How to Optimally Apply Impedance in the Evaluation of Esophageal Dysmotility

Interpretation of Impedance Data on High-resolution Impedance Manometry Studies-A Worldwide Survey

Background/Aims

Esophageal manometry is the gold standard for esophageal motility evaluation. High-resolution esophageal manometry with impedance (HRIM) allows concurrent assessment of bolus transit and manometry. Inconsistencies between concomitant impedance and manometry data pose a clinical dilemma and has not yet been addressed. We aim to assess interpretation trends of HRIM data among gastroenterologists worldwide.

Methods

A cross-sectional study using an anonymous survey was conducted among gastroenterologists worldwide. Statistical analysis was performed to compare responses between providers.

Results

We received responses from 107 gastroenterologists (26 countries). Most were adult providers (69, 64.5%), and most (77, 72.0%) had > 5 years of experience. Impedance was found to be helpful by 83 (77.6%) participants, but over 30% reported inconsistencies between impedance and manometry data. With incomplete bolus clearance and normal manometry 41 (38.7%) recommended observation, 41 (38.7%) recommended 24-hours pH-impedance, and 16 (15.1%) recommended prokinetics. With abnormal manometry and complete bolus clearance, 60 (57.1%) recommended observation while 18 (17.1%) recommended 24-hours pH impedance and 15 (14.3%) recommended prokinetics. A significant difference was found between providers from different continents in treating cases with discrepancy between impedance and manometry findings (P < 0.001). No significant differences were seen in responses between adult versus pediatric providers and between providers with different years of experience.

Conclusions

There is no consensus on interpreting HRIM data. Providers' approaches to studies with inconsistencies between manometry and impedance data vary. There is an unmet need for guidelines on interpreting impedance data in HRIM studies.

Towards a more precise classification of esophageal motility disorders in patients with systemic sclerosis

Systemic sclerosis (SSc) is a chronic and generalized disease affecting the connective tissue of the skin and many internal organs, in particular the gastrointestinal tract. The esophagus is involved in up to 80% of the cases and represents a major cause of serious morbidities that deeply impact on the quality of life and survival of patients. Indeed, the presence of esophageal dysfunction is a good prognostic indicator in SSc, primarily due to its impact on pulmonary disease. Thus, the detection of esophageal motility alterations plays a critical role to prevent the development of both esophageal and pulmonary complications and to improve the survival of these patients. Currently, this diagnostic work-up has been limited to the use of esophageal manometry, which is considered the gold standard for the evaluation of motor physiology and pathophysiology of this organ in different clinical situations. However, in recent years, new equipments such as high-resolution (-impedance) manometry and functional luminal imaging probe have been developed and used in many esophageal clinical settings, including SSc. In this mini-review, we summarize current evidence regarding esophageal dysmotility, in the light of new data on secondary peristalsis published in this issue of the journal.

Predictors of Abnormal Functional Luminal Impedance Planimetry Findings in Non-mechanical Esophagogastric Junction Outflow Obstruction

BACKGROUND

Esophagogastric junction outflow obstruction (EGJOO) is a common but nonspecific motility pattern identified by esophageal high-resolution manometry (HRM). Functional luminal impedance planimetry (FLIP) provides information regarding lower esophageal sphincter (LES) mechanics, which can identify achalasia spectrum disorders and is useful in evaluating EGJOO. However, the relationship between HRM and FLIP parameters in EGJOO is not clearly defined.

AIMS

To identify predictors of abnormal FLIP findings in patients with non-mechanical EGJOO.

METHODS

This is a retrospective cohort study of patients with non-mechanical EGJOO who underwent FLIP between 10/1/16 and 7/1/19. Demographic data including age and gender, examination indication, concomitant medications, HRM parameters, symptom burden, and FLIP metrics of diameter and distensibility index (DI) were collected. DI was categorized as not low (DI > 2.8), borderline low (DI 1.1-2.8), and definitely low (DI ≤ 1). Kruskal-Wallis and Fisher's exact tests were used to assess the relationship between HRM and FLIP parameters and to identify predictors of abnormal FLIP.

