Esophageal impedance baselines in infants before and after placebo and proton pump inhibitor therapy

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.

Pediatric Eosinophilic Esophagitis is Associated With Low Baseline Impedance

BACKGROUND AND AIMS

Eosinophilic esophagitis (EoE) is a chronic inflammatory disorder that requires repeat endoscopic evaluation(s) to assess response to treatment. This results in high health care costs and a procedural burden in affected children. Noninvasive alternate modalities to reassess disease activity have not been established. Low baseline impedance measured by multichannel pH impedance (pH-MII) is seen in adults with EoE, in keeping with poor mucosal integrity. We aimed to investigate the relationship between esophageal eosinophilia (or severity of eosinophilic infiltration) and baseline impedance in children with EoE.

METHODS

We retrospectively identified 15 children diagnosed with EoE at our institution who had undergone pH-MII within 30 days of 3-level esophageal biopsy. This group were not concurrently prescribed proton pump inhibitors and had negligible reflux parameters on pH-MII. Average impedance baseline was calculated upper, mid, and lower esophageal segments via baseline impedance automated analysis (RIAA) and mean nocturnal baseline impedance (MNBI) methods. Eosinophil count data for upper, mid, and lower esophageal segments in the EoE group was collated.

RESULTS

A significantly lower baseline impedance was seen across the esophageal length in children with EoE, compared with 30 controls who had no differences in age or reflux burden on nonparametric testing. A relationship between baseline impedance and eosinophil number at corresponding esophageal segments was not established.

CONCLUSIONS

Baseline impedance may be an important, less invasive adjunct in clinical practice to monitor treatment response in children with EoE. Larger prospective cohort studies should delineate optimally predictive baseline impedance thresholds for active and inactive disease.

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.

Response to therapy among neonates with gastro-esophageal reflux is associated with esophageal clearance

BACKGROUND

Few studies evaluated the efficacy of pharmacological therapy for gastro-esophageal reflux disease (GERD) in newborns, whose safety has been questioned. Esophageal basal impedance (BI) is a marker of mucosal integrity, and treatment with proton pump inhibitors significantly increases BI in infants; however, no correlation with clinical improvement was reported.

AIMS

To evaluate the relationship between BI and other esophageal pH-impedance parameters and clinical response to therapy in newborns with GERD.

STUDY DESIGN

Multicenter retrospective study.

SUBJECTS

Infants who received omeprazole or ranitidine for GERD.

OUTCOME MEASURES

Complete response to therapy was defined as symptom decrease by ≥50% compared to baseline, partial response as symptom decrease <50%, no response as no symptom decrease based on chart analysis. Response to therapy was assessed 2 and 4 weeks after the onset of therapy. Univariate and multivariate statistics were performed to assess associations between response to therapy and clinical/pH-impedance parameters.

RESULTS

We studied 60 infants (51 born preterm): 47 received omeprazole, 13 ranitidine. Response to therapy was associated with decreasing esophageal clearance time: odds ratio 0.308, 95%CI 0.126-0.753, p = 0.010 at 2 weeks, odds ratio 0.461, 95%CI 0.223-0.955, p = 0.037 at 4 weeks.

CONCLUSIONS

Clinical response to therapy among infants with GERD was associated with esophageal clearance but not with esophageal BI level.

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.

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.

Characterization of Upper Gastrointestinal Motility in Infants With Persistent Distress and Non-IgE-mediated Cow's Milk Protein Allergy

BACKGROUND

Persistent crying in infancy is common and may be associated with gastroesophageal reflux disease (GERD) and/or non-IgE-mediated cow's milk protein allergy (CMPA). We aimed to document upper gastrointestinal motility events in infants with CMPA and compare these to findings in infants with functional GERD.

METHODS

Infants aged 2 to 26 weeks with persistent crying, GERD symptoms and possible CMPA were included. Symptoms were recorded by 48-hour cry-fuss chart and validated reflux questionnaire (infant GERD questionnaire [IGERDQ]). Infants underwent a blinded milk elimination-challenge sequence to diagnose CMPA. GERD parameters and mucosal integrity were assessed by 24-hour pH-impedance monitoring before and after cow's milk protein (CMP) elimination. C-octanoate breath testing for gastric emptying dynamics, dual-sugar intestinal permeability, fecal calprotectin, and serum vitamin D were also measured.

RESULTS

Fifty infants (mean age 13 ± 7 weeks; 27 boys) were enrolled. On the basis of CMP elimination-challenge outcomes, 14 (28%) were categorized as non-IgE-mediated CMPA, and 17 (34%) were not allergic to milk; 12 infants with equivocal findings, and 7 with incomplete data were excluded. There were no baseline differences in GERD parameters between infants with and without CMPA. In the CMPA group, CMP elimination resulted in a significant reduction in reflux symptoms, esophageal acid exposure (reflux index), acid clearance time, and an increase in esophageal mucosal impedance.

