Chicago Classification Diagnoses Research Articles

The broad impact of functional lumen imaging probe panometry in addition to high-resolution manometry in an esophageal clinical practice.

High-resolution manometry (HRM) with the Chicago Classification (CC) is the standard paradigm to define esophageal motility disorders. Functional lumen imaging probe (FLIP) panometry utilizes impedance planimetry to characterize esophageal compliance and secondary peristalsis. The aim of this study was to explore the clinical impact of FLIP panometry in addition to HRM. A retrospective chart review was performed on FLIP panometry cases utilizing the 322N catheter. Cases with prior foregut surgeries or botulinum injection within 6 months of FLIP panometry were excluded. EGJ-diameter and distensibility index (DI) and secondary contraction patterns at increasing balloon volumes were recorded. An EGJ-DI of ≥2.8mm2/mm Hg at 60mL was considered as a normal EGJ distensibility. CC diagnosis, Eckhardt score, Brief Esophageal Dysphagia Questionnaire, and clinical outcomes were obtained for each FLIP case. A total of 186 cases were included. Absent contractility and achalasia types 1 and 2 showed predominantly absent secondary contraction patterns, while type 3 had a variety of secondary contractile patterns on FLIP panometry. Among 77 cases with EGJ outflow obstruction (EGJOO), 60% had a low EGJ-DI. Among those with no motility disorder or ineffective esophageal motility on HRM, 27% had a low DI and 47% had sustained contractions on FLIP, raising concern for an esophageal dysmotility process along the achalasia and/or spastic spectrum. FLIP panometry often confirmed findings on HRM in achalasia and absent contractility. FLIP panometry is useful in characterizing EGJOO cases. Spastic features on FLIP panometry may raise concern for a motility disorder on the spastic spectrum not captured by HRM. Further studies are needed on FLIP panometry to determine how to proceed with discrepancy with HRM and explore diagnoses beyond the CC.

A multi-stage machine learning model for diagnosis of esophageal manometry

High-resolution manometry (HRM) is the primary procedure used to diagnose esophageal motility disorders. Its manual interpretation and classification, including evaluation of swallow-level outcomes and then derivation of a study-level diagnosis based on Chicago Classification (CC), may be limited by inter-rater variability and inaccuracy of an individual interpreter. We hypothesized that an automatic diagnosis platform using machine learning and artificial intelligence approaches could be developed to accurately identify esophageal motility diagnoses. Further, a multi-stage modeling framework, akin to the step-wise approach of the CC, was utilized to leverage advantages of a combination of machine learning approaches including deep-learning models and feature-based models. Models were trained and tested using a dataset comprised of 1741 patients' HRM studies with CC diagnoses assigned by expert physician raters. In the swallow-level stage, three models based on convolutional neural networks (CNNs) were developed to predict swallow type and swallow pressurization (test accuracies of 0.88 and 0.93, respectively), and integrated relaxation pressure (IRP)(regression model with test error of 4.49 mmHg). At the study-level stage, model selection from families of the expert-knowledge-based rule models, xgboost models and artificial neural network(ANN) models were conducted. A simple model-agnostic strategy of model balancing motivated by Bayesian principles was utilized, which gave rise to model averaging weighted by precision scores. The averaged (blended) models and individual models were compared and evaluated, of which the best performance on test dataset is 0.81 in top-1 prediction, 0.92 in top-2 predictions. This is the first artificial-intelligence style model to automatically predict esophageal motility (CC) diagnoses from HRM studies using raw multi-swallow data and it achieved high accuracy. Thus, this proposed modeling framework could be broadly applied to assist with HRM interpretation in a clinical setting.

S360 Effects of Body Position on High-Resolution Manometry Data and Chicago Classification Diagnosis

S360 Effects of Body Position on High-Resolution Manometry Data and Chicago Classification Diagnosis

Esophageal Motility Patterns After Peroral Endoscopic Myotomy in Patients With Achalasia.

