Automated impedance manometry analysis as a method to assess esophageal function

Four-Dimensional Impedance Manometry in Esophageal Motility Disorders

INTRODUCTION

Four-dimensional high-resolution impedance manometry (4D HRM) uses impedance to estimate esophageal luminal cross-sectional area and track nadir impedance to measure intrabolus pressure (IBP). We aimed to determine whether 4D HRM metrics could define abnormal esophagogastric junction (EGJ) opening between Chicago Classification version 4.0 motility disorders and compare 4D HRM with functional lumen imaging probe (FLIP) metrics.

METHODS

Symptomatic adult patients who completed high-resolution impedance manometry and FLIP were included and compared with an asymptomatic control group. 4D HRM analysis used custom-built software to measure IBP, maximum EGJ diameter, and distensibility index on supine test swallows. 4D HRM metrics were compared with FLIP EGJ metrics.

RESULTS

Ninety patients (31 normal motility, 16 ineffective esophageal manometry, 9 absent contractility, 8 conclusive EGJ outflow obstruction [EGJOO], 12 type I achalasia, 14 type II achalasia, 12 type III achalasia, and 34 asymptomatic controls) were included. Phase 2 and 3 IBP was higher in type II and III achalasia compared with controls and normal motility groups ( P < 0.03). Maximum EGJ diameter and EGJ-distensibility index in the conclusive EGJOO and achalasia groups were significantly lower than in controls and normal motility groups ( P < 0.03). 4D HRM identified 37 of 44 (84%) subjects with normal EGJ opening and 29 of 39 (74%) subjects with reduced EGJ opening on FLIP.

DISCUSSION

4D HRM metrics correlated with expected clinical observations across a spectrum of esophageal motility disorders and defined EGJ obstruction. 4D HRM metrics may have value in defining EGJ obstruction in equivocal cases related to EGJOO or absent peristalsis.

Pharyngeal electrical stimulation favorably modifies healthy human pharyngoesophageal function: a randomized trial using high-resolution manometry impedance

Despite positive clinical evidence for the effects of pharyngeal electrical stimulation (PES) on swallowing performance in disease, it remains unknown which specific swallow characteristics improve. Using high-resolution manometry impedance (HRMI) with pressure flow analysis (PFA), we aimed to assess the effects of PES on normal swallow function and to evaluate the impact of pharyngeal length variability on electrode placement. As part of a prospective randomized controlled trial (RCT), 20 asymptomatic volunteers were randomly assigned to 3 days of PES or SHAM treatment. HRMI assessments were conducted at baseline (during which pharyngeal length measurements were acquired) and repeated at 1-2 h, and at 24-72 h following PES or SHAM treatment. Twenty healthy adults [10 males, median age: 28.0 (interquartile range, IQR 23.8-45.0) yr, age range: 20-65 yr] participated in this RCT. We developed an objective, standardized method of catheter placement based on pharyngeal length measurements. Over 3 days, the median stimulation intensity of PES was 11 mA. When compared with the SHAM group, the PES group scored better on multiple pharyngeal and esophageal metrics resulting in improved global swallow function values 1-2 h after treatment (P = 0.029). One day later, most of these beneficial effects were no longer present. This study suggests that PES can temporarily alter swallow function in healthy individuals. Functional reserve in healthy individuals may be further enhanced by PES. In the majority of volunteers, electrode position needed to be adjusted 1-3 cm to account for variations in pharyngeal length.NEW & NOTEWORTHY Pharyngeal electrical stimulation (PES) positively influences clinical swallow-outcomes in patients with neurogenic dysphagia. Its effect on the underlying swallowing physiology remains unknown. Our study evaluated this effect of PES in healthy individuals using high-resolution manometry impedance. PES showed short-term improved pharyngeal contractility, upper esophageal sphincter relaxation, proximal esophageal contractility and bolus flow, resulting in improved swallowing. One day later, most of these beneficial effects were no longer present as expected in already intact swallow systems.

The Use of Pharyngeal High-Resolution (Impedance) Manometry in Patients With Head and Neck Cancer: A Scoping Review

PURPOSE

This scoping review aims to summarize and explore current literature on the usefulness and clinical implications of pharyngeal high-resolution (impedance) manometry (HRM/HRIM) in head and neck cancer (HNC) patients.

METHOD

Three online databases (MEDLINE, Embase, Scopus, and additionally Google Scholar) were searched until December 2023. Studies using pharyngeal HRM/HRIM to assess swallowing or voicing in HNC patients, written in any language and published in peer-reviewed journals, were considered eligible. Quality check was performed using the Quality Assessment Tool for Quantitative Studies from the Effective Public Healthcare Practice Project. Information about the study population and HRM/HRIM data (equipment, protocol, analysis, and outcomes) were extracted.

RESULTS

Eight papers met the inclusion criteria, six utilizing HRM and two HRIM. The study design consisted of case-series (five) and case-control (three). The quality assessment indicated a weak global rating for seven papers and a moderate rating for one for the remaining study. Findings suggest that HNC patients with dysphagia suffer from reduced pressures in the pharynx and upper esophageal sphincter compared to healthy individuals, potentially influenced by tumor characteristics and treatment. Decreased pressures may indicate poor functioning of swallowing musculature and mechanism.

CONCLUSIONS

Pharyngeal HRM/HRIM is sparsely used for swallowing assessment in HNC patients. However, wider use seems warranted, as it can offer valuable insights into swallowing biomechanics. This can help quantifying the degree and timing of pressures involved in swallowing (problems) and holds potential for clinical applications, such as earlier diagnosis of radiation-induced therapy or surgery complications. Additionally, it can be beneficial in evaluating therapeutic swallowing strategies.

The Multichannel Intraoesophageal Impedance Transit Concept

Introduction/aims The multichannel intraoesophageal impedance transit (MIIT) is a new clinical concept that is being introduced to measure the oesophageal transit during a 24-hour multichannel impedance-pH (MII-pH) study. Methods MIIT was tested in a case-control study between January 2020 and December 2023. A laboratory test was first conducted to determine the saline baseline impedance (SBI) using MII-pH catheters. SBI was later used to reference the oesophageal transit of saline during the MIIT test. In the MIIT test, patients rapidly drank 200 ml of saline within 20 seconds. The saline transit was identified by the temporal impedance changes from the oesophageal mucosal baseline impedance (MBI) to the approximate SBI level. The duration of SBI was recorded from multiple impedance sensors in the proximal, mid and distal oesophagus which form the MIIT. The regional MIIT were correlated to the Hospital Odynophagia Dysphagia Questionnaire (HODQ) scores for clinical dysphagia and severity. Regional MIIT were also compared between achalasia patients (case group) and non-achalasia patients (control group) based on high-resolution manometry (HRM) and barium swallow (BS) diagnosis. Descriptive statistics, t-test and chi-squared test compared the MIIT with respect to HODQ scores, HRM and BS outcomes. Receiver operating characteristic curves with Youden's J indices determined the optimal MIIT cut-off threshold for achalasia. This research was approved by the North West Haydock NHS Health Research Authority (REC 18/NW/0120) and the Integrated Research Application System (Project ID: 333800). Results Nine hundred and eleven patients undertook the MIIT test prospectively to HRM study (females 554, mean age 50.9 years). Three hundred and thirty-three patients (36.6%) additionally underwent the BS study (the BS-HRM diagnostic concordance outcome was 83.8%). Oesophageal luminal transit of saline was identifiable during MIIT and found to be significantly lower than the MBI (t-value=3.59-9.07, p<0.001). Regional MIIT increased with higher dysphagia severity (r≈0.33, p<0.001) and positive HODQ scores for clinical dysphagia (t-value=6.18-6.30, p<0.001). Similarly, prolonged regional MIIT was observed in achalasia patients based on BS study diagnosis (t-values: 9.86-11.2, p<0.001) and HRM study diagnosis (t-values: 23-27.4, p<0.001). Patients with concordant BS-HRM study for achalasia also showed prolonged regional MIIT (t-value: 13.9-16.4, p<0.001). The optimal MIIT of the distal oesophagus for achalasia diagnosis is between 4.05 minutes and 5.45 minutes (sensitivity: 73.8-100%, positive predictive values: 90.5-94.4%). MIIT thresholds for achalasia show higher concordance to the HRM study than the BS study at 4.05 minutes (χ2=4.69, p<0.030). Conclusions The MIIT concept was demonstrated to be a simple and effective transit assessment that showed exceptional reliability to BS and HRM studies. The MIIT technique can be easily incorporated into the MII-pH investigation without causing additional risk or burden to patients.

Four-dimensional impedance manometry volume metrics for predicting abnormal bolus retention

BACKGROUND

The objective measurement for esophageal bolus volume and bolus clearance could classify abnormal high-resolution manometry (HRM) beyond the current Chicago classification. We aimed to compare the novel four-dimensional impedance manometry (4D HRM) volume metrics with timed barium esophagram (TBE).

METHODS

Adults with esophageal symptoms undergoing HRM and TBE were included. A custom-built program for 4D HRM analysis measured esophageal luminal cross-sectional area (CSA) from impedance and subsequently derived esophageal bolus volume and clearance. 4D HRM volume metrics included pre-swallow residual volume, maximal volume, retention volume, and clearance ratio defined as 1.0-retention volume divided by the maximal volume. An abnormal TBE was defined as a column height >5 cm at 1 min or 5 min.

KEY RESULTS

A total of 95 patients (normal motility: 33%; ineffective esophageal motility: 12%; absent contractility: 10%; esophagogastric junction outflow obstruction: 30%; type I achalasia: 5%; type II achalasia: 12%) were categorized into normal TBE (58%), abnormal TBE at 1 min (17%), and abnormal TBE at 5 min (25%). The AUROC demonstrated that, among all 4D HRM volume metrics, the clearance ratio had the best performance in predicting abnormal TBE at 5 min (AUROC, 95% confidence interval: 0.89, 0.82-0.96), and exhibited a strong negative correlation with TBE at 5 min (r = -0.65; p < 0.001).