CONCLUSIONS

In infants with persistent crying, upper gastrointestinal motility parameters did not reliably differentiate between non-IgE-mediated CMPA and functional GERD. In the group with non-IgE-mediated CMPA, elimination of CMP significantly improved GERD symptoms, esophageal peristaltic function, and mucosal integrity.

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.

Detection of gastro-oesophageal reflux in the neonatal unit

AIM

To determine whether a pH probe or multichannel intraluminal impedance (MII) more frequently detected gastro-oesophageal reflux and test the hypothesis that acid reflux was associated with lower baseline impedance.

METHODS

A prospective study of infants in whom reflux was suspected and evaluated using combined pH and multichannel impedance. Studies were considered abnormal if the acid index was >10% or there were >79MII reflux events in 24 hours. The acid index was the percentage of total study time with a pH

RESULTS

Forty-two infants [median gestational age 31 (range 23-42) weeks] were assessed. Only nine infants (21%) had abnormal studies, seven detected by pH monitoring, one by MII monitoring and one by both techniques (p = 0.04). After correcting for gestational age and post-natal age, baseline impedance remained negatively correlated with the acid index (r = -0.34, p = 0.038) and the maximum ACT (r = -0.44, p = 0.006).

CONCLUSION

Clinical suspicion of reflux was frequently incorrect, and reflux was more frequently detected by a pH probe. The inverse relationship of acid reflux to baseline impedance suggests that mucosal disruption may result from acid reflux in this population.

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Key Words

• Baseline oesophageal impedance
• Multichannel intraluminal impedance
• pH study

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MESH Headings Collapse

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Affiliation(s)

Thomas Rossor MRC Centre in Allergic Mechanisms of Asthma, King's College London, London, UK Department of Women and Children's Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
Ingran Lingam Neonatal Intensive Care Centre, King's College Hospital NHS Foundation Trust, London, UK
Abdel Douiri Department of Primary Care and Public Health Sciences, King's College London, London, UK NIHR Biomedical Research Centre, Guy's and St Thomas' NHS Foundation Trust, King's College London, London, UK
Ravindra Bhat Neonatal Intensive Care Centre, King's College Hospital NHS Foundation Trust, London, UK
Anne Greenough MRC Centre in Allergic Mechanisms of Asthma, King's College London, London, UK Department of Women and Children's Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK NIHR Biomedical Research Centre, Guy's and St Thomas' NHS Foundation Trust, King's College London, London, UK

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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.

Variations in Definitions and Outcome Measures in Gastroesophageal Reflux Disease: A Systematic Review

CONTEXT

Gastroesophageal reflux (GER) is defined as GER disease (GERD) when it leads to troublesome symptoms and/or complications. We hypothesized that definitions and outcome measures in randomized controlled trials (RCTs) on pediatric GERD would be heterogeneous.

OBJECTIVES

Systematically assess definitions and outcome measures in RCTs in this population.

DATA SOURCES

Data were obtained through Cochrane, Embase, Medline, and Pubmed databases.

STUDY SELECTION

We selected English-written therapeutic RCTs concerning GERD in children 0 to 18 years old.

DATA EXTRACTION

Data were tabulated and presented descriptively. Each individual parameter or set of parameters with unique criteria for interpretation was considered a single definition for GER(D). Quality was assessed by using the Delphi score.

RESULTS

A total of 2410 unique articles were found; 46 articles were included. Twenty-six (57%) studies defined GER by using 25 different definitions and investigated 25 different interventions. GERD was defined in 21 (46%) studies, all using a unique definition and investigating a total of 23 interventions. Respectively 87 and 61 different primary outcome measures were reported by the studies in GER and GERD. Eight (17%) studies did not report on side effects. Of the remaining 38 (83%) studies that did report on side effects, 18 (47%) included this as predefined outcome measure of which 4 (22%) as a primary outcome measure. Sixteen studies (35%) were of good methodological quality.

LIMITATIONS

Only English-written studies were included.

CONCLUSIONS

Inconsistency and heterogeneity exist in definitions and outcome measures used in RCTs on pediatric GER and GERD; therefore, we recommend the development of a core outcome set.

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.

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.