RESULTS

Among the 44 patients studied, most were female (n = 33, 75%) and the median age was 63. The median IRP was 18.2, and 10 (23%) patients used chronic narcotics. Lower total heartburn and regurgitation scores, and LES diameter by FLIP are associated with definitely low DI.

CONCLUSIONS

In patients with non-mechanical EGJOO, reflux burden scores and FLIP diameters can aid in predicting DI. These results may provide useful adjunctive data to help in differentiating which patients have meaningful outflow obstruction.

Chicago Classification update (version 4.0): Technical review on diagnostic criteria for achalasia

The recommended diagnostic criteria for achalasia have been recently updated by Chicago Classification version 4.0 (CCv4.0), the widely accepted classification scheme for esophageal motility disorders using metrics from high-resolution manometry (HRM). CCv4.0 continued upon prior versions by subtyping achalasia into type I, type II, and type III on HRM. The achalasia subgroup of the CCv4.0 Working Group developed both conclusive and inconclusive statements for the HRM diagnoses of achalasia subtypes. Conclusive achalasia on HRM is defined as an abnormal median integrated relaxation pressure (IRP) in the primary position of wet swallows along with 100% failed peristalsis, with type I achalasia having 100% failed peristalsis without panesophageal pressurization (PEP), type II achalasia with PEP in at least 20% of swallows, and type III achalasia having at least 20% of swallows premature with no appreciable peristalsis. An inconclusive HRM diagnosis of achalasia can arise when there is an integrated relaxation pressure (IRP) that is borderline or at the upper limit of normal in at least one position, there is an abnormal IRP in both positions but evidence of peristalsis with PEP or premature swallows, or there is peristalsis in the secondary position after apparent achalasia in the primary position. In patients with dysphagia and an inconclusive HRM diagnosis of achalasia, supportive testing beyond HRM such as a timed barium esophagram (TBE) for functional lumen imaging probe (FLIP) is recommended. The review recommends a diagnostic algorithm for achalasia, discusses therapeutic options for the disease, and outlines future needs on this topic.

The Clinical Utility of Provocative Maneuvers at Esophageal High-resolution Manometry (HRM)

Esophageal high-resolution manometry (HRM) assesses esophageal motor function and is indicated both for evaluation of esophageal symptoms and before antireflux interventions. HRM studies are interpreted and esophageal motor diagnoses made according to the Chicago Classification, version 3.0 algorithm, which is based on ten 5 mL supine water swallows. However, this practice of single liquid swallows performed in the supine position does not reflect typical "real-life" swallowing, and may not reproduce the patient's presenting symptoms. Therefore, provocative maneuvers at HRM-beyond these 10 standard swallows-can afford additional insights into esophageal motor function with clinically significant implications, and represent areas of exciting investigation and innovation. Accordingly, the 2020 American College of Gastroenterology Guidelines on Esophageal Physiologic Testing conditionally recommend their inclusion in the HRM protocol. In this clinical review, we discuss the supporting data for and clinical utility of provocative maneuvers at HRM that include changes in body position or accessories (upright swallows, "bridge" position, straight leg raise, abdominal compression), bolus consistency (solid swallows, test meals, postprandial high-resolution impedance manometry), bolus frequency (multiple rapid swallows), the volume of bolus (rapid drink challenge/multiple water swallows), and the use of pharmacological agents.

