Esophageal motility disorders on high-resolution manometry: Chicago classification version 4.0©

Chicago Classification v4.0 (CCv4.0) is the updated classification scheme for esophageal motility disorders using metrics from high-resolution manometry (HRM). Fifty-two diverse international experts separated into seven working subgroups utilized formal validated methodologies over two-years to develop CCv4.0. Key updates in CCv.4.0 consist of a more rigorous and expansive HRM protocol that incorporates supine and upright test positions as well as provocative testing, a refined definition of esophagogastric junction (EGJ) outflow obstruction (EGJOO), more stringent diagnostic criteria for ineffective esophageal motility and description of baseline EGJ metrics. Further, the CCv4.0 sought to define motility disorder diagnoses as conclusive and inconclusive based on associated symptoms, and findings on provocative testing as well as supportive testing with barium esophagram with tablet and/or functional lumen imaging probe. These changes attempt to minimize ambiguity in prior iterations of Chicago Classification and provide more standardized and rigorous criteria for patterns of disorders of peristalsis and obstruction at the EGJ.

The spectrum of achalasia: lessons from studies of pathophysiology and high-resolution manometry

High-resolution manometry and recently described analysis algorithms, summarized in the Chicago Classification, have increased the recognition of achalasia. It has become apparent that the cardinal feature of achalasia, impaired lower esophageal sphincter relaxation, can occur in several disease phenotypes: without peristalsis, with premature (spastic) distal esophageal contractions, with panesophageal pressurization, or with peristalsis. Any of these phenotypes could indicate achalasia; however, without a disease-specific biomarker, no manometric pattern is absolutely specific. Laboratory studies indicate that achalasia is an autoimmune disease in which esophageal myenteric neurons are attacked in a cell-mediated and antibody-mediated immune response against an uncertain antigen. This autoimmune response could be related to infection of genetically predisposed subjects with herpes simplex virus 1, although there is substantial heterogeneity among patients. At one end of the spectrum is complete aganglionosis in patients with end-stage or fulminant disease. At the opposite extreme is type III (spastic) achalasia, which has no demonstrated neuronal loss but only impaired inhibitory postganglionic neuron function; it is often associated with accentuated contractility and could be mediated by cytokine-induced alterations in gene expression. Distinct from these extremes is progressive plexopathy, which likely arises from achalasia with preserved peristalsis and then develops into type II achalasia and then type I achalasia. Variations in its extent and rate of progression are likely related to the intensity of the cytotoxic T-cell assault on the myenteric plexus. Moving forward, we need to integrate the knowledge we have gained into treatment paradigms that are specific for individual phenotypes of achalasia and away from the one-size-fits-all approach.

Esophagogastric junction distensibility identifies achalasia subgroup with manometrically normal esophagogastric junction relaxation

BACKGROUND

Manometric criteria to diagnose achalasia are absent peristalsis and incomplete relaxation of the esophagogastric junction (EGJ), determined by an integrated relaxation pressure (IRP) >15 mm Hg. However, EGJ relaxation seems normal in a subgroup of patients with typical symptoms of achalasia, no endoscopic abnormalities, stasis on timed barium esophagogram (TBE), and absent peristalsis on high-resolution manometry (HRM). The aim of our study was to further characterize these patients by measuring EGJ distensibility and assessing the effect of achalasia treatment.

METHODS

Impedance planimetry (EndoFLIP) was used to measure EGJ distensibility and compared to previous established data of 15 healthy subjects. In case the EGJ distensibility was impaired, achalasia treatment followed. Eckardt score, HRM, TBE, and EGJ distensibility measurements were repeated >3 months after treatment.

KEY RESULTS

We included 13 patients (5 male; age 19-59 years) with typical symptoms of achalasia, Eckardt score of 7 (5-7). High-resolution manometry showed absent peristalsis with low basal EGJ pressure of 10 (5.8-12.9) mm Hg and IRP of 9.3 (6.1-12) mm Hg. Esophageal stasis was 4.6 (2.7-6.9) cm after 5 minutes. Esophagogastric junction distensibility was significantly reduced in patients compared to healthy subjects (0.8 [0.7-1.2] mm² /mm Hg vs 6.3 [3.8-8.7] mm² /mm Hg). Treatment significantly improved the Eckardt score (7 [5-7] to 2 [1-3.5]) and EGJ distensibility (0.8 [0.7-1.2] mm² /mm Hg to 3.5 [1.5-6.1] mm² /mm Hg).