Effects and efficacy of laparoscopic fundoplication in children with GERD: a prospective, multicenter study

INTRODUCTION

Laparoscopic antireflux surgery (LARS) in children primarily aims to decrease reflux events and reduce reflux symptoms in children with therapy-resistant gastroesophageal reflux disease (GERD). The aim was to objectively assess the effect and efficacy of LARS in pediatric GERD patients and to identify parameters associated with failure of LARS.

METHODS

Twenty-five children with GERD [12 males, median age 6 (2-18) years] were included prospectively. Reflux-specific questionnaires, stationary manometry, 24-h multichannel intraluminal impedance pH monitoring (MII-pH monitoring) and a ¹³C-labeled Na-octanoate breath test were used for clinical assessment before and 3 months after LARS.

RESULTS

After LARS, three of 25 patients had persisting/recurrent reflux symptoms (one also had persistent pathological acid exposure on MII-pH monitoring). New-onset dysphagia was present in three patients after LARS. Total acid exposure time (AET) (8.5-0.8 %; p < 0.0001) and total number of reflux episodes (p < 0.001) significantly decreased and lower esophageal sphincter (LES) resting pressure significantly increased (10-24 mmHg, p < 0.0001) after LARS. LES relaxation, peristaltic contractions and gastric emptying time did not change. The total number of reflux episodes on MII-pH monitoring before LARS was a significant predictor for the effect of the procedure on reflux reduction (p < 0.0001).

CONCLUSIONS

In children with therapy-resistant GERD, LARS significantly reduces reflux symptoms, total acid exposure time (AET) and number of acidic as well as weakly acidic reflux episodes. LES resting pressure increases after LARS, but esophageal function and gastric emptying are not affected. LARS showed better reflux reduction in children with a higher number of reflux episodes on preoperative MII-pH monitoring.

Biomarkers of Reflux Disease

Gastroesophageal reflux disease (GERD) encompasses an array of disorders unified by the reflux of gastric contents. Because there are many potential disease manifestations, esophageal and extraesophageal, there is no single biomarker of the entire disease spectrum; a set of GERD biomarkers that each quantifies specific aspects of GERD-related pathology might be needed. We review recent reports of biomarkers of GERD, specifically in relation to endoscopically negative esophageal disease and excluding conventional pH-impedance monitoring. We consider histopathologic biomarkers, baseline impedance, and serologic assays to determine that most markers are based on manifestations of impaired esophageal mucosal integrity, which is based on increased ionic and molecular permeability, and/or destruction of tight junctions. Impaired mucosal integrity quantified by baseline mucosal impedance, proteolytic fragments of junctional proteins, or histopathologic features has emerged as a promising GERD biomarker.

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.

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.

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.

Oesophageal baseline impedance values are decreased in patients with eosinophilic oesophagitis

BACKGROUND

Gastro-oesophageal reflux has been suggested to play a role in eosinophilic oesophagitis (EoO). Oesophageal acid exposure decreases baseline intraluminal impedance, a marker of mucosal integrity, in patients with gastro-oesophageal reflux disease (GORD).

OBJECTIVES

The aim of this study was to assess oesophageal baseline impedance levels in EoO patients and to investigate their relationship with oesophageal acid exposure.

METHODS

Ambulatory 24-h pH-impedance monitoring was performed in 11 EoO patients and in 11 healthy controls with matched oesophageal acid exposure. We assessed baseline impedance levels in the distal, mid-, and proximal oesophageal impedance channels.

RESULTS

BASELINE IMPEDANCE LEVELS IN EOO PATIENTS WERE MARKEDLY LOWER COMPARED TO CONTROLS IN THE DISTAL OESOPHAGUS (MEDIAN (INTERQUARTILE RANGE): 988 (757-1978) vs. 2259 (1767-2896) Ω, p = 0.015), mid-oesophagus (1420 (836-2164) vs. 2614 (2374-3879) Ω, p = 0.003), and proximal oesophagus (1856 (1006-2625) vs. 2868 (2397-3439) Ω, p = 0.005). Whereas baseline impedance decreased from proximal to distal in healthy subjects (p = 0.037), no such gradient was seen in EoO patients (p = 0.123).

CONCLUSIONS

Throughout the oesophagus, baseline impedance values are decreased in EoO patients, indicating impaired mucosal integrity. Our findings suggest that factors other than acid reflux are the cause of low baseline impedance in EoO.

