal reflux burden.

EXPERT OPINION

Pathogenesis, clinical presentation, diagnosis, and treatment of nonachalasic esophageal motor disorders still represent a challenging area, requiring future evaluation by multicenter outcome studies carried out in a large cohort of patients and asymptomatic subjects. However, we believe that an accurate clinical, endoscopic, and HRM evaluation is, nowadays, helpful in addressing patients with nonachalasic esophageal motor disorders to optimal treatment options.

Low Mean Nocturnal Baseline Impedance is Associated With a Pathological Acid Exposure Time in Children

BACKGROUND

The baseline impedance (BI) and the mean nocturnal baseline impedance (MNBI) serve as markers of mucosal integrity in patients with pathologic acid exposure time (AET). This work aims to investigate the association between the BI and MNBI with the AET in children.

METHODOLOGY

A retrospective study was performed in children ≤18 years old with suspicion of gastroesophageal reflux disease who underwent both endoscopy and pH-impedance monitoring (pH-MII). Esophagitis was graded according to the Los Angeles classification. The pathological AET was determined depending on the age (≥5% in patients >1 year and ≥10% in those ages ≤1 year). For the BI, 60 s measurements were taken every 4 h, and for the MNBI, 3 10 min measurements were taken between 1.00 and 3:00 am; then, they were averaged. The means of BI and MNBI were compared with each other, with the AET, and other variables.

RESULTS

Sixty-eight patients were included, 25% of patients presented pathological AET. The mean of the MNBI was higher than BI in channels 6 (2195 vs 1997 Ω, P = 0.011) and 5 (2393 vs 2228 Ω, P = 0.013). BI and MNBI at channel 6 were lower in patients with pathological AET than in those with normal AET (1573 vs 2138 Ω, P = 0.007) and (1592 vs 2396 Ω, P = 0.004), respectively.

CONCLUSIONS

Children with pathological AET had lower impedance values than those with normal AET. BI and MNBI measurements should be part of the routine MII-pH assessment in children.

Esophageal impedance baseline in infants with bronchopulmonary dysplasia: A pilot study

BACKGROUND

Bronchopulmonary dysplasia (BPD) may induce gastroesophageal reflux (GER). Esophageal impedance baseline values (BI) reflect mucosal inflammation. Our aim was to evaluate BI levels in preterm infants with BPD compared with those without BPD and to identify BI predictors.

METHODS

This is a retrospective pilot study including infants born <32 weeks' gestational age (GA) who underwent esophageal multichannel intraluminal impedance (MII)-pH. Univariate/multivariate analysis were performed to compare data between BPD and non-BPD infants and to identify BI predictors. A subgroup analysis was performed in infants born <29 weeks' GA, at highest risk for BPD.

RESULTS

Ninety-seven patients (median GA 28^5/7 weeks, mean postnatal age 49 days, 29 with BPD), were studied. BPD infants had significantly lower birth weight compared with non-BPD infants (750 vs. 1275 g), were more immature (27^4/7 vs. 29^0/7 weeks GA), were older at MII-pH (79 vs. 38 days) and received less fluids during MII-pH (147 vs. 161 ml/kg/day). The same findings were found in the group of 53 infants born <29 weeks. BPD versus non-BPD infants had significantly lower BI (2050 vs. 2574 ohm, p = 0.007) (<1000 ohm in five BPD infants vs. one non-BPD) whereas the other MII-pH parameters were not significantly different. Multiple regression analysis found that increasing chronological age was positively associated with BI (B = 9.3, p = 0.013) whereas BPD was associated with lower BI (B = -793.4, p < 0.001).

CONCLUSIONS

BPD versus non-BPD infants had significantly lower BI despite similar MII-pH data. BPD and chronological age predicted BI, whereas only BPD predicted BI in the most immature infants.

Oesophageal pH-Impedance for the Diagnosis of Gastro-Oesophageal Reflux Disease: Validation of General Population Reference Values in Children with Chronic Neurological Impairments

Diagnosis of gastro-oesophageal reflux disease (GORD) in children with chronic neurological impairment (NI) remains a clinical challenge. The study aimed to validate the relevance of the reference values used to assess gastro-oesophageal reflux (GOR) in children with NI and to determine the optimal cut-off level of the pH-impedance parameter with the best predictive value for outcomes associated with endoscopic assessments of the oesophagus. Sixty-seven children (32 male, 35 female; age: interquartile range, 5 years 6 months-14 years 10 months; median, 11 years 3 months) with NI were prospectively recruited for the study. The exclusion criteria were previous fundoplication and lack of consent for the study. All patients underwent evaluations for GOR disease, including pH-impedance and gastroscopy. Based on endoscopy, oesophagitis was diagnosed in 22/67 children (32.8%); 9/67 (13.4%) were classified as having Hetzel-Dent grade III or IV. GOR was present in 18/67 children (26.9%), as determined by pH-impedance. Patients with endoscopic lesions had a significantly higher number of total reflux (p = 0.0404) and acidic episodes (p = 0.0219). The total number of reflux episodes, with a cut-off level of 44 episodes, was the pH-impedance parameter most strongly predictive of the presence of lesions in gastroscopy (specificity: 50%, sensitivity: 73%). These findings suggest that endoscopic lesions may be present in children with chronic NI with a low number of GOR episodes, as recorded by pH-impedance. The use of standardised reference norms determined for the general population may underestimate GOR episodes in this group of patients.

Multichannel impedance monitoring for distinguishing nonerosive reflux esophagitis with minor changes on endoscopy in children

Objectives:

There are reports describing the relationship between baseline impedance level and esophageal mucosal integrity at endoscopy, such as erosive and nonerosive reflux esophagitis. However, many children with symptoms of gastroesophageal reflux disease have normal findings or minor changes on esophagogastroduodenoscopy. We aimed to examine whether modest changes at esophagogastroduodenoscopy can be evaluated and correlated with esophageal multichannel intraluminal impedance monitoring.

Methods:

Patients (ages 0–17 years) with upper gastrointestinal symptoms who underwent combined esophagogastroduodenoscopy and multichannel intraluminal impedance monitoring at the Women’s and Children’s Hospital, Adelaide, Australia, between 2014 and 2016 were retrospectively studied and the following data were collected and used for analysis: demographics, multichannel intraluminal impedance data, included baseline impedance. Endoscopic findings were classified by modified Los Angeles grading, Los Angeles N as normal, Los Angeles M as with minimal change such as the erythema, pale mucosa, or friability of the mucosa following biopsy. Patients on proton pump inhibitor were excluded.

Results:

Seventy patients (43 boys; 61%) were enrolled with a mean age of 7.9 years (range 10 months to 17 years). Fifty-one patients (72.9%) were allocated to Los Angeles N, while Los Angeles M was evident in 19 patients (27.1%). Statistically significant differences were observed in the following parameters: frequency of acid and nonacid reflux and baseline impedance in channels 5 and 6. The median values of the data were 18.3 episodes, 16.0 episodes, 2461.0 Ω, 2446.0 Ω in Los Angeles N, 36.0 episodes, 31.0 episodes, 2033.0 Ω, 2009.0 Ω in Los Angeles M, respectively.

Conclusion:

Lower baseline impedance is helpful in predicting minimal endoscopic changes in the lower esophagus. A higher frequency of acid and nonacid reflux episodes was also predictive of minimal endoscopic change in the lower esophagus.