Esophageal contractile segment impedance from high-resolution impedance manometry correlates with mean nocturnal baseline impedance and acid exposure time from 24-hour pH-impedance monitoring

Esophageal baseline impedance (BI) acquired during esophageal contraction (contractile segment impedance [CSI]) is proposed to improve BI accuracy in gastroesophageal reflux disease (GERD). We evaluated associations between CSI and conventional and novel GERD metrics. We analyzed high-resolution impedance manometry (HRIM) and ambulatory pH-impedance studies from 51 patients (58.6 ± 1.5 years; 26% F) with GERD symptoms studied off antisecretory therapy. Patients with achalasia or absent contractility were excluded. CSI (averaged across 10 swallows) and BI-HRIM (from the resting landmark phase) were acquired from the distal impedance sensors (distal sensor and 5 cm above the lower esophageal sphincter). Acid exposure time (AET) and mean nocturnal baseline impedance (MNBI) were calculated. Associations between CSI, BI-HRIM, MNBI, and AET were evaluated using correlation (Pearson) and receiver operating characteristic (ROC) analysis. Presenting symptoms included heartburn (67%), regurgitation (12%), cough (12%), and chest pain (10%). CSI-distal and CSI-5 each correlated with BI-HRIM, AET, and distal MNBI. Associations with AET were numerically stronger for CSI-distal (r = -0.46) and BI-HRIM-distal (r = -0.44) than CSI-5 (r = -0.33), BI-HRIM-5 (r = -0.28), or distal MNBI (r < -0.36). When compared to AET <4%, patients with AET >6% had significantly lower CSI-distal and BI-HRIM-distal values but not CSI-5, BI-HRIM-5, or MNBI. ROC areas under the curve for AET >6% were numerically higher for CSI-distal (0.81) than BI-HRIM-distal (0.77), distal MNBI (0.68-0.75), CSI-5 (0.68), or BI-HRIM-5 (0.68). CSI from HRIM studies inversely correlates with pathologic AET and has potential to augment the evaluation of GERD.

The esophageal mucosal barrier in health and disease: mucosal pathophysiology and protective mechanisms

Diseases of the esophagus, such as gastroesophageal reflux (GER), can result in changes to mucosal integrity, neurological function, and the microbiome. Although poorly understood, both age and GER can lead to changes to the enteric nervous system. In addition, the esophagus has a distinct microbiome that can be altered in GER. Mucosal integrity is also at risk due to persistent damage from acid. Diagnostic tools, such as ambulatory pH/impedance testing and esophageal mucosal impedance, can assess short-term and longitudinal GER burden, which can also assess the risk for mucosal compromise. The quality of the mucosal barrier is determined by its intercellular spaces, tight junctions, and tight junction proteins, which are represented by claudins, occludins, and adhesion molecules. Fortunately, there are protective factors for mucosal integrity that are secreted by the esophageal submucosal mucous glands and within saliva that are augmented by mastication. These protective factors have potential as therapeutic targets for GER. In this article, we aim to review diagnostic tools used to predict mucosal integrity, aging, and microbiome changes to the esophagus and esophageal mucosal defense mechanisms.

Esophageal Baseline Impedance From High-resolution Impedance Manometry Correlates With Mean Nocturnal Baseline Impedance From pH-impedance Monitoring

Background/Aims

Esophageal baseline impedance (BI) can be extracted from pH-impedance tracings as mean nocturnal baseline impedance (MNBI), and from high-resolution impedance manometry (HRIM), but it is unknown if values are similar between acquisition methods across HRIM manufacturers. We aim to assess correlations between MNBI and BI from HRIM (BI-HRIM) from 2 HRIM manufacturers in the setting of physiologic acid exposure time (AET).

Methods

HRIM and pH-impedance monitoring demonstrating physiologic AET (< 4%) off proton pump inhibitors were required. BI-HRIM was extracted as the average from 5 cm and 10 cm above the lower esophageal sphincter. Distal BI-HRIM (DBI-HRIM) was also extracted from the most distal channel (Medtronic studies). MNBI was extracted from 6 channels. Concordance between BI-HRIM across manufacturers with MNBI was analyzed.

