Neuronal Control of Esophageal Peristalsis and Its Role in Esophageal Disease

PURPOSE OF REVIEW

Esophageal peristalsis is a highly sophisticated function that involves the coordinated contraction and relaxation of striated and smooth muscles in a cephalocaudal fashion, under the control of central and peripheral neuronal mechanisms and a number of neurotransmitters. Esophageal peristalsis is determined by the balance of the intrinsic excitatory cholinergic, inhibitory nitrergic and post-inhibitory rebound excitatory output to the esophageal musculature.

RECENT FINDINGS

Dissociation of the longitudinal and circular muscle contractions characterizes different major esophageal disorders and leads to esophageal symptoms. Provocative testing during esophageal high-resolution manometry is commonly employed to assess esophageal body peristaltic reserve and underpin clinical diagnosis. Herein, we summarize the main factors that determine esophageal peristalsis and examine their role in major and minor esophageal motility disorders and eosinophilic esophagitis.

The 2018 ISDE achalasia guidelines

Achalasia is a relatively rare primary motor esophageal disorder, characterized by absence of relaxations of the lower esophageal sphincter and of peristalsis along the esophageal body. As a result, patients typically present with dysphagia, regurgitation and occasionally chest pain, pulmonary complication and malnutrition. New diagnostic methodologies and therapeutic techniques have been recently added to the armamentarium for treating achalasia. With the aim to offer clinicians and patients an up-to-date framework for making informed decisions on the management of this disease, the International Society for Diseases of the Esophagus Guidelines proposed and endorsed the Esophageal Achalasia Guidelines (I-GOAL). The guidelines were prepared according the Appraisal of Guidelines for Research and Evaluation (AGREE-REX) tool, accredited for guideline production by NICE UK. A systematic literature search was performed and the quality of evidence and the strength of recommendations were graded according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE). Given the relative rarity of this disease and the paucity of high-level evidence in the literature, this process was integrated with a three-step process of anonymous voting on each statement (DELPHI). Only statements with an approval rate >80% were accepted in the guidelines. Fifty-one experts from 11 countries and 3 representatives from patient support associations participated to the preparations of the guidelines. These guidelines deal specifically with the following achalasia issues: Diagnostic workup, Definition of the disease, Severity of presentation, Medical treatment, Botulinum Toxin injection, Pneumatic dilatation, POEM, Other endoscopic treatments, Laparoscopic myotomy, Definition of recurrence, Follow up and risk of cancer, Management of end stage achalasia, Treatment options for failure, Achalasia in children, Achalasia secondary to Chagas' disease.

Treatment of supragastric belching with cognitive behavioral therapy improves quality of life and reduces acid gastroesophageal reflux

OBJECTIVES

Excessive supragastric belching (SGB) manifests as troublesome belching, and can be associated with reflux and significant impact on quality of life (QOL). In some GERD patients, SGB-associated reflux contributes to up to 1/3 of the total esophageal acid exposure. We hypothesized that a cognitive-behavioral intervention (CBT) might reduce SGB, improve QOL, and reduce acid gastroesophageal reflux (GOR). We aimed to assess the effectiveness of CBT in patients with pathological SGB.

METHODS

Patients with SGB were recruited at the Royal London Hospital. Patients attended CBT sessions focused on recognition of warning signals and preventative exercises. Objective outcomes were the number of SGBs, esophageal acid exposure time (AET), and proportion of AET related to SGBs. Subjective evaluation was by patient-reported questionnaires.

RESULTS

Of 51 patients who started treatment, 39 completed the protocol, of whom 31 had a follow-up MII-pH study. The mean number of SGBs decreased significantly after CBT (before: 116 (47-323) vs. after 45 (22-139), P<0.0003). Sixteen of 31 patients were shown to have a reduction in SGB by >50%. In patients with increased AET at baseline, AET after CBT was decreased: 9.0-6.1% (P=0.005). Mean visual analog scale severity scores decreased after CBT (before: 260 (210-320) mm vs. after: 140 (80-210) mm, P<0.0001).

CONCLUSIONS

Cognitive behavioral therapy reduced the number of SGB and improved social and daily activities. Careful analysis of MII-pH allows identification of a subgroup of GERD patients with acid reflux predominantly driven by SGB. In these patients, CBT can reduce esophageal acid exposure.

Role of TRPV1 receptor in inflammation and impairment of esophageal mucosal integrity in a murine model of nonerosive reflux disease

BACKGROUND

Microscopic inflammation and impairment of the esophageal epithelial barrier are considered relevant for perception of symptoms in patients with nonerosive reflux disease (NERD). In these patients, the receptor transient receptor potential vanilloid 1 (TRPV1) is overexpressed in the esophageal mucosa, but its role is not yet fully understood. We evaluated the role of TRPV1 in esophageal inflammation and mucosal barrier impairment in a murine model of NERD.

METHODS

Nonerosive reflux disease was surgically induced in Swiss mice by pyloric substenosis and ligature of the gastric fundus, and the mice were killed 7 days post surgery. The experimental groups were: I, sham surgery (negative control); II, NERD untreated; III and IV, NERD + SB366791 or capsazepine (TRPV1 antagonists); and V, NERD + resiniferatoxin (for long-term desensitization of TRPV1). The esophagus was collected for western blotting and histopathology and for evaluation of wet weight, myeloperoxidase (MPO), keratinocyte-derived chemokine (KC), transepithelial electrical resistance (TEER), and basal permeability to fluorescein.

KEY RESULTS

Compared to sham, NERD mice had increased esophageal wet weight and MPO and KC levels. The mucosa had no ulcers but exhibited inflammation. NERD mice showed mucosal TRPV1 overexpression, a more pronounced decrease in TEER at pH 0.5 (containing pepsin and taurodeoxycholic acid), and increased basal permeability. Pharmacological modulation of TRPV1 prevented esophageal inflammation development, TEER changes by acidic exposure, and increase in esophageal permeability.

CONCLUSIONS & INFERENCES

The TRPV1 receptor has a critical role in esophageal inflammation and mucosal barrier impairment in NERD mice, suggesting that TRPV1 might be a pharmacological target in patients with NERD.

Ambulatory pH-impedance-pressure monitoring as a diagnostic tool for the reflux-cough syndrome

Gastroesophageal reflux is considered to be a significant contributing factor to chronic unexplained cough. Patients are often presumed to have reflux-induced cough and are exposed to high-dose and long-term empirical therapy with proton pump inhibitors (PPIs) despite the limited treatment efficacy in this population. We aimed to assess the diagnostic value of 24-hour ambulatory pH-impedance-pressure monitoring for the diagnosis of reflux-induced chronic cough. In this multicenter study, we evaluated 192 patients with chronic cough using 24-hour pH-impedance-pressure monitoring off PPIs. Manometry was used to detect all cough bursts while pH-impedance allowed for the evaluation of all reflux episodes, including weakly acidic reflux. The symptom association probability was used to determine a temporal relationship between reflux and cough. A diagnosis of reflux-induced cough was made in 25.5% of the patients. If only acid reflux episodes were used, 22.4% of those patients would not have been diagnosed. Significantly more patients with reflux-induced cough had typical reflux symptoms (P = 0.031) and a pathological distal acid exposure time (P = 0.025) in comparison to patients without the diagnosis. A diagnosis of cough-induced reflux was made in 24.0% of the patients. Only 59% of all cough bursts were registered by the patients. Overall, only approximately one quarter of patients with chronic unexplained cough have reflux-induced cough, explaining the observation that the vast majority of patients with chronic cough do not benefit from antireflux therapy. pH-impedance-pressure monitoring helps to identify patients who are likely to have reflux as a cause of their chronic cough.