CONCLUSIONS & INFERENCES

A subgroup of patients with clinical and radiological features of achalasia but manometrically normal EGJ relaxation has an impaired EGJ distensibility and responds favorably to achalasia treatment. Our data suggest that this condition can be considered as achalasia and treated as such.

Clinicomanometric factors associated with clinically relevant esophagogastric junction outflow obstruction from the Sandhill high-resolution manometry system

BACKGROUND

Integrated relaxation pressure (IRP) is a key metric for diagnosing esophagogastric junction outflow obstruction (EGJOO). However, its normal value might be different according to the manufacturer of high-resolution manometry (HRM). This study aimed to investigate optimal value of IRP for diagnosing EGJOO in Sandhill HRM and to find clinicomanometric variables to segregate clinically relevant EGJOO.

METHODS

We analyzed 262 consecutive subjects who underwent HRM between June 2011 and December 2016 showing elevated median IRP (> 15 mm Hg) but did not satisfy criteria for achalasia. Clinically relevant subjects were defined as follows: (i) subsequent HRM met achalasia criteria during follow-up (early achalasia); (ii) Eckardt score was decreased at least two points without exceeding a score of 3 after pneumatic dilatation (variant achalasia); and (iii) significant passage disturbance on esophagogram without structural abnormality (possible achalasia).

KEY RESULTS

Seven subjects were clinically relevant, including two subjects with early achalasia, four subjects with variant achalasia, and one subject with possible achalasia. All clinically relevant subjects had IRP 20 mm Hg or above. Among subjects (n = 122) with IRP 20 mm Hg or more, clinically relevant group (n = 7) had significantly higher rate of dysphagia (100% vs 24.3%, P < .001) and compartmentalized pressurization (85.7% vs 21.7%, P = .001) compared to clinically non-relevant group (n = 115).

CONCLUSIONS & INFERENCES

Our results suggest that IRP of 20 mm Hg or higher could segregate clinically relevant subjects showing EGJOO in Sandhill HRM. Additionally, if subjects have both dysphagia and compartmentalized pressurization, careful follow-up is essential.

Elevated intrabolus pressure identifies obstructive processes when integrated relaxation pressure is normal on esophageal high-resolution manometry

Elevated integrated relaxation pressure (IRP) on esophageal high-resolution manometry (HRM) identifies obstructive processes at the esophagogastric junction (EGJ). Our aim was to determine whether intrabolus pressure (IBP) can identify structural EGJ processes when IRP is normal. In this observational cohort study, adult patients with dysphagia and undergoing HRM were evaluated for endoscopic evidence of structural EGJ processes (strictures, rings, hiatus hernia) in the setting of normal IRP. HRM metrics [IRP, distal contractile integral (DCI), distal latency (DL), IBP, and EGJ contractile integral (EGJ-CI)] were compared among 74 patients with structural EGJ findings (62.8 ± 1.6 yr, 67.6% women), 27 patients with normal EGD (52.9 ± 3.2 yr, 70.3% women), and 21 healthy controls (27.6 ± 0.6 yr, 52.4% women). Findings were validated in 85 consecutive symptomatic patients to address clinical utility. In the primary cohort, mean IBP (18.4 ± 0.9 mmHg) was higher with structural EGJ findings compared with dysphagia with normal EGD (13.5 ± 1.1 mmHg, P = 0.002) and healthy controls (10.9 ± 0.9 mmHg, P < 0.001). However, mean IRP, DCI, DL, and EGJ-CI were similar across groups (P > 0.05 for each comparison). During multiple rapid swallows, IBP remained higher in the structural findings group compared with controls (P = 0.02). Similar analysis of the prospective validation cohort confirmed IBP elevation in structural EGJ processes, but correlation with dysphagia could not be demonstrated. We conclude that elevated IBP predicts the presence of structural EGJ processes even when IRP is normal, but correlation with dysphagia is suboptimal.NEW & NOTEWORTHY Integrated relaxation pressure (IRP) above the upper limit of normal defines esophageal outflow obstruction using high-resolution manometry. In patients with normal IRP, elevated intrabolus pressure (IBP) can be a surrogate marker for a structural restrictive or obstructive process at the esophagogastric junction (EGJ). This has the potential to augment the clinical value of esophageal HRM by raising suspicion for a structural EGJ process when IBP is elevated.