Measurement of low-grade inflammation of the esophageal mucosa with electrical conductivity shows promise in assessing PPI responsiveness in patients with GERD

A device that can easily measure electrical impedance might be a helpful tool for investigating the pathophysiology of gastroesophageal reflux disease. The first aim of this study was to validate our newly developed bioelectrical admittance measurement (BAM) through in vitro experimentation. The second aim was to investigate whether evaluation of BAM by this measurement differed between patients with heartburn according to their response to proton pump inhibitor (PPI) therapy. Caco-2 cell monolayers and three-dimensional tissues were examined by BAM using a frequency response analyzer. BAM was also used to measure the impedance through cell layers. Subsequently, BAM was performed during endoscopy in 41 patients experiencing heartburn without esophageal mucosal breaks. After 2-wk administration of 20-mg rabeprazole twice daily, patient responses to PPI were classified as "good" or "poor" according to their clinical course. In each patient, histological alterations and gene expression levels of inflammation mediators and tight junction proteins were evaluated. Impedance profiles indicated that monolayer Caco-2 cells on top of eight-layered normal human dermal fibroblasts had the highest magnitude of impedance over the range of frequencies. In vivo results revealed that patients with good responses to PPI displayed significantly higher admittance. Severity of low-grade inflammation was significantly associated with esophageal wall admittance. Moreover, esophageal wall admittance may be more closely related to basal zone hyperplasia than dilatation of intercellular spaces. Thus, BAM may be able to detect abnormalities in the subepithelial layer of the esophagus.NEW & NOTEWORTHY Bioelectrical admittance measurement is a new method to evaluate esophageal mucosal permeability vertically during upper gastrointestinal endoscopy. Measurement of low-grade inflammation of the esophageal mucosa with electrical conductivity shows promise in assessing proton pump inhibitor responsiveness in patients with gastroesophageal reflux disease. As various gastrointestinal diseases are associated with changes in mucosal permeability, bioelectrical admittance measurement is expected to be clinically applied to therapeutic decision-making for these diseases in the future.

Simultaneous Evaluation of Laryngopharyngeal Reflux and Swallowing Function Using Hypopharyngeal Multichannel Intraluminal Impedance Measurements in Neurologically Impaired Patients

Background/Aims

This study aims to evaluate the presence of laryngopharyngeal reflux (LPR) and to investigate the use of hypopharyngeal baseline impedance (BI) for assessing swallowing dysfunction and gastroesophageal reflux disease (GERD) using hypopharyngeal multichannel intraluminal impedance and pH (HMII-pH) monitoring in neurologically impaired patients (NIPs).

Methods

The study population in this retrospective study comprised 20 NIPs (mean age, 36.1 ± 15.0 years; age range, 13-64 years) who underwent multichannel intraluminal impedance and pH (MII-pH), HMII-pH, and laryngoscopy using the Hyodo scoring method from December 2016 to April 2019. The MII-pH and HMM-pH parameters were compared in the NIPs, whereas hypopharyngeal BI values were compared between NIPs with ≥ 5 and < 5 in Hyodo scores. Correlations between the hypopharyngeal BI values and the Hyodo score were analyzed using Spearman’s correlation coefficient. A receiver operator characteristic curve was created to determine the optimum cut-off of hypopharyngeal BI value to discriminate SD.

Results

Three NIPs were diagnosed with pathological LPR and GERD by the HMII-pH monitoring. No significant differences in parameters were observed between MII-pH and HMII-pH monitoring. The correlation analysis demonstrated a significant negative correlation between the hypopharyngeal BI values and Hyodo scores. The optimal cutoff value for hypopharyngeal BI was 1552 Ω.

Conclusions

This study demonstrated the usefulness of HMII-pH monitoring in identifying NIP with pathological LPR. Considering the difficulties in performing examinations in NIPs, HMII-pH monitoring may be a potentially useful technique for the simultaneous evaluation of swallowing dysfunction, LPR, and GERD in NIP.

Effects of upper airway obstruction or hypoxia on gastroesophageal reflux in newborn lambs

BACKGROUND

Although it is commonly accepted that upper airway obstruction (UAO) increases gastroesophageal reflux (GER), the link is poorly understood and insufficiently documented. In addition, while hypoxia is often encountered in infants with UAO, its consequences on GER are virtually unknown. The two aims of the present study were to characterize the effects of (1) UAO and (2) hypoxia on GER.

METHODS

Seventeen lambs underwent polysomnographic and esophageal impedance/pH-metry monitoring during UAO vs. a control condition (6 h, ten lambs) or 10% hypoxia vs. normoxic condition (3 h, seven other lambs).

RESULTS

Moderate-to-severe UAO was maintained throughout monitoring (inspiratory tracheal pressure of -13 (-15, -12) cm H₂O vs. -1 (-1, -1) cm H₂O in control condition, p = 0.005). While the number of GERs increased with UAO (2 (1, 4) vs. 0 (0, 3) in the control condition, p = 0.03), the increase was less than anticipated and inconsistent among the lambs. Also, sustained 10% hypoxia did not alter the number of GERs (2 (1, 3) vs. 0 (0, 5) in the control condition, p = 0.9).

CONCLUSIONS

The presence of an UAO for 6 h mildly increased the number of GERs, whereas hypoxia for 3 h had no significant effect.

IMPACT

The effect of upper airway obstruction and hypoxia on gastroesophageal reflux is poorly documented in the neonatal period. A moderate-to-severe upper airway obstruction for 6 h results in a mild, inconsistent increase in the number of gastroesophageal refluxes. Overall, a hypoxia of 10% for 3 h had no significant impact on gastroesophageal reflux. The prescription of an antireflux medication in infants with upper airway obstruction must not be systematic but rely on objective signs of a pathologic gastroesophageal reflux.

Understanding the relationship between esophageal motor disorders and reflux disease

INTRODUCTION

The management of gastro-esophageal reflux disease (GERD) patients is often complex as the clinical presentation is heterogeneous and the mechanisms underlying symptoms are multifactorial. In the past decades, investigations conducted with conventional manometry and, above all, the more accurate high resolution manometry (HRM), helped us in exploring the field of esophageal motility and in understanding the link between motor features and GERD pathogenesis.

AREAS COVERED

Several studies carried out with conventional manometry and HRM have confirmed a relevant role of esophageal motor function in GERD pathogenesis. In particular, HRM studies have shown a direct correlation between impaired esophageal body motility, disruption of the esophagogastric junction and reflux burden. These findings impact the clinical and therapeutical management of GERD patients. Moreover, HRM findings might be helpful in evaluating patients with proton pump inhibitor (PPI) resistance and inconclusive evidences of GERD.

EXPERT OPINION

The relationship between esophageal motility and GERD pathogenesis needs to be further evaluated by multicenter outcome studies involving a large number of GERD patients and healthy controls. However, other more promising areas could be progressed.

Characterization of Esophageal Motility in Children With Operated Esophageal Atresia Using High-resolution Impedance Manometry and Pressure Flow Analysis

OBJECTIVES

Esophageal dysmotility is common in patients with esophageal atresia (EA). High-resolution impedance manometry and pressure flow analysis (PFA) allow characterization of biomechanical events that drive bolus flow. The aims were to assess esophageal motility in children with EA, using PFA, and to test whether there is a correlation between PFA parameters and symptoms or endoscopic/histologic findings.