Background/AimsSeveral studies have reported partial recovery of peristalsis in patients with achalasia after myotomy. The aim of our study is to analyze esophageal motility patterns after peroral endoscopic myotomy (POEM) and to assess the potential predictors and clinical impact of peristaltic recovery.MethodsWe performed a retrospective analysis of prospectively collected data of consecutive patients with achalasia undergoing POEM at a tertiary center. High-resolution manometry (HRM) studies prior to and after POEM were reviewed and the Chicago classification was applied.ResultsA total of 237 patients were analyzed. The initial HRM diagnoses were achalasia type I, 42 (17.7%); type II, 173 (73.0%); and type III, 22 (9.3%). Before POEM, peristaltic fragments were present in 23 (9.7%) patients. After POEM the Chicago classification diagnoses were 112 absent contractility, 42 type I achalasia, 15 type II, 11 type III, 26 ineffective esophageal motility, 18 esophagogastric junction outflow obstruction, 10 fragmented peristalsis, and 3 distal esophageal spasm. Altogether 68 patients (28.7%) had signs of contractile activity, but the contractions newly appeared in 47 patients (47/214, 22.0%). Type II achalasia showed a trend for appearance of contractions (P = 0.097). Logistic regression analysis did not identify any predictors of peristaltic recovery. The post-POEM Eckardt score did not differ between patients with and without contractions nor did the parameters of timed barium esophagogram.ConclusionsMore than 20% of achalasia patients have signs of partial recovery of esophageal peristalsis after POEM. It occurs predominantly in type II achalasia but the clinical relevance seems to be negligible.

S0452 Impact of EndoFLIP in an Esophageal Clinical Practice

INTRODUCTION: High resolution manometry (HRM) with Chicago Classification (CC) interpretation is the gold standard for defining esophageal motility disorders. However, HRM may reveal abnormalities that do not meet CC criteria, or may be normal in patients with esophageal symptoms. Also, EGJ outflow obstruction (EGJOO) comprises a heterogeneous group of disorders that may require disparate treatments. We have utilized EndoFLIP for suspected dysmotility, and have reviewed our experience to explore the impact of EndoFLIP on management. METHODS: We reviewed medical records for patients in our Center for Esophageal Disease with EndoFLIP performed November 2018-March 2020. We recorded EGJ diameter (D) and distensibility index (DI) at the 60 mL volume, and topography contraction patterns [repetitive antegrade (RACs), repetitive retrograde, disorganized diminished, hypercontractile, and sustained esophageal contractions (SECs), or absent contractility] at the 40 and 60 mL volumes. We also recorded CC diagnosis, symptoms [Eckardt score and Brief Esophageal Dysphagia Questionnaire (BEDQ)], working diagnosis, and EndoFLIP-guided change of therapy (botulinum injection, pneumatic dilation, or myotomy). RESULTS: We performed EndoFLIP on 249 patients with esophageal symptoms who had HRM and no prior foregut surgery. Table 1 shows D, DI, symptom scores, and EndoFLIP impact on diagnosis and therapy. Endoflip confirmed the diagnosis in all patients with achalasia by HRM and did not alter management. Among 97 patients with EGJOO, 50/97 (52%) of EGJOO patients had low DI (mean 1.3) with abnormal patterns on FLIP in all cases and were considered to have a primary EGJOO dysmotility disorder. These cases were also less likely to have any RACs compared to those with normal DI (12% v 32%, P < 0.05). In 2 (18%) of 11 patients with absent contractility and IRP <15 mmHg, a low DI on Endoflip suggested a diagnosis of achalasia. Among 49 patients with ineffective esophageal motility (IEM), 12 (24%) had low DI (mean 1.4) and 6 (12%) had SECs. In 37 patients with a normal HRM, 9 (24%) had SECs. CONCLUTION: We found EndoFLIP especially useful in evaluation of patients with EGJOO, IEM and absent contractility in whom it supported dysmotility on the achalasia spectrum in 52%, 24%, and 18% of patients respectively. Overall, we found Endoflip guided escalation of therapy in 9% of patients. The clinical implications of the FLIP topography in these cases requires further investigation.Table 1.: Endoflip characteristics and Clinical Impact by HRM associated Diagnosis