Results

Thirty-six patients met the inclusion criteria (59.6 ± 1.7 years; 22% female; body mass index 30.5 ± 0.7; AET 1.6 ± 0.2%). Although MNBI was similar at all channels (P ≥ 0.18), Diversatek BI-HRIM was lower than Medtronic BI-HRIM (P = 0.003). Overall, BI-HRIM correlated with MNBI at corresponding recording sites, 7 cm and 9 cm (P < 0.05), but not at other sites (P ≥ 0.19). Pearson’s correlations > 0.5 were seen at MNBI at 7 cm for both systems, and at 9 cm for Medtronic. DBI-HRIM correlated with MNBI at 3 cm and 5 cm (P < 0.03), but not at other locations (P > 0.1).

Conclusions

While numeric differences exist between manufacturers, BI-HRIM correlates with MNBI from corresponding channels in patients with physiologic AET. Comparison with AET elevation is needed to determine correlations between pathologic MNBI with BI-HRIM across manufacturers. The optimal HRIM channels from which BI values should be extracted also warrants further study.

Endoscope presence during endoluminal functional lumen imaging probe (FLIP) influences FLIP metrics in the evaluation of esophageal dysmotility

BACKGROUND

The functional lumen imaging probe (FLIP) system is an FDA-approved tool for dynamic evaluation of the esophagogastric junction (EGJ). Even though commercially available since 2009, FLIP utilization remains low, partly due to lack of consensus in methodology and interpretation. Therefore, we aimed to analyze the influence of concurrent endoscopy on FLIP measurements.

METHODS

In this single-center study, we reviewed data from 93 patients undergoing FLIP for symptomatic esophageal motility disorders between 2016 and 2018. During sedated endoscopy, we measured luminal values (distensibility, cross-sectional area (CSA), and balloon pressure) at the EGJ and distal esophagus using 30, 40, and 50 mL distension volumes, with and without concurrent endoscope presence. All recorded values were compared at the various distension volumes between the two measurements using a Wilcoxon rank sum test.

KEY RESULTS

There was a significant difference in distensibility and CSA with index distension volume (40 mL) at the EGJ comparing the two measurements: Lower median distensibility was 2.1 mm²  mm Hg^-1 in the group with concurrent inserted endoscope, respectively, 3.4 mm²  mm Hg^-1 without endoscope (P < .001), and median CSA was 86.0 resp. 110.0 mm² (P < .001). No significant difference could be found in the measurements of the distal esophagus.

CONCLUSIONS & INFERENCES

Our results show a significant difference in FLIP measurements with and without endoscope presence. This underlines the importance of establishing a consensus of a standardized FLIP protocol to define normal luminal values and guiding future FLIP diagnostic studies.

Advancements in the use of manometry and impedance testing for esophageal functional disorders

The utilization of high-resolution manometry (HRM) has enhanced our understanding and assessment of esophageal motor disorders. Moreover, the combination of impedance technology with HRM (HRIM) has further improved our knowledge of esophageal physiology and the clinical evaluation of dysmotility, thanks to the addition of accurate measurement of bolus transit. Areas covered. This paper provides an overview of current knowledge in the use of HRIM for the study of esophageal functional disorders by reporting mainly the results of many publications and several systematic reviews in this field. Expert opinion. HRIM has represented a relevant improvement in the assessment of esophageal motility and has required the development of new metrics, such as the esophageal impedance integral ratio, the bolus flow time, the nadir impedance pressure and the impedance bolus height, which increase the evaluation of esophageal bolus transit. An extension of impedance is represented by functional lumen imaging probe (FLIP), which determines the biophysical properties and the distensibility of the esophagus and permits to detect contractility patterns not seen on HRM alone. We eagerly wait for a new and fruitful iteration of the Chicago Classification, now in version 3.0, which can cover the ongoing clinical experience of HRIM.