CONCLUSIONS & INFERENCES

Novel 4D HRM volume metrics provide objective measurement of esophageal bolus volume and bolus clearance. The clearance ratio has a strong correlation with TBE and could potentially serve as a substitute for TBE to measure esophageal retention.

Dysphagia associated with esophageal wall thickening in patients with nonspecific high-resolution manometry findings: Understanding motility beyond the Chicago classification version 4.0

BACKGROUND

Previous studies have demonstrated that 50% of patients with normal high-resolution manometry (HRM) findings or ineffective esophageal motility (IEM) may have abnormal functional luminal imaging probe (FLIP) results. However, the specific HRM findings associated with abnormal FLIP results are unknown. Herein, we investigated the relationship between nonspecific manometry findings and abnormal FLIP results.

METHODS

We retrospectively analyzed 684 patients who underwent HRM at a tertiary care center in Seoul, Korea, based on the Chicago Classification version 4.0 protocol.

KEY RESULTS

Among the 684 patients, 398 had normal HRM findings or IEM. Of these 398 patients, eight showed esophageal wall thickening on endoscopic ultrasonography or computed tomography; however, no abnormalities were seen during esophagogastroduodenoscopy. Among these eight patients, seven showed repetitive simultaneous contractions (RSCs) in at least one of the two positions: 61% (±29%) in 10 swallows in the supine position and 51% (±30%) in five swallows in the upright position. Four patients who underwent FLIP had a significantly decreased esophagogastric junction distensibility index (1.0 ± 0.5m m 2 mmHg - 1 at 60 mL). Two of these patients underwent per-oral endoscopic myotomy (POEM) due to a lack of response to medication. Esophageal muscle biopsy revealed hypertrophic muscle with marginal eosinophil infiltration.

CONCLUSIONS & INFERENCES

A subset of patients (2%) with normal HRM findings or IEM and RSCs experienced dysphagia associated with poor distensibility of the thickened esophageal wall. FLIP assessment or combined HRM and impedance protocols may help better define these patients who may respond well to POEM.

High-resolution impedance manometry for comparing bolus transit between patients with non-obstructive dysphagia and asymptomatic controls

BACKGROUND

Currently, there are no high-resolution impedance manometry (HRIM)-based diagnostic criteria for non-obstructive dysphagia (NOD). New impedance parameters, such as the esophageal impedance integral (EII) and volume of inverted impedance (VII) ratios, have shown strong correlations with bolus transit. This study compared the EII and VII ratios as diagnostic tools for NOD.

METHODS

We analyzed 36 participants (12 patients with achalasia, 12 patients with NOD [7 with normal motility and 5 with ineffective esophageal motility], and 12 asymptomatic controls) who underwent HRIM with a maximum of 5 swallows per participant. The EII and VII ratios were calculated as Z2 (post-swallow)/Z1 (pre-swallow). Bolus transit was retrospectively evaluated using transluminal impedance analysis.

KEY RESULTS

Both EII and VII ratios could effectively distinguish the achalasia group from the non-achalasia groups (area under the receiver operating characteristic curve [AUROC]: 0.83 for VII vs. 0.80 for EII; p = 0.73). However, the VII ratio was significantly better in discriminating asymptomatic controls from patients with dysphagia (NOD + achalasia) (AUROC: 0.81 vs. 0.68; p = 0.01). Moreover, the VII ratio was better in discriminating asymptomatic controls from patients with NOD (AUROC: 0.68 vs. 0.51; p = 0.06). In repeated swallows, the VII ratio was consistently the lowest in controls and the highest in patients with achalasia, whereas the EII ratio did not show a consistent pattern.

CONCLUSIONS & INFERENCES

The VII ratio was more reliable than the EII ratio for describing bolus transit and distinguishing patients with NOD from asymptomatic controls, even during repeated measures of subsequent swallows.

Normative values of intra-bolus pressure and esophageal compliance based on 4D high-resolution impedance manometry

BACKGROUND

This study aimed to quantify normative values of phase-specific intra-bolus pressure (IBP) and esophageal distensibility using 4D analysis of high-resolution-impedance manometry (HRIM).

METHODS

HRIM studies of supine swallows from 34 normal controls were analyzed with respect to the four phases of bolus transit: (1) accommodation, (2) compartmentalization, (3) peristalsis/esophageal emptying, and (4) ampullary emptying. Phase-specific IBP, bolus volume, and distensibility index (DI) in the esophageal body and esophagogastric junction (EGJ) during phases 1-3 were extracted.

RESULTS

The median (5-95th/IQR) IBP values were as follows: phase 1: 4.0 (-2.0-10.4/1.9-5.8) mmHg, phase 2: 5.7 (0.2-14.1/3.6-8.9) mmHg, and phase 3: 11.2 (2.9-19.4/7.7-15.1) mmHg. The median bolus volume calculated by integrating impedance planimetry cross-sectional areas was 4.1 ml during the compartmentalization phase. The EGJ-DI at max EGJ diameter during phase 2 and 3 was 2.8 (1.1-9.5/1.8-3.7) mm² /mmHg and 6.0 (3.2-20.3/5.1-7.8) mm² /mmHg, respectively. The phase 3 EGJ-DI values (6.0 (3.2-20.3/5.1-7.8) mm² /mmHg) were similar to those calculated using functional lumen imaging probe (FLIP) at the 60 ml volume on the same subjects (5.8 [3.5-7.2/5.0-6.4] mm² /mmHg).

CONCLUSIONS AND INFERENCES

4D-HRIM provides a standardized methodology to track the nadir impedance and provide measurements of IBP during maximal distention across phases 1-3 of bolus transit. Median IBP and delta IBP were different across the phases, supporting the need to define IBP by phase. Additionally, the EGJ-DI calculated during phase 3 was similar to the 60-ml EGJ-DI from FLIP in the same subjects suggesting that 4D-HRIM can quantify EGJ opening during primary peristalsis.

Characterizing Esophageal Motility in Neonatal Intensive Care Unit Patients Using High Resolution Manometry

OBJECTIVE

To characterize esophageal motility and esophago-gastric junction (EGJ) function during feeding in neonatal intensive care unit (NICU) patients.

PATIENTS AND METHODS

High resolution manometry with impedance (HRIM) was used to investigate esophageal motility and EGJ function in patients admitted to the NICU. Twenty-eight preterm born infants with bronchopulmonary dysplasia (BPD), 12 born with isolated congenital diaphragmatic hernia (iCDH), and 10 with esophageal atresia (EA) were included. Thirteen healthy infants were included as controls. Esophageal motility and EGJ function were analyzed using objective esophageal bolus transport parameters.

RESULTS

Normal esophageal peristaltic wave patterns were observed in all investigated infants without EA. Nine of 10 patients with EA presented with abnormal esophageal motor wave patterns. A total of 224 nutritive swallows were analyzed (controls, n = 48; BPD, n = 96; iCDH, n = 60; EA, n = 20). Infants with BPD and iCDH had similar distal contractile strength (DCI) compared to healthy controls, while in patients with EA, DCI was significantly lower (Kruskal-Wallis test, p = 0.001). In most infants, EGJ relaxation after swallowing was unaffected. EGJ barrier function, in terms of EGJ-contractile integral, also appeared well-developed and did not differ significantly among patient groups.

CONCLUSIONS

We conclude that esophageal motility studies using pressure-impedance analysis are feasible in young infants. Bolus transport mechanisms following nutritive swallows appeared well-established in all investigated infants with the exception of those with EA. EGJ relaxation was also functional after deglutition and EGJ function as an anti-reflux barrier appeared well-developed in all investigated NICU groups.

Dysphagia: Novel and Emerging Diagnostic Modalities

Among recent advances in diagnostics for dysphagia and esophageal motility disorders is the update to the Chicago Classification (version 4.0) for interpretation of high-resolution manometry (HRM) and diagnosis of esophageal motility disorders. The update incorporates application of complementary testing strategies during HRM, such as provocative HRM maneuvers, and recommendation for barium esophagram or functional luminal imaging probe (FLIP) panometry to help clarify inconclusive HRM findings. FLIP panometry also represents an emerging technology for evaluation of esophageal distensibility and motility at the time of endoscopy.

European Society for Neurogastroenterology and Motility (ESNM) recommendations for the use of high-resolution manometry of the esophagus

BACKGROUND

Several patients in gastroenterology practice present with esophageal symptoms, and in case of normal endoscopy with biopsies, high-resolution manometry (HRM) is often the next step. Our aim was to develop a European consensus on the clinical application of esophageal HRM, to offer the clinician guidance in selecting patients for HRM and using its results to optimize clinical outcome.

METHODS

A Delphi consensus was initiated with 38 multidisciplinary experts from 16 European countries who conducted a literature summary and voting process on 71 statements. Quality of evidence was evaluated using grading of recommendations assessment, development, and evaluation (GRADE) criteria. Consensus (defined as >80% agreement) was reached for 33 statements.

RESULTS

The process generated guidance on when to consider esophageal HRM, how to perform it, and how to generate the report. The Delphi process also identified several areas of uncertainty, such as the choice of catheters, the duration of fasting and the position in which HRM is performed, but recommended to perform at least 10 5-ml swallows in supine position for each study. Postprandial combined HRM impedance is considered useful for diagnosing rumination. There is a large lack of consensus on treatment implications of HRM findings, which is probably the single area requiring future targeted research.

