Analysis of intersegmental trough and proximal latency of smooth muscle contraction using high-resolution esophageal manometry

Esophageal motor abnormalities in gastroesophageal reflux disorders

Gastroesophageal reflux disease (GERD), a prevalent condition with multifactorial pathogenesis, involves esophageal motor dysmotility as a key contributing factor to its development. When suspected GERD patients have an inadequate response to proton-pump inhibitor (PPI) therapy and normal upper endoscopy results, high-resolution manometry (HRM) is utilized to rule out alternative diagnosis such as achalasia spectrum disorders, rumination, or supragastric belching. At present, HRM continues to provide supportive evidence for diagnosing GERD and determining the appropriate treatment. This review focuses on the existing understanding of the connection between esophageal motor findings and the pathogenesis of GERD, along with the significance of esophageal HRM in managing GERD patients. The International GERD Consensus Working Group introduced a three-step method, assessing the esophagogastric junction (EGJ), esophageal body motility, and contraction reserve with multiple rapid swallow (MRS) maneuvers. Crucial HRM abnormalities in GERD include frequent transient lower esophageal sphincter relaxations, disrupted EGJ, and esophageal body hypomotility. Emerging HRM metrics like EGJ-contractile integral and innovative provocative maneuver like straight leg raise have the potential to enhance our understanding of factors contributing to GERD, thereby increasing the value of HRM performed in patients who experience symptoms suspected of GERD.

Esophageal body adaptation to Nissen fundoplication: Increased esophagogastric outflow resistance yields delayed and sustained peristaltic contractions without increased amplitude

BACKGROUND

Improvement in lower esophageal sphincter (LES) competency after laparoscopic Nissen fundoplication (LNF) is well established, yet esophageal body physiology data are limited. We aimed to describe the impact of LNF on whole esophagus physiology using standard and novel manometric characteristics.

METHODS

A cohort of patients with an intact fundoplication without herniation and no postoperative dysphagia were selected and underwent esophageal manometry at one-year after surgery. Pre- and post-operative manometry files were reanalyzed using standard and novel manometric characteristics and compared.

KEY RESULTS

A total of 95 patients were included in this study. At 16.1 (8.7) months LNF increased LES overall and abdominal length and resting pressure (p < 0.0001). Outflow resistance (IRP) increased [5.8 (3-11) to 11.1 (9-15), p < 0.0001] with a 95th percentile of 20 mmHg in this cohort of dysphagia-free patients. Distal contractile integral (DCI) also increased [1177.0 (667-2139) to 1321.1 (783-2895), p = 0.002], yet contractile amplitude was unchanged (p = 0.158). There were direct correlations between pre- and post-operative DCI [R: 0.727 (0.62-0.81), p < 0.0001] and postoperative DCI and postoperative IRP [R: 0.347 (0.16-0.51), p = 0.0006]. Contractile front velocity [3.5 (3-4) to 3.2 (3-4), p = 0.0013] was slower, while distal latency [6.7 (6-8) to 7.4 (7-9), p < 0.0001], the interval from swallow onset to proximal smooth muscle initiation [4.0 (4-5) to 4.4 (4-5), p = 0.0002], and the interval from swallow onset to point when the peristaltic wave meets the LES [9.4 (8-10) to 10.3 (9-12), p < 0.0001] were longer. Esophageal length [21.9 (19-24) to 23.2 (21-25), p < 0.0001] and transition zone (TZ) length [2.2 (1-3) to 2.5 (1-4), p = 0.004] were longer. Bolus clearance was inversely correlated with TZ length (p = 0.0002) and time from swallow onset to proximal smooth muscle initiation (p < 0.0001). Bolus clearance and UES characteristics were unchanged (p > 0.05).

CONCLUSIONS & INFERENCES

Increased outflow resistance after LNF required an increased DCI. However, this increased contractile vigor was achieved through sustained, not stronger, peristaltic contractions. Increased esophageal length was associated with increased TZ and delayed initiation of smooth muscle contractions.

Chicago Classification of esophageal motility disorders: Past, present, and future

The Chicago Classification (CC) is a dynamic, evolving classification scheme created by a diverse group of international esophageal experts. Its application has transformed the way esophageal motor data are used to define motility disorders, each iteration seeking to advance, simplify, and standardize the way clinicians worldwide diagnose esophageal dysmotility. The most recent update, CC version 4.0 (CCv4.0), emphasizes the importance of clinical context and distinguishes clinically relevant, conclusive manometric diagnoses from irrelevant manometric observations. Future iterations of CC may refine the classification of spastic esophageal disorders and incorporate machine learning and physics-based modeling to improve metrics.