METHODS

High-resolution impedance manometry was performed in 16 children with EA (median age 11 years), compared with 13 patient controls (median age 14 years; P = NS vs patients). Wet swallows were analyzed using PFA. Medical charts were reviewed for symptoms and pathology results of the attendant esophagoscopy. Patients with EA were arbitrarily subgrouped according to their motility pattern: group A with presence of distal contraction in ≥50% of the swallows and group B with presence of distal contractions in <50% of the swallows.

RESULTS

Esophageal peristaltic motor patterns were abnormal in all patients with EA. Bolus transport was impaired as shown by the higher impedance ratio in EA than in controls (0.47 vs 0.22; P < 0.001). Impedance ratio was also higher in group B (n = 8) versus group A (n = 8) (P < 0.001). Symptoms of dysphagia were not correlated with the PFA measures. Contractile segment impedance, a marker of mucosal integrity, was significantly lower in the EA group.

CONCLUSIONS

Bolus transport was severely altered in patients with EA but was not predictive of symptoms. The presence of residual distal contractions is associated with a more efficient bolus propulsion.

Gastroesophageal Reflux Disease in the Neonatal Intensive Care Unit Neonate: Controversies, Current Understanding, and Future Directions

Gastroesophageal reflux (GER) is considered physiologic and is a normal process; whereas, when aerodigestive consequences are associated, it is often interpreted as GER disease (GERD). However, the distinction between them remains a challenge in infants in the NICU. Reflux-type of symptoms are heterogeneous, and often managed with changes in diet, feeding methods, and acid-suppressive therapy; all these empiric therapies lack objectivity; hence, practice variation is universal. We clarify the current controversies, explain the potential role of GERD in causing symptoms and complications, and highlight current advances. The evidence basis for the diagnostic strategies is discussed.

Esophageal pH-impedance monitoring in children: position paper on indications, methodology and interpretation by the SIGENP working group

Multichannel intraluminal impedance pH (MII-pH) monitoring currently represents the gold standard diagnostic technique for the detection of gastro-esophageal reflux (GER), since it allows to quantify and characterize all reflux events and their possible relation with symptoms. Over the last ten years, thanks to its strengths and along with the publication of several clinical studies, its worldwide use has gradually increased, particularly in infants and children. Nevertheless, factors such as the limited pediatric reference values and limited therapeutic options still weaken its current clinical impact. Through an up-to-date review of the available scientific evidence, our aim was to produce a position paper on behalf of the working group on neurogastroenterology and acid-related disorders of the Italian Society of Pediatric Gastroenterology, Hepatology and Nutrition (SIGENP) on MII-pH monitoring technique, indications and interpretation in pediatric age, in order to standardise its use and to help clinicians in the diagnostic approach to children with GER symptoms.

Acid and bolus exposure in pediatric reflux disease according to the presence and severity of esophageal mucosal lesions

PURPOSE

The relationship between reflux index (RI) and bolus exposure parameters in multichannel intraluminal impedance (MII) has not been examined sufficiently among children. The significance of acid and bolus exposure in evaluating pediatric reflux disease (RD) was explored by focusing on mucosal lesions.

METHODS

We conducted MII-pH on 28 patients (median age 8 years) with suspected RD. We assessed relationships between RI and bolus exposure indices, and also compared acid and bolus exposures across patients grouped by endoscopic esophageal mucosal lesions.

RESULTS

RI correlated significantly with distal acid reflux events (r = 0.60), acid bolus exposure time (BET) (0.55), and bolus clearance time (BCT) (0.48). Significant differences were observed among the control, non-erosive RD (NERD), and erosive RD (ERD) groups in all acid and several bolus exposure indices (distal and proximal frequencies, and BCT), while no significant difference was apparent between NERD and ERD. Acid exposure tended to be more severe in high-grade than in low-grade ERD, while no similar tendency was found in any bolus parameters other than BCT.

CONCLUSIONS

MII-pH showed great potential for investigating the pathophysiology of pediatric RD, with RI revealing different correlations with variable bolus exposure indices. However, no specific parameters allowing precise discrimination between RDs or mucosal severities were identified.

Is There a Role for pH Impedance Monitoring in Identifying Eosinophilic Esophagitis in Children with Esophageal Atresia?

OBJECTIVES

To evaluate clinical, endoscopic, and pH-impedance measures in a cohort of children with esophageal atresia and concomitant eosinophilic esophagitis (EoE) and compared it with disease-matched controls, to identify predictive factors for the development of EoE and esophageal stricture.

STUDY DESIGN

We reviewed 63 patients with esophageal atresia assessed for refractory upper gastrointestinal symptoms between January 2015 and September 2017 at 2 tertiary referral centers. All patients underwent upper gastrointestinal endoscopy and pH-impedance monitoring. Based on esophageal histology, patients were classified as (1) esophageal atresia without evidence of esophagitis; (2) esophageal atresia with evidence of esophagitis (including esophageal eosinophilia not meeting the criteria for EoE); (3) esophageal atresia with concomitant EoE. Age and sex matched patients with gastroesophageal reflux disease were used as disease controls.

RESULTS

The presence of atopy and peripheral eosinophilia at baseline were significantly associated with EoE (P < .05). Although there was a tendency toward an increased number of strictures in patients with esophageal atresia-EoE, this did not reach statistical significance (P = .06). Higher esophageal acid exposure time and lower baseline impedance values were significantly associated with eosinophilic infiltration (P < .05 and P < .01, respectively). Using logistic regression analysis, the presence of mucosal eosinophilia was the most predictive factor for stricture formation (P < .05).

CONCLUSIONS

A history of atopy and the presence of peripheral eosinophilia in patients with esophageal atresia are predictive factors for the development of EoE, which in turn is a predictive factor for stricture occurrence. Higher esophageal acid exposure time and lower baseline impedance are associated with esophageal eosinophilic infiltration, suggesting their value in selecting which patients with esophageal atresia should undergo endoscopic examination.

The assessment of the esophageal motility of children with esophageal disorders by the detailed observation of the pH-multichannel intraluminal impedance waveform and baseline impedance: screening test potential

BACKGROUND

The present study aimed to evaluate whether the detailed observation of pH/MII waveforms and the analysis of baseline impedance (BI) values could detect esophageal dysmotility in pediatric patients with esophageal disorders.

PATIENTS AND METHODS

Eleven patients with congenital esophageal disorder in whom pH/MII was conducted from April 2011 to June 2015, were enrolled in this study. The diagnoses of the patients were as follows: postoperative esophageal atresia (EA), n = 6; esophageal achalasia (EAch), n = 4; and congenital esophageal stenosis (CES), n = 1. The characteristics of the pH/MII waveform, pathological GERD, BI value, and the average BI value of the 2 distal channels (distal BI; DBI) were analyzed in each disorder.

RESULTS

Two EA (33%) patients and one EAch (25%) patient were diagnosed with GERD. The mean DBI values of the EA, EAch and CES patients was 912 ± 550, 2153 ± 915 and 1392 Ω, respectively. The EA patients showed consistently low DBI values. One CES patient and two infantile EAch patients showed postprandial prolonged low DBI values. Whereas, the pH/MII waveforms of the adolescent EAch patients were difficult to interpret due to their extremely low BI values.