Diagnostic differences in the pharmacologic response to cholecystokinin and amyl nitrite in patients with absent contractility vs type I Achalasia

BACKGROUND

Absent esophageal contractility (AC) is distinguished from type 1 achalasia (ACH1) during high-resolution manometry (HRM) on the basis of normal or elevated deglutitive integrated relaxation pressure (IRP) values. However, IRP measurements are subject to pressure recording error. We hypothesized that distinctive responses to pharmacologic provocation using amyl nitrite (AN) and cholecystokinin (CCK) could reliably distinguish AC patients from those with ACH1.

AIM

To compare esophageal response with AN and CCK in a well-defined cohort of ACH1 and AC patients.

METHOD

All available clinical, radiographic, endoscopic, and manometric information in 34 patients with aperistalsis was reviewed to determine the final diagnosis of ACH1 and AC. The differences in response to provocative challenges with the rapid drink challenge (RDC) test and administration of AN and CCK were compared between these two groups.

RESULTS

Eighteen patients were diagnosed with ACH1 and sixteen with AC. While IRP values were significantly higher in ACH1, the standard criterion value misclassified four AC patients as having ACH1 and five ACH1 patients as having AC. IRP values on the RDC did not accurately segregate AC from ACH1, but we were able to identify AN and CCK esophageal motor response criteria that allowed correct classification of ACH1 and AC patients.

CONCLUSIONS

Nearly a quarter of AC and ACH1 patients may be misdiagnosed based on manometric IRP criteria alone. Differences in the esophageal motor responses to AN and CCK have the potential to facilitate the correct diagnosis in these challenging patients.

Comparison of two high-resolution manometry software systems in evaluating esophageal motor function

BACKGROUND

High-resolution manometry (HRM) utilizes software tools to diagnose esophageal motor disorders. Performance of these software metrics could be affected by averaging and by software characteristics of different manufacturers.

METHODS

High-resolution manometry studies on 86 patients referred for antireflux surgery (61.6 ± 1.4 year, 70% F) and 20 healthy controls (27.9 ± 0.7 year, 45% F) were first subject to standard analysis (Medtronic, Duluth, GA, USA). Coordinates for each of 10 test swallows were exported and averaged to generate a composite swallow. The swallows and averaged composites were imported as ASCII file format into Manoview (Medtronic) and Medical Measurement Systems database reporter (MMS, Dover, NH, USA), and analyses repeated. Comparisons were made between standard and composite swallow interpretations.

KEY RESULTS

Correlation between the two systems was high for mean distal contractile integral (DCI, r² ≥ 0.9) but lower for integrated relaxation pressure (IRP, r² = 0.7). Excluding achalasia, six patients with outflow obstruction (mean IRP 23.2 ± 2.1 with 10-swallow average) were identified by both systems. An additional nine patients (10.5%) were identified as outflow obstruction (15 mmHg threshold) with MMS 10-swallow and four with MMS composite swallow evaluation; only one was confirmed. Ineffective esophageal motility was diagnosed by 10-swallow evaluation in 19 (22.1%) with Manoview, and 20 (23.3%) with MMS. On Manoview composite, 17 had DCI <450 mmHg/cm/s, and on MMS composite, 21, (p ≥ 0.85 for each comparison) but these did not impact diagnostic conclusions.

CONCLUSIONS & INFERENCES

Comparison of 10 swallow and composite swallows demonstrate variability in software metrics between manometry systems. Our data support use of manufacturer specific software metrics on 10-swallow sequences.

High-resolution manometry in the upright position could improve the manometric evaluation of morbidly obese patients with esophagogastric junction outflow obstruction

BACKGROUND

Esophagogastric junction outflow obstruction (EGJOO) detected by manometry in the supine position is prevalent in patients with morbid obesity, but not all EGJOOs are clinically significant. We investigated whether including upright swallows during high-resolution manometry (HRM) could help identify non-clinically significant EGJOO in patients with morbid obesity.