CONCLUSIONS AND INFERENCES

A multinational and multidisciplinary group of European experts summarized the current state of consensus on technical aspects, indications, performance, analysis, diagnosis, and therapeutic implications of esophageal HRM.

[Diagnosis of Dysphagia: High Resolution Manometry & EndoFLIP]

Esophageal motility disorders were re-defined when high-resolution manometry was employed to better understand their pathogenesis. Newly developed parameters including integrated relaxation pressure (IRP), distal contractile integral, and distal latency showed better diagnostic yield compared with previously used conventional parameters. Therefore, Chicago classification was formulated, and its diagnostic cascade begins by assessing the IRP value. However, IRP showed limitation due to its inconsistency, and other studies have tried to overcome this. Recent studies showed that provocative tests, supplementing the conventional esophageal manometry protocol, have improved the diagnostic yield of the esophageal motility disorders. Therefore, position change from supine to upright, solid or semi-solid swallowing, multiple rapid swallows, and the rapid drink challenge were newly added to the manometry protocol in the revised Chicago classification version 4.0. Impedance planimetry enables measurement of bag cross-sectional area at various locations. The functional lumen imaging probe (FLIP) has been applied to assess luminal distensibility. This probe can also measure pressure, serial cross-sectional areas, and tension-strain relationship. The esophagogastric junction's distensibility is decreased in achalasia. Therefore, EndoFLIP can be used to assess contractility and distensibility of the esophagus in the patients with achalasia, including repetitive antegrade or retrograde contractions. EndoFLIP can detect achalasia patients with relatively low IRP, which was difficult to diagnose using the current high-resolution manometry. EndoFLIP also provides information on the contractile activity and distensibility of the esophageal body in patients with achalasia. The use of provocative tests, newly added in Chicago classification 4.0 version, and EndoFLIP can expand understanding of esophageal motility disorders.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Enhancing High-Resolution Esophageal Manometry: Use of Ancillary Techniques and Maneuvers

High-resolution manometry evaluates esophageal motor function using 10 supine water swallows. Superimposing impedance over high-resolution manometry pressure topography assesses the relationship between contraction and bolus propulsion and identifies inadequate clearance. Ancillary techniques and maneuvers augment the standard supine high-resolution manometry evaluation by challenging peristaltic function. Increasing bolus volume (rapid drink challenge) and altering bolus consistency (standardized test meal, solid swallows) enhance identification of esophageal outflow obstruction syndromes. Physiologic maneuvers (multiple rapid swallows, abdominal compression) address the ability of the esophageal smooth muscle to augment contraction vigor. Pharmacologic challenge is less commonly used clinically, and elucidates pathophysiology of esophageal motor disorders.

High-Resolution Manometry-Observations After 15 Years of Personal Use-Has Advancement Reached a Plateau?

PURPOSE OF REVIEW

In the absence of mucosal or structural disease, the aim of investigating the oesophagus is to provide clinically relevant measurements of function that can explain the cause of symptoms, identify pathology and guide effective management. One of the most notable recent advances in the field of oesophageal function has been high-resolution manometry (HRM). This review explores how innovation in HRM has progressed and has far from reached a plateau.

RECENT FINDINGS

HRM technology, methodology and utility continue to evolve; simple additions to the swallow protocol (e.g. eating and drinking), shifting position, targeting symptoms and adding impedance sensors to the HRM catheter have led to improved diagnoses, therapeutic decision-making and outcomes. Progress in HRM persists and shows little sign of abating. The next iteration of the Chicago Classification of motor disorders will highlight these advances and will also identify opportunities for further research and innovation.

Pressure-impedance analysis: Assist the diagnosis and classification of ineffective esophageal motility disorder

BACKGROUND AND AIM

We elucidated the clinical significance of distal contractile integral-to-esophageal impedance integral (EII) ratio (DCIIR) in ineffective esophageal motility (IEM) adult patients.

METHODS

We recruited 101 patients with IEM (48.38 ± 1.58 years) and 42 matched healthy volunteers (44.28 ± 1.85 years) in this case-control study. All subjects underwent esophageal high-resolution impedance manometry from October 2014 to May 2018. The diagnosis of IEM was based on the Chicago Classification version 3.0. The EII, EII ratio, and DCIIR were analyzed by matlab software.

RESULTS

The EII, EII ratio, and DCIIR calculated at an impedance threshold of 1500 Ω (EII1500, EII ratio1500, and DCIIR1500, respectively) were significantly lower in the IEM group than in healthy controls (P < 0.0001, < 0.0001, and < 0.0001, respectively). Receiver operating characteristic analysis showed that DCIIR1500 < 0.008 mmHg/Ω, EII1500 > 71 000 Ω.s.cm, and EII ratio1500 > 0.43 were all predictive of IEM. Only DCIIR1500 < 0.008 mmHg/Ω remained significant in diagnosing IEM in the multivariate logistic regression analysis (odds ratio = 72.13, P < 0.001). The DCIIR1500 is negatively correlated with Eckardt score and the Reflux Disease Questionnaire (correlation coefficient = -0.2844 and -0.3136; P = 0.0006 and 0.0002, respectively). Receiver operating characteristic analysis further showed that a DCIIR1500 cut-off of 0.002 mmHg/Ω achieved the best differentiation between the IEM-alternans and IEM-persistens subtypes among IEM patients (P < 0.001).

CONCLUSIONS

The novel pressure-impedance parameter of high-resolution impedance manometry, DCIIR1500, may assist in the diagnosis and classification of IEM and correlated with clinical symptoms.

New parameter for quantifying bolus transit with high-resolution impedance manometry: A comparison with simultaneous esophagogram

BACKGROUND

Esophageal bolus transit can be assessed using esophagogram or high-resolution impedance manometry (HRIM). The three-dimensional volume of inverted impedance (VII) has been developed to quantify the residual bolus between each swallow through spatiotemporal analysis. However, this novel metric has not been validated against simultaneous esophagogram.

METHODS

A total of nine healthy volunteers (Seven males, aged 19-45 years) were prospectively evaluated with HRIM and barium esophagogram. In addition, 21 symptomatic patients (12 males, aged 20-85 years) without major motility disorder were also included. The VII was estimated from HRIM data using MATLAB program and was compared with residual bolus volume in the esophagus estimated from simultaneous esophagogram.

KEY RESULTS

A total of 80 swallows (24 in controls and 56 in patients) were analyzed. Results from the VII method were concordant with the bolus transit pattern estimated from the esophagogram in 91.3% (73/80) of swallows. The correlation between quantitative data from VII and the volume of residual bolus estimated from esophagogram was strong in both groups with a Pearson's correlation coefficient of 0.805 for healthy volunteers and 0.730 for symptomatic patients. The intraclass correlation coefficient of VII between the three swallows within a subject was 0.901 in healthy subjects and 0.705 in patients, indicating a modest reliability of this method.

CONCLUSIONS AND INFERENCES

The newly developed VII method is a reliable method in assessing residual bolus volume in the esophagus based on comparison with bolus volume estimated from simultaneous esophagogram.

Mucosal impedance for esophageal disease: evaluating the evidence

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

High-resolution esophageal manometry in pediatrics: Effect of esophageal length on diagnostic measures

BACKGROUND

High-resolution esophageal manometry (HREM), derived esophageal pressure topography metrics (EPT), integrated relaxation pressure (IRP), and distal latency (DL) are influenced by age and size. Combined pressure and intraluminal impedance also allow derivation of metrics that define distension pressure and bolus flow timing. We prospectively investigated the effects of esophageal length on these metrics to determine whether adjustment strategies are required for children.

METHODS

Fifty-five children (12.3 ± 4.5 years) referred for HREM, and 30 healthy adult volunteers (46.9 ± 3.8 years) were included. Studies were performed using the MMS system and a standardized protocol including 10 × 5 mL thin liquid bolus swallows (SBM kit, Trisco Foods) and analyzed via Swallow Gateway (www.swallowgateway.com). Esophageal distension pressures and swallow latencies were determined in addition to EGJ resting pressure and standard EPT metrics. Effects of esophageal length were examined using partial correlation, correcting for age. Adult-derived upper limits were adjusted for length using the slopes of the identified linear equations.

KEY RESULTS

Mean esophageal length in children was 16.8 ± 2.8 cm and correlated significantly with age (r = 0.787, P = .000). Shorter length correlated with higher EGJ resting pressure and 4-s integrated relaxation pressures (IRP), distension pressures, and shorter contraction latencies. Ten patients had an IRP above the adult upper limit. Adjustment for esophageal length reduced the number of patients with elevated IRP to three.

CONCLUSIONS & INFERENCES

We prospectively confirmed that certain EPT metrics, as well as potential useful adjunct pressure-impedance measures such as distension pressure, are substantially influenced by esophageal length and require adjusted diagnostic thresholds specifically for children.

British Society of Gastroenterology guidelines for oesophageal manometry and oesophageal reflux monitoring

These guidelines on oesophageal manometry and gastro-oesophageal reflux monitoring supersede those produced in 2006. Since 2006 there have been significant technological advances, in particular, the development of high resolution manometry (HRM) and oesophageal impedance monitoring. The guidelines were developed by a guideline development group of patients and representatives of all the relevant professional groups using the Appraisal of Guidelines for Research and Evaluation (AGREE II) tool. A systematic literature search was performed and the GRADE (Grading of Recommendations Assessment, Development and Evaluation) tool was used to evaluate the quality of evidence and decide on the strength of the recommendations made. Key strong recommendations are made regarding the benefit of: (i) HRM over standard manometry in the investigation of dysphagia and, in particular, in characterising achalasia, (ii) adjunctive testing with larger volumes of water or solids during HRM, (iii) oesophageal manometry prior to antireflux surgery, (iv) pH/impedance monitoring in patients with reflux symptoms not responding to high dose proton pump inhibitors and (v) pH monitoring in all patients with reflux symptoms responsive to proton pump inhibitors in whom surgery is planned, but combined pH/impedance monitoring in those not responsive to proton pump inhibitors in whom surgery is planned. This work has been endorsed by the Clinical Services and Standards Committee of the British Society of Gastroenterology (BSG) under the auspices of the oesophageal section of the BSG.