Gastroesophageal reflux disease: key messages for clinicians

Gastroesophageal reflux disease (GERD) is a chronic common disorder for which patients often refer to specialists. In the last decades, numerous studies helped to clarify the pathophysiology and the natural history of this disease. Currently, in the clinical setting, GERD is defined by the presence of symptoms that, when endoscopic investigation is required, permit to distinguish between cases with or without associated esophageal mucosal injuries. These conditions are called erosive reflux disease and non-erosive reflux disease (NERD), respectively. The latter is the most common manifestation of GERD. Symptoms are defined typical, as heartburn and regurgitation, and atypical (also called extra-esophageal), as coughing and/or wheezing, hoarseness, sore throat, otitis media, and dental manifestations. In this context, it is crucial for clinicians to investigate the presence of features of suspected malignancy, as unexplained weight loss, anemia, dysphagia, persistent vomiting, familiar history of cancer, long history of GERD, and beginning of GERD symptoms after the age of 50 years. The presence of these risk factors should induce to perform an endoscopic examination. Particular attention should be given to functional conditions that can mimic GERD, such as functional heartburn and hypersensitive esophagus as well as, more rarely, eosinophilic esophagitis. The former ones have different pathophysiology and this explains the frequent non-response to proton pump inhibitor drugs. This narrative review provides to clinicians a useful and practical overview of the state-of-the-art on advancements in the knowledge of GERD.

Esophageal Function Abnormalities in Patients With Barrett's Esophagus

Various esophageal functional abnormalities have been described in patients with Barrett's esophagus (BE). A significantly higher esophageal acid exposure especially in the supine position has been documented in BE, as compared with the other gastroesophageal reflux disease phenotypes. In addition, weakly acidic reflux and duodenogastroesophageal reflux are more common in BE patients. The presence of Barrett's mucosa reduces esophageal mucosal impedance, occasionally to a level that prevents detection of reflux episodes. Reduced amplitude contractions and lower esophageal sphincter basal pressure are more common in BE patients as compared with the other gastroesophageal reflux disease groups. Ineffective esophageal motility is the most commonly defined motor disorder in BE. Reduced chemoreceptor and mechanoreceptor sensitivity to acid and balloon distention, respectively, have been suggested to explain lack or significantly less reports of reflux-related symptoms by BE patients.

Correlation between reflux burden, peristaltic function, and mucosal integrity in GERD patients

BACKGROUND

Mean nocturnal baseline impedance (MNBI) augments the diagnostic yield of multichannel intraluminal impedance-pH (MII-pH) monitoring. While acid exposure time (AET) correlates with MNBI, it remains unclear whether esophageal motility affects MNBI values. The present study was aimed at evaluating the respective roles of esophageal motor function and AET on MNBI.

METHODS

High-resolution manometry (HRM) studies and ambulatory 24-hour MII-pH monitoring tracings were retrospectively analyzed from consecutive endoscopy-negative GERD patients with typical symptoms responsive to previous acid-suppressive therapy from three tertiary care centers. Univariate and multivariate analyses were performed to determine predictors of pathologic MNBI values at 3 cm and 5 cm above the lower esophageal sphincter (LES).

KEY RESULTS

Patients with pathological AET displayed lower MNBI values at 3 cm and 5 cm (P < .01) compared to patients with non-pathological AET. Similarly, significantly lower MNBI values were also noted at both sites with type 3 EGJ compared to type 1 EGJ (P ≤ .02 for each comparison), and with absent contractility compared to normal peristalsis (P ≤ .02 for each comparison). On multivariate analysis, the presence of type 2 or 3 EGJ and absent contractility were associated with a significantly higher probability of pathological MNBI values at 3 cm and 5 cm above the LES.

CONCLUSIONS AND INFERENCES

Disruption of the EGJ and absent contractility on HRM are both associated with lower MNBI values. HRM findings complement reflux testing using MII-pH monitoring.

Fragmented and failed swallows on esophageal high-resolution manometry associate with abnormal reflux burden better than weak swallows

BACKGROUND

Association between proportions of hypomotile swallows on esophageal high-resolution manometry (HRM) and esophageal reflux burden remains incompletely understood. We investigated relationships between hypomotility, acid exposure time (AET), and mean nocturnal baseline impedance (MNBI) on ambulatory reflux monitoring.

METHODS

Clinical data, HRM, and ambulatory pH-impedance studies (performed off acid suppression) from patients with persisting reflux symptoms were reviewed from five international centers. AET (abnormal > 6%) and MNBI (abnormal < 2292 ohms) were extracted from pH-impedance studies. Distal contractile integral (DCI) designated esophageal peristalsis into normal (DCI > 450 mmHg.cm.s), fragmented (DCI > 450 mmHg.cm.s with breaks > 5 cm), weak (DCI 100-450 mmHg.cm.s), and failed (DCI < 100 mm mmHg.cm.s) sequences. Univariate and multivariate analyses were performed to identify motor associations of abnormal reflux burden.