CONCLUSIONS

The present study demonstrated that the detailed observation of the pH/MII waveforms in all channels and the analysis of BI were useful for evaluating esophageal motility in children with congenital esophageal disorders. In particular, infantile patients with EAch showed DBI findings that were distinct from those of adult EAch patients. Considering the difficulty of performing esophageal manometry in young children, the detailed observation of the pH/MII waveform may help in the diagnosis of esophageal dysmotility in children.

Differentiation of esophageal pH-impedance characteristics classified by the mucosal integrity marker in human neonates

BACKGROUND

In adults, distal baseline impedance (BI) is a determinant of esophageal mucosal integrity with values <900 Ω indicating inflammation. Relationships between acid gastroesophageal reflux (GER) and BI in neonates are unclear.

METHODS

NICU infants (N = 198, 30.4 ± 0.3 weeks gestation) were evaluated at 43 ± 0.4 weeks postmenstrual age using 24-h pH-impedance. Ten randomly selected 1-min windows during rest from the distal impedance channel (Z6) were averaged. Chi-square, t-tests, and ANOVA were used to compare pH-impedance and symptom characteristics by BI severity (BI < 900 Ω, BI 900-2000 Ω, BI > 2000 Ω). Regression analysis was used to identify potential contributing factors of BI.

RESULTS

In BI < 900 Ω: (1) pH-impedance characteristics were increased (acid reflux event frequency, duration, and severity, all P < 0.05 vs. BI > 2000 Ω), and (2) positive symptom correlations were noted with bolus (73%) and acid events (55%). Significant predictors of BI included chronological age, acid reflux index, and BPD diagnosis (all P < 0.05).

CONCLUSIONS

Low BI is associated with prolonged acid exposure, delayed clearance, and greater aerodigestive symptom prevalence, likely associated with inflammation and or increased mucosal permeability. BI > 2000 Ω likely involves little or no inflammation because acid exposure is minimal. Combination of SAP, pH-impedance metrics, and BI along with the clarification of dysmotility mechanisms provides the rationale for personalized anti-reflux therapies as needed.

Mucosal Impedance Measurements Differentiate Pediatric Patients With Active Versus Inactive Eosinophilic Esophagitis

BACKGROUND AND AIMS

Eosinophilic esophagitis (EoE) is a chronic disorder in children that requires continued assessment of disease activity, involving repeated sedation, endoscopy, and biopsy analysis. We investigated whether mucosal impedance measurements can be used to monitor disease activity in pediatric patients with EoE.

METHODS

We measured mucosal impedance at 3 locations in the esophagus in pediatric patients (1-18 years old; 32 with active EoE, 10 with inactive EoE, 32 with nonerosive reflux disease [NERD]) and 53 children with symptoms but normal findings from histologic analyses (controls) undergoing routine esophagogastroduodenoscopy at the Vanderbilt Pediatric Gastroenterology Clinic. Pathologists reviewed biopsies per routine protocol, determined eosinophilic density, and graded spongiosis on an ordinal visual scale. Mucosal impedance measurements were compared within patient groups. The primary outcome was correlation of mucosal impedance measurements with disease activity, based on severity of spongiosis and eosinophil counts.

RESULTS

Mucosal impedance measurements were significantly lower in patients with active EoE at 2, 5, and 10 cm above the squamo-columnar junction (median values of 1069, 1368, and 1707, respectively) compared to patients with inactive EoE (median values of 3663, 3657, and 4494, respectively), NERD (median values of 2754, 3243, and 4387), and controls (median values of 3091, 3760, and 4509) (P < 0.001 for all comparisons to patients with active EoE). We found inverse correlations between mucosal impedance measurements and eosinophil count (P < 0.001), and spongiosis severity (P < 0.001).

CONCLUSIONS

Mucosal impedance measurements may provide immediate information about mucosal inflammation in children. Patients with active EoE have significantly lower mucosal impedance values than patients with inactive EoE, NERD, or controls; mucosal impedance measurements correlate inversely with eosinophil counts and spongiosis severity. Mucosal impedance is a promising rapid and less-invasive method to monitor EoE activity in pediatric patients with EoE; it could reduce costs and risks of disease monitoring.

Analyses of the relationship between a 'number of reflux episodes' exceeding 70 and the pH index in neurologically impaired children by evaluating esophageal combined pH-multichannel intraluminal impedance measurements

BACKGROUND

The present study aimed to evaluate the characteristics associated with a number of reflux episodes (NoRE) of 70 by comparing the clinical and multichannel intraluminal impedance pH measurements (pH/MII) and pH index (pHI) in neurologically impaired (NI) children.

PATIENTS AND METHODS

NI children (1-16 years of age) in whom pH/MII had been measured for GERD study were enrolled in this study. All children were divided into NoRE >70 or ≤70 and pHI >4.0 or ≤4.0, >5.0 or ≤5.0 or >7.0 or ≤7.0. In addition, the NI children with pHI >4.0, >5.0 and >7.0 were subdivided into NoRE >70 and ≤70 groups. The clinical and pH/MII measurements were compared between each of the two groups. The cutoff values of pHI and baseline impedance (BI) (Z6) were calculated to discriminate NoRE >70 and ≤70.

RESULTS

A total of 61 NI children were enrolled in this study. There was a significant difference in the acid-related parameters, the NoRE (nonacid) and BI between NoRE >70 and ≤70, acid-related parameters and BI between pHI >4.0 and ≤4.0, >5.0 and ≤5.0 and >7.0 and ≤7.0 groups. Furthermore, a significant difference was still observed in the BI between NoRE >70 and ≤70 groups among patients with pHI >4.0, >5.0 or >7.0. The cutoff values of pHI and BI (Z6) for discriminating NoRE >70 and ≤70 were 9.2 and 1049Ω, respectively.

CONCLUSION

The present study indicates that NoRE 70 corresponds to GERD in which patients suffer severe acid exposure with pH of around 9% and esophageal mucosal damage with low BI value in NI children.

Esophageal Baseline Impedance Reflects Mucosal Integrity and Predicts Symptomatic Outcome With Proton Pump Inhibitor Treatment

Background/Aims

Esophageal baseline impedance, which is decreased in gastroesophageal reflux disease (GERD) patients, is related to the severity of acid reflux and the integrity of the esophageal mucosa. The study aims to compare the baseline impedance and the dilated intercellular spaces (DIS) within patients with typical reflux symptoms and to evaluate the correlation of baseline impedance with DIS, esophageal acid exposure, as well as the efficacy of proton pump inhibitor (PPI) treatment.

Methods

Ninety-two patients and 10 healthy controls were included in the study. Erosive esophagitis (EE) was defined by esophageal mucosal erosion under upper endoscopy. Patients without mucosa erosion were divided into groups with pathologic acid reflux (non-erosive reflux disease [NERD]) or with hypersensitive esophagus. The biopsies of esophageal mucosa were taken 2–4 cm above the gastroesophageal junction Z-line during upper endoscopy for DIS measurement. All the patients received esomeprazole 20 mg twice-daily treatment for 8 weeks. The efficacy of esomeprazole was evaluated among all patients.