Classification of esophageal motor findings in gastro-esophageal reflux disease: Conclusions from an international consensus group

BACKGROUND

High-resolution manometry (HRM) has resulted in new revelations regarding the pathophysiology of gastro-esophageal reflux disease (GERD). The impact of new HRM motor paradigms on reflux burden needs further definition, leading to a modern approach to motor testing in GERD.

METHODS

Focused literature searches were conducted, evaluating pathophysiology of GERD with emphasis on HRM. The results were discussed with an international group of experts to develop a consensus on the role of HRM in GERD. A proposed classification system for esophageal motor abnormalities associated with GERD was generated.

KEY RESULTS

Physiologic gastro-esophageal reflux is inherent in all humans, resulting from transient lower esophageal sphincter (LES) relaxations that allow venting of gastric air in the form of a belch. In pathological gastro-esophageal reflux, transient LES relaxations are accompanied by reflux of gastric contents. Structural disruption of the esophagogastric junction (EGJ) barrier, and incomplete clearance of the refluxate can contribute to abnormally high esophageal reflux burden that defines GERD. Esophageal HRM localizes the LES for pH and pH-impedance probe placement, and assesses esophageal body peristaltic performance prior to invasive antireflux therapies and antireflux surgery. Furthermore, HRM can assess EGJ and esophageal body mechanisms contributing to reflux, and exclude conditions that mimic GERD.

CONCLUSIONS & INFERENCES

Structural and motor EGJ and esophageal processes contribute to the pathophysiology of GERD. A classification scheme is proposed incorporating EGJ and esophageal motor findings, and contraction reserve on provocative tests during HRM.

Ambulatory reflux monitoring for diagnosis of gastro-esophageal reflux disease: Update of the Porto consensus and recommendations from an international consensus group

BACKGROUND

An international group of experts evaluated and revised recommendations for ambulatory reflux monitoring for the diagnosis of gastro-esophageal reflux disease (GERD).

METHODS

Literature search was focused on indications and technical recommendations for GERD testing and phenotypes definitions. Statements were proposed and discussed during several structured meetings.

KEY RESULTS

Reflux testing should be performed after cessation of acid suppressive medication in patients with a low likelihood of GERD. In this setting, testing can be either catheter-based or wireless pH-monitoring or pH-impedance monitoring. In patients with a high probability of GERD (esophagitis grade C and D, histology proven Barrett's mucosa >1 cm, peptic stricture, previous positive pH monitoring) and persistent symptoms, pH-impedance monitoring should be performed on treatment. Recommendations are provided for data acquisition and analysis. Esophageal acid exposure is considered as pathological if acid exposure time (AET) is greater than 6% on pH testing. Number of reflux episodes and baseline impedance are exploratory metrics that may complement AET. Positive symptom reflux association is defined as symptom index (SI) >50% or symptom association probability (SAP) >95%. A positive symptom-reflux association in the absence of pathological AET defines hypersensitivity to reflux.

CONCLUSIONS AND INFERENCES

The consensus group determined that grade C or D esophagitis, peptic stricture, histology proven Barrett's mucosa >1 cm, and esophageal acid exposure greater >6% are sufficient to define pathological GERD. Further testing should be considered when none of these criteria are fulfilled.

Mechanisms underlying reflux symptoms and dysphagia in patients with joint hypermobility syndrome, with and without postural tachycardia syndrome

BACKGROUND

The joint hypermobility syndrome (JHS) is a common non-inflammatory connective tissue disorder which frequently co-exists with postural tachycardia syndrome (PoTS), a form of orthostatic intolerance. Gastrointestinal symptoms and dysmotility have been reported in PoTS. Dysphagia and reflux are common symptoms in JHS, yet no studies have examined the physiological mechanism for these, subdivided by PoTS status.

METHODS

Thirty patients (28 female, ages: 18-62) with JHS and symptoms of reflux (n=28) ± dysphagia (n=25), underwent high-resolution manometry and 24 hour pH-impedance monitoring after questionnaire-based symptom assessment. Esophageal physiology parameters were examined in JHS, subdivided by PoTS status.

RESULTS

Fifty-three percent of JHS patients with reflux symptoms had pathological acid reflux, 21% had reflux hypersensitivity, and 25% had functional heartburn. Acid exposure was more likely to be increased in the recumbent than upright position (64% vs 43%). The prevalence of hypotensive lower esophageal sphincter (33%) and hiatus hernia (33%) was low. Forty percent of patients with dysphagia had minor disorders of motility, 60% had functional dysphagia. Eighteen (60%) patients had coexistent PoTS-they had significantly higher dysphagia (21 vs 11.5, P=.04) and reflux scores (24.5 vs 16.5, P=.05), and double the prevalence of pathological acid reflux (64% vs 36%, P=.1) and esophageal dysmotility (50% vs 25%, P=.2) though this was not significant.

CONCLUSIONS AND INFERENCES

A large proportion of JHS patients with esophageal symptoms have true reflux-related symptoms or mild esophageal hypomotility, and this is more likely if they have PoTS.

Jackhammer esophagus: Observations on a European cohort

BACKGROUND

With the advent of high-resolution manometry (HRM), a new diagnosis, jackhammer esophagus, was introduced. Little is known about this rare condition, and the relationship between symptoms and hypercontractility is not always straightforward. The aim of our study was to describe a large cohort of patients with jackhammer esophagus and to investigate whether manometric findings are associated with the presence of symptoms.

METHODS

All patients from 06, 2014 until 12, 2015 seen at two tertiary centers with at least one hypercontractile swallow (distal contractile integral [DCI] >8000 mm Hg/s/cm) on HRM were analyzed. Patients with ≥20% premature swallows, or patients with another diagnosis explaining their symptoms were excluded.

KEY RESULTS

Of the 34 patients identified with jackhammer esophagus, most suffered from dysphagia (67.6%) and/or chest pain (47.1%). The symptom chest pain was not associated with any of the manometric findings, whereas dysphagia was associated with the DCI of the hypercontractile swallows and with intrabolus pressure. In addition, all patients who had an isolated DCI of the lower esophageal sphincter (LES) zone >2000 mm Hg/s/cm had dysphagia. The differences in HRM and clinical characteristics between subgroups based on the contraction type (single- or multi-peaked) or based on meeting criteria of the Chicago Classification v3.0 and v2.0 were limited.

CONCLUSIONS & INFERENCES

The symptom dysphagia is accompanied with strong contractions of the LES, signs of a possible outflow obstruction, and a very high DCI. The presence of a multipeaked contraction seems to be of limited relevance, and caution is warranted in labeling patients with one hypercontractile swallow as normal.

Validation of criteria for the definition of transient lower esophageal sphincter relaxations using high-resolution manometry

BACKGROUND

Criteria for transient lower esophageal sphincter relaxations (TLESRs) are well-defined for Dentsleeve manometry. As high-resolution manometry (HRM) is now the gold standard to assess esophageal motility, our aim was to propose a consensus definition of TLESRs using HRM.