KEY RESULTS

Of 351 patients (52.1 ± 0.8 years, 67%F), 29.3% had AET > 6% and 61.8% had MNBI < 2292 ohms. On univariate analysis, both fragmented peristalsis and IEM associated with abnormal AET (P ≤ .01) and MNBI (P ≤ .03); reflux burden was more profound with >70% fragmented as well as ineffective sequences compared to ≤70% for each (P < .05 for each comparison). When weak and failed sequences within IEM were separately analyzed, ≥50% failed sequences predicted abnormal AET (P ≤ .009), and ≥50% weak sequences did not (P = .14). On multivariate regression, ≥50% failed sequences predicted abnormal AET (P = .02), and >70% ineffective sequences trended strongly (P = .069); >70% ineffective sequences predicted abnormal MNBI (P = .046), and >70% fragmented sequences trended strongly (P = .076).

CONCLUSIONS AND INFERENCES

Breaks in esophageal peristaltic integrity seen with fragmented and failed sequences are more relevant to abnormal esophageal acid burden than weak sequences.

Evaluation of Esophageal Contraction Reserve Using HRM in Symptomatic Esophageal Disease

Esophageal high resolution manometry (HRM) is the gold standard for assessment of esophageal motor disorders, but motor responses to the standard 5 mL water swallow protocol may not provide precision in defining minor motor disorders. Provocative maneuvers, particularly multiple rapid swallows (MRS), have been used to assess deglutitive inhibition during the repetitive swallows, and the contractile response following the final swallow of the sequence. The augmentation of esophageal smooth muscle contraction following MRS is termed contraction reserve. This is determined as the ratio between esophageal body contraction vigor (distal contractile integral, DCI) following MRS to the mean DCI after single swallows, which is ≥1 in the presence of contraction reserve. Reliable assessment of contraction reserve requires the performance of 3 MRS maneuvers during HRM. Absence of contraction reserve is associated with a higher likelihood of late postfundoplication dysphagia and may correlate with higher esophageal reflux burden on ambulatory reflux monitoring. Esophageal motor responses to abdominal compression, functional lumen imaging probe (FLIP) balloon distension, and pharmacologic testing (using edrophonium and cisapride) may correlate with contraction reserve. Other provocative tests useful during HRM include rapid drink challenge, solid and viscous swallows, and standardized test meals, which are more useful in evaluation of esophageal outflow obstruction and dysphagia syndromes than in identification of contraction reserve. Provocative maneuvers have been recommended as part of routine HRM protocols, and while useful clinical information can be gleaned from these maneuvers, further research is necessary to determine the precise role of provocative testing in clinical esophagology.

Characteristics of esophageal motility and acid exposure in patients with gastroesophageal reflux disease

AIM

To investigate the characteristics of esophageal motility and acid exposure in patients with gastroesophageal reflux disease (GERD) by analyzing the results of high resolution manometry and 24-h esophageal pH-impedance monitoring.

METHODS

Fifty and nine outpatient or inpatient GERD patients with typical symptoms (acid reflux and heartburn) at the Department of Gastroenterology, First Affiliated Hospital of Shihezi University from July 2017 to July 2018 were selected and analyzed. Gastroscopy, high-resolution esophageal manometry, and 24-h esophageal pH-impedance monitoring were performed. The patients were divided into a reflux esophagitis (RE) group (27 cases, male/female: 12/15) and a nonerosive reflux disease (NERD) group (32 cases, male/female: 14/18) according to the diagnosis of RE by gastroscopy.

RESULTS

The resting pressure of the lower esophageal sphincter in the RE group was significantly lower than that in the NERD group (P < 0.05). There was no significant difference in the resting pressure of the upper esophageal sphincter or the residual pressure of the upper and lower esophageal sphincter between the RE group and NERD group (P > 0.05). There was no significant difference in time, onset velocity, or distal latency between the two groups (P > 0.05); 24-h esophageal pH-impedance monitoring results showed that the DeMeester score in the RE group was significantly higher than that in the NERD group (P < 0.05), while total acid reflux time was significantly lower than that in the NERD group (P < 0.05). There was no significant difference in the number of times of reflux in the standing or supine position, total reflux times, or different physical properties (P > 0.05).

CONCLUSION

Esophageal motility and acid reflux are different in different GERD patients. Esophageal motility disturbance and acid reflux in RE patients are more obvious than those in NERD patients.

Chicago Classification normative metrics in a healthy Indian cohort for a 16-channel water-perfused high-resolution esophageal manometry system

BACKGROUND

High-resolution esophageal manometry (HREM) interpretation by the Chicago Classification (CC) derives its normal values from western volunteers using solid-state catheters. There is no normative data for the 16-channel water-perfused HREM system commonly used in India.