METHODS

We performed a retrospective study of consecutive morbidly obese patients diagnosed with EGJOO by HRM from July 2012 through July 2018. The HRM protocol included 10 supine and five upright 5-mL water swallows. Endoscopy, esophagram, and computed tomography were performed to identify whether the patients should be diagnosed as having clinically significant EGJOO.

KEY RESULTS

A total of 230 patients with morbid obesity underwent HRM in the supine position during the study period. Fifty (21.7%) patients were diagnosed with EGJOO, among which 32 completed HRM both in the supine and upright positions. Only 8/32 patients were diagnosed with EGJOO in an upright position. Fewer artifacts were displayed in esophageal pressure topography in the upright position. None of the 32 patients could be diagnosed as clinically significant EGJOO based on all the examinations. Median esophageal gastric junction pressure, integrated relaxation pressure, and distal contractile integral were higher, and median distal latency was longer in the supine position compared with the upright position (all P < .05).

CONCLUSIONS AND INFERENCES

Esophagus manometry in the upright position could reduce EGJOO overdiagnosis in patients with morbid obesity. Prolongation of the HRM study with some swallows in the upright position could be recommended in obese patients.

Interrater Reliability of Functional Lumen Imaging Probe Panometry and High-Resolution Manometry for the Assessment of Esophageal Motility Disorders

INTRODUCTION

High-resolution manometry (HRM) and functional lumen imaging probe (FLIP) are primary and/or complementary diagnostic tools for the evaluation of esophageal motility. We aimed to assess the interrater agreement and accuracy of HRM and FLIP interpretations.

METHODS

Esophageal motility specialists from multiple institutions completed the interpretation of 40 consecutive HRM and 40 FLIP studies. Interrater agreement was assessed using intraclass correlation coefficient (ICC) for continuous variables and Fleiss' κ statistics for nominal variables. Accuracies of rater interpretation were assessed using the consensus of 3 experienced raters as the reference standard.

RESULTS

Fifteen raters completed the HRM and FLIP studies. An excellent interrater agreement was seen in supine median integral relaxation pressure (ICC 0.96, 95% confidence interval 0.95-0.98), and a good agreement was seen with the assessment of esophagogastric junction (EGJ) outflow, peristalsis, and assignment of a Chicago Classification version 4.0 diagnosis using HRM (κ = 0.71, 0.75, and 0.70, respectively). An excellent interrater agreement for EGJ distensibility index and maximum diameter (0.91 [0.90-0.94], 0.92 [0.89-0.95]) was seen, and a moderate-to-good agreement was seen in the assignment of EGJ opening classification, contractile response pattern, and motility classification (κ = 0.68, 0.56, and 0.59, respectively) on FLIP. Rater accuracy for Chicago Classification version 4.0 diagnosis on HRM was 82% (95% confidence interval 78%-84%) and for motility diagnosis on FLIP Panometry was 78% (95% confidence interval 72%-81%).

DISCUSSION

Our study demonstrates high levels of interrater agreement and accuracy in the interpretation of HRM and FLIP metrics and moderate-to-high levels for motility classification in FLIP, supporting the use of these approaches for primary or complementary evaluation of esophageal motility disorders.

Validity of the Cutoff Value for Integrated Relaxation Pressure Used in the Starlet High-Resolution Manometry System

BACKGROUND

In a previous study that used the Starlet high-resolution manometry system to assess integrated relaxation pressure (IRP) in healthy adults, the predicted cutoff value was about 26 mm Hg. However, some patients with achalasia have an IRP value of <26 mm Hg. This study examined the validity of the Starlet IRP cutoff value in patients with achalasia.

METHODS

Among 37 patients with achalasia, the percentage of patients with a Starlet IRP value ≥26 mm Hg was calculated. Patients were then classified as IRP-high (IRP ≥26 mm Hg) and IRP-low (IRP <26 mm Hg), and the groups were compared in relation to basal lower esophageal sphincter (LES) pressure, Chicago classification achalasia subtype, and esophagography subtype.

RESULTS

Twenty (54%) of the 37 patients had an IRP of ≥26 mm Hg. Basal LES pressure was significantly higher in the IRP-high group than in the IRP-low group. Chicago classification Type II achalasia was most common in the IRP-high group, whereas Type I was most common in the IRP-low group. No significant difference was noted in the distribution of esophagography subtypes between groups.