METHODS

Postprandial esophageal HRM combined with impedance was performed in 10 patients with gastroesophageal reflux disease. Transient lower esophageal sphincter relaxations identification was performed by 17 experts using a Delphi process. Four investigators then characterized TLESR candidates that achieved 100% agreement (TLESR events) and those that achieved less than 25% agreement (non-events) after the third round. Logistic regression and decision tree analysis were used to define optimal diagnostic criteria.

KEY RESULTS

All diagnostic criteria were more frequently encountered in the 57 TLESR events than in the 52 non-events. Crural diaphragm (CD) inhibition and LES relaxation duration >10 seconds had the highest predictive value to identify TLESR. Based on decision tree analysis, reflux on impedance, esophageal shortening, common cavity, upper esophageal sphincter relaxation without swallow and secondary peristalsis were alternate diagnostic criteria.

CONCLUSION & INFERENCES

Using HRM, TLESR might be defined as LES relaxation occurring in absence of swallowing, lasting more than 10 seconds and associated with CD inhibition.

Anatomical and functional deficiencies of the crural diaphragm in patients with esophagitis

BACKGROUND

Inspiratory esophagogastric junction (EGJ) pressure is lower in gastroesophageal reflux disease (GERD) and patients fail to increase EGJ pressure during the inspiratory effort. The aim of this study was to assess the EGJ activity during inspiratory maneuvers (high-resolution manometry, HRM) and the crural diaphragm (CD) thickness (endoscopic ultrasound, EUS) in GERD.

METHODS

Twenty esophagitis patients (average age 45 years, 7 grade A, 13 grade B) had HRM and EUS. Forty-three controls were recruited; 30 had HRM (average age 33 years), and 13 had EUS (average age 40 years). The EGJ contractility index (EGJ-CI) (mm Hg×cm) was measured during normal respiration and two inspiratory maneuvers: without and with inspiratory loads of 12, 24, and 48 cmH₂ O (TH-maneuvers). A composite metric for TH-maneuvers ("EGJ total activity") was defined as the product of the maximal EGJ pressure and the length of its aboral excursion during the maneuver (mm Hg×cm). The CD thickness (cm) was measured during expiration (12 MHz).

KEY RESULTS

Expiratory lower esophageal sphincter pressure and integrated relaxation pressure were lower in GERD. The EGJ-CI and the "EGJ total activity" were lower in GERD during TH-maneuvers (48-cmH₂ O load: 168.4 ± 13.8 vs 114.8 ± 9.6, P=.006). Patients failed to sustain the inspiratory CD activity across the 12 and 48-cmH₂ O efforts. The CD was thinner in GERD patients (0.37 ± 0.03 vs 0.49 ± 0.04, P=.02). The CD thickness correlated with the increment in the "EGJ total activity" in GERD without a hiatal hernia (r=.702, P=.016, n=11).

CONCLUSIONS & INFERENCES

There are anatomical changes and functional failure of the CD in esophagitis patients supporting the possibility of a skeletal muscle deficiency in GERD.

Topical protection of human esophageal mucosal integrity

Patients with nonerosive reflux disease exhibit impaired esophageal mucosal integrity, which may underlie enhanced reflux perception. In vitro topical application of an alginate solution can protect mucosal biopsies against acid-induced changes in transepithelial electrical resistance (TER). We aimed to confirm this finding in a second model using 3D cell cultures and to assess prolonged protection in a biopsy model. We assessed the protective effect of a topically applied alginate solution 1 h after application. 3D cell cultures were grown by using an air-liquid interface and were studied in Ussing chambers. The apical surface was "protected" with 200 μl of either alginate or viscous control or was unprotected. The tissue was exposed to pH 3 + bile acid solution for 30 min and TER change was calculated. Distal esophageal mucosal biopsies were taken from 12 patients and studied in Ussing chambers. The biopsies were coated with either alginate or viscous control solution. The biopsies were then bathed in pH 7.4 solution for 1 h. The luminal chamber solution was replaced with pH 2 solution for 30 min. Percentage changes in TER were recorded. In five biopsies fluorescein-labeled alginate solution was used to allow immunohistological localization of the alginate after 1 h. In the cell culture model, alginate solution protected tissue against acid-induced change in TER. In biopsies, 60 min after protection with alginate solution, the acidic exposure caused a -8.3 ± 2.2% change in TER compared with -25.1 ± 4.5% change after protection with the viscous control (P < 0.05). Labeled alginate could be seen coating the luminal surface in all cases. In vitro, alginate solutions can adhere to the esophageal mucosa for up to 1 h and exert a topical protectant effect. Durable topical protectants can be further explored as first-line/add-on therapies for gastroesophageal reflux disease.

Normal esophageal pressure topography metrics for data derived from the Sandhill-Unisensor high-resolution manometry assembly in supine and sitting positions

BACKGROUND

Normal values of the esophageal motor function parameters for high-resolution manometry (HRM-EPT) adopted by the Chicago classification were established using the proprietary system of Given Imaging. It is conceivable that normal values of a system do not apply to data from others. Most studies using HRM were based on supine swallows, whereas deglutition occurs mostly in the upright position. We wished to establish normal values for HRM-EPT parameters obtained with the Sandhill's HRM-EPT system and compare the results in supine and sitting positions.

METHODS

Sixty-nine healthy volunteers, 38 females, median age 27 years, were included in this study. All underwent supine HRM, and 34 of them underwent sitting HRM, with at least 10 single 5-mL swallows for analysis obtained in each position.

KEY RESULTS

The normal range (5-95th percentiles) for the following parameters was calculated: distal contractile integral (DCI), 606-4998 mmHg·s·cm; contractile front velocity (CFV), 2.0-6.5 cm/s; distal latency (DL), 5.1-8.8 s; intrabolus pressure (IBP), 1.9-17.6 mmHg; upper esophageal sphincter (UES) pressure, 45.2-186.9 mmHg; esophagogastric junction (EGJ) length, 1.8-4 cm; EGJ resting pressure, 8.1-61.6 mmHg, and integrated relaxation pressure (IRP) 2.5-23.5 mmHg. Normal values of EGJ resting pressure, IRP, DCI, and IBP but not CFV, DL, and UES resting pressure were significantly lower in the sitting posture.

CONCLUSIONS & INFERENCES

Studies performed with Sandhill's HRM-EPT system should use its own specific normal data. Normal values should be established for different study.

Regionally dependent neuromuscular functions of motilin and 5-HT₄ receptors in human isolated esophageal body and gastric fundus

BACKGROUND

Motilin agonists promote human gastric motility and cholinergic activity, but excitatory and inhibitory actions are reported in the esophagus. The effect of 5-HT₄ agonists in esophagus is also unclear. Perhaps the use of drugs with additional actions explains the variation. The aim, therefore, was to examine how motilin and prucalopride, selective motilin and 5-HT₄ receptor agonists, modulate neuromuscular functions in human esophagus and gastric fundus.

METHODS

Electrical field stimulation (EFS) evoked nerve-mediated contractions of circular and longitudinal muscle from human esophageal body and circular muscle from gastric fundus.