A129 THE VALUE OF REPEAT MANOMETRIC TESTING

Abstract Background While motility disorders may evolve over time, there is scant guidance around the role of repeat high-resolution esophageal manometry (HRM). Given the invasive nature of HRM and the implications on financial cost and patient discomfort, it is obvious that the emphasis should be on minimizing unnecessary repeat examinations. However, there are no recommendations around indications or timing of repeat HRM. Aims We aimed to determine the outcomes in patients who underwent repeat manometry and look for predictors of progression to achalasia or major motility disorder. Methods Consecutive reports from HRM studies performed between Aug 2013 – May 2017 were retrospectively analyzed. All patients with ≥ 2 HRM studies were included. Studies without a Chicago classification diagnosis were excluded. Chi-squared analysis was performed to determine if initial HRM diagnosis was associated with change in diagnosis on follow-up HRM. Initial and follow-up manometric parameters were compared with paired T-tests. Binary logistic regression analysis was performed to look for predictors of progression to achalasia or major motility disorder. Results 134 patients underwent ≥ 2 HRM studies. Initial diagnoses were IEM (45 patients [33.6%], EGJOO (34 [25.4%], absent peristalsis (18 [13.4%], achalasia (11 [8.2%], DES (4 [3.0%]), and JH (3 [2.2%]; 29 (14.2%) of patients had a normal HRM. 109 (81.3%) patients underwent 2 HRM, 18 (13.4%) 3 HRM, 4 (3%) 4 HRM, and 3 (2.2%) 5 HRM. The final follow-up HRM occurred after a median 496 [80 – 1823] days. 72 (53.7%) of patients had no change from their initial diagnosis. Patients with an initial diagnosis of DES were significantly more likely to have a change in diagnosis on the final follow-up (3 normal:1 IEM) (p = .043). No other classes reached significance. Patients with IEM had a significantly higher mean DCI (395.1 [0 - 3248] vs 790.8 [0 – 10715.0], p = .006) and IRP (4.5 [-10.4 – 14.2] vs [6.6 [-6.2 – 21.0], p = .017) on their follow-up HRM. 4 patients without achalasia (3 EGJOO:1 IEM) on their index HRM had a diagnosis of achalasia on their final HRM. The median IRP in non-achalasia patients with a diagnosis of achalasia on final HRM (22.3 [8.4 – 30.7] was significantly higher than those without a diagnosis of achalasia on final HRM (6.6 [-10.4 – 39.8]) (p = .013); however no manometric criteria or initial HRM diagnoses predicted progression to achalasia or major motility disorder on binary logistic regression analysis. Conclusions In most patients, repeat manometry did not change the manometric diagnosis. Patients with DES were significantly likely to have their diagnosis change with repeat HRM, and most of these patients had normalization of their HRM. Manometric parameters in IEM appear to improve over time. This finding could reflect interval therapy, or shed some light on the natural history of this disease. Funding Agencies None

Normative Values for Esophageal Motility Assessed in the Physiological Seated Position for 16-Channel Water Perfused High-resolution Esophageal Manometry System and Postural Variations in Healthy Volunteers.

Background/AimsConsensus guidelines for performance and analysis of high-resolution esophageal manometry (HREM) recommend use of equipment, population and posture specific normative values. To provide normative values for Chicago classification (CC) metrics in the physiological seated position for a 16-channel water perfused system (Dentsleeve HREM catheter, Advanced Manometry Systems, Melbourne, Australia) widely used in India and other countries with limited access to solid-state equipment. The results are compared with published CC metrics in supine position done using the same system and volunteers.MethodsHREM tracings of ten 5 mL water swallows in sitting posture were acquired in healthy volunteers and normative values for CC version 3.0 metrics calculated. Individual swallows were paired with previously reported supine swallows for postural variations (Wilcoxon sign rank test) and concordance of CC diagnoses (Pearson coefficient).ResultsAnalysis of 530 sitting posture water swallows (53 subjects) and comparison with their supine data revealed significantly higher integrated relaxation pressure (IRP; median 6.7 mmHg vs 6.1 mmHg) but lower distal latency (DL; mean 6.3 seconds vs 6.8 seconds) and distal contractile integral (DCI; mean 1224 mmHg sec cm vs 1456 mmHg sec cm). Sitting posture normal was defined as: IRP < 13.9, DL > 4.5, and DCI = 115–4500 (absent contractility: DCI < 30). CC diagnoses concordance using posture-specific cut-offs was moderate (k = 0.47).ConclusionsThis paper provides normative values for the Advanced Manometry Systems 16-channel water perfused system in the physiological seated position for CC metrics. Our findings of higher IRP and lower DCI in sitting posture than previously reported supine CC cut-offs, confirm the need to use posture-specific cut-offs for reporting HREM tracings.