AIMS

To determine normal values for a 16-channel water-perfused HREM catheter in supine posture using healthy volunteers and substitute these normal values (if different from CC values) in the CC v3.0 algorithm.

METHODS

After ethics approval and informed consent, 53 volunteers (31 men) with no gastrointestinal (GI) symptoms or medications affecting GI motility underwent HREM by standard protocol. Age, gender, body mass index (BMI), and manometry parameters analyzed using Trace 1.3.3 software were collected. The median, range, and 5, 10, 75, and 95 percentiles (where applicable) were obtained for all HREM metrics. Normal value percentiles were defined as 95th (integrated relaxation pressure [IRP]), 10th-100th (distal contractile integral [DCI]), and minimum (distal latency [DL]).

RESULTS

The mean age was 30 years and the BMI was 24.2 kg m^-2 . Compared to CC, our normal metrics were lower for IRP (13 mm Hg) and DCI (350-4500 mm Hg s cm). DCI >4500 and <70 (<5th percentile) were defined as hypercontractile and failed contraction, respectively. Abnormal DL (<4.5 s) and peristaltic break size (>5 cm) were similar to CC metrics. Applying these metrics, CC diagnoses changed in 15% (8/53) with downgrading of ineffective motility to fragmented peristalsis or normal, due to lower DCI cutoff used.

CONCLUSIONS

This is the first report of normative data for the 16-channel water-perfused system in supine posture. It revealed lower IRP and DCI, necessitating modification of CC cutoffs for this system.

Modern diagnosis of GERD: the Lyon Consensus

Clinical history, questionnaire data and response to antisecretory therapy are insufficient to make a conclusive diagnosis of GERD in isolation, but are of value in determining need for further investigation. Conclusive evidence for reflux on oesophageal testing include advanced grade erosive oesophagitis (LA grades C and D), long-segment Barrett's mucosa or peptic strictures on endoscopy or distal oesophageal acid exposure time (AET) >6% on ambulatory pH or pH-impedance monitoring. A normal endoscopy does not exclude GERD, but provides supportive evidence refuting GERD in conjunction with distal AET <4% and <40 reflux episodes on pH-impedance monitoring off proton pump inhibitors. Reflux-symptom association on ambulatory reflux monitoring provides supportive evidence for reflux triggered symptoms, and may predict a better treatment outcome when present. When endoscopy and pH or pH-impedance monitoring are inconclusive, adjunctive evidence from biopsy findings (histopathology scores, dilated intercellular spaces), motor evaluation (hypotensive lower oesophageal sphincter, hiatus hernia and oesophageal body hypomotility on high-resolution manometry) and novel impedance metrics (baseline impedance, postreflux swallow-induced peristaltic wave index) can add confidence for a GERD diagnosis; however, diagnosis cannot be based on these findings alone. An assessment of anatomy, motor function, reflux burden and symptomatic phenotype will therefore help direct management. Future GERD management strategies should focus on defining individual patient phenotypes based on the level of refluxate exposure, mechanism of reflux, efficacy of clearance, underlying anatomy of the oesophagogastric junction and psychometrics defining symptomatic presentations.

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

BACKGROUND

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

METHODS

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

KEY RESULTS

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

CONCLUSIONS & INFERENCES

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

Classification for esophagogastric junction (EGJ) complex based on physiology

We propose a new classification for esophagogastric junction (EGJ) incorporating both physiologic and morphologic characteristics. Additionally, we contrast it with the Chicago v 3.0 EGJ classification. With Institutional Review Board (IRB) approval, prospectively maintained database was queried to identify patients who underwent high-resolution manometry (HRM) and pH-study between October 2011 and October 2015. Patients with prior foregut intervention, pH study on acid suppression, esophageal dysmotility, or lower esophageal sphincter-crural diaphragm separation of >5 cm were excluded. We classified patients into three groups-Type-A: Complete overlap of lower esophageal sphincter-crural diaphragm (single high-pressure zone); Type-B: Double high-pressure zone with pressure inversion point (PIP) at or above lower esophageal sphincter; Type-C: Double high-pressure zone with PIP below lower esophageal sphincter. A total of 214 included patients were divided into Type-A (n = 101), Type-B (n = 32), and Type-C (n = 81). Abdominal lower esophageal sphincter length (AL), lower esophageal sphincter pressure (LESP), and lower esophageal sphincter pressure integral (LESPI) were significantly lower in Type-C than both Type-A and Type-B [AL(cm): 0.2 vs. 2(P < 0.001) vs. 1.6(P <0.001); LESP(mmHg): 20.1 vs. 32.1(P < 0.001) vs. 29.2(P < 0.001); LESPI(mmHg.cm.s): 187 vs. 412(P < 0.001) vs. 343(P < 0.05)] while overall lower esophageal sphincter length(OL) and Integrated Relaxation Pressure (IRP) were significantly lower in Type-C than Type-A [OL(cm): 2.9 vs. 3.6(P < 0.001); IRP(mmHg): 8.2 vs. 9.6(P < 0.05)]. Type-C patients had significantly higher positive pH score (>14.7) than Type-A and Type-B [72% vs. 47% (P < 0.05) vs. 41% (P < 0.001)]. In Type-C morphology, there is both anatomical and physiological deterioration, weakest lower esophageal sphincter function (abdominal length, lower esophageal sphincter pressure, and lower esophageal sphincter pressure integral) and is most likely to be associated with pathological reflux. This proposed classification incorporates both physiological and morphological derangements in a graded fashion.