Results

The intercellular spaces were dilated in both EE and NERD patients (P < 0.05). The value 0.73 μm could be used as the cut-off DIS value to distinguish patients from controls (area under the curve [AUC] = 0.849, P < 0.01). One thousand seven hundred sixty-four ohms could be used as the cut-off impedance values to distinguish patients from controls (AUC = 0.794, P < 0.01). The baseline impedance was decreased in both EE patients and NERD patients, and negatively correlated to the acid exposure time (r = −0.527, P < 0.05). There was a weak correlation between DIS and baseline impedance (r = −0.230, P < 0.05). “Baseline impedance > 1764 Ω” was an independent predictor for PPI failure (OR, 11.9; 95% CI, 2.4–58.9; P < 0.01).

Conclusions

The DIS and decreased baseline impedance was observed in patients with mucosa erosion or pathological acid reflux. The baseline impedance reflected the mucosal integrity, it was more sensitive to esophageal acid exposure. Patients with high impedance might not benefit from the PPI treatment.

Low-impedance Baseline Values Predict Severe Esophagitis

OBJECTIVES

The aim of the study was to determine whether esophageal baseline impedance (BI) values in children could be predictive of esophagitis.

MATERIALS AND METHODS

Multichannel intraluminal impedance (MII) tracings of children 3 to 17 years of age suspected of having gastroesophageal reflux and esophagitis, who had also undergone upper endoscopy with multiple esophageal biopsies, were reviewed. Patients with eosinophilic esophagitis were excluded. Esophagitis was assessed by macroscopic and microscopic parameters. Esophageal histology was reported by 2 blinded independent pathologists unaware of the MII results. Mean BI was automatically calculated in the different MII channels (ch) by the specific software without removing any episode of increased/decreased BI. BI results were plotted against macroscopic and histological scores for each channel.

RESULTS

Tracings of 87 children, 53 boys, were evaluated. Mean age was 7.4 years: 45 had histologic esophagitis, 8 macroscopic. Histologic mild esophagitis (grade 1) was observed in 30, and 15 had moderate to severe esophagitis (grade 2-3). Ten had grade 3 esophagitis. Eight had macroscopic esophagitis as well.

RESULTS

in channel 6 of the MII, all 10 patients with grade 3 esophagitis and the 8 with macroscopic esophagitis had a BI <900 Ω/s (positive predictive value 100% and negative predictive value 100%), whereas none of those having a biopsy score of 0 to 2 or no endoscopic evidence of esophagitis had a mean BI below 2000 Ω/s.

CONCLUSIONS

The evaluation of the BI measured in channel 6 gave us 100% prediction of grade 3 and macroscopic esophagitis. BI on channel 6 may be useful to predict severe esophageal mucosa inflammation and could potentially be used for follow-up evaluation, rather than repeating an upper endoscopy. In addition, it would seem that grade 3 esophagitis even in the absence of macroscopic esophagitis affects the integrity of the esophageal epithelium.

BSPGHAN Motility Working Group position statement: paediatric multichannel intraluminal pH impedance monitoring-indications, methods and interpretation

BACKGROUND

Combined pH-impedance monitoring has been suggested as the investigation of choice for diagnosing gastro-oesophageal reflux in children. Although it is superior to oesophageal pH monitoring in detecting all types of reflux episodes (acid, weakly acidic and alkaline) with the ability to evaluate symptom association with reflux events, it is still limited by the lack of true paediatric normal value and the high cost involved (equipment and personnel).

OBJECTIVE

To produce a position statement on behalf of the Motility Working Group of the British Society of Paediatric Gastroenterology, Hepatology and Nutrition on the indications and practical application of combined oesophageal pH-impedance monitoring in children.

METHODS

Up-to-date review of available evidence.

RESULTS

This document provides a practical guide to clinician on indications, methods and results interpretation of paediatric multichannel intraluminal impedance pH (MII-pH).

CONCLUSIONS

MII-pH is increasingly used by paediatricians as the diagnostic tool for assessing gastro-oesophageal reflux disease and symptom association. There is wide variation in paediatric practice and a need for standardised practice.

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.

Esophageal mucosal integrity improves after laparoscopic antireflux surgery in children with gastroesophageal reflux disease

Background

Esophageal intraluminal baseline impedance reflects the conductivity of the esophageal mucosa and may be an instrument for in vivo evaluation of mucosal integrity in children with gastroesophageal reflux disease (GERD). Laparoscopic antireflux surgery (LARS) is a well-established treatment option for children with proton pump inhibitory (PPI) therapy resistant GERD. The effect of LARS in children on baseline impedance has not been studied in detail. The aim of this study was to evaluate the effect of LARS on baseline impedance in children with GERD.

Methods

This is a prospective, multicenter, nationwide cohort study (Dutch national trial registry: NTR2934) including 25 patients [12 males, median age 6 (range 2–18) years] with PPI-resistant GERD scheduled to undergo LARS. Twenty-four hour multichannel intraluminal impedance pH monitoring (MII-pH monitoring) was performed before and 3 months after LARS. Baseline impedance was evaluated during consecutive 2-h intervals in the 24-h tracings.

Results

LARS reduced acid exposure time from 8.5 % (6.0–16.2 %) to 0.8 % (0.2–2.8 %), p < 0.001. Distal baseline impedance increased after LARS from 2445 Ω (1147–3277 Ω) to 3792 Ω (3087–4700 Ω), p < 0.001. Preoperative baseline impedance strongly correlated with acid exposure time (r −0.76, p < 0.001); however, no association between symptomatic outcome and baseline impedance was identified.

Conclusions

LARS significantly increased baseline impedance likely reflecting recovery of mucosal integrity. As the change in baseline impedance was not associated with the clinical outcome of LARS, other factors besides mucosal integrity may contribute to symptom perception in children with GERD.

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.

Reflux monitoring in children

Recently, multichannel intraluminal impedance (MII) monitoring was added to the repertoire of tests to evaluate the (patho)physiology of gastroesophageal reflux (GER) in children. Its advantage above the sole monitoring of the esophageal pH lies in the ability of the detection of both acid and nonacid GER and to discern between liquid and gas GER. Currently, combined 24 h pH-MII monitoring is recommended for evaluation of gastro-esophageal reflux disease (GERD) and its relation to symptoms in infants and children, despite the lack of reference values in these age groups. There is new evidence in the current issue of this Journal supporting the role of pH-MII monitoring for the evaluation of children presenting with gastrointestinal symptoms suggestive of GERD and the prediction of the presence of reflux esophagitis. However, several issues should be taken into account when performing pH-MII clinically.

Adult and paediatric GERD: diagnosis, phenotypes and avoidance of excess treatments

Detailed investigations and objective measurements in patients with symptoms of gastro-oesophageal reflux should be performed with the intent of making the correct diagnosis, thus enabling choice of appropriate therapy. Establishing the most effective therapy is particularly important in adults who do not respond to standard treatment and in children. The use of PPIs for suspected GERD has increased substantially over the past decade, providing great relief in patients with acid-related symptoms, but also leading to adverse effects and a considerable economic burden. Adults with functional heartburn do not benefit from PPIs, while prolonged PPI use in patients with extraoesophageal symptoms remains a controversial area. Moreover, PPIs are not indicated in infants with GERD unless symptoms are proven to be acid-related. With regard to antireflux surgery, patients must be carefully selected to avoid the need for ongoing PPI treatment postoperatively. Correct diagnosis and phenotyping of patients with symptoms attributed to gastro-oesophageal reflux through detailed investigations is therefore imperative, leading to improved patient outcomes and rationalized use of available treatment options. In this Review, we outline currently available diagnostic tests and discuss approaches to limit any unnecessary medical or surgical interventions.