378 Resting Upper Esophageal Sphincter Pressure Is Elevated in Proton Pump Inhibitor-Refractory Chronic Cough Patients and May Be a Marker for Laryngeal Hypersensitivity

INTRODUCTION: Chronic cough is difficult to treat when unresponsive to proton-pump inhibitor (PPI) and sinus therapy. In this setting it is presumed to be neurogenic in etiology. Despite the role of the upper esophageal sphincter (UES) as a barrier to laryngopharyngeal reflux disease, it has not been well characterized in chronic cough patients. We aim to assess UES tonicity in patients with PPI-refractory chronic cough and otherwise intact esophageal motor function. METHODS: Patients with a Chicago Classification diagnosis of normal esophageal motility on high-resolution esophageal manometry (HRM) on studies performed for the indication of chronic cough were retrospectively studied. All studies were performed at a GI motility lab at a tertiary care center from January 2013 to August 2018. Patients with prior cervical spinal surgery, foregut surgery, gastroparesis, severe pulmonary disease or manometric hiatal hernia were excluded. All HRM were performed with a solid-state assembly with a 4.2 mm outer diameter catheter. Upper esophageal resting pressure and residual pressure (mmHg) were recorded from HRM studies and compared to a control group of patients with normal esophageal motility on studies performed for an indication of non-cardiac chest pain. Available pH-metry tests in chronic cough patients were also reviewed for acid exposure time. RESULTS: Fourteen patients with chronic cough (mean age 63 ± 25, 71% female) and twenty patients with non-cardiac chest pain (mean age 55 ± 14, 60% female) were included. Median resting UES pressure (mmHg) was higher in the chronic cough group (80) vs the chest pain group (50.8) with a p value of 0.004 (Figure 1). There was no difference in residual UES pressure (3.5 in chronic cough vs 3.15 in chest pain). A total of 12 pH studies were performed in chronic cough patients; 9 of these were on PPI. Median distal acid exposure time % was 1.35 [IQR 0.5-6]. CONCLUSION: UES hypertonicity found in PPI-refractory chronic cough patients may be a marker of laryngeal hypersensitivity. A second possibility is that primary UES dysfunction is the cause of cough in this subgroup.

Tu1284 – Swallow-To-Swallow Variation in Esophageal Motor Patterns Impact Chicago Classification Diagnoses on High Resolution Manometry

Tu1284 – Swallow-To-Swallow Variation in Esophageal Motor Patterns Impact Chicago Classification Diagnoses on High Resolution Manometry

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

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. 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. 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]). The mean age was 30years and the BMI was 24.2kgm-2 . Compared to CC, our normal metrics were lower for IRP (13mm Hg) and DCI (350-4500mm Hgscm). DCI >4500 and <70 (<5th percentile) were defined as hypercontractile and failed contraction, respectively. Abnormal DL (<4.5s) and peristaltic break size (>5cm) 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. 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.

Clinical Significance of Esophageal Hypertensive Peristaltic Contractions on High-resolution Manometry(Neurogastroenterol Motil 2015;27:229-236).

Esophageal peristalsis consists of a chain of relaxing sphincters and contracting segments. First, the segment of skeletal muscle (S1) contracts, then the proximal segment of smooth muscle (S2), and finally the distal segment of smooth muscle (S3).1 The esophageal hypercontractility disorder has been postulated to be caused by imbalance between esophageal contraction and relaxation. A variant of this disorder, where contraction amplitudes of S3 are disproportionately exaggerated compared with those of S2, can produce esophageal symptoms.2 However, some of these contraction patterns could be averaged out and may not be registered as abnormal. Therefore, Mello et al3 tried to determine the clinical significance of these contraction patterns and the diagnostic sensitivity of Chicago classification for these patterns. The authors found that merged segments were in 5.6%, and exaggerated S3 in another 12.5%, but only 17–50% had a Chicago classification diagnosis. The cohorts with merged segments and exaggerated S3 had significantly higher proportions of abnormal relaxation of esophageal body during multiple rapid swallowing (MRS) (P < 0.005 for each comparison) and presenting symptoms (chest pain and dysphagia, P = 0.040) than healthy controls. The authors concluded that merged segments and exaggerated S3 may represent esophageal hypercontractility disorder from abnormal relaxation and/or contraction, and the Chicago classification for these contraction patterns may not be sensitive.