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.

Post-fundoplication symptoms and complications: Diagnostic approach and treatment

Laparoscopic Nissen fundoplication is currently considered the surgical treatment of choice for gastroesophageal reflux disease (GERD) and its long-term effectiveness is above 90%. Adequate patient selection and the experience of the surgeon are among the predictive factors of good clinical response. However, there can be new, persistent, and recurrent symptoms after the antireflux procedure in up to 30% of the cases. There are numerous causes, but in general, they are due to one or more anatomic abnormalities and esophageal and gastric function alterations. When there are persistent symptoms after the surgical procedure, the surgery should be described as "failed". In the case of a patient that initially manifests symptom control, but the symptoms then reappear, the term "dysfunction" could be used. When symptoms worsen, or when symptoms or clinical situations appear that did not exist before the surgery, this should be considered a "complication". Postoperative dysphagia and dyspeptic symptoms are very frequent and require an integrated approach to determine the best possible treatment. This review details the pathophysiologic aspects, diagnostic approach, and treatment of the symptoms and complications after fundoplication for the management of GERD.

[Current issues on gastroesophageal reflux disease]

Gastroesophageal reflux disease (GERD) is one of the most common problems in gastrointestinal disorders. With the increase in our understanding on the pathophysiology of GERD along with the development of proton pump inhibitors, the diagnostic and therapeutic approaches to GERD have changed dramatically over the past decade. However, GERD still poses a problem to many clinicians since the spectrum of the disease has evolved to encompass more challenging presentations such as refractory GERD and extraesophageal manifestations. This has led to significant confusion regarding the optimal approach to these patients. This article aims to discuss current issues on GERD.

Ineffective esophageal motility phenotypes following fundoplication in gastroesophageal reflux disease

BACKGROUND

Ineffective esophageal motility (IEM) is associated with reflux disease, but its natural history is unclear. We evaluated patients undergoing repeat esophageal high resolution manometry (HRM) for symptomatic presentations after antireflux surgery (ARS) to understand the progression of IEM.

METHODS

Patients with repeat HRM after ARS were included. Ineffective esophageal motility was diagnosed if ≥5 sequences had distal contractile integral (DCI) <450 mmHg cm s. Augmentation of DCI following multiple rapid swallows (MRS) was assessed. The esophagogastric junction (EGJ) was interrogated using the EGJ contractile integral (EGJ-CI). Esophageal motor function was compared between patients with and without IEM.

KEY RESULTS

Sixty-eight patients (53.9 ± 1.8 years, 66.2% female) had pre- and post-ARS HRM studies 2.1 ± 0.19 years apart. Esophagogastric junction-CI augmented by a mean of 26.3% following ARS. Four IEM phenotypes were identified: 14.7% had persistent IEM, 8.8% resolved IEM after ARS, 19.1% developed new IEM, and 57.4% had no IEM at any point. Patients with IEM had a lower DCI pre- and post-ARS, lower pre-ARS EGJ CI, and lower pre-ARS-integrated relaxation pressure (p ≤ 0.02 for all comparisons); presenting symptoms and other EGJ metrics were similar (p ≥ 0.08 for all comparisons). The IEM phenotypes could be predicted by MRS DCI response patterns (p = 0.008 across groups); patients with persistent IEM had the least DCI augmentation (p = 0.007 compared to no IEM), while those who resolved IEM had DCI augmentation comparable to no IEM (p = 0.08).

CONCLUSIONS & INFERENCES

Distinct phenotypes of IEM exist among symptomatic reflux patients following ARS. Provocative testing with MRS may help identify these phenotypes pre-ARS.