Laparoscopic Nissen fundoplication mainly reduces the volume of acid reflux and potentially improves mucosal integrity up to the middle esophagus in neurologically impaired children detected by esophageal combined pH-multichannel intraluminal impedance measurements

BACKGROUND

The aim of this study was to evaluate detailed changes of gastroesophageal reflux disease (GERD) in children before and after laparoscopic Nissen fundoplication (LNF) utilizing esophageal combined pH-multichannel intraluminal impedance (pH/MII) measurements.

PATIENTS AND METHODS

Thirteen patients with neurological impairment, who received laparoscopic Nissen fundoplication (LNF) owing to refractory pathological GERD, were enrolled in this study. 24h pH/MII was conducted in all patients before and one year after LNF. Each parameter of the pH/MII was evaluated and compared each other.

RESULTS

Both the mean pH index and bolus exposure index after LNF were significantly lower than those before LNF. The mean numbers of total and nonacid reflux episodes after LNF were significantly lower than those before LNF. The mean numbers of total, acid and nonacid proximal reflux episodes after LNF were significantly lower than those before LNF. The mean baseline impedance values from Z3 to Z6 after LNF were significantly higher than those before LNF.

CONCLUSIONS

The present study provides new insights into the effects of LNF in pediatric patients, which prevents mainly acid reflux episodes from rising to the proximal esophagus, and is expected to improve the mucosal integrity up to the middle esophagus.

Utility of baseline impedance level measurement in patients with gastroesophageal reflux symptoms

OBJECTIVE

Twenty-four-hour multichannel intraluminal impedance (MII) and pH monitoring is used for detecting reflux episodes in patients with gastroesophageal reflux (GER) disease. However, the clinical significance of baseline impedance levels (BILs) has not been well studied. We aimed to evaluate whether BILs are related to various reflux events or acid-related parameters and to determine whether BILs during specific intervals could be substituted for 24-h BILs.

MATERIAL AND METHODS

One-hundred forty-two patients GER symptoms underwent 24-h pH/impedance monitoring. We measured pH [(5 cm above the low esophageal sphincter (LES)] and BILs from three sites (3, 5, and 15 cm above the LES).

RESULTS

Eighty-one subjects (57.0%) were diagnosed with gastroesophageal reflux disease, and 53 (37.3%) had acid reflux and 28 (19.7%) had nonacid reflux. The 24-h BILs at distal sites were lower in the "reflux" group than in the "no reflux" group (p < 0.001) and lower in the "acid reflux" group than in the "nonacid reflux" group (p < 0.001). However, there was no significant difference in 24-h BILs at the proximal site among the "no reflux", "acid reflux", and "nonacid reflux" groups. The interclass correlation coefficient value of 24-h BILs with daytime 6-h BILs was 0.916 (95% CI 0.882-0.940) and that with nighttime 6-h BILs was 0.909 (95% CI 0.871-0.935).

CONCLUSION

BILs are related to GER, especially acid reflux. Location and duration of assessment for BILs needs to be standardized. Six-hour BILs could be substitutes for 24-h BILs. During analysis of MII-pH, more attention should be paid to BILs in the lower esophagus.

Low mean impedance in 24-hour tracings and esophagitis in children: a strong connection

Esophageal multiple intraluminal impedance baseline is an additional impedance parameter that was recently related to esophageal integrity. The aim of this study was to assess the relationship between mean esophageal impedance value and endoscopic findings in a large group of children. Children with symptoms of gastroesophageal reflux submitted to both endoscopy and impedance were included. Esophagitis was graded according to the Los Angeles classification. Mean impedance value was automatically calculated over 24-hour tracings. Data were adjusted for age through z-score transformation using percentiles normalized by the LMS (Lambda for the skew, Mu for the median, and Sigma for the generalized coefficient of variation) method. Nonparametric Mann-Whitney and Kruskal-Wallis tests, multiple, and stepwise regression were used. P-value <0.05 was considered as statistically significant. A total of 298 impedance tracings were analyzed. Endoscopic and histological esophagitis were detected in 30 and 29% patients, respectively. Median baseline z-score was significantly decreased both in proximal (P = 0.02) and distal (P = 0.01) esophagus in patients with endoscopic (but not histological) esophagitis. Patients with more severe esophagitis showed the lowest z-score. Bolus exposure index and the number of reflux episodes were the variables that were significantly associated with the baseline z-score. Impedance z-score is significantly decreased in infants and children with endoscopic esophagitis. Severity of esophagitis, bolus exposure index, and number of reflux episodes are factors influencing mean esophageal impedance.

Correlation between hypersensitivity induced by esophageal acid infusion and the baseline impedance level in patients with suspected gastroesophageal reflux

OBJECTIVES

To evaluate the relevance between the pH parameters and baseline impedance level or esophageal hypomotility in patients with suspected gastroesophageal reflux.

METHOD

The recordings of 51 patients with heartburn, acid regurgitation, globus or noncardiac chest pain were analyzed. Evaluation included a 24-h multichannel intraluminal impedance-pH test while on off-proton pump inhibitor therapy over 1 week, high-resolution manometry and Bernstein test. Mean baseline impedance level at the most distal portion of the impedance channel was assessed manually. Esophageal hypomotility was evaluated using transitional zone defect (TZD) and distal break (DB) length measurement.

RESULT

In the study subjects (n = 51), 6 had a DeMeester score of more than 14.7 and 14 had a positive symptom index. The Bernstein test was positive in ten patients. The baseline impedance level was inversely correlated with the acid exposure time % (r = -0.660, P < 0.001). Also, all reflux and weakly acid reflux time % measured by impedance monitoring showed a weak correlation with TZD + DB length (r = 0.327 and 0.324, P = 0.019 and 0.020, respectively). Although a positive Bernstein test has no relevance for the acid exposure time or acid-related symptoms as represented by the DeMeester score or symptom index, the baseline impedance level was significantly lower in patients with a positive Bernstein test than in those with a negative one (2,628.4 ± 862.7 vs. 1,752.2 ± 611.1 Ω, P = 0.004).

CONCLUSION

A lower baseline impedance level is closely related to increased esophageal acid exposure. Hypersensitivity induced by esophageal acid infusion might be attributed to acid-induced mucosal changes of the esophagus.

Esophageal intraluminal baseline impedance differentiates gastroesophageal reflux disease from functional heartburn

BACKGROUND & AIMS

Mucosal integrity can be assessed in patients with gastroesophageal reflux disease (GERD) by measuring intraluminal baseline impedance (BI). However, it is not clear whether BI is abnormal in patients with functional heartburn (FH), or can be used to distinguish them from patients with GERD. We compared differences in BI between patients with FH vs GERD.

METHODS

We performed a prospective study of 52 patients (16 men; mean age, 55 y; range, 23-78 y) seen at a tertiary university hospital from February 2009 through December 2012. Thirty-five patients had GERD (19 had nonerosive reflux disease [NERD], 16 had erosive reflux disease [ERD]) and 17 had FH. All patients discontinued proton pump inhibitor therapy and then underwent esophagogastroduodenoscopy and multichannel intraluminal impedance and pH monitoring. BI was assessed at 3, 5, 7, 9, 15, and 17 cm proximal to the lower esophageal sphincter in recumbent patients. Biopsy specimens were taken from 3 cm above the gastroesophageal junction; histology analysis was performed to identify and semiquantitatively score (scale, 0-3) dilated intercellular spaces.