Oesophageal atresia

Oesophageal atresia (EA) is a congenital abnormality of the oesophagus that is caused by incomplete embryonic compartmentalization of the foregut. EA commonly occurs with a tracheo-oesophageal fistula (TEF). Associated birth defects or anomalies, such as VACTERL association, trisomy 18 or 21 and CHARGE syndrome, occur in the majority of patients born with EA. Although several studies have revealed signalling pathways and genes potentially involved in the development of EA, our understanding of the pathophysiology of EA lags behind the improvements in surgical and clinical care of patients born with this anomaly. EA is treated surgically to restore the oesophageal interruption and, if present, ligate and divide the TEF. Survival is now ~90% in those born with EA with severe associated anomalies and even higher in those born with EA alone. Despite these achievements, long-term gastrointestinal and respiratory complications and comorbidities in patients born with EA are common and lead to decreased quality of life. Oesophageal motility disorders are probably ubiquitous in patients after undergoing EA repair and often underlie these complications and comorbidities. The implementation of several new diagnostic and screening tools in clinical care, including high-resolution impedance manometry, pH-multichannel intraluminal impedance testing and disease-specific quality of life questionnaires now provide better insight into these problems and may contribute to better long-term outcomes in the future.

High-resolution impedance manometry parameters in the evaluation of esophageal function of non-obstructive dysphagia patients

BACKGROUND

High-resolution impedance manometry (HRIM) allows evaluation of esophageal bolus retention, flow, and pressurization. We explored novel HRIM measures and assessed their temporal relationship to dysphagia symptoms for boluses of different volume and consistency in non-obstructive dysphagia (NOD) patients.

METHODS

Thirty-three NOD patients (n = 19 minor or no disorder of peristalsis ("Normal") and n = 14 esophagogastric junction outflow obstruction ("EGJOO")) were evaluated with HRIM. Patients were administered 5 and 10 mL liquid, semisolid, and 2 and 4 cm solid boluses and indicated bolus perception during individual swallows using a 5-point Likert scale. HRIM was analyzed to assess Chicago Classification and pressure flow metrics, esophageal impedance integral (EII) ratio, and bolus flow time (BFT).

KEY RESULTS

Overall, bolus perception increased with increasing bolus consistency (P < 0.001), but did not differ significantly between EGJOO and Normal patients. EGJOO patients had higher IRP4, higher levels of bolus residual (ie, EII ratio and IR), and restricted esophageal emptying. The results for linking semisolid bolus perception to semisolid-derived measures revealed more biomechanically plausible and consistent patterns when compared to those derived for liquid boluses. In Normal patients, perception of boluses of heavier viscosity was related to higher bolus flow resistance during transport, whilst in EGJOO, perception was related to restriction of esophageal emptying.

CONCLUSION & INFERENCES

These novel pressure-impedance measures may aid in the evaluation of NOD patients by revealing abnormal motor patterns, which may explain symptom generation. Future studies are needed to evaluate which of these measures are worthy of calculation and to establish protocol settings that allow for their meaningful interpretation.

Distal contractile to impedance integral ratio assist the diagnosis of pediatric ineffective esophageal motility disorder

OBJECTIVES

We investigated the diagnostic utility of distal contractile integral (DCI) to esophageal impedance integral (EII) ratio (DCIIR) in high-resolution impedance manometry (HRIM) of ineffective esophageal motility (IEM) in children.

METHODS

We performed HRIM in 31 children with dysphagia, odynophagia, chronic vomiting, chest pain, or heartburn sensation. Based on the Chicago classification version 3.0, 20 subjects were diagnosed with IEM, and 11 subjects were normal. We analyzed the EII and DCIIR using MATLAB software.

RESULTS

The DCIIR calculated at the impedance cutoff at 1500 Ω (DCIIR1500) were significantly lower in IEM group than patients with normal motility (P = 0.007). Receiver operating characteristic (ROC) curve analysis showed that a DCIIR1500 < 0.009 mmHg/Ω best predicted IEM in children (P < 0.001). A DCIIR1500 < 0.008 mmHg/Ω is associated with significant body weight loss > 10% within 6 months in children. (P < 0.001).

CONCLUSIONS

The calculation of DCIIR1500 may assist the automatic analysis of bolus transit in HRIM study to diagnose IEM in children. An DCIIR1500 < 0.009 mmHg/Ω may assist in the diagnosis of IEM in children, and DCIIR1500 < 0.008 mmHg/Ω correlated with significant body weight loss. The calculation of DCIIR may serve as possible parameters for HRIM.

The critical importance of pharyngeal contractile forces on the validity of intrabolus pressure as a predictor of impaired pharyngo-esophageal junction compliance

INTRODUCTION

Restrictive defects of the pharyngo-esophageal junction (PEJ) are common in both structural and neurological disorders and are amenable to therapies aiming to reduce outflow resistance. Intrabolus pressure (IBP) acquired with high-resolution manometry and impedance (HRMI) is an indicator of resistance and a marker of reduced PEJ compliance. Constraints and limitations of IBP as well as the optimal IBP parameter remain undefined.

AIMS

To determine: (i) the impact of peak pharyngeal pressure (PeakP) on the diagnostic accuracy of IBP for the detection of a restrictive defect at the PEJ and (ii) the optimal IBP parameter for this purpose.

METHODS

In 52 dysphagic patients previously treated for head and neck cancer. Five candidate IBP measures and PeakP were obtained with HRMI, as well as a presence of a stricture determined by a mucosal tear after endoscopic dilatation. Predictive values of IBP measures were evaluated by receiver operating characteristic (ROC) analysis for all patients and reiterated as patients with lowest PeakP were progressively removed from the cohort.

RESULTS

All IBP parameters had fair to good accuracy at predicting strictures. Intrabolus pressure measured at a discrete point of maximum admittance 1 cm above the maximal excursion of the upper esophageal sphincter had highest sensitivity (0.76) and specificity (0.78). When PeakP was at least 57 mm Hg both sensitivity and specificity improved to 0.9.

CONCLUSIONS

Pharyngeal propulsive force has substantial impact on the accuracy of IBP as a predictor of a PEJ stricture. When PeakP is ≥57 mm Hg, an elevated IBP is highly predictive of a restrictive defect at the PEJ.

Roles of High-resolution Manometry in Predicting Incomplete Bolus Transit in Patients With Dysphagia

BACKGROUND

High-resolution manometry (HRM) is used to assess esophageal motility diseases. Abnormalities in a number of HRM parameters have been reported in patients with dysphagia. However, it is unclear whether some of abnormal HRM parameters are predictive of dysphagia. The aim of this retrospective study was to investigate the roles of HRM parameters in predicting incomplete bolus clearance (IBC) in patients with dysphagia using high-resolution impedance manometry.

METHODS

A total of 644 wet swallows were reviewed and analyzed in 63 patients with symptoms of dysphagia or reflux who underwent a clinical high-resolution impedance manometry test. IBC was defined based on impedance measurement. The relationship of each of abnormal HRM parameters with IBC was analyzed and their roles in predicting IBC were determined.

RESULTS

Patients with symptoms of both dysphagia and reflux showed the highest IBC rate, and patients with symptoms of reflux had the lowest IBC rate. The IBC was more prevalent in the distal esophagus. Premature contractions and peristalsis with large breaks were associated with a higher IBC rate in the proximal esophagus (P<0.05); large breaks, ineffective peristalsis, and abnormalities of the esophageal gastric junction functions were associate with higher IBC rates in the distal esophagus (P<0.05). Abnormalities in a number of motility parameters were able to predict IBC with high specificities and/or high sensitivity, such as pan esophageal pressurization, ineffective peristalsis, and large breaks. Abnormal integrative relaxation pressure of the lower esophageal sphincter with concurrent pan esophageal pressurization, ineffective peristalsis, or large breaks is predictive of IBC with nearly 100% of specificity.

CONCLUSIONS

Abnormalities in a number of HRM parameters are not only useful in diagnosing esophageal motility diseases, but also valuable in predicting IBC during swallowing.

A study of dysphagia symptoms and esophageal body function in children undergoing anti-reflux surgery

BACKGROUND

The role of high-resolution esophageal impedance manometry (HRIM) for establishing risk for dysphagia after anti-reflux surgery is unclear. We conducted a prospective study of children with primary gastroesophageal reflux (GER) disease, for whom symptoms of dysphagia were determined pre-operatively and then post-operatively and we examined for features that may predict post-operative dysphagia.

METHODS

Thirteen children (aged 6.8-15.5 years) undergoing work-up prior to 360o Nissen fundoplication were included in the study. A dysphagia score assessed symptoms at pre-operative study and post-operatively (mean 1.4 years). A HRIM procedure recorded 5-ml liquid, 5-ml viscous and 2-cm solid boluses. We assessed esophageal motility, esophago-gastric junction (EGJ) morphology, EGJ contractility and pressure-flow variables indicative of bolus distension pressures and bolus clearance pressures. A composite pressure-flow index score was also derived.

RESULTS

Pre-operative pressure-flow index was positively correlated with post-operative dysphagia score (viscous bolus r = 0.771, p < 0.005). Of three variables that comprise the pressure-flow index, the ramp pressure measured during bolus clearance was the main driver of the effect seen (viscous bolus r = 0.819, p < 0.005).