Clinical Application of Esophageal High-resolution Manometry in the Diagnosis of Esophageal Motility Disorders

Esophageal high-resolution manometry (HRM) is replacing conventional manometry in the clinical evaluation of patients with esophageal symptoms, especially dysphagia. The introduction of HRM gave rise to new objective metrics and recognizable patterns of esophageal motor function, requiring a new classification scheme: the Chicago classification. HRM measurements are more detailed and more easily performed compared to conventional manometry. The visual presentation of acquired data improved the analysis and interpretation of esophageal motor function. This led to a more sensitive, accurate, and objective analysis of esophageal motility. In this review we discuss how HRM changed the way we define and categorize esophageal motility disorders. Moreover, we discuss the clinical applications of HRM for each esophageal motility disorder separately.

Evaluation of esophageal motility after endoscopic submucosal dissection for superficial esophageal cancer

INTRODUCTION

Endoscopic submucosal dissection (ESD) is a standard treatment for superficial esophageal cancer. Some patients complain of dysphagia after ESD even without any postoperative strictures. Although ineffective esophageal motility might be associated with dysphagia after ESD, its effect on esophageal motility after ESD remains unknown. Therefore, we aimed to elucidate esophageal motility after ESD and the cause of dysphagia using high-resolution manometry (HRM).

PATIENTS AND METHODS

Seventy-six patients (men/women, 64/12; mean age, 71.2 years) who had undergone ESD for superficial esophageal cancer were enrolled. The results of ESD were retrospectively investigated using endoscopic images from the ESD and patient questionnaire for dysphagia. Each patient underwent HRM, and the results were evaluated using metrics and contraction patterns, according to the Chicago classification.

RESULTS

Data were obtained from 71 patients. The circumferential mucosal defect ratio (β=0.284, P=0.017), number of ESD (β=0.346, P=0.003), and number of endoscopic balloon dilatations (EBDs) (β=0.416, P<0.001) were correlated with the number of weak contraction with large breaks on HRM. The circumferential mucosal defect (odds ratio=1.074, P<0.001) and number of EBDs (odds ratio=1.200, P=0.035) were also significant predictors for dysphagia after ESD.

CONCLUSION

Circumferential mucosal defect ratio, EBD, and repeated ESD were predictors for impaired esophageal motility after ESD. Because circumferential mucosal defect ratios and EBD were also correlated with dysphagia after ESD, impaired esophageal motility could explain dysphagia after ESD.

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

OBJECTIVES

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

METHOD

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

RESULT

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

CONCLUSION

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

Predictive value of routine esophageal high-resolution manometry for gastro-esophageal reflux disease

BACKGROUND

Using conventional manometry, gastro-esophageal reflux disease (GERD) was associated with a reduced lower esophageal sphincter (LES) pressure and impaired peristalsis. However, with a large overlap between GERD patients and controls, these findings are of limited clinical relevance. It is uncertain whether the more detailed information of high-resolution manometry (HRM) can discriminate GERD patients. Therefore, we aimed to determine to which extent HRM findings can predict GERD.

METHODS

HRM measurements in 69 patients with GERD and 40 healthy subjects were compared and the predictive value of HRM for the diagnosis of GERD was explored.

KEY RESULTS

GERD patients had a significantly lower contraction amplitude (55 vs 64 mmHg; p = 0.045) and basal LES pressure (10 vs 13.2 mmHg; p = 0.034) than healthy controls. GERD patients more often had a hiatal hernia than healthy subjects (30% vs 7%; p = 0.005). Patients with reflux esophagitis had a lower DCI than patients without reflux esophagitis (558 vs 782 mmHg cm s; p = 0.045). No significant difference was seen in contractile front velocity, distal latency, number of peristaltic breaks, residual LES pressure and LES length. On multivariate logistic regression analysis, both esophagogastric junction type I (OR 4.971; 95% CI 1.33-18.59; p = 0.017) and mean wave amplitude (OR 0.95; 95% CI 0.90-0.98; p = 0.013) were found to be independent predictors of GERD. However, the sensitivity and specificity of these findings were low.

CONCLUSIONS & INFERENCES

Hiatal hernia, low contraction amplitude and LES pressure are associated with GERD, but do not predict the disease with sufficient accuracy. Routine esophageal HRM can therefore not be used to distinguish GERD patients from healthy subjects.