RESULTS

Baseline impedance in the distal esophagus was significantly lower in patients with NERD or erosive reflux disease (ERD) than FH (P = .0006). At a cut-off value of less than 2100 Ω, BI measurements identified patients with GERD with 78% sensitivity and 71% specificity, with positive and negative predictive values of 75%. Also in the proximal esophagus, reduced levels of BI levels were found only in patients with ERD. There were negative correlations between level of BI and acid exposure time (r = -0.45; P = .0008), number of acidic reflux episodes (r = -0.45; P = .001), and proximal extent (r = -0.40; P = .004). Biopsy specimens from patients with NERD or ERD had significant increases in dilation of intercellular spaces, compared with those from patients with FH; there was an inverse association between dilated intercellular spaces and BI in the distal esophagus (r = -0.28; P = .06).

CONCLUSIONS

Measurement of BI in the lower esophagus can differentiate patients with ERD or NERD from patients with FH (78% sensitivity and 71% specificity), and therefore should be considered as a diagnostic tool for patients with proton pump inhibitor-refractory reflux. Low levels of BI are associated with increased exposure to acid and dilation of intercellular spaces, indicating that BI is a marker of mucosal integrity.

Clinical relevance of esophageal baseline impedance measurement: just an innocent bystander

OBJECTIVE

The clinical relevance of esophageal baseline impedance (BI) remains to be determined. In the present study, we explored the impact of gastroesophageal reflux disease (GERD) and esophageal dysmotility on BI.

METHODS

A total of 18 children with esophageal atresia, 26 children with GERD, and 17 controls prospectively underwent esophagogastroduodenoscopy and pH-impedance monitoring. BI was measured in both proximal and distal esophagus. Gastroesophageal reflux (GER) and bolus transit indicators were defined according to published criteria.

RESULTS

Patients with esophageal atresia showed significantly lower proximal and distal BI values (952 [716-1811] Ω; 895 [284-1189] Ω; respectively) compared with those with GERD (3015 [2368-3975] Ω; 2231 [1770-3032] Ω, P < 0.001 and <0.001, respectively) and controls (3699 [3194-4358] Ω; 3522 [2927-3994] Ω, P < 0.001 and <0.001, respectively). Using linear regression, proximal BI strongly correlated with total bolus transit time (r(2) = 0.61, P < 0.001) and bolus presence time (BPT; r(2) = 0.63, P < 0.001). Distal BI weakly correlated with acid exposure time (r(2) = 0.16, P < 0.01) and longstanding reflux episodes (r(2) = 0.17, P < 0.01), and strongly correlated with total bolus transit time (r(2) = 0.53, P < 0.001) and BPT (r(2) = 0.58, P < 0.001). By logistic regression, BPT predicted low proximal BI values (odds ratio [OR] 1.052; P < 0.05), whereas both GER indicators (acid exposure time: OR 1.56, P < 0.05; longstanding reflux episodes: OR 2.8, P < 0.05) and BPT (OR 1.66, P < 0.01) predicted low distal BI values.

CONCLUSIONS

Along the length of esophagus, both bolus transit variables and GER significantly affect BI. This suggests that BI may merely mirror phenomena occurring within the esophageal lumen or wall, limiting its value as a discrete clinical entity to replace variables already used for assessing both GERD and esophageal dysmotility.

The effect of endoscopic fundoplication and proton pump inhibitors on baseline impedance and heartburn severity in GERD patients

BACKGROUND

Antireflux therapy may lead to recovery of impaired mucosal integrity in gastro-esophageal reflux disease (GERD) patients as reflected by an increase in baseline impedance. The study objective was to evaluate the effect of endoscopic fundoplication and proton pump inhibitor (PPI) PPI therapy on baseline impedance and heartburn severity in GERD patients.

METHODS

Forty-seven GERD patients randomized to endoscopic fundoplication (n = 32) or PPI therapy (n = 15), and 29 healthy controls were included. Before randomization and 6 months after treatment, baseline impedance was obtained during 24-h pH-impedance monitoring. Heartburn severity was evaluated using the GERD-HRQL questionnaire.

KEY RESULTS

Before treatment, baseline impedance in GERD patients was lower than in healthy controls (p < 0.001). Antireflux therapy increased baseline impedance (from 1498 [IQR 951-2472] to 2393 [IQR 1353-3027] Ω, p = 0.001), however it only led to a partial recovery when compared to healthy controls (2393 [IQR 1353-3027] vs 2983 [2335-3810] Ω, p < 0.01). The effect of both treatment options was not significantly different (p = 0.13) despite the increased number of non-acid reflux events in the PPI group. No correlation was found between baseline impedance and GERD symptoms before or after treatment.

CONCLUSIONS & INFERENCES

Reduction in acid reflux by endoscopic fundoplication or PPI therapy leads to an increase in baseline impedance in GERD patients, likely to reflect recovery of mucosal integrity. The impact of non-acid reflux events on esophageal mucosal integrity may be limited as no difference in the increase in baseline impedance was observed after both treatment options. The lack of association between impedance baseline and heartburn severity indicates that other factors may contribute to heartburn perception in GERD.

Reflux pattern and role of impedance-pH variables in predicting PPI response in patients with suspected GERD-related chronic cough

BACKGROUND

Gastro-oesophageal reflux disease (GERD) may contribute to the onset of chronic cough (CC); however, the multichannel intraluminal impedance-pH (MII-pH) monitoring is often within the normal range and the response to proton pump inhibitors (PPIs) unsatisfactory. The measure of impedance baseline (IB) increases the sensitivity of MII-pH in patients with typical symptoms.

AIM

To evaluate the role of MII-pH variables, including IB, in predicting PPI response and to define the characteristics of the reflux pattern in CC patients.

METHODS

Prospectively selected CC patients suspected GERD-related underwent MII-pH monitoring and, therefore, received a double dose of PPIs for at least 6 weeks. Patients filled symptom scores before MII-pH and after PPI therapy. MII-pH data were compared with those obtained in 60 non-erosive reflux disease patients with typical symptoms.

RESULTS

A total of 156 CC patients entered the study: 68 (43.5%) responders and 88 (56.5%) nonresponders to PPIs. The number of reflux episodes was significantly higher in CC compared with that in typical symptoms patients. Nonresponder CC patients with a pathological acid exposure time (AET) and/or IB value were 43/88 (49%), while 15/88 (17%) presented only pathological AET (P < 0.001). CC patients with a pathological AET or IB, or with both a pathological AET and IB, showed a probability of PPI response twofold greater than patients with normal AET and IB.

CONCLUSIONS

The presence of a pathological AET or pathological IB in CC patients is associated with a greater probability of PPI response. IB is a promising variable in patients with CC, as it increases the diagnostic yield of MII-pH and allows confirmation of the GERD diagnosis in these patients.

Dilated intercellular space diameter as marker of reflux-related mucosal injury in children with chronic cough and gastro-oesophageal reflux disease

BACKGROUND

The diagnostic corroboration of the relationship between gastro-oesophageal reflux disease (GERD) and chronic cough remains challenging.