CONCLUSIONS

In order to mitigate symptoms in relation to anti-reflux surgery, dysphagia symptoms and esophageal function need to be pre-operatively assessed. In patients with normal motility, an elevated pressure-flow index may predict post-operative dysphagia.

Normative values and factors affecting water-perfused esophageal high-resolution impedance manometry for a Chinese population

BACKGROUND

Combined esophageal high-resolution impedance manometry (HRIM) measures multiple pressures and bolus transit simultaneously, facilitating detailed assessment of esophageal motility. Currently, normative values for water-perfused HRIM systems for Chinese populations are lacking.

METHODS

Healthy volunteers were enrolled for comprehensive anthropometric measures, blood biochemistry tests, and an HRIM study using 22 water-perfused pressure sensors and 12 impedance channels. Ten 5-mL liquid swallows of saline at 30-second intervals were conducted. The following parameters were calculated: distal contractile integral (DCI), distal latency (DL), lower esophageal sphincter (LES) basal pressure, 4-second integrated relaxation pressure (IRP-4s), and complete bolus transit percentage. Normal values were established based on the 5th and 95th percentiles.

KEY RESULTS

All 66 participants (34 male, 32 female, aged 21-64 years) completed the study and tolerated the HRIM procedure well. The upper normal limit (95th percentile) of IRP-4 second was 20 mmHg. The 5th-95th percentile range for DCI, DL, and complete bolus transit was 99-2186 mmHg●s●cm, 6.2-11.3 second, and 50%-100%, respectively. Age was negatively correlated with DL. Females had significantly higher upper limits for IRP-4s and median DCI than males. Multivariate analyses confirmed that IRP-4s was higher in females, and that higher body mass index and waist circumference were associated with reduced DL and better bolus transit, respectively.

CONCLUSIONS AND INFERENCES

We established normative values for the water-perfused HRIM system for a Chinese population. Gender and anthropometric factors may affect various major HRIM parameters and should be taken into account when interpreting HRIM results in clinical practice.

Impedance spectroscopy measurements as a tool for distinguishing different luminal content during bolus transit studies

BACKGROUND

Intraluminal electrical impedance is a well-known diagnostic tool used to study bolus movement in the human esophagus. However, it is use in the human colon it is hindered by the fact that the content cannot be controlled and may include liquid, gas, solid, or a mixture of these at any one time. This article investigates the use of complex impedance spectroscopy to study different luminal content (liquid and gas).

METHODS

An excised section of guinea pig proximal colon was placed in an organ bath with Krebs solution at 37°C and a custom built bioimpedance catheter was placed in the lumen. Liquid (Krebs) and gas (air) content was pumped through the lumen and the intraluminal impedance was measured at five different frequencies (1, 5.6, 31.6, 177.18 kHz and 1 MHz) at 10 samples per second. A numerical model was created to model the passage of bolus with different content and compared to the experimental data.

KEY RESULTS

Differences in mean impedance magnitude and phase angle were found (from 1 to 177.18 kHz) for different contents. The numerical results qualitatively agreed with those in the experimental study. Conductivities of bolus had an effect on detecting its passage.

CONCLUSIONS & INFERENCES

Complex impedance spectroscopy can distinguish between different luminal content within a range of measuring frequencies. The numerical model showed the importance of bolus conductivities for bolus transit studies in those where the bolus is controlled.

Inter-rater agreement of novel high-resolution impedance manometry metrics: Bolus flow time and esophageal impedance integral ratio

BACKGROUND

Novel high-resolution impedance manometry (HRIM) metrics of bolus flow time (BFT) and esophageal impedance integral (EII) ratio have demonstrated clinical utility, though the reliability of their analysis has not been assessed. We aimed to evaluate the inter-rater agreement of the BFT and EII ratio.

METHODS

HRIM studies including five upright, liquid swallows from 40 adult patients were analyzed by two raters using a customized MATLAB program to generate the BFT and EII ratio. Inter-rater agreement was assessed using the intraclass correlation coefficient (ICC) for median values generated per patient and also for all 200 swallows.

KEY RESULTS

The ICC (95% confidence interval, CI) for BFT was 0.873 (0.759-0.933) for median values and 0.838 (0.778-0.881) for all swallows. The ICC (95% CI) for EII ratio was 0.983 (0.968-0.991) for median values and 0.905 (0.875-0.928) for all swallows. Median values for both BFT and EII ratio were similar between the two raters (P-values .05).

CONCLUSIONS AND INFERENCES

The BFT and EII ratio can be reliably calculated as supported by generally excellent inter-rater agreement. Thus, broader utilization of these measures appears feasible and would facilitate further evaluation of their clinical utility.

Improved Assessment of Bolus Clearance in Patients With Achalasia Using High-Resolution Impedance Manometry

BACKGROUND & AIMS

Esophageal retention is typically evaluated by timed-barium esophagram in patients treated for achalasia. Esophageal bolus clearance can also be evaluated using high-resolution impedance manometry. We evaluated the associations of conventional and novel high-resolution impedance manometry metrics, esophagram, and patient-reported outcomes (PROs) in achalasia.

METHODS

We performed a prospective study of 70 patients with achalasia (age, 20-81 y; 30 women) treated by pneumatic dilation or myotomy who underwent follow-up evaluations from April 2013 through December 2015 (median, 12 mo after treatment; range, 3-183 mo). Patients were assessed using timed-barium esophagrams, high-resolution impedance manometry, and PROs, determined from Eckardt scores (the primary outcome) and the brief esophageal dysphagia questionnaire. Barium column height was measured from esophagrams taken 5 minutes after ingestion of barium (200 mL). Impedance-manometry was analyzed for bolus transit (dichotomized) and with a customized MATLAB program (The MathWorks, Inc, Natick, MA) to calculate the esophageal impedance integral (EII) ratio.

RESULTS

Optimal cut points to identify a good PRO (defined as Eckardt score of ≤3) were esophagram barium column height of 3 cm (identified patients with a good PRO with 63% sensitivity and 75% specificity) and an EII ratio of 0.41 (identified patients with a good PRO with 83% sensitivity and 75% specificity). Complete bolus transit identified patients with a good PRO with 28% sensitivity and 75% specificity. Of the 25 patients who met these cut points for both esophagram barium column height and EII ratio, 23 (92%) had a good PRO. Of the 17 patients who met neither cut point, 14 (82%) had a poor PRO (Eckardt score above 3).

CONCLUSIONS

In a prospective study of 70 patients with achalasia, we found EII ratio identified patients with good PROs with higher levels of sensitivity (same specificity) than timed-barium esophagram or impedance-manometry bolus transit assessments. The EII ratio should be added to achalasia outcome evaluations that involve high-resolution impedance manometry as an independent measure and to complement timed-barium esophagram.

Physiological augmentation of esophageal distension pressure and peristalsis during conditions of increased esophageal emptying resistance

BACKGROUND

Abdominal compression has been implemented as a provocative maneuver in high-resolution impedance manometry (HRIM) to "challenge" normal esophageal physiology with the aim of revealing abnormal motor patterns which may explain symptoms. In this study, we measured the effects of abdominal compression on esophageal functioning utilizing novel pressure-impedance parameters and attempted to identify differences between healthy controls and globus patients.

METHODS

Twenty-two healthy volunteers (aged 23-32 years, 41% female) and 22 globus patients (aged 23-72 years, 68% female) were evaluated with HRIM using a 3.2-mm water perfused manometric and impedance catheter. All participants received 10 × 5 mL liquid swallows; healthy controls also received 10 × 5 mL liquid swallows with abdominal compression created using an inflatable cuff. All swallows were analyzed to assess esophageal pressure topography (EPT) and pressure-flow metrics, indicative of distension pressure, flow timing and bolus clearance were derived.

KEY RESULTS

The effect of abdominal compression was shown as a greater contractile vigor of the distal esophagus by EPT and higher distension pressure based on pressure-flow metrics. Age and body mass index also increased contractile vigor and distension pressure. Globus patients were similar to controls.

CONCLUSIONS AND INTERFERENCES

Intrabolus pressure and contractile vigor are indicative of the physiological modulation of bolus transport mechanisms. Provocative testing by abdominal compression induces changes in these esophageal bolus dynamics.

Effects of remifentanil on esophageal and esophagogastric junction (EGJ) bolus transit in healthy volunteers using novel pressure-flow analysis

BACKGROUND

Remifentanil is associated with subjective dysphagia and an objective increase in aspiration risk. Studies of opioid effects have shown decreased lower esophageal sphincter relaxation. We assessed bolus transit through the esophagus and esophagogastric junction (EGJ) during remifentanil administration using objective pressure-flow analysis.

METHODS

Data from 11 healthy young participants (23±3 years, 7 M) were assessed for bolus flow through the esophagus and EGJ using high-resolution impedance manometry (Manoscan™, Sierra Scientific Instruments, Inc., LES Angeles, CA, USA) with 36 pressure and 18 impedance segments. Data were analyzed for esophageal pressure topography and pressure-flow analysis using custom Matlab analyses (Mathworks, Natick, USA). Paired t tests were performed with a P-value of < .05 regarded as significant.

KEY RESULTS

Duration of bolus flow through (remifentanil/R 3.0±0.3 vs baseline/B 5.0 ± 0.4 seconds; P < .001) and presence at the EGJ (R 5.1 ± 0.5 vs B 7.1 ± 0.5 seconds; P = .001) both decreased during remifentanil administration. Distal latency (R 5.2 ± 0.4 vs B 7.5 ± 0.2 seconds; P < .001) and distal esophageal distension-contraction latency (R 3.5 ± 0.1 vs B 4.7 ± 0.2 seconds; P < .001) were both reduced. Intrabolus pressures were increased in both the proximal (R 5.3 ± 0.9 vs B 2.6 ± 1.3 mm Hg; P = .01) and distal esophagus (R 8.6 ± 1.7 vs B 3.1 ± 0.8 mm Hg; P = .001). There was no evidence of increased esophageal bolus residue.