Inter- and intrarater reliability of the Chicago Classification in pediatric high-resolution esophageal manometry recordings.

The Chicago Classification (CC) facilitates interpretation of high-resolution manometry (HRM) recordings. Application of this adult based algorithm to the pediatric population is unknown. We therefore assessed intra and interrater reliability of software-based CC diagnosis in a pediatric cohort. Thirty pediatric solid state HRM recordings (13M; mean age 12.1 ± 5.1 years) assessing 10 liquid swallows per patient were analyzed twice by 11 raters (six experts, five non-experts). Software-placed anatomical landmarks required manual adjustment or removal. Integrated relaxation pressure (IRP4s), distal contractile integral (DCI), contractile front velocity (CFV), distal latency (DL) and break size (BS), and an overall CC diagnosis were software-generated. In addition, raters provided their subjective CC diagnosis. Reliability was calculated with Cohen's and Fleiss' kappa (κ) and intraclass correlation coefficient (ICC). Intra- and interrater reliability of software-generated CC diagnosis after manual adjustment of landmarks was substantial (mean κ = 0.69 and 0.77 respectively) and moderate-substantial for subjective CC diagnosis (mean κ = 0.70 and 0.58 respectively). Reliability of both software-generated and subjective diagnosis of normal motility was high (κ = 0.81 and κ = 0.79). Intra- and interrater reliability were excellent for IRP4s, DCI, and BS. Experts had higher interrater reliability than non-experts for DL (ICC = 0.65 vs ICC = 0.36 respectively) and the software-generated diagnosis diffuse esophageal spasm (DES, κ = 0.64 vs κ = 0.30). Among experts, the reliability for the subjective diagnosis of achalasia and esophageal gastric junction outflow obstruction was moderate-substantial (κ = 0.45-0.82). Inter- and intrarater reliability of software-based CC diagnosis of pediatric HRM recordings was high overall. However, experience was a factor influencing the diagnosis of some motility disorders, particularly DES and achalasia.

Exaggerated smooth muscle contraction segments on esophageal high-resolution manometry: prevalence and clinical relevance.

Two smooth muscle contraction segments (S2, S3) on esophageal high-resolution manometry (HRM) demonstrate varying contraction vigor in symptomatic patients. Significance of isolated exaggerated smooth muscle contraction remains unclear. High-resolution manometry studies were reviewed in 272 consecutive patients (56.4± 0.8 years, 62% F) and compared to 21 healthy controls (27.6±0.6years, 52% F), using HRM tools (distal contractile integral, DCI; distal latency, DL; integrated relaxation pressure, IRP), Chicago Classification (CC) and multiple rapid swallows (MRS). Segments were designated merged when the trough between S2 and S3 was ≥150mmHg, and exaggerated S3 when peak S3 amplitude was ≥150mmHg without merging with S2. Presenting symptoms and global symptom severity (on 100mm visual analog scale) were recorded. Prevalence of merged and exaggerated segments was determined, and characteristics compared to symptomatic patients with normal HRM, and to healthy controls. Merged segments were identified in 5.6%, and exaggerated S3 in another 12.5%, but only 17-50% had a CC diagnosis; one healthy control had merged segments. DCI with wet swallows was similar in cohorts with merged and exaggerated segments (p=0.7), significantly higher than symptomatic patients with normal HRM and healthy controls (p≤0.003 for each comparison). Incomplete inhibition and prominent DCI augmentation on MRS (p≤0.01), and presenting symptoms (chest pain and dysphagia, p=0.04) characterized exaggerated segments, but not demographics or symptom burden. Merged esophageal smooth muscle segments and exaggerated S3 may represent hypermotility phenomena from abnormal inhibition and/or excitation, and are not uniformly identified by the CC algorithm.