CONCLUSIONS

It is difficult to determine an IRP cutoff value with Starlet. When diagnosing achalasia with Starlet, comprehensive assessment must consider findings other than IRP values. In addition, IRP was associated with Chicago classification type.

Integrated Relaxation Pressure Classification and Probe Positioning Failure Detection in High-Resolution Esophageal Manometry Using Machine Learning

High-resolution esophageal manometry is used for the study of esophageal motility disorders, with the help of catheters with up to 36 sensors. Color pressure topography plots are generated and analyzed and using the Chicago algorithm a final diagnosis is established. One of the main parameters in this algorithm is integrated relaxation pressure (IRP). The procedure is time consuming. Our aim was to firstly develop a machine learning based solution to detect probe positioning failure and to create a classifier to automatically determine whether the IRP is in the normal range or higher than the cut-off, based solely on the raw images. The first step was the preprocessing of the images, by finding the region of interest—the exact moment of swallowing. Afterwards, the images were resized and rescaled, so they could be used as input for deep learning models. We used the InceptionV3 deep learning model to classify the images as correct or failure in catheter positioning and to determine the exact class of the IRP. The accuracy of the trained convolutional neural networks was above 90% for both problems. This work is just the first step in fully automating the Chicago Classification, reducing human intervention.

Reference high-resolution manometry values after magnetic sphincter augmentation

BACKGROUND

Magnetic sphincter augmentation (MSA) is an innovative antireflux procedure that can improve lower esophageal sphincter (LES) competency and reduce symptoms of gastroesophageal reflux disease (GERD). Some patients report postoperative dysphagia. To date, no studies have described reference high-resolution manometry (HRM) values after MSA implantation.

METHODS

High-resolution manometry was performed in patients free of dysphagia after MSA with or without concurrent crura repair. Reference values for all parameters of the Chicago Classification were defined as those between the 5th and 95th percentiles. The contribution of concurrent crura repair to LES competency and to reference values was also analyzed.

KEY RESULTS

Eighty-four patients met the study inclusion criteria. The upper limit of normality for integrated relaxation pressure (IRP) and intrabolus pressure (IBP) was 20.2 mmHg and 30.3 mmHg, respectively. Both variables were higher after MSA compared to normative Chicago Classification v3.0 values. The Distal Contractile Integral upper limit was in the range of normality. Patients undergoing crura repair had a significantly higher IRP (p = 0.0378) and lower GERDQ-A scores (p = 0.0374) and Reflux Symptom Index (p = 0.0030) compared to those who underwent MSA device implantation alone.

CONCLUSION & INFERENCES

This study provides HRM reference values for patients undergoing successful MSA implantation. Crural repair appears to be a key component of LES augmentation and is associated with improved clinical outcomes.

Effects of viscosity and volume on the patterns of esophageal motility in healthy adults using high-resolution manometry

The purpose of this study was to determine the effects of age, sex, body mass index (BMI), viscosity, and volume on esophageal motility using high-resolution manometry (HRM). Manometric studies were performed on 60 asymptomatic volunteers (27 men and 33 women, age: 19-56 years) while in a supine position. Manometric protocol included 10 water swallows (5 cc), 10 jelly swallows (5 cc), and 1 water swallow (20 cc). Evaluation of HRM parameters including length of proximal pressure trough (PPT length), distal latency (DL), contractile front velocity (CFV), distal contractile integral (DCI), and 4-second integrated relaxation pressure (IRP) was performed using MATLAB. Significant differences were noted in median IRP between water 5 cc (median 7.2 mmHg [range 5.5-9.6]), jelly 5 cc (median 6.0 mmHg [range 3.8-8.0]), and water 20 cc {(Median 4.8 mmHg [range 3.3-7.4]), P < 0.01}. DL were significantly different between water 5 cc, jelly 5 cc, and water 20 cc (P < 0.01), and in terms of PPT, proportions of small (2 cm ≤ < 5 cm) and large (5 cm≤) break for jelly 5 cc were significantly higher than those for the water 5 cc swallow (P < 0.05). Furthermore, DCI increased with age for water 5 cc, and a significant negative correlation was noticed between proportions of small break and BMI for water 5 cc. Manometric measurements vary depending on age, BMI, viscosity, and volume. These findings need to be taken into account in the interpretation of manometry results.