CONCLUSIONS AND INFERENCES

Remifentanil-induced effects were different for proximal and distal esophagus, with a reduced time for trans-sphincteric bolus flow at the EGJ, suggestive of central and peripheral μ-opioid agonism. There were no functional consequences in healthy subjects.

Novel Pressure-Impedance Parameters for Evaluating Esophageal Function in Pediatric Achalasia

OBJECTIVE

In achalasia, absent peristalsis and reduced esophagogastric junction (EGJ) relaxation and compliance underlie dysphagia symptoms. Novel high-resolution impedance manometry variables, that is, bolus presence time (BPT) and trans-EGJ-bolus flow time (BFT) have been developed to estimate the duration of EGJ opening and trans-EGJ bolus flow. The aim of this study was to evaluate esophageal motor function and bolus flow in children diagnosed with achalasia using these variables.

METHODS

High-resolution impedance manometry recordings from 20 children who fulfilled the Chicago Classification (V3) criteria for achalasia were compared with recordings of 15 children with normal esophageal high-resolution manometry findings and no other evidence suggestive of achalasia. Matlab-based analysis software was used to calculate BPT and BFT.

RESULTS

Both BPT and BFT were significantly reduced in achalasia patients compared with children with normal esophageal motility (BPT 3.3 s vs 5.1 s P < 0.01; BFT 1.4 s vs 4.3 s P < 0.001). BFT was significantly lower than BPT (achalasia difference 1.9 s ± 1.3 s, P = 0.001 and normal difference 0.9 ± 0.3 s, P = 0.001). Overall, there was a significant correlation between BPT and BFT (r = 0.825, P < 0.001). We observed a 2-way differentiation of achalasia patients; those in whom the BPT and BFT were proportional, but significantly lower than in patients with normal peristalsis, and those in whom BFT was disproportionately lower than BPT.

CONCLUSIONS

Calculation of BPT and BFT may help determine whether esophageal bolus transport to the EGJ and/or esophageal emptying through the EGJ are aberrant. For achalasia, this may detect flow resistance at the EGJ, potentially improving both diagnosis and objective assessment of therapeutic effects.

How to Care for Patients with EA-TEF: The Known and the Unknown

PURPOSE OF REVIEW

Guidelines were recently published highlighting why esophageal atresia (EA) patients are prone to complication risks, and the need for long-term follow-up. In this review, we will focus on how to investigate and treat potential complications, as well as the pros and cons of different investigative and treatment modalities, and what areas continue to need further research.

RECENT FINDINGS

EA patients are at high risk for gastroesophageal reflux and esophageal strictures, and the sequela that result. Extraintestinal manifestations of gastroesophageal reflux disease (GERD) can appear similar to other pathologic diagnoses commonly found in EA patients, such as congenital stricture, eosinophilic esophagitis, esophageal dysmotility, tracheomalacia, recurrent fistula, aspiration, etc. Therefore, it is important to have a standardized way to monitor for these issues. pH impedance allows for detection of nonacid reflux and the height of reflux, which are important in correlating symptoms with reflux episodes. A multidisciplinary approach is beneficial in evaluating and monitoring EA patients in the long term.

Anxiety can significantly explain bolus perception in the context of hypotensive esophageal motility: Results of a large multicenter study in asymptomatic individuals

BACKGROUND

Previous studies have not been able to correlate manometry findings with bolus perception. The aim of this study was to evaluate correlation of different variables, including traditional manometric variables (at diagnostic and extreme thresholds), esophageal shortening, bolus transit, automated impedance manometry (AIM) metrics and mood with bolus passage perception in a large cohort of asymptomatic individuals.

METHODS

High resolution manometry (HRM) was performed in healthy individuals from nine centers. Perception was evaluated using a 5-point Likert scale. Anxiety was evaluated using Hospitalized Anxiety and Depression scale (HAD). Subgroup analysis was also performed classifying studies into normal, hypotensive, vigorous, and obstructive patterns.

KEY RESULTS

One hundred fifteen studies were analyzed (69 using HRM and 46 using high resolution impedance manometry (HRIM); 3.5% swallows in 9.6% of volunteers were perceived. There was no correlation of any of the traditional HRM variables, esophageal shortening, AIM metrics nor bolus transit with perception scores. There was no HRM variable showing difference in perception when comparing normal vs extreme values (percentile 1 or 99). Anxiety but not depression was correlated with perception. Among hypotensive pattern, anxiety was a strong predictor of variance in perception (R² up to .70).

CONCLUSION AND INFERENCES

Bolus perception is less common than abnormal motility among healthy individuals. Neither esophageal motor function nor bolus dynamics evaluated with several techniques seems to explain differences in bolus perception. Different mechanisms seem to be relevant in different manometric patterns. Anxiety is a significant predictor of bolus perception in the context of hypotensive motility.

Age-related impairment of esophagogastric junction relaxation and bolus flow time

AIM

To investigate the functional effects of abnormal esophagogastric (EGJ) measurements in asymptomatic healthy volunteers over eighty years of age.

METHODS

Data from 30 young controls (11 M, mean age 37 ± 11 years) and 15 aged subjects (9 M, 85 ± 4 years) were compared for novel metrics of EGJ-function: EGJ-contractile integral (EGJ-CI), “total” EGJ-CI and bolus flow time (BFT). Data were acquired using a 3.2 mm, 25 pressure (1 cm spacing) and 12 impedance segment (2 cm) solid-state catheter (Unisensor and MMS Solar GI system) across the EGJ. Five swallows each of 5 mL liquid (L) and viscous (V) bolus were analyzed. Mean values were compared using Student’s t test for normally distributed data or Mann Whitney U-test when non-normally distributed. A P value < 0.05 was considered significant.

RESULTS

EGJ-CI at rest was similar for older subjects compared to controls. “Total” EGJ-CI, measured during liquid swallowing, was increased in older individuals when compared to young controls (O 39 ± 7 mmHg.cm vs C 18 ± 3 mmHg.cm; P = 0.006). For both liquid and viscous bolus consistencies, IRP4 was increased (L: 11.9 ± 2.3 mmHg vs 5.9 ± 1.0 mmHg, P = 0.019 and V: 14.3 ± 2.4 mmHg vs 7.3 ± 0.8 mmHg; P = 0.02) and BFT was reduced (L: 1.7 ± 0.3 s vs 3.8 ± 0.2 s and V: 1.9 ± 0.3 s vs 3.8 ± 0.2 s; P < 0.001 for both) in older subjects, when compared to young. A matrix of bolus flow and presence above the EGJ indicated reductions in bolus flow at the EGJ occurred due to both impaired bolus transport through the esophageal body (i.e., the bolus never reached the EGJ) and increased flow resistance at the EGJ (i.e., the bolus retained just above the EGJ).

CONCLUSION

Bolus flow through the EGJ is reduced in asymptomatic older individuals. Both ineffective esophageal bolus transport and increased EGJ resistance contribute to impaired bolus flow.

High-resolution impedance manometry parameters enhance the esophageal motility evaluation in non-obstructive dysphagia patients without a major Chicago Classification motility disorder

BACKGROUND

High-resolution impedance manometry (HRIM) allows evaluation of esophageal bolus retention, flow, and pressurization. We aimed to perform a collaborative analysis of HRIM metrics to evaluate patients with non-obstructive dysphagia.

METHODS

Fourteen asymptomatic controls (58% female; ages 20-50) and 41 patients (63% female; ages 24-82), 18 evaluated for dysphagia and 23 for reflux (non-dysphagia patients), with esophageal motility diagnoses of normal motility or ineffective esophageal motility, were evaluated with HRIM and a global dysphagia symptom score (Brief Esophageal Dysphagia Questionnaire). HRIM was analyzed to assess Chicago Classification metrics, automated pressure-flow metrics, the esophageal impedance integral (EII) ratio, and the bolus flow time (BFT).

KEY RESULTS

Significant symptom-metric correlations were detected only with basal EGJ pressure, EII ratio, and BFT. The EII ratio, BFT, and impedance ratio differed between controls and dysphagia patients, while the EII ratio in the upright position was the only measure that differentiated dysphagia from non-dysphagia patients.

CONCLUSIONS & INFERENCES

The EII ratio and BFT appear to offer an improved diagnostic evaluation in patients with non-obstructive dysphagia without a major esophageal motility disorder. Bolus retention as measured with the EII ratio appears to carry the strongest association with dysphagia, and thus may aid in the characterization of symptomatic patients with otherwise normal manometry.

How to Optimally Apply Impedance in the Evaluation of Esophageal Dysmotility

The utilization of impedance technology has enhanced our understanding and assessment of esophageal dysmotility. Esophageal high-resolution manometry (HRM) catheters incorporated with multiple impedance electrodes help assess esophageal bolus transit, and the combination is termed high-resolution impedance manometry (HRIM). Novel metrics have been developed with HRIM-including esophageal impedance integral ratio, bolus flow time, nadir impedance pressure, and impedance bolus height-that augments the assessment of esophageal bolus transit. Automated impedance-manometry (AIM) analysis has enhanced understanding of the relationship between bolus transit and pressure phenomena. Impedance-based metrics have improved understanding of the dynamics of esophageal bolus transit into four distinct phases, may correlate with symptomatic burden, and can assess the adequacy of therapy for achalasia. An extension of the use of impedance involves impedance planimetry and the functional lumen imaging probe (FLIP), which assesses esophageal biophysical properties and distensibility, and could detect patterns of esophageal contractility not seen on HRM. Impedance technology, therefore, has a significant impact on esophageal function testing in the present day.