KEY RESULTS

In esophageal circular muscle EFS evoked brief contraction, followed by another contraction on termination of EFS, each prevented by atropine. Nitric oxide synthase inhibition facilitated contraction during EFS and the overall contraction became monophasic. In esophagus longitudinal muscle and gastric fundus, EFS evoked cholinergically mediated, monophasic contractions, attenuated by simultaneous nitrergic activation. Motilin (100-300 nM) reduced esophagus circular muscle contractions during EFS, unaffected by L-NAME or apamin. Motilin 300 nM also reduced EFS-evoked contractions of longitudinal muscle. Similar concentrations of motilin facilitated cholinergic activity in the fundus and increased baseline muscle tension. Prucalopride facilitated EFS-evoked contractions in esophagus (tested at 30 μM) and fundus (0.1-30 μM).

CONCLUSIONS & INFERENCES

Selective motilin and 5-HT₄ agonists have different, region-dependent abilities to modulate human esophageal and stomach neuromuscular activity, exemplified by weak inhibition (motilin) or excitation (5-HT₄) in esophageal body and excitation for both in stomach. In different patients with motility dysfunctions, motilin and 5-HT₄ agonists may reduce gastro-esophageal reflux in different ways.

Postprandial cardiac vagal tone and transient lower esophageal sphincter relaxation (TLESR)

BACKGROUND

Transient lower esophageal sphincter relaxation (TLESR) is a vagally mediated reflex that occurs most frequently after a meal. Cardiac vagal tone (CVT) decreases after a meal, and correlates with changes in gastric electrical activity. Furthermore, decreased CVT has been reported in patients with gastro-esophageal reflux disease. We therefore aimed to characterize the association between postprandial changes in CVT and the occurrence of TLESR and reflux.

METHODS

Ten healthy volunteers underwent simultaneous autonomic nervous system, gastric myoelectric activity, lower esophageal-sphincter pressure, and reflux monitoring for 30 min in the fasting state, followed by a standard meal, and a further 4 h postprandially. Results are in mean ± SEM.

KEY RESULTS

The number of TLESRs (P < 0.0001) and reflux episodes (P < 0.0001) increased after the meal, while CVT decreased (P < 0.01). Cardiac sensitivity to baroreceptor reflex (CSB) showed similar time course changes to CVT (P = 0.06). During the first postprandial hour there was a strong correlation between the number of TLESRs and reflux episodes with CVT (R(2)  = 0.51 and R(2)  = 0.50, respectively; P < 0.05). There was also an increase in the dominant power and power ratio on electrogastrography (P < 0.05) after the meal.

CONCLUSIONS & INFERENCES

In healthy volunteers, the increase in the number of TLESRs and reflux episodes after a meal occurred mostly at a time of reduced CVT. Further studies should explore whether modulation of CVT can modify frequency of TLESRs and also this relationship should be further explored in patients with reflux disease.

Anatomy and physiology of the esophageal body

The primary role of the esophagus is to propel swallowed food or fluid into the stomach and to prevent or clear gastroesophageal reflux. This function is achieved by an organized pattern that involves a sensory pathway, neural reflexes, and a motor response that includes esophageal tone, peristalsis, and shortening. The motor function of the esophagus is controlled by highly complex voluntary and involuntary mechanisms. There are three different functional areas in the esophagus: the upper esophageal sphincter, the esophageal body, and the LES. This article focused on anatomy and physiology of the esophageal body.

Evaluation of esophageal contractile propagation using esophageal pressure topography

BACKGROUND

High-resolution manometry and esophageal pressure topography have enhanced our ability to analyze esophageal motor disturbances by improving the detail and accuracy of measurements of peristaltic activity.This has been extremely helpful in the evaluation of disorders of rapid propagation as the technique is able to define important time points and physiologic landmarks that are crucial in defining peristaltic velocity and latency intervals.

PURPOSE

The goal of the current review will be to assess how esophageal pressure topography has impacted our ability to define important phenotypes of rapid propagation. Additionally, this review will also be utilized to complement the description of the Chicago Classification of Esophageal Motor Disorders, which is presented in this supplement issue.

Gastric emptying and different types of reflux in adult patients with cystic fibrosis

BACKGROUND

Increased gastro-oesophageal reflux (GER) is common in patients with cystic fibrosis (CF). Previous studies showed delayed gastric emptying (GE) and a high prevalence of bile acids in saliva suggesting duodenogastro-oesophageal reflux (DGER).

AIM

To assess different types of reflux (acid, weakly acidic and bile) and their relationship with rate of GE in adult CF patients.

METHODS

Gastric emptying was assessed in 33 CF patients using breath tests, reflux was monitored in 42 patients using impedance-pH-metry and 14 CF patients underwent combined impedance-pH-Bilitec monitoring.

RESULTS

Delayed GE was found in 33%, increased GER (predominantly acid) in 67% and pathological DGER in 35% of the CF patients. There was a significant correlation between oesophageal bile and acid exposure (P < 0.0001, r = 0.85). Patients with increased DGER had a higher proximal extent of reflux compared to those without DGER [17 (9-35) vs. 5 (1-12), P = 0.04]. There was no correlation between GE and reflux parameters, however, in a subgroup of 10 patients studied by impedance-pH-Bilitec and GE, there was a strong correlation between GE rate and bile exposure (P = 0.005, r = 0.83).

CONCLUSIONS

Delayed gastric emptying is present in 1/3 of patients with cystic fibrosis. There is a subgroup of these patients with both delayed gastric emptying and increased acidic duodenogastro-oesophageal reflux with high proximal extent and risk of aspiration. Controlled studies should be performed to evaluate the effect of prokinetics or antireflux surgery on the clinical cystic fibrosis evolution in these patients.

The relationship between gastroesophageal reflux and cough in children with chronic unexplained cough using combined impedance-pH-manometry recordings

INTRODUCTION

Assessment of the reflux-cough association in children is challenging. Esophageal (impedance) pH recording is sensitive to recognize reflux. However, cough recorded by an event marker, possibly lacks accuracy. We aimed to study the exact time relationship between reflux and cough in children with chronic cough.

METHODS

Twenty-six children (12 boys; 1-10.5 years) with chronic unexplained cough underwent ambulatory impedance-pH-manometry recordings. Manometry was used for precise cough recognition. Reflux was assessed with impedance-pH monitoring and defined as acid (pH <4), weakly acidic (WA) (pH 4-7), weakly alkaline (WALK) (pH ≥7), or acid only (pH <4 for ≥4 sec without impedance pattern). Cough was considered "induced by" reflux, if it started ≤2 min after reflux. The Symptom Association Probability (SAP) was calculated and considered positive if >95%. Cough-induced reflux if it occurred 30 sec before the reflux event.

RESULTS

Impedance-pH detected 30 (21-52) reflux episodes/patient (55.2% acid, 41.5% WA, and 3.3% WALK). Additionally 59 acid only events were identified [1 (0-21)/patient]. Manometry detected 47 (5-203) cough bursts/patient. Reflux-cough was found in 22/26 patients. Ten patients had a +SAP for reflux-cough (one acid, six WA, and three acid + WA gastroesophageal reflux [GER]), of which nine had a normal acid exposure. Six out of 10 patients with +SAP using manometry had a +SAP using the event marker. Cough-reflux was detected in 19 patients [3 (0-7)/patient]. Only a small fraction of the esophageal acid exposure [9.6 (0.4-31.8%)] was secondary to cough.