Esophageal hypomotility and spastic motor disorders: current diagnosis and treatment

Esophageal hypomotility (EH) is characterized by abnormal esophageal peristalsis, either from a reduction or absence of contractions, whereas spastic motor disorders (SMD) are characterized by an increase in the vigor and/or propagation velocity of esophageal body contractions. Their pathophysiology is not clearly known. The reduced excitation of the smooth muscle contraction mediated by cholinergic neurons and the impairment of inhibitory ganglion neuronal function mediated by nitric oxide are likely mechanisms of the peristaltic abnormalities seen in EH and SMD, respectively. Dysphagia and chest pain are the most frequent clinical manifestations for both of these dysfunctions, and gastroesophageal reflux disease (GERD) is commonly associated with these motor disorders. The introduction of high-resolution manometry (HRM) and esophageal pressure topography (EPT) has significantly enhanced the ability to diagnose EH and SMD. Novel EPT metrics in particular the development of the Chicago Classification of esophageal motor disorders has enabled improved characterization of these abnormalities. The first step in the management of EH and SMD is to treat GERD, especially when esophageal testing shows pathologic reflux. Smooth muscle relaxants (nitrates, calcium channel blockers, 5-phosphodiesterase inhibitors) and pain modulators may be useful in the management of dysphagia or pain in SMD. Endoscopic Botox injection and pneumatic dilation are the second-line therapies. Extended myotomy of the esophageal body or peroral endoscopic myotomy (POEM) may be considered in highly selected cases but lack evidence.

Normative values in esophageal high-resolution manometry

BACKGROUND

Esophageal high-resolution manometry (HRM) has rapidly gained much popularity worldwide. The Chicago Classification for esophageal motility disorders is based on a set of normative values for key metrics that was obtained using one of the commercially available HRM systems. Thus, it is of great importance to evaluate whether these normative values can be used for other HRM systems as well.

PURPOSE

In this review, we describe the presently available HRM systems, the currently known normative thresholds and the factors that influence them, and assess the use of these thresholds. Numerous factors including the type of HRM system, demographic factors, catheter diameter, body position during testing, consistency of bolus swallows, and esophageal length have an influence on the normative data. It would thus be ideal to have different sets of normal values for each of these factors, yet at the moment the amount of normative data is limited. We suggest broadening the normal range for parameters, as this would allow abnormal values to be of more significance. In addition, we suggest conducting studies to assess the physiological relevance of abnormal values and stress that for each system different normative thresholds may apply.

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.

Mechanisms of Barrett's oesophagus (clinical): LOS dysfunction, hiatal hernia, peristaltic defects

Barrett's oesophagus, with the potential to develop into oesophageal adenocarcinoma (OAC), is a major complication of gastrooesophageal reflux disease (GORD). However, about 50% of patients developing OAC had no known GORD beforehand. Hence, while GORD symptoms, oesophagitis, and Barrett's have a number of common determinants (oesophagogastric junction (OGJ) incompetence, impaired oesophageal clearance mechanisms, hiatus hernia) they also have some independent determinants. Further, although excess oesophageal acid exposure plays a major role in the genesis of long-segment Barrett's oesophagus there is minimal evidence supporting this for short-segment Barrett's. Hence, these may have unique pathophysiological features as well. Long-segment Barrett's seems to share most, if not all, of the risk factors for oesophagitis, particularly high-grade oesophagitis. However, it is uncertain if OGJ function and acid clearance are more severely impaired in patients with long-segment Barrett's compared to patients with high-grade oesophagitis. With respect to short-segment Barrett's, the acid pocket may play an important pathogenic role. Conceptually, extension of the acid pocket into the distal oesophagus, also known as intra-sphincteric reflux, provides a mechanism or acid exposure of the distal osophageal mucosa without the occurrence of discrete reflux events, which are more likely to prompt reflux symptoms and lead to the development of oesophagitis. Hence, intra-sphincteric reflux related to extension of the acid/no acid interface at the proximal margin of the acid pocket may be key in the development of short segment Barrett's. However, currently this is still somewhat speculative and further studies are required to confirm this.

Assessment of upper esophageal sphincter function on high-resolution manometry: identification of predictors of globus symptoms

BACKGROUND

Globus is commonly encountered in clinical practice, but high-resolution manometry (HRM) characteristics are incompletely characterized. We evaluated HRM metrics in globus subjects, compared with age-matched and sex-matched dysphagia subjects and healthy controls.

STUDY

Twenty-four subjects with globus (53.3 ± 2.3 y, 58% female) were compared with 24 age-matched and sex-matched subjects with nonobstructive dysphagia (52.5 ± 2.5 y, 58% female), and 21 healthy controls (27.6 ± 0.6 y, 52% female). Sphincter and segment anatomy, and pressure volume metrics assessed skeletal (proximal contractile integral) and smooth muscle contraction (distal contractile integral). Parameters significantly different across groups on univariate analysis were subjected to multivariate logistic regression and receiver-operating characteristic analysis to identify HRM predictors of globus.