Advances with Neonatal Aerodigestive Science in the Pursuit of Safe Swallowing in Infants: Invited Review

Feeding, swallowing, and airway protection are three distinct entities. Feeding involves a process of sequential, neurosensory, and neuromotor interactions of reflexes and behaviors facilitating ingestion. Swallowing involves anterograde bolus movement during oral-, pharyngeal-, and esophageal phases of peristalsis into stomach. During these events, coordination with airway protection is vital for homeostasis in clearing any material away from airway vicinity. Neurological-airway-digestive inter-relationships are critical to the continuum of successful feeding patterns during infancy, either in health or disease. Neonatal feeding difficulties encompass a heterogeneous group of neurological, pulmonary, and aerodigestive disorders that present with multiple signs posing as clinical conundrums. Significant research breakthroughs permitted understanding of vagal neural pathways and functional aerodigestive connectivity involved in regulating swallowing and aerodigestive functions either directly or indirectly by influencing the supra-nuclear regulatory centers and peripheral effector organs. These neurosensory and neuromotor pathways are influenced by pathologies during perinatal events, prematurity, inflammatory states, and coexisting medical and surgical conditions. Approaches to clarify pathophysiologic mapping of aerodigestive interactions, as well as translating these discoveries into the development of personalized and simplified feeding strategies to advance child health are discussed in this review article.

The Potential Benefits of Applying Recent Advances in Esophageal Motility Testing in Patients with Esophageal Atresia

Infants and children with esophageal atresia commonly present with swallowing dysfunction or dysphagia. Dysphagia can lead to a range of significant consequences such as aspiration pneumonia, malnutrition, dehydration, and food impaction. To improve oral intake, the clinical diagnosis of dysphagia in patients with esophageal atresia should focus on both the pharynx and the esophagus. To characterize the complex interactions of bolus flow and motor function between mouth, pharynx, and esophagus, a detailed understanding of normal and abnormal deglutition is required through the use of adequate and objective assessment techniques. As clinical symptoms do not correlate well with conventional assessment methods of motor function such as radiology or manometry but do correlate with bolus flow, the current state-of-the-art diagnosis involves high-resolution manometry combined with impedance measurements to characterize the interplay between esophageal motor function and bolus clearance. Using a novel pressure flow analysis (PFA) method as an integrated analysis method of manometric and impedance measurements, differentiation of patients with impaired esophago-gastric junction relaxation from patients with bolus outflow disorders is clinically relevant. In this, pressure flow matrix categorizing the quantitative PFA measures may be used to make rational therapeutic decisions in patients with esophageal atresia. Through more advanced diagnostics, improved understanding of pathophysiology may improve our patient care by directly targeting the failed biomechanics of both the pharynx and the esophagus.

Impaired bolus clearance in asymptomatic older adults during high-resolution impedance manometry

BACKGROUND

Dysphagia becomes more common in old age. We performed high-resolution impedance manometry (HRIM) in asymptomatic healthy adults (including an older cohort >80 years) to assess HRIM findings in relation to bolus clearance.

METHODS

Esophageal HRIM was performed in a sitting posture in 45 healthy volunteers (n = 30 young control, mean age 37 ± 11 years and n = 15 older subjects aged 85 ± 4 years) using a 3.2-mm solid-state catheter (Solar GI system; MMS, Enschede, The Netherlands) with 25 pressure (1-cm spacing) and 12 impedance segments (2-cm intervals). Five swallows each of 5- and 10-mL liquid and viscous bolus were performed and analyzed using esophageal pressure topography metrics and Chicago classification criteria as well as pressure-flow parameters. Bolus transit was determined using standard impedance criteria. A p-value <0.05 was considered significant.

KEY RESULTS

Impaired bolus clearance occurred more frequently in asymptomatic older subjects compared with young controls (YC) during liquid (40 vs 18%, χ²  = 4.935; p < 0.05) and viscous (60 vs 17%; χ²  = 39.08; p < 0.001) swallowing. Longer peristaltic breaks (p < 0.05) and more rapid peristalsis (L: p < 0.004, V: p = 0.003) occurred in the older cohort, with reduced impedance-based clearance for both bolus consistencies (L: p < 0.05, V: p < 0.001). Decreased peristaltic vigor (distal contractile integral <450 mmHg/s/cm) was associated with reduced liquid clearance in both age groups (p < 0.001) and of viscous swallows in the older group (p < 0.001). Impedance ratio, a marker of bolus retention, was increased in older subjects during liquid (p = 0.002) and viscous (p < 0.001) swallowing.

CONCLUSIONS & INFERENCES

Impaired liquid and viscous bolus clearance, esophageal pressure topography, and pressure-flow changes were seen in asymptomatic older subjects.

High-Resolution Impedance Manometry Metrics of the Esophagogastric Junction for the Assessment of Treatment Response in Achalasia

OBJECTIVES

We aimed to evaluate the value of novel high-resolution impedance manometry (HRIM) metrics, bolus flow time (BFT), and esophagogastric junction (EGJ) contractile integral (CI), as well as EGJ pressure (EGJP) and the integrated relaxation pressure (IRP), as indicators of treatment response in achalasia.

METHODS

We prospectively evaluated 75 patients (ages 19-81, 32 female) with achalasia during follow-up after pneumatic dilation or myotomy with Eckardt score (ES), timed-barium esophagram (TBE), and HRIM. Receiver-operating characteristic (ROC) curves for good symptomatic outcome (ES≤3) and good radiographic outcome (TBE column height at 5 min<5 cm) were generated for each potential predictor of treatment response (EGJP, IRP, BFT, and EGJ-CI).

RESULTS

Follow-up occurred at a median (range) 12 (3-291) months following treatment. A total of 49 patients had good symptomatic outcome and 46 had good radiographic outcome. The area-under-the-curves (AUCs) on the ROC curve for symptomatic outcome were 0.55 (EGJP), 0.62 (IRP), 0.77 (BFT) and 0.56 (EGJ-CI). The AUCs for radiographic outcome were 0.64 (EGJP), 0.48 (IRP), 0.73 (BFT), and 0.65 (EGJ-CI). Optimal cut-points were determined as 11 mm Hg (EGJP), 12 mm Hg (IRP), 0 s (BFT), and 30 mm Hg•cm (EGJ-CI) that provided sensitivities/specificities of 57%/46% (EGJP), 65%/58% (IRP), 78%/77% (BFT), and 53%/62% (EGJ-CI) to predict symptomatic outcome and 57%/66% (EGJP), 57%/41% (IRP), 76%/69% (BFT), and 57%/66% (EGJ-CI) to predict radiographic outcome.

CONCLUSIONS

BFT, a novel HRIM metric, provided an improved functional assessment over manometric measures of EGJP, IRP, and EGJ-CI at follow-up after achalasia treatment and may help direct clinical management.

Maximum upper esophageal sphincter (UES) admittance: a non-specific marker of UES dysfunction

BACKGROUND

Assessment of upper esophageal sphincter (UES) motility is challenging, as functionally, UES relaxation and opening are distinct. We studied novel parameters, UES admittance (inverse of nadir impedance), and 0.2-s integrated relaxation pressure (IRP), in patients with cricopharyngeal bar (CPB) and motor neuron disease (MND), as predictors of UES dysfunction.

METHODS

Sixty-six healthy subjects (n = 50 controls 20-80 years; n = 16 elderly >80 years), 11 patients with CPB (51-83 years) and 16 with MND (58-91 years) were studied using pharyngeal high-resolution impedance manometry. Subjects received 5 × 5 mL liquid (L) and viscous (V) boluses. Admittance and IRP were compared by age and between groups. A p < 0.05 was considered significant.

KEY RESULTS

In healthy subjects, admittance was reduced (L: p = 0.005 and V: p = 0.04) and the IRP higher with liquids (p = 0.02) in older age. Admittance was reduced in MND compared to both healthy groups (Young: p < 0.0001 for both, Elderly L: p < 0.0001 and V: p = 0.009) and CPB with liquid (p = 0.001). Only liquid showed a higher IRP in MND patients compared to controls (p = 0.03), but was similar to healthy elderly and CPB patients. Only admittance differentiated younger controls from CPB (L: p = 0.0002 and V: p < 0.0001), with no differences in either parameter between CPB and elderly subjects.

CONCLUSIONS & INFERENCES

The effects of aging and pathology were better discriminated by UES maximum admittance, demonstrating greater statistical confidence across bolus consistencies as compared to 0.2-s IRP. Maximum admittance may be a clinically useful determinate of UES dysfunction.

High-resolution manometry combined with impedance measurements discriminates the cause of dysphagia in children

Pressure-flow analysis allows assessing esophageal bolus transport in relation to esophageal pressures. This study aimed to characterize pressure-flow metrics in relation to dysphagia in paediatric patients. We analysed esophageal pressure-impedance recordings of 5 ml liquid and viscous swallows from 35 children (17 M, mean 10.5 ± 0.8 years). Primary indication for referral was gastroesophageal reflux disease (GERD) (9), post-fundoplication dysphagia (5), idiopathic dysphagia (16), trachea-esophageal fistula (2) and other (3). Peristaltic function was assessed using the 20 mmHg iso-contour defect and the timing between bolus pressure and flow was assessed using the Pressure Flow Index, a metric elevated in relation to dysphagia. Patients were stratified in relation to dysphagia and to peristaltic defect size. Dysphagia was characterized by a weaker peristalsis for liquids and higher Pressure Flow Index for viscous. When patients were stratified based on weak or normal peristalsis, dysphagia with weak peristalsis related to a larger iso-contour defect size and dysphagia with normal peristalsis related to higher Pressure Flow Index.