CONCLUSION

Both acid and WA GER may precede cough in children with unexplained cough, but cough does not induce GER. Objective cough recording improves symptom association analysis.

Bile acids aspiration reduces survival in lung transplant recipients with BOS despite azithromycin

Azithromycin (AZM) improved bronchiolitis obliterans syndrome (BOS) and reduced aspiration in lung transplant (LTx) recipients. We hypothesize that AZM could improve graft and overall survival more efficiently in LTx patients with BOS who have bile acid (BA) aspiration by protecting against the aspiration-induced progression of BOS. The goal was to compare FEV(1) (% baseline), BOS progression and overall survival in LTx recipients treated with AZM for BOS, both with versus without BA aspiration. Therefore, LTx recipients treated with AZM for BOS were recruited and broncho-alveolar lavage (BAL) samples were analyzed for the presence of BA and neutrophilia before the start of AZM treatment. Short-term effect of AZM on FEV(1) and BAL neutrophilia was assessed, progression of BOS and survival were followed-up for 3 years and results were compared between patients with/without BA aspiration. 19/37 LTx patients had BA in BAL. BA aspiration predisposed to a significantly worse outcome, in terms of decline in FEV(1) , progression of BOS ≥ 1 and survival. AZM does not seem to protect against the long-term allograft dysfunction caused by gastroesophageal reflux (GER) and aspiration and an additional treatment targeting aspiration may be indicated in those LTx patients.

Perception of dysphagia: lack of correlation with objective measurements of esophageal function

BACKGROUND

The mechanism underlying increased perception of food bolus passage in the absence of esophageal mechanical obstruction has not been completely elucidated. A correlation between the intensity of the symptom and the severity of esophageal dysfunction, either motility (manometry) or bolus transit (impedance) has not been clearly demonstrated. The aim of this study was to analyze the correlation between objective esophageal function assessment (with manometry and impedance) and perception of bolus passage in healthy volunteers (HV) with normal and pharmacologically-induced esophageal hypocontractility, and in patients with gastro-esophageal reflux disease (GERD) with and without ineffective esophageal motility (IEM).

METHODS

Combined manometry-impedance was performed in 10 HV, 19 GERD patients without IEM and nine patients with IEM. Additionally, nine HV were studied after 50 mg sildenafil, which induced esophageal peristaltic failure. Perception of each 5 mL viscous swallow was evaluated using a 5-point scale. Manometry identified hypocontractility (contractions lower than 30 mmHg) and impedance identified incomplete bolus clearance.

KEY RESULTS

In HV and in GERD patients with and without IEM, there was no association between either manometry or impedance and perception on per swallow analysis (OR: 0.842 and OR: 2.017, respectively), as well as on per subject analysis (P = 0.44 and P = 0.16, respectively). Lack of correlation was also found in HV with esophageal hypocontractility induced by sildenafil.

CONCLUSIONS & INFERENCES

There is no agreement between objective measurements of esophageal function and subjective perception of bolus passage. These results suggest that increased bolus passage perception in patients without mechanical obstruction might be due to esophageal hypersensitivity.

Rumination or belching-regurgitation? Differential diagnosis using oesophageal impedance-manometry

BACKGROUND

Rumination is an eating disorder clinically suspected in the presence of chronic regurgitation of recently ingested food with subsequent re-mastication and swallowing. Oesophageal manometry is currently used to confirm the diagnosis, however, it is difficult to distinguish rumination from postprandial belching-regurgitation, being the manometric pattern identical in both situations. Oesophageal impedance allows recognition between liquid and gas gastro-oesophageal reflux. Our aims were (i) to improve diagnosis of rumination using combined impedance-manometry (ii) to assess the gastro-oesophageal pressure-flow pattern in rumination events.

METHODS

Sixteen patients with clinically suspected rumination underwent impedance-manometry monitoring for 1 h after a solid liquid meal. Manometry was first analysed blindly to the impedance pattern. All events marked by the patients and straining episodes were identified. After the manometric analysis, impedance tracings were unblinded and each straining episode was analysed for presence of liquid and/or gas oesophageal retrograde flow. Only rumination events were included for additional evaluation.

KEY RESULTS

Postprandial manometry showed a pattern compatible with rumination in 12/16 patients. In total, impedance-manometry confirmed the clinical diagnosis of rumination in eight of the 16 patients with clinical suspicion of rumination. In 102 clearly identified rumination events, the onset of gastric strain (manometry) occurred before the onset of oesophageal liquid retroflow (impedance) in 58% of cases or simultaneously in 37% of cases. In most cases (86%), oesophageal retrograde flow started after an initial increase in abdominal pressure but before the peak gastric strain pressure.

CONCLUSIONS & INFERENCES

Postprandial impedance-manometry monitoring improves diagnosis of rumination because it allows distinction between rumination and postprandial belching and regurgitation. During rumination, oesophageal liquid retrograde flow is first driven by an early small rise in intragastric pressure preceding the peak pressure observed during straining.

The spectrum of motor function abnormalities in gastroesophageal reflux disease and Barrett's esophagus

Barrett's esophagus has traditionally been regarded as the most severe end of the spectrum of gastroesophageal reflux disease and is of great clinical importance in view of the association with esophageal adenocarcinoma. Studies have documented high levels of esophageal acid exposure in Barrett's esophagus. Various pathogenetic mechanisms underlie this phenomenon. These include abnormalities in esophageal peristalsis, defective lower esophageal sphincter pressures, gastric dysmotility and bile reflux. Whilst these factors provide evidence for an acquired cause of Barrett's esophagus, an underlying genetic predisposition cannot be ruled out. Although the past decade has brought about many new discoveries in the pathogenesis of Barrett's esophagus, it has also added further controversy to this complex disorder. A detailed analysis of the gastrointestinal motor abnormalities occurring in Barrett's esophagus follows, with a review of the currently available literature and an update on this condition that continues to be of interest to the gastroenterologist.

Characterization of intraluminal impedance patterns associated with gas reflux in healthy volunteers

Multichannel intraluminal impedance (MII) recording allows assessment of flow through the oesophagus and differentiation between liquid and gas contents. Existing MII criteria for recognition of gas gastro-oesophageal reflux (GOR) have not been validated during known gas GOR in humans.

AIMS

(i) Characterize MII patterns of known gas GOR and optimize criteria. (ii) Clarify interrelationships between magnitude of maximal impedance change, luminal diameter and electrode-mucosa contact. Ten healthy volunteers (six male, 21-37 years) were studied using an oesophageal MII-manometry catheter. After catheter placement, subjects were asked to drink 600 mL of carbonated soft drink. Recordings were made for 20 min and the protocol repeated. Reported belches confirmed manometrically (triggered by transient lower oesophageal sphincter relaxations) were included for analysis. Those episodes were compared against commonly used criteria. Another five subjects (three male, 26-52 years) underwent simultaneous MII and videofluoroscopy using the same protocol. Videofluoroscopic images were analyzed for luminal diameter and the presence of electrode-mucosa contact. All analyzed gas GOR episodes (n = 88) were associated with a pattern of impedance rise which was either retrograde (62.5%), synchronous (19.3%) or antegrade (18.2%). Depending on the exact criteria used, sensitivity ranged from 33% to 75%. A multivariate regression model including luminal diameter and the presence of electrode-mucosa contact as independent factors accounted for 53% of all variation in impedance changes. In conclusion, a significant number of gas GOR episodes does not meet criteria for their recognition. New criteria are proposed to include specific antegrade patterns of impedance rise. Luminal diameter and the extent of contact between the oesophageal mucosa and MII-electrodes influence the magnitude and patterning of impedance change.