RESULTS

Upper esophageal sphincter (UES) postswallow residual pressures were highest in globus (2.6 ± 0.5 vs. 2.3 ± 0.5 mm Hg in dysphagia and 0.6 ± 0.6 mm Hg in controls, P = 0.03); 66.7% had recordable UES residual pressure, in contrast to 9.5% of controls, and 37.5% of dysphagia patients (P = 0.0002). Although different from controls, UES length and basal pressure, and segment 1 parameters did not differ from dysphagia controls. In a multivariate model, measurable UES residual pressure (odds ratio, 6.33; 95% confidence interval, 1.79-25.96) independently predicted globus. Receiver-operating characteristic analysis identified a threshold of 0.4 mm Hg UES residual pressure in segregating globus (sensitivity 66.7%, specificity 71.5%, positive predictive value 55.2%, and negative predictive value 80.0%).

CONCLUSION

HRM with measurement of UES residual pressure allows objective assessment of patients with globus sensation, and has potential to complement current diagnostic strategies.

The Chicago classification of motility disorders: an update

The Chicago Classification defines esophageal motility disorders in high resolution manometry. This is based on individual scoring of 10 swallows performed in supine position. Disorders of esophago-gastric junction (EGJ) outflow obstruction are defined by a median integrated relaxation pressure above the limit of normal and divided into 3 achalasia subtypes and EGJ outflow obstruction. Major motility disorders (aperistalsis, distal esophageal spasm, and hypercontractile esophagus) are patterns not encountered in controls in the context of normal EGJ relaxation. Finally with the latest version of the Chicago Classification, only two minor motor disorders are considered: ineffective esophageal motility and fragmented peristalsis.

Esophageal manometry in gastroesophageal reflux disease

High-resolution manometry (HRM) allows nuanced evaluation of esophageal motor function, and more accurate evaluation of lower esophageal sphincter (LES) function, in comparison with conventional manometry. Pathophysiologic correlates of gastroesophageal reflux disease (GERD) and esophageal peristaltic performance are well addressed by this technique. HRM may alter the surgical decision by assessment of esophageal peristaltic function and exclusion of esophageal outflow obstruction before antireflux surgery. Provocative testing during HRM may assess esophageal smooth muscle peristaltic reserve and help predict the likelihood of transit symptoms following antireflux surgery. HRM represents a continuously evolving new technology that compliments the evaluation and management of GERD.

Evaluation of esophageal motor function in clinical practice

Esophageal motor function is highly coordinated between central and enteric nervous systems and the esophageal musculature, which consists of proximal skeletal and distal smooth muscle in three functional regions, the upper and lower esophageal sphincters, and the esophageal body. While upper endoscopy is useful in evaluating for structural disorders of the esophagus, barium esophagography, radionuclide transit studies, and esophageal intraluminal impedance evaluate esophageal transit and partially assess motor function. However, esophageal manometry is the test of choice for the evaluation of esophageal motor function. In recent years, high-resolution manometry (HRM) has streamlined the process of acquisition and display of esophageal pressure data, while uncovering hitherto unrecognized esophageal physiologic mechanisms and pathophysiologic patterns. New algorithms have been devised for analysis and reporting of esophageal pressure topography from HRM. The clinical value of HRM extends to the pediatric population, and complements preoperative evaluation prior to foregut surgery. Provocative maneuvers during HRM may add to the assessment of esophageal motor function. The addition of impedance to HRM provides bolus transit data, but impact on clinical management remains unclear. Emerging techniques such as 3-D HRM and impedance planimetry show promise in the assessment of esophageal sphincter function and esophageal biomechanics.

Fragmented esophageal smooth muscle contraction segments on high resolution manometry: a marker of esophageal hypomotility

BACKGROUND

Esophageal peristalsis consists of a chain of contracting striated and smooth muscle segments on high resolution manometry (HRM). We compared smooth muscle contraction segments in symptomatic subjects with reflux disease to healthy controls.

METHODS

High resolution manometry Clouse plots were analyzed in 110 subjects with reflux disease (50 ± 1.4 years, 51.5% women) and 15 controls (27 ± 2.1 years, 60.0% women). Using the 30 mmHg isobaric contour tool, sequences were designated fragmented if either smooth muscle contraction segment was absent or if the two smooth muscle segments were separated by a pressure trough, and failed if both smooth muscle contraction segments were absent. The discriminative value of contraction segment analysis was assessed.

KEY RESULTS

A total of 1115 swallows were analyzed (reflux group: 965, controls: 150). Reflux subjects had lower peak and averaged contraction amplitudes compared with controls (P < 0.0001 for all comparisons). Fragmented sequences followed 18.4% wet swallows in the reflux group, compared with 7.5% in controls (P < 0.0001), and were seen more frequently than failed sequences (7.9% and 2.5%, respectively). Using a threshold of 30% in individual subjects, a composite of failed and/or fragmented sequences was effective in segregating reflux subjects from control subjects (P = 0.04).

CONCLUSIONS & INFERENCES

Evaluation of smooth muscle contraction segments adds value to HRM analysis. Specifically, fragmented smooth muscle contraction segments may be a marker of esophageal hypomotility.