Reproducibility patterns of multiple rapid swallows during high resolution esophageal manometry provide insights into esophageal pathophysiology.

Multiple rapid swallows (MRS) during esophageal high resolution manometry (HRM) assess esophageal neuromuscular integrity by evaluating postdeglutitive inhibition and rebound contraction, but most reports performed only a single MRS sequence. We assessed patterns of MRS reproducibility during clinical HRM in comparison to a normal cohort. Consecutive clinical HRM studies were included if two separate MRS sequences (four to six rapid swallows ≤4s apart) were successfully performed. Chicago Classification diagnoses were identified; contraction wave abnormalities were additionally recorded. MRS-induced inhibition (contraction ≤3cm during inhibition phase) and rebound contraction was assessed, and findings compared to 18 controls (28.0±0.7year, 50.0% female). Reproducibility consisted of similar inhibition and contraction responses with both sequences; discordance was segregated into inhibition and contraction phases. Multiple rapid swallows were successfully performed in 89.3% patients and all controls; 225 subjects (56.2±0.9year, 62.7% female) met study inclusion criteria. Multiple rapid swallows were reproducible in 76.9% patients and 94.4% controls (inhibition phase: 88.0% vs 94.4%, contraction phase 86.7% vs 100%, respectively, p=ns). A gradient of reproducibility was noted, highest in well-developed motor disorders (achalasia spectrum, hypermotility disorders, and aperistalsis, 91.7-100%, p=ns compared to controls); and lower in lesser motor disorders (contraction wave abnormalities, esophageal body hypomotility) or normal studies (62.2-70.8%, p<0.0001 compared to well-developed motor disorders). Inhibition phase was most discordant in contraction wave abnormalities, while contraction phase was most discordant when studies were designated normal. Multiple rapid swallows are highly reproducible, especially in well-developed motor disorders, and complement the standard wet swallow manometry protocol.

Esophageal Disorders Not Yet Addressed by High-resolution Manometry

TO THE EDITOR: We greatly appreciate the insight provided by Wang et al1 regarding their recent review of the esophageal disorders not assessed by the Chicago classification of motility disorders of the esophagus. This is an important issue as many people still fail to understand that the Chicago classification was designed to describe and categorize distal esophageal motor disorders focused on dysphagia and was not meant to be a global classification across the entire spectrum of esophageal disorders. All patients undergoing manometry will have a Chicago classification diagnosis, however, there may be other motor abnormalities of the upper esophageal sphincter, proximal esophagus or esophagogastric junction and proximal stomach that may be important in the patients presenting complaints and these need to be described separately from the Chicago classification diagnosis. To utilize the Chicago classification, one has to follow specific rules and calculate specific metrics in a predefined order and the analysis is confined to an assessment during 10 supine 5 mL water swallows.2 We experienced that changing position elicited a change in diagnosis in about 10% of studies, and that provocative bolus challenges modified the diagnoses by increasing the number of patients classified with an esophagogastric junction outflow obstruction.3 However, this did require utilization of different standard values and thresholds to allow for a refined characterization and represents one aspect where the Chicago classification diagnosis can be complemented. Similarly, the Chicago classification is also restricted to assessing patients before definitive treatment and although the Chicago classification can be modified to assess patients after antireflux procedures, bariatric surgery or treatments focused on disrupting the lower esophageal sphincter in achalasia; there are no reference ranges to define what is normal in the post-operative state. Nevertheless, the Chicago classification metrics, such as the integrated relaxation pressure and intrabolus pressure pattern, can help one discern whether there is an outflow obstruction after intervention and continued abnormal peristalsis.4,5 Thus, it is likely that the metrics described in the Chicago classification can be utilized, or modified, to help define disorders outside of those that are focused on distal esophageal motor function. Moving forward, the next steps in the evolution of high resolution manometry and esophageal pressure topography should focus on describing specific disease related processes highlighted in the review published by Wang et al,1 such as disorders related to gastroesophageal reflux, upper esophageal sphincter and proximal esophageal dysfunction in dysphagia, post-prandial complaints of regurgitation/possible rumination syndrome and postoperative assessment of symptomatic patients. This will require rigorous evaluation with careful description of normal thresholds and will require outcome data. This is no easy task as the evolution of the Chicago classification to its final version took almost 5 years and it is still being refined. Initial steps in the process of categorizing esophageal motor dysfunction as it relates to gastroesophageal reflux, are currently underway. Hoshino et al6 have described new metrics of defining esophagogastric junction function as an antireflux barrier using modifications of the Chicago classification metrics and correlates of ineffective motility have been defined for esophageal pressure topography.7 Additionally, more emphasis on post-prandial assessments and provocative meals are also being studied to help elucidate mechanism of reflux that may be contributing to the patients underlying symptoms and there are new definitions for the assessment of transient lower esophageal sphincter relaxation using high resolution manometry.8,9 These are promising advances, however, we are only in the preliminary stages and although many have described motor abnormalities in the upper sphincter and post-prandial state, there is a paucity of reference data and consensus regarding terminology and definitions to help define new classifications for these disorders. Thus, the Chicago classification should be utilized as it was intended and designed with the idea that it can be complemented by an assessment of motor function that extends beyond the distal esophagus and 10 supine water swallows. We look forward to future work that may lead to a parallel classification scheme for other disorders not covered by the Chicago classification and we look forward to another great city taking over where Chicago left off.