Multiple rapid swallowing: a complementary test during standard oesophageal manometry

Multiple rapid swallowing (MRS) stimulates neural inhibition resulting in abolition of contractions in the oesophageal body (OB) and complete lower oesophageal sphincter (LOS) relaxation which is followed by peristalsis and LOS contraction. The aim of this study was to evaluate the yield of MRS to detect abnormalities in inhibitory or excitatory oesophageal mechanisms in patients with oesophageal symptoms and either normal standard manometry or ineffective oesophageal motility (IOM). MRS (five water swallows, 2 mL, separated by 2-3 s) was evaluated in 23 healthy subjects, 109 symptomatic patients with normal standard sleeve manometry and in 48 patients with IOM. Healthy subjects had complete inhibition of OB motility during MRS and a strong motor response after MRS, i.e. amplitude of OB contractions in the oesophageal body and LOS tone being higher than after single swallows. Almost 70% of patients with oesophageal symptoms and normal manometry had abnormal MRS, mainly consistent on inability to increase amplitude of OB contractions after MRS. Nearly, half of the patients with IOM were able to normalize OB contractions after MRS. MRS is a simple complementary test that can be added to standard oesophageal manometry. Two-thirds of patients with normal manometry show abnormal MRS that could potentially underlie their symptoms. A normal response to MRS in patients with severe IOM might be used to predict response to prokinetic treatment.

Azithromycin reduces gastroesophageal reflux and aspiration in lung transplant recipients

Azithromycin (AZI) is a macrolide antibiotic that improves lung function in lung transplant recipients (LTx). Gastroesophageal reflux (GER) has been implicated in the pathogenesis of chronic rejection after LTx. Macrolide antibiotics may affect GER by modifying esophageal and gastric motility. The purpose of this study was to evaluate the effect of AZI on GER and gastric aspiration after LTx. Acid and weakly acidic GER was measured with 24-h pH-impedance monitoring in 47 LTx patients (12 patients "on" AZI). Gastric aspiration was assessed in a separate group of 30 LTx patients before and after AZI by measurements of pepsin and bile acid in bronchoalveolar lavage fluid (BALF). Patients "on" AZI had a significant lower total number of reflux events [41 (30-61) vs. 22.5 (7-37.5)], number of acid reflux events [24 (16-41) vs. 8 (4-18)], esophageal acid exposure [2.9% (0.7-7.3) vs. 0.2% (0.1-2.0)], bolus exposure [0.73% (0.5-1.4) vs. 0.21% (0.12-0.92)], and proximal extent of reflux [14 (9-24) vs. 5 (2-7)]. AZI reduced the concentration of bile acids in BALF without affecting levels of pepsin. LTx patients "on" AZI have less GER and bile acids aspiration. This effect might be due to enhanced esophageal motility and accelerated gastric emptying.

Influence of ghrelin on the gastric accommodation reflex and on meal-induced satiety in man

Ghrelin increases gastric tone in the fasting state and enhances gastric emptying in gastroparesis. The aims of the study were to evaluate the effect of ghrelin on postprandial gastric tone and on meal-induced satiety in health. Ten healthy volunteers underwent a barostat study on two occasions. After determination of intra-abdominal pressure (minimal distending pressure, MDP), isobaric volume measurement was performed for 90 min at MDP + 2 mmHg. After 20 min, ghrelin (40 microg) or saline was administered i.v. over 30 min in a double-blind-randomized cross-over design, followed 10 min later by a liquid meal (200 mL, 300 kcal). Stepwise isobaric distentions (+2 mmHg per 2 min) were performed 60 min after the meal. Data (mean +/- SEM) were compared using paired Student's t-test and ANOVA. Separately, a satiety drinking test (15 mL min(-1) until satiety score 5) was performed on 10 subjects twice, after treatment with placebo or ghrelin. Ghrelin infusion significantly inhibited gastric accommodation (mean volume increase adjusted means 108.0 +/- 50 vs 23.0 +/- 49 mL, P = 0.03, ANCOVA with the premeal postinfusion volume as covariate) and reduced postprandial gastric volumes (197.2 +/- 24.6 vs 353.5 +/- 50.0 mL, P = 0.01). Pressures inducing perception or discomfort during postprandial gastric distentions were not altered. During satiety testing, ghrelin did not alter nutrient volume ingested till maximal satiety (637.5 +/- 70.9 vs 637.5 +/- 56.2 mL, ns). Ghrelin administered during the meal significantly inhibits gastric accommodation in health, but this is not associated with early satiation.

Regional oesophageal sensitivity to acid and weakly acidic reflux in patients with non-erosive reflux disease

The mechanisms underlying symptoms in non-erosive reflux disease (NERD) remain to be elucidated. Non-erosive reflux disease patients appear to be more sensitive to intraluminal stimula than erosive patients, the proximal oesophagus being the most sensitive. In order to assess regional oesophageal changes in reflux acidity and sensitivity to reflux, according either to the acidity or the composition of the refluxate, combined multiple pH and multiple pH-impedance (pH-MII) was performed in 16 NERD patients. According to multiple pH-metry, 29% and 12% of reflux events reached the middle and proximal oesophagus respectively, and 35% and 19% according to conventional pH-MII (P < 0.05). The per-individual analysis confirmed the difference between the two techniques. According to combined distal and proximal pH-MII, approximately 30% of distal acid reflux became weakly acidic at the proximal oesophagus. In all patients, the frequency of symptomatic refluxes, both acid and weakly acidic, was significantly higher at the proximal, compared with distal oesophagus (25 +/- 8%vs 11 +/- 2% for acid reflux and 27 +/- 8%vs 8 +/- 2% for weakly acidic reflux; P < 0.05). Compared with multiple pH-metry, pH-MII shows a higher sensitivity in the detection of proximal reflux. As approximately 30% of acid reflux becomes weakly acidic along the oesophageal body, to better characterize proximal reflux, in clinical practice, combined proximal pH-impedance monitoring should be used. In NERD patients, the proximal oesophagus seems to be more sensitive to both acid and weakly acidic reflux.

Continuous distal oesophageal acidification decreases postprandial gastric acidity in healthy human subjects

BACKGROUND

Previously, we hypothesized that exposing the distal oesophagus to acid signals the stomach to decrease gastric acidity.

AIM

To test the hypothesis that exposing the distal oesophagus to acid signals the stomach to decrease gastric acidity.

METHODS

Twenty-two healthy humans ingested a standard meal containing [(14)C]octanoic acid and [(13)C]glycine over 30 min on 2 separate occasions. Gastric pH was measured for 90 min before and 240 min after the meal. 10 mm HCl was infused continuously at 1 mL/min into either the distal oesophagus or stomach in a 2-way crossover fashion for 60 min before and 240 min after the meal. Gastric emptying of solid and liquid were determined with breath tests.