CONCLUSION

Pressure-flow analysis enables differentiation of patients with dysphagia due to weak peristalsis (poor bolus clearance) from abnormal bolus flow resistance (esophageal outflow obstruction). This new dichotomous categorization of esophageal function may help guide the selection of optimal treatment such as pharmacological or endoscopic therapy.

WHAT IS KNOWN

• Pressure-flow analysis (PFA) can detect abnormalities in esophageal motility using integrated analysis of bolus propulsion and bolus flow during swallowing. • AIM analysis has recently been reported to be useful in identifying subtle pre-operative esophageal dysfunction in adult patients who developed post-fundoplication dysphagia as well as in patients with non-obstructive dysphagia.

WHAT IS NEW

• Pressure-flow parameters can distinguish the cause of dysphagia in paediatric patients. • Combined high-resolution manometry and impedance measurements with pressure-flow analysis can differentiate paediatric patients with dysphagia symptoms in relation to either weak peristalsis (poor bolus clearance) or over-pressurization (abnormal bolus flow resistance). HOW MIGHT IT IMPACT ON CLINICAL PRACTICE IN THE FUTURE? • This study supports the use of a novel objective analysis method on recordings that are readily used in paediatric clinical practice. • The pressure-flow approach allows discriminating esophageal dysfunction in relation to dysphagia symptoms in children. This has not been achieved in children with current analysis methods. • The new findings of this study allow a dichotomous categorization of esophageal function, which may help to guide the selection of the most optimal treatment such as pharmacological or endoscopic therapy.

Assessment of bolus transit with intraluminal impedance measurement in patients with esophageal motility disorders

BACKGROUND

The clinical management of patients with non-obstructive dysphagia is notoriously difficult. Esophageal impedance measurement can be used to measure esophageal bolus transit without the use of radiation exposure to patients. However, validation of measurement of bolus transit with impedance monitoring has only been performed in healthy subjects with normal motility and not in patients with dysphagia and esophageal motility disorders. The aim was, therefore, to investigate the relationship between transit of swallowed liquid boluses in healthy controls and in patients with dysphagia.

METHODS

Twenty healthy volunteers and 20 patients with dysphagia underwent concurrent impedance measurement and videofluoroscopy. Each subject swallowed five liquid barium boluses. The ability of detecting complete or incomplete bolus transit by means of impedance measurement was assessed, using radiographic bolus transit as the gold standard.

KEY RESULTS

Impedance monitoring recognized stasis and transit in 80.5% of the events correctly, with 83.9% of bolus transit being recognized and 77.2% of stasis being recognized correctly. In controls 79.8% of all swallows were scored correctly, whereas in patients 81.3% of all swallows were scored correctly. Depending on the contractility pattern, between 77.0% and 94.3% of the swallows were scored correctly.

CONCLUSIONS & INFERENCES

Impedance measurement can be used to assess bolus clearance patterns in healthy subjects, but can also be used to reliably assess bolus transit in patients with dysphagia and motility disorders.

High-resolution impedance manometry measurement of bolus flow time in achalasia and its correlation with dysphagia

BACKGROUND

We assessed whether a high-resolution impedance manometry (HRIM) metric, bolus flow time (BFT) across the esophagogastric junction (EGJ), was abnormal in achalasia patients subtyped by the Chicago Classification and compared BFT to other HRM metrics.

METHODS

HRIM studies were performed in 60 achalasia patients (14 type I, 36 type II and 10 type III) and 15 healthy controls. Studies were analyzed with a MATLAB program to calculate BFT using a virtual HRIM sleeve. Integrated relaxation pressure (IRP) and basal end-expiratory EGJ pressure were also calculated. The relationship between BFT and dysphagia symptom scores was assessed using the impaction dysphagia questionnaire (IDQ).

KEY RESULTS

Median BFT was significantly lower in achalasia patients (0.5 s, range 0.0-3.5 s) compared to controls (3.5 s, range 2.0-5.0 s; p < 0.05). BFT was significantly lower in types I and II than in type III achalasia in both the supine and upright positions (p < 0.0001). BFT was the only HRIM metric significantly associated with IDQ score in both the supine (R(2)  = 0.20, p = 0.0046) and upright positions (R(2)  = 0.27, p = 0.0002).

CONCLUSIONS & INFERENCES

BFT was significantly reduced in all subtypes of achalasia and complementary to the IRP as a diagnostic discriminant in equivocal achalasia cases. Additionally, BFT had a more robust correlation with dysphagia severity compared to other metrics of EGJ function.

Current Therapeutic Options for Esophageal Motor Disorders as Defined by the Chicago Classification

With the development of high-resolution manometry and specific metrics to characterize esophageal motility, the Chicago Classification has become the gold standard for the diagnosis of esophageal motor disorders. Major and significant disorders, that is, never observed in healthy subjects, are achalasia, esophagogastric junction outflow obstruction, distal esophageal spasm, absent peristalsis, and hypercontractile (Jackhammer) esophagus. Achalasia subtyping is relevant to predict the response to endoscopic and surgical therapies as several studies suggest that, pneumatic dilation is less effective than Heller myotomy, in type III achalasia. Peroral endoscopic myotomy, initially developed in expert centers, is a promising technique for the treatment of achalasia. The medical therapeutic options for distal esophageal spasm and hypercontractile esophagus are smooth muscle relaxants and pain modulators. Intraesophageal injection of botulinum toxin might be an interesting option for treatment of these disorders but further studies are required to determine the optimal injection protocol and the best candidates based on manometric patterns. The treatment of hypotensive motility disorders is disappointing and relies mainly on dietary and lifestyle changes as no effective esophageal prokinetic is currently available.

Oesophageal dysphagia: manifestations and diagnosis

Oesophageal dysphagia is a common symptom, which might be related to severe oesophageal diseases such as carcinomas. Therefore, an organic process must be ruled out in the first instance by endoscopy in all patients presenting with dysphagia symptoms. The most prevalent obstructive aetiologies are oesophageal cancer, peptic strictures and eosinophilic oesophagitis. Eosinophilic oesophagitis is one of the most common causes of dysphagia in adults and children, thus justifying the need to obtain oesophageal biopsy samples from all patients presenting with unexplained dysphagia. With the advent of standardized high-resolution manometry and specific metrics to characterize oesophageal motility, the Chicago classification has become a gold-standard algorithm for manometric diagnosis of oesophageal motor disorders. In addition, sophisticated investigations and analysis methods that combine pressure and impedance measurement are currently in development. In the future, these techniques might be able to detect subtle pressure abnormalities during bolus transport, which could further explain pathophysiology and symptoms. The degree to which novel approaches will help distinguish dysphagia caused by motor abnormalities from functional dysphagia still needs to be determined.

Pressure-flow characteristics of normal and disordered esophageal motor patterns

OBJECTIVE

To perform pressure-flow analysis (PFA) in a cohort of pediatric patients who were referred for diagnostic manometric investigation.

STUDY DESIGN

PFA was performed using purpose designed Matlab-based software. The pressure-flow index (PFI), a composite measure of bolus pressurization relative to flow and the impedance ratio, a measure of the extent of bolus clearance failure were calculated.

RESULTS

Tracings of 76 pediatric patients (32 males; 9.1 ± 0.7 years) and 25 healthy adult controls (7 males; 36.1 ± 2.2 years) were analyzed. Patients mostly had normal motility (50%) or a category 4 disorder and usually weak peristalsis (31.5%) according to the Chicago Classification. PFA of healthy controls defined reference ranges for PFI ≤142 and impedance ratio ≤0.49. Pediatric patients with pressure-flow (PF) characteristics within these limits had normal motility (62%), most patients with PF characteristics outside these limits also had an abnormal Chicago Classification (61%). Patients with high PFI and disordered motor patterns all had esophagogastric junction outflow obstruction.

CONCLUSIONS

Disordered PF characteristics are associated with disordered esophageal motor patterns. By defining the degree of over-pressurization and/or extent of clearance failure, PFA may be a useful adjunct to esophageal pressure topography-based classification.

The Chicago Classification of esophageal motility disorders, v3.0

BACKGROUND

The Chicago Classification (CC) of esophageal motility disorders, utilizing an algorithmic scheme to analyze clinical high-resolution manometry (HRM) studies, has gained acceptance worldwide.

METHODS

This 2014 update, CC v3.0, developed by the International HRM Working Group, incorporated the extensive clinical experience and interval publications since the prior (2011) version.

KEY RESULTS

Chicago Classification v3.0 utilizes a hierarchical approach, sequentially prioritizing: (i) disorders of esophagogastric junction (EGJ) outflow (achalasia subtypes I-III and EGJ outflow obstruction), (ii) major disorders of peristalsis (absent contractility, distal esophageal spasm, hypercontractile esophagus), and (iii) minor disorders of peristalsis characterized by impaired bolus transit. EGJ morphology, characterized by the degree of overlap between the lower esophageal sphincter and the crural diaphragm and baseline EGJ contractility are also part of CC v3.0. Compared to the previous CC version, the key metrics of interpretation, the integrated relaxation pressure (IRP), the distal contractile integral (DCI), and the distal latency (DL) remain unchanged, albeit with much more emphasis on DCI for defining both hypo- and hypercontractility. New in CC v3.0 are: (i) the evaluation of the EGJ at rest defined in terms of morphology and contractility, (ii) 'fragmented' contractions (large breaks in the 20-mmHg isobaric contour), (iii) ineffective esophageal motility (IEM), and (iv) several minor adjustments in nomenclature and defining criteria. Absent in CC v3.0 are contractile front velocity and small breaks in the 20-mmHg isobaric contour as defining characteristics.

CONCLUSIONS & INFERENCES

Chicago Classification v3.0 is an updated analysis scheme for clinical esophageal HRM recordings developed by the International HRM Working Group.