The effect of a sitting vs supine posture on normative esophageal pressure topography metrics and Chicago Classification diagnosis of esophageal motility disorders

Although, the current protocol for high resolution manometry (HRM) using the Chicago Classification is based on the supine posture, some practitioners prefer a sitting posture. Our aims were to establish normative esophageal pressure topography data for the sitting position and to determine the effect of applying those norms to Chicago Classification diagnoses. Esophageal pressure topography studies including test swallows in both a supine and sitting position of 75 healthy volunteers and 120 patients were reviewed. Integrated relaxation pressure (IRP), distal contractile integral (DCI), contractile front velocity (CFV), and distal latency were measured and compared between postures. Normative ranges were established from the healthy volunteers and the effect of applying sitting normative values to the patients was analyzed. Normative values of IRP, DCI, and CFV all decreased significantly in the sitting posture. Applying normative sitting metrics to patient studies [27% reduction in IRP (15 to 11 mmHg), 69% reduction in DCI (8000-2500 mmHg-s-cm)] reclassified 13/120 (11%) patients as having abnormal esophagogastric junction relaxation and 26/120 (22%) as hypercontractile. Three patients with an abnormal supine IRP normalized when sitting with elimination of a vascular artifact. Clinical HRM studies should include both a supine and sitting position to minimize misdiagnoses attributable to anatomical factors. However, until outcome studies demonstrating the significance of isolated abnormalities of IRP or DCI in the sitting position are available, the Chicago Classification of esophageal motility disorders should continue to be based on supine swallows using normative data from the supine posture.

Optimizing the swallow protocol of clinical high‐resolution esophageal manometry studies

The Chicago Classification (CC) of Esophageal Motility Disorders is based on 10 water swallows performed in the supine position. The aim of the study was to assess whether upright and provocative swallows (PS) provided important information beyond that obtained from the standard supine manometric protocol. Two independent investigators reviewed high-resolution manometry (HRM) studies of 148 patients with both supine and upright liquid swallows and additional studies from patients with PS (increased volume, viscosity, and a marshmallow) for a resultant change in CC diagnoses. Significant diagnostic changes were defined as a change from normal or borderline motor function to abnormal motor function, esophagogastric junction (EGJ) outflow obstruction, or achalasia. Discordant diagnoses were reviewed and the Kappa test was used to evaluate the agreement between diagnoses in the different protocols. The overall agreement in diagnosis between the five supine swallows and the five upright swallows was good (k = 0.583). Changing to the upright position elicited a significant diagnostic change in 10.1% (15/148) of cases. The PS suggested an alternative diagnosis from the supine position in 14 of 75 studies (18.7%); 11 of these changed to EGJ obstruction during viscous or solid bolus challenges. Changing position in HRM elicited a significant change in diagnosis in about 10% of studies, whereas provocative bolus challenges with viscous liquid and marshmallows increased the detection of EGJ outflow obstruction. Performing manometric evaluations in both positions with PS may increase the yield of standard HRM technique.