RESULTS

Compared to gastric infusion, oesophageal infusion significantly decreased gastric acidity after the meal, but not before the meal and the magnitude of the decrease varied directly with gastric acidity. Gastric emptying of solid or liquid with oesophageal infusion was not significantly different from that with gastric infusion.

CONCLUSIONS

These findings support the hypothesis of the existence of a physiological oesophago-gastric feedback mechanism that might contribute to regulation of postprandial gastric acidity. Oesophageal acidification might decode gastric information and signal the stomach to decrease gastric acidity. Further studies are needed to assess the characteristics of such feedback mechanism in-patients with gastro-oesophageal reflux disease (GERD).

Management of heartburn not responding to proton pump inhibitors

Patients with gastro-oesophageal reflux disease (GORD) who are not responding to proton pump inhibitors (PPIs) given once daily are very common. Various underlying mechanisms have been shown to contribute to the failure of PPI treatment. These include weakly acidic reflux, duodenogastro-oesophageal reflux, residual acid reflux and functional heartburn, as well as others. Diagnostic evaluation of patients with GORD who have failed PPI treatment may include an upper endoscopy, pH testing and oesophageal impedance with pH monitoring. Commonly, doubling the PPI dose or switching to another PPI will be pursued by the treating physician. Failure of such a therapeutic strategy may result in the addition of a transient lower oesophageal sphincter reducer or pain modulator. Anti-reflux surgery may be suitable for a subset of carefully studied patients.

Short exposure of oesophageal mucosa to bile acids, both in acidic and weakly acidic conditions, can impair mucosal integrity and provoke dilated intercellular spaces

BACKGROUND

Severe duodeno-gastro-oesophageal reflux (DGOR) is a risk factor for oesophagitis and Barrett's oesophagus. Patients with non-erosive reflux disease (NERD) have a slight increase in DGOR. Patients with gastro-oesophageal reflux disease (GORD), who are taking proton pump inhibitors (PPIs), still have reflux but of weakly acidic pH and persistence of bile. In these two groups of patients, heartburn might be due to increased oesophageal mucosal permeability and dilated intercellular spaces (DIS). We aimed to assess whether experimental short exposure of the oesophageal mucosa to bile acids, in low concentrations (at acidic, weakly acidic and neutral conditions) can increase mucosal permeability and provoke DIS.

METHODS

Rabbit oesophageal mucosa was studied in diffusion and Ussing chambers. We assessed the effects of different solutions containing bile acids, applied to the mucosal side, on transepithelial electrical resistance (R(T)) and permeability to fluorescein. The diameter of intercellular spaces was assessed by using transmission electron microscopy.

RESULTS

Incubation of oesophageal mucosa with acidic solutions (pH 2.0) containing a range of bile acids (0.5-5 mmol/l) markedly decreased R(T) and increased mucosal permeability. Weakly acidic solutions (pH 5.0), and to some extent neutral solutions (pH 7.4), containing some bile acids also decreased R(T) and increased permeability, although the effects were much less marked and in some combinations no effect was seen. Exposure to bile acids provoked DIS in acid and weakly acidic conditions but not in neutral (pH 7.4) solutions.

CONCLUSIONS

Experimental short exposure of the oesophageal mucosa to solutions with a bile acid concentration and acidity similar to that observed in the gastric contents of patients with NERD or ERD, and who are taking PPIs, may impair oesophageal mucosal integrity and even induce dilated intercellular spaces. Such a situation could, theoretically, underlie the occurrence and/or persistence of symptoms in these patients.

Gastro-oesophageal reflux and aspiration of gastric contents in adult patients with cystic fibrosis

BACKGROUND

Gastro-oesophageal reflux (GOR) is increased in cystic fibrosis (CF), but its prevalence, characteristics, association with gastric aspiration and respiratory impact are not well characterised. We investigated acid and weakly acidic reflux, aspiration and respiratory symptoms/function in adult CF patients.

METHODS

Thirty-three CF patients [19 men; 29 (18-55) years, [10 post-lung transplant (LTx)] underwent impedance-pH monitoring for detection of acid (pH<4) and weakly acid GOR (pH 4-7). In 16 patients cough was objectively recorded with oesophageal manometry, and the symptom association probability (SAP) was calculated. Saliva and bronchoalveolar lavage fluid (BALF) were tested for bile acids.

RESULTS

Twenty-eight patients had increased GOR (21 acid, 5 weakly acidic and 2 acid+weakly acidic) and 10 had a positive SAP for reflux cough. GOR parameters were similar in non-LTx and post-LTx CF patients. The sequence reflux cough was significantly more common than cough reflux. Sixteen of 38 patients had bile acids in saliva and 6/10 in BALF and this was almost exclusively observed in patients with genotype DF508/DF508. Only 12/28 with increased GOR and 9/22 with bile acids in saliva/BALF had typical reflux symptoms. There was a positive correlation (r = 0.53, p = 0.03) between oesophageal acid exposure and cough. SAP-positive patients with for reflux cough had a lower lung function than SAP-negative patients.

CONCLUSION

Increased GOR is prevalent in CF and not secondary to cough. Acid GOR is common, but weakly acidic GOR may also occur. CF patients have a high risk of aspiration and reflux seems to be associated with more cough and poorer lung function. Outcome studies with intense anti-reflux therapy are needed to confirm the deleterious role of reflux in CF progression.

Multivariate analysis of the association of acid and duodeno-gastro-oesophageal reflux exposure with the presence of oesophagitis, the severity of oesophagitis and Barrett's oesophagus

BACKGROUND

Exposure to acid and duodeno-gastro-oesophageal reflux (DGOR) both increase with oesophageal lesions in gastro-oesophageal reflux disease (GORD). It is unknown whether DGOR exposure is an independent risk factor for oesophageal lesions. A multivariate analysis was performed on the relationship between oesophageal lesions and demographics and acid and DGOR exposure.

METHODS

In 422 patients with suspected GORD, upper endoscopy, oesophageal manometry, and pH and DGOR monitoring were performed. Stepwise logistic regression was used to identify factors associated with the presence of oesophagitis, severity of oesophagitis and the presence of Barrett's oesophagus. ORs and 95% CIs were computed at different cut-offs.

RESULTS

54% of the patients had no oesophagitis, 36% had grade A-B oesophagitis, 3% had grade C-D oesophagitis and 7% had Barrett's oesophagus. In multivariate analysis, oesophagitis was associated with hiatal hernia (OR 3.621, 95% CI 2.263 to 5.794) and DGOR exposure (OR up to 2.236, 95% CI 1.356-3.685), while a low body mass index (BMI) seemed protective (OR for BMI >first quartile 2.245, 95% CI 1.371 to 3.677). Severity of oesophagitis was only associated with acid exposure (OR up to 5.038, 95% CI 1.452 to 17.480). The presence of Barrett's oesophagus was associated with male sex (OR 3.621, 95% CI 2.263 to 5.794), DGOR (OR up to 5.017, 95% CI 2.051 to 12.274) and acid exposure (OR up to 3.031, 95% CI 1.216 to 7.556).