Utility of Esophageal High-Resolution Manometry in Clinical Practice: First, Do HRM

Esophageal high-resolution manometry (HRM) has advanced the understanding of esophageal motor function and the ability to diagnose and manage disorders of esophageal motility. In this review, we describe the indications for and the technical performance of HRM. The Chicago classification of esophageal motor function, now in its third iteration, streamlines and standardizes the nomenclature and basic interpretation of HRM data depicted as Clouse topographic plots. In clinical practice, HRM is an important diagnostic test for patients with dysphagia as well as patients with suspected gastroesophageal reflux disease (GERD), particularly in those patients with a suboptimal symptomatic response to antisecretory therapy. HRM can support diagnoses such as achalasia, as well as provide evidence for behavioral disorders such as rumination syndrome or supragastric belching with the assistance of postprandial HRM with impedance. Further, the GERD classification of motor function introduces a three-part hierarchical evaluation of esophageal motor function in GERD, highlighting the value of assessment of esophageal contractile reserve through provocative maneuvers during HRM such as multiple rapid swallows.

The Relevance of Spastic Esophageal Disorders as a Diagnostic Category

PURPOSE OF REVIEW

This review addresses the similarities and differences between the spastic esophageal disorders, including jackhammer esophagus, distal esophageal spasm (DES), and type III (spastic) achalasia. The pathophysiology, diagnosis, and treatment of each separate disorder are discussed herein, with an emphasis on overlapping and discordant features.

RECENT FINDINGS

The Chicago Classification is a hierarchical organizational scheme for esophageal motility disorders, currently in its third iteration, with direct impact on the definitions of these three disorders. Complementary diagnostic tools such as impedance planimetry and novel manometric parameters continue to evolve. The suite of potential treatments for these disorders is also expanding, with progressive interest in the role of peroral endoscopic myotomy alongside established pharmacologic and mechanical interventions. Although jackhammer esophagus, distal esophageal spasm, and type III achalasia frequently overlap in terms of their clinical presentation and available management approaches, the divergences in their respective diagnostic criteria suggest that additional study may reveal additional mechanistic distinctions that lead in turn to further refinements in therapeutic decision-making.

Liraglutide Effects on Upper Gastrointestinal Investigations: Implications Prior to Bariatric Surgery

Liraglutide is a glucagon-like peptide type 1 (GLP-1) analogue that is approved for long-term obesity management in North America. While bariatric surgery remains the gold standard for weight loss, an increasing number of patients are on liraglutide in the setting of ongoing workup for bariatric surgery. The presence of gastrointestinal symptoms prior to bariatric surgery may prompt testing for dysmotility, which affects surgical decision making. Here we report six cases where treatment with liraglutide was associated with reversible reduction in gastric and esophageal motility in screening for bariatric surgery. While liraglutide is known to delay gastric emptying, there are minimal reports of how this medication affects gastrointestinal investigations used in this context. The implications of these abnormal screening investigations on candidacy for bariatric surgery are discussed.

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.

High-resolution esophageal manometry: interpretation in clinical practice

PURPOSE OF REVIEW

Esophageal high-resolution manometry (HRM) is the current state-of-the-art diagnostic tool to evaluate esophageal motility patterns and, as such, is widely adopted in clinical practice. This article will review the interpretation of esophageal HRM in clinical practice.

RECENT FINDINGS

HRM uses a high-resolution catheter to transmit intraluminal pressure data that are subsequently converted into dynamic esophageal pressure topography (EPT) plots. Metric data from EPT plots are synthesized to yield an esophageal motility diagnosis according to the Chicago Classification, a formal analytic scheme for esophageal motility disorders, which is currently in version 3.0. The standard HRM protocol consists of a baseline phase and a series of 10 wet swallows in the supine or reclined position. In addition, data from swallows in the seated position and provocative HRM maneuvers provide useful information about motility properties. Combined high-resolution impedance technology is also clinically available and enables concurrent assessment of bolus transit and postprandial responses. Finally, there is ongoing interest to optimize the training and competency assessment for interpretation of HRM in clinical practice.

SUMMARY

Esophageal HRM is a valuable and sophisticated clinical tool to evaluate esophageal motility patterns. Emerging clinical applications of esophageal HRM include combined impedance technology, provocative maneuvers, and postprandial evaluation.