AIMS

To compare oesophageal mucosal intercellular space diameter (ISD) in children with GERD, children with gastro-oesophageal reflux (GER)-related cough (GrC) and a control group, and to explore the relationship between baseline impedance levels and dilated ISD in children with GER-related cough.

METHODS

Forty children with GERD, 15 children with GrC and 12 controls prospectively underwent oesophagogastroduodenoscopy (EGD) with oesophageal biopsies taken 2-3 cm above squamocolumnar junction. ISD were quantified using transmission electron microscopy. Impedance-pH monitoring with evaluation of baseline impedance in the most distal impedance channel was performed in both patient groups.

RESULTS

A significant difference in mean ISD values was found between GrC patients (0.9 ± 0.2 μm) and controls (0.5 ± 0.2 μm, P < 0.001), whereas there was no difference between GrC and GERD group (1 ± 0.3 μm, NS). No difference was found in the mean ISD between GrC children with or without pathological oesophageal acid exposure time (1 ± 0.3 vs. 0.9 ± 0.2 μm), and there was no correlation between ISD and any reflux parameter. Finally, there was no correlation between ISD and distal baseline impedance values (r:-0.35; NS).

CONCLUSIONS

In children with reflux-related cough, dilated intercellular space diameter appears to be an objective and useful marker of oesophageal mucosal injury regardless of acid exposure, and its evaluation should be considered for those patients where the diagnosis is uncertain. In children with reflux-related cough, baseline impedance levels have no role in identifying reflux-induced oesophageal mucosal ultrastructural changes.

Behind the (impedance) baseline in children

Impedance baseline is a new parameter recently related to esophageal integrity. The aim of this study was to assess the effect of different factors on impedance baseline in pediatric patients. We analyzed the impedance baseline of 800 children with symptoms of gastroesophageal reflux. Mean impedance baseline was automatically calculated throughout 24-hour tracings. The presence of different age groups and of esophagitis was evaluated. Unpaired t-test, Spearman rank correlation, polynomial, and regression plot were used for statistical analysis. Age-related percentile curves were created. We considered a P-value<0.05 as statistically significant. Impedance baseline was significantly (P<0.001) lower in younger compared to older children up to 48 months. The mean increase of baseline per month was much higher in the first 36 months of life (47.5 vs. 2.9 Ohm in Channel 1 and 29.9 vs. 2.3 Ohm in Channel 6, respectively) than in older ages. Patients with esophagitis showed significantly decreased impedance baseline (P<0.05). Infants (especially in the first months of life) and young children present a significantly lower impedance baseline compared to older children both in proximal and distal esophagus. The presence of esophagitis may also determine a decreased impedance baseline regardless of the age of the patients.

Esophageal impedance baseline is age dependent

OBJECTIVE

Esophageal impedance (multichannel intraluminal impedance [MII]) baseline (impedance baseline [IB]) has been recently considered to be related to esophageal integrity. The aim of this study was to analyze the age effect on IB in a large population of pediatric patients.

DESIGN

A total of 816 children with symptoms of gastroesophageal reflux and submitted to MII were included. Mean IB was automatically calculated in the different MII channels (Chs) throughout 24-hour tracings by the specific software without removing any episode of increased/decreased IB. Acid and nonacid reflux parameters and age subgroups analysis were performed. Unpaired t test, Spearman rank correlation, polynomial and regression plot, multiple regression analysis, factorial analysis of variance, and the least mean squares method were used for statistical analysis and age-related percentile curves. P < 0.05 was considered as statistically significant.

RESULTS

Mean IB was significantly (P < 0.001) lower in younger compared with older children up to 48 months. The mean increase of IB per month was 2.9 Ω in Ch 1 and 2.3 Ω in Ch 6, but much higher in the first 36 months of life (47.5 Ω in Ch 1 and 29.9 Ω in Ch 6, respectively). From 48 months onward, there was no significant increase of the mean IB (P = 0.73). In the multiple regression analysis, only age and reflux index (but no other reflux parameters) significantly correlated with IB. Distal IB was significantly (P < 0.05) lower in patients with esophagitis and in subjects taking proton pump inhibitors compared with subjects off (any) treatment. Percentiles of IB in proximal and distal Chs were provided according to different age groups.

CONCLUSIONS

IB is significantly lower in infants (especially in the first months of life) compared with older children. Low IB in both proximal and distal esophagus in young infants may be related to anatomical and functional difference other than the presence of esophagitis.

Pathophysiology of gastro-esophageal reflux disease: a role for mucosa integrity?

BACKGROUND

Gastro-esophageal reflux disease (GERD) is very prevalent and has a high burden on health security system costs. Nevertheless, pathophysiology is complex and not well-understood. Several mechanisms have been proposed: decreased salivation, impaired esophageal clearance, decreased lower esophageal sphincter pressure resting tone, presence of hiatal hernia, increased number of transient lower esophageal sphincter relaxations (TLESRs), increased acid, and pepsin secretion, pyloric incompetence provoking duodeno-gastro-esophageal reflux of bile acids and trypsin. Independent of the relevance of each mechanism, the ultimate phenomenon is that mucosal epithelium is exposed for a longer time to agents as acid and pepsin or is in contact to luminal agents not commonly present in gastric refluxate as trypsin or bile acids. This leads to a visible damage of the epithelium (erosive esophagitis -EE) or impairing mucosal integrity without any sign of macroscopic alteration as occurs in non-erosive reflux disease (NERD). Luminal factors are not the only responsible for such impairment; more recent data indicate that endogenous factors may also play a role.

PURPOSE

This review will update the most recent findings on the putative pathophysiological mechanisms and specially will focus on the role of esophageal mucosal integrity in GERD. Methodologies used for the evaluation of mucosal integrity, its relevance in EE and NERD, its involvement in symptoms perception and the effect of luminal and endogenous factors will be discussed.

The role of baseline impedance as a marker of mucosal integrity in children with gastro esophageal reflux disease

OBJECTIVES

Diagnosis of gastro esophageal reflux disease (GERD) in children is challenging. 24-h-pH-multichannel-intraluminal-impedance measurement (pH-MII) is the best diagnostic tool to display gastro esophageal reflux whereas esophageal endoscopy indicates mucosal lesions. The aim of this study was to compare esophageal endoscopy results with reflux parameters such as acid exposure time (reflux index RI), bolus exposure time (bolus index BI), baseline impedance level (BIL) detected by pH-MII in children with suspected GERD.

METHODS

Analysis of data from 285 children (38 infants) referred to our hospital with suspected GERD. Division into three 'reflux esophagitis' (RE)-stages depending on the severity of endoscopic and histological findings and comparison with reflux parameters in these stages. Further categorization into four groups based on the pH-MII-results.

RESULTS

Children with high-grade esophagitis had a significantly lower BIL; otherwise there was no significant association between elevated reflux parameters and esophagitis. Pathological pH-MII results (RI and BI) were associated with lower BIL in the distal impedance channel. The BIL was significantly lower in infants compared to children >1 year regardless of the RI or BI. The main difference between these groups regarding reflux parameters was a longer BI and a higher number of retrograde bolus movements.

CONCLUSION

Pathologic pH-MII results are not predictive for an erosive esophagitis and vice versa. Therefore, these two procedures cannot replace each other. A lower BIL is associated with esophagitis ≥ LA-grade B and may be caused by longer acid but also by longer bolus exposure and thus may be another useful parameter in GERD monitoring.