CONCLUSIONS

Several independent factors are associated with oesophageal lesions in GORD. The risk of oesophagitis is associated with hiatal hernia, BMI and DGOR exposure; severity of oesophagitis depends on acid exposure; and Barrett's oesophagus is associated with male sex and exposure to both acid and DGOR.

Oesophageal tone and sensation in the transition zone between proximal striated and distal smooth muscle oesophagus

Previous studies have shown that the proximal striated muscle oesophagus is less compliant and more sensitive than the distal smooth muscle oesophagus. Conventional and high resolution manometry described a transition zone between striated and smooth muscle oesophagus. We aimed to evaluate oesophageal tone and sensitivity at the transition zone of oesophagus in healthy volunteers. In 18 subjects (seven men, mean age: 28 years) an oesophageal barostat study was performed. Tone and sensitivity were assessed using stepwise isobaric distensions with the balloon located at transition zone and at distal oesophagus in random order. To study the effect induced on transition zone by a previous distension at the distal oesophagus and vice versa, identical protocol was repeated after 7 days with inverted order. Initial distension of a region is referred to as 'naïf' distension and distension of a region following the distension of the other segment as 'primed' distension. Assessment of three oesophageal symptoms (chest pain, heartburn and 'other') was obtained at the end of every distension step. Compliance was significantly higher in the transition zone than in the distal oesophagus (1.47 +/- 0.14 vs 1.09 +/- 0.09 mL mmHg(-1), P = 0.03) after 'naif' distensions. This difference was not observed during 'primed' distensions. Higher sensitivity at transition zone level was found in 11/18 (61%) subjects compared to 6/18 (33%, P < 0.05) at smooth muscle oesophagus. Chest pain and 'other' symptom were more often induced by distention of the transition zone, whereas heartburn was equally triggered by distension of either region. The transition zone is more complaint and more sensitive than smooth muscle oesophagus.

Presence of gas in the refluxate enhances reflux perception in non-erosive patients with physiological acid exposure of the oesophagus

OBJECTIVE

The mechanisms underlying symptoms in gastro-oesophageal reflux disease, particularly in non-erosive reflux disease (NERD), remain to be fully elucidated. Weakly acidic reflux and the presence of gas in the refluxate could be relevant in the pathogenesis of symptoms.

METHODS

To assess the relationship between symptoms and weakly acidic, acid and mixed (liquid-gas) reflux, 24 h oesophageal pH-impedance monitoring was performed in 32 NERD and in 20 oesophagitis patients. In 12 NERD patients the study was repeated following 4 weeks treatment with a proton pump inhibitor (PPI). Impedance-pH data were compared with those of 10 asymptomatic controls. Heartburn and acid regurgitation were considered in the analysis of symptoms.

RESULTS

15 NERD patients showed a physiological acid exposure time (pH-negative). Weakly acidic reflux was significantly less frequent in patients (25% (2%), mean (SE)) than in controls (54% (4%), p<0.01). Gas was present in 45-55% of reflux events in patient groups and controls, and decreased following PPI treatment. In NERD pH-negative patients, weakly acidic reflux accounted for 32% (10%) (vs 22% (6%) in NERD pH-positive and 12% (8%) in oesophagitis patients) and mixed reflux for more than two-thirds of all symptom-related refluxes. Multivariate logistic analysis showed that in NERD pH-negative patients, the risk of reflux perception was significantly higher when gas was present in the refluxate (odds ratio, 3.2; 95% CI, 1.2 to 10; p<0.01).

CONCLUSIONS

The large majority of symptoms, in all patients, are related to acid reflux. In NERD patients, the presence of gas in the refluxate significantly enhances the probability of reflux perception. These patients are also more sensitive to less acidic reflux than oesophagitis patients.

Esophageal impedance-pH monitoring

Classical techniques like endoscopy and esophageal pH-metry are routinely used to study patients with symptoms related to gastroesophageal reflux disease (GERD). Although these techniques have been useful over the years both for diagnosis and therapeutic guidance, there are still many patients with typical or atypical GERD symptoms with normal endoscopy and pH-metry that do not respond adequately to antisecretory therapy. Ambulatory esophageal impedance-pH monitoring is a new technique that can be used to evaluate all types of gastroesophageal reflux, achieving higher rates of sensitivity and specificity than standard techniques. This review describes esophageal impedance-pH monitoring, summarizing the current literature on validation studies and clinical application.

Gastro-oesophageal reflux and gastric aspiration in lung transplant patients with or without chronic rejection

Acid gastro-oesophageal reflux (GOR) and gastric aspiration have been labelled as risk factors for chronic rejection bronchiolitis obliterans syndrome (BOS) after lung transplantation (LTx). The present study aimed to further characterise GOR (both acid and nonacid) and the degree of gastric aspiration in LTx recipients both with and without BOS. Impedance-pH recordings were used for GOR detection. Pepsin and bile acid levels were measured in bronchoalveolar lavage fluid (BALF). A total of 48% of patients had increased GOR, of which 27% had exclusively increased nonacid reflux. Cystic fibrosis patients had the highest prevalence of GOR. Pepsin was found in BALF of all patients and bile acids in BALF of 50% of the patients. Patients with BOS had neither increased GOR nor elevated pepsin in BALF. However, 70% of the patients with BOS had bile in BALF compared with 31% of stable patients. Proton pump inhibitor (PPI) treatment reduced acid reflux but did not affect nonacid reflux. Moreover, pepsin and bile levels in BALF were not reduced by PPI. One-half of the lung transplant patients had increased reflux, and nonacid reflux was common. Gastric aspiration occurred in most lung transplant patients. Pepsin was a more general marker and bile acids a more specific marker that might be associated with bronchiolitis obliterans syndrome. Proton pump inhibitor treatment did not prevent nonacid reflux and gastric aspiration.

Relevance of mild ineffective oesophageal motility (IOM) and potential pharmacological reversibility of severe IOM in patients with gastro-oesophageal reflux disease

BACKGROUND

Several studies showed high prevalence of ineffective oesophageal motility (IOM) in gastro-oesophageal reflux disease (GERD) and suggested an important role for ineffective oesophageal motility in increased acid exposure. However, impedance-manometric studies proposed that only severe ineffective oesophageal motility might affect oesophageal clearance.

OBJECTIVES

(i) To re-assess the relevance of mild IOM in GERD and (ii) to test the reversibility of IOM.

METHODS

Oesophageal motility, clearance and acid exposure were assessed in 191 GERD patients: 99 without IOM; 58 with mild IOM (30-80% ineffective contractions) and 34 with severe IOM (>80% ineffective contractions). In 30 patients with oesophagitis, the potential reversibility of IOM was evaluated with edrophonium intravenously.

RESULTS

Patients with mild IOM had identical oesophageal clearance and acid exposure in comparison with those without IOM. Patients with severe IOM had a higher probability of prolonged supine clearance and acid exposure [odds ratio: 2.88 (1.16-7.17); 2.48 (0.99-6.17)]. This effect was independent of the presence of hiatal hernia and male sex. Severe IOM could be transiently reverted in 55% of patients.

CONCLUSIONS

Mild IOM does not affect oesophageal clearance. Only severe IOM is associated with prolonged clearance and acid exposure, particularly in supine periods. The edrophonium test might be useful to predict severe IOM response to prokinetic medications.