Pharmacological therapy of gastroesophageal reflux in preterm infants

Although gastroesophageal reflux (GER) is a very common phenomenon among preterm infants, its therapeutic management is still an issue of debate among neonatologists. A step-wise approach should be advisable, firstly promoting nonpharmacological interventions and limiting drugs to selected infants unresponsive to the conservative measures or who are suffering from severe GER with clinical complications. Despite of this, a concerning pharmacological overtreatment has been increasingly reported. Most of the antireflux drugs, however, have not been specifically assessed in preterm infants; moreover, serious adverse effects have been noticed in association to their administration. This review mainly aims to draw the state of the art regarding the pharmacological management of GER in preterm infants, analyzing the best piecies of evidence currently available on the most prescribed anti-reflux drugs. Although further trials are required, sodium alginate-based formulations might be considered promising; however, data regarding their safety are still limited. Few piecies of evidence on the efficacy of histamine-2 receptor blockers and proton pump inhibitors in preterm infants with GER are currently available. Nevertheless, a significantly increased risk of necrotizing enterocolitis and infections has been largely reported in association with their use, thereby leading to an unfavorable risk-benefit ratio. The efficacy of metoclopramide in GER's improvement still needs to be clarified. Other prokinetic agents, such as domperidone and erythromycin, have been reported to be ineffective, whereas cisapride has been withdrawn due to its remarkable cardiac adverse effects.

Gastroesophageal reflux, esophageal function, gastric emptying, and the relationship to dysphagia before and after antireflux surgery in children

OBJECTIVES

To assess gastroesophageal reflux (GER), esophageal motility, and gastric emptying in children before and after laparoscopic fundoplication and to identify functional measures associated with postoperative dysphagia.

STUDY DESIGN

Combined impedance-manometry, 24-hour pH-impedance, and gastric-emptying breath tests were performed before and after laparoscopic anterior partial fundoplication. Impedance-manometry studies were analyzed with the use of conventional analysis methods and a novel automated impedance manometry (AIM) analysis.

RESULTS

Children with therapy resistent GER disease (n = 25) were assessed before fundoplication, of whom 10 (median age 6.4 years; range, 1.1-17.1 years; 7 male; 4 with neurologic impairment) underwent fundoplication. GER episodes reduced from 97 (69-172) to 66 (18-87)/24 hours (P = .012). Peristaltic contractions were unaltered. Complete lower esophageal sphincter relaxations decreased after fundoplication (92% [76%-100%] vs 65% [29%-91%], P = .038). Four (40%) patients developed postoperative dysphagia, which was transient in 2. In those patients, preoperative gastric emptying was delayed compared with patients without postoperative dysphagia, 96 minutes (71-104 minutes) versus 48 minutes (26-68 minutes), P = .032, and AIM analysis derived dysphagia risk index was greater (56 [15-105] vs 2 [2-6] P = .016). Two patients underwent a repeat fundoplication.

DISCUSSION

Fundoplication in children reduced GER without altering esophageal motility. Four patients who developed dysphagia demonstrated slower gastric emptying and greater dysplasia risk index preoperatively. AIM analysis may allow detection of subtle esophageal abnormalities potentially leading to postoperative dysphagia.

Outcomes of endoscopy and novel pH-impedance parameters in children: is there a correlation?

OBJECTIVES

Discordance exists between outcomes of endoscopy, multichannel intraluminal impedance monitoring (pH-MII), MII baselines, and gastroesophageal reflux symptoms. The aim of the present study was to determine the association between endoscopy, pH-MII and MII baselines, in children with gastroesophageal reflux symptoms.

METHODS

Endoscopies were graded for reflux esophagitis (RE). Biopsies of the distal esophagus were assessed for signs suggestive of esophagitis. Reflux index (RI), symptom association probability (SAP), number of reflux episodes, and mean baseline values were calculated. pH-MII was considered positive in children when RI was ≥ 3% and/or SAP was ≥ 95% and for infants when RI was ≥ 10% and/or SAP was ≥ 95%. Baselines were manually calculated and compared with an automated analysis. For MII baselines, patients were divided in 3 groups: normal endoscopy and negative overall pH-MII; normal endoscopy and an overall positive pH-MII; and RE.

RESULTS

A total of 26 children and 14 infants were included, median age: 26.5 months (2 months-16.2 years). Thirteen (32.5%) had RE. A significant negative association was found for RI and MII baselines (P = 0.009) and between SAP and RE (P = 0.039, odds ratio 1.018). MII baseline values were predictive for neither conventional pH-MII parameters nor RE. Manual analysis and automated calculation of MII baselines showed a perfect correlation. Distal MII baselines were significantly lower in children with a positive overall pH-MII outcome compared with the proximal esophagus (P = 0.049). No significant changes were found in baselines among the different groups 1 to 3.

CONCLUSIONS

Acid-related parameters are significantly related to MII baselines. A perfect correlation between manual- and automated analysis of MII baselines was found. Large prospective studies are needed to confirm the exact role of endoscopy and MII baselines.