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

[Diagnosis of esophageal motility disorders - Significance of the new Chicago classification v4.0]

Esophageal motility disorders are diseases in which there are malfunctions of the act of swallowing due to a change in neuromuscular structures. The main symptom is therefore dysphagia for solid and/or liquid foods, often accompanied by symptoms such as chest pain, regurgitation, heartburn, and weight loss. Esophageal manometry is the gold standard in diagnostics. Endoscopy and radiology serve to exclude inflammatory or malignant changes. With the introduction of high-resolution esophageal manometry (HRM), the diagnosis of esophageal motility disorders has improved and led to a new classification with the Chicago Classification, which has been modified several times in the last decade, most recently in 2021 with the Chicago Classification v4.0. Compared to the previous version 3.0, there are some important changes that are presented based on the most important esophageal motility disorders in everyday clinical practice.

Clinical utility of the solid meal test during high-resolution esophageal manometry. A study in a Latin American population

INTRODUCTION AND AIMS

The solid test meal (STM) is a challenge test that is done during esophageal manometry and appears to increase the diagnostic yield of the study. The aim of our analysis was to establish the normal values for STM and evaluate its clinical utility in a group of Latin American patients with esophageal disorders versus healthy controls.

MATERIAL AND METHODS

A cross-sectional study was conducted on a group of healthy controls and consecutive patients that underwent high-resolution esophageal manometry, in which STM was done at the final part of the study and consisted of asking the subjects to eat 200 g of precooked rice. The results were compared during the conventional protocol and the STM.

RESULTS

Twenty-five controls and 93 patients were evaluated. The majority of the controls (92%) completed the test in under 8 min. The STM changed the manometric diagnosis in 38% of the cases. The STM diagnosed 21% more major motor disorders than the conventional protocol; it doubled the cases of esophageal spasm and quadrupled the cases of jackhammer esophagus, whereas it demonstrated normal esophageal peristalsis in 43% of the cases with a previous diagnosis of ineffective esophageal motility.

CONCLUSIONS

Our study confirms the fact that complementary STM during esophageal manometry adds information and enables a more physiologic assessment of esophageal motor function to be made, compared with liquid swallows, in patients with esophageal motor disorders.

[Diagnosis of esophageal motility disorders - Significance of the new Chicago classification v4.0]

Esophageal motility disorders are diseases in which there are malfunctions of the act of swallowing due to a change in neuromuscular structures. The main symptom is therefore dysphagia for solid and/or liquid foods, often accompanied by symptoms such as chest pain, regurgitation, heartburn, and weight loss. Esophageal manometry is the gold standard in diagnostics. Endoscopy and radiology serve to exclude inflammatory or malignant changes. With the introduction of high-resolution esophageal manometry (HRM), the diagnosis of esophageal motility disorders has improved and led to a new classification with the Chicago Classification, which has been modified several times in the last decade, most recently in 2021 with the Chicago Classification v4.0. Compared to the previous version 3.0, there are some important changes that are presented based on the most important esophageal motility disorders in everyday clinical practice.

Esophageal hypercontractility is abolished by cholinergic blockade

BACKGROUND

Esophageal hypercontractility (EHC) is considered a major esophageal motor disorder of unclear etiology. Different mechanisms have been proposed, including an imbalance in inhibitory and excitatory esophageal innervation. We hypothesized that patients with EHC suffer from cholinergic hyperactivity.

AIM

To interrogate the excitatory and inhibitory neurotransmission in EHC by assessing the esophageal motor response to atropine (ATR) and cholecystokinin (CCK), respectively, in EHC patients.

METHOD

We retrospectively reviewed patients who underwent high-resolution manometry (HRM) with pharmacologic challenge in a tertiary referral center between 2007 and 2017. We identified 49 EHC patients who were categorized based on frequency of hypercontractile peristaltic sequence into "frequent" and "infrequent" and motility diagnosis groups. Deglutitive pressure metrics and esophageal motor responses to ATR (12 mcg/kg iv) and CCK (40 ng/kg iv) were analyzed across groups.

RESULTS

Atropine abolished hypercontractility across all groups studied, converting nearly half of patients to a motor pattern of ineffective esophageal motility. Abnormal CCK responses primarily occurred in the patient groups with concomitant outflow obstruction.

CONCLUSIONS

Hypercontractility is cholinergically mediated in all esophageal motor disorders. Most patients with isolated EHC appear to have excessive cholinergic drive, rather than loss of inhibitory innervation, and might be candidates for treatment with anticholinergic agents.

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

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

Chicago classification version 4.0© technical review: Update on standard high-resolution manometry protocol for the assessment of esophageal motility

The Chicago Classification v4.0 (CCv4.0) is the updated classification scheme for esophageal motility disorders using metrics from high-resolution manometry (HRM). A key feature of CCv.4.0 is the more rigorous and expansive protocol that incorporates single wet swallows acquired in different positions (supine, upright) and provocative testing, including multiple rapid swallows and rapid drink challenge. Additionally, solid bolus swallows, solid test meal, and/or pharmacologic provocation can be used to identify clinically relevant motility disorders and other conditions (eg, rumination) that occur during and after meals. The acquisition and analysis for performing these tests and the evidence supporting their inclusion in the Chicago Classification protocol is detailed in this technical review. Provocative tests are designed to increase the diagnostic sensitivity and specificity of HRM studies for disorders of esophageal motility. These changes attempt to minimize ambiguity in prior iterations of Chicago Classification, decrease the proportion of HRM studies that deliver inconclusive diagnoses and increase the number of patients with a clinically relevant diagnosis that can direct effective therapy. Another aim in establishing a standard manometry protocol for motility laboratories around the world is to facilitate procedural consistency, improve diagnostic reliability, and promote collaborative research.

Evaluation of the Esophagogastric Junction on High Resolution Manometry

The esophagogastric junction (EGJ) is a complex barrier between the thoracic and abdominal luminal gut compartments, comprised primarily of the lower esophageal sphincter (LES) and crural diaphragm. Although closed at rest, the EGJ relaxes to allow antegrade bolus transit and retrograde venting of air. Abnormal relaxation is the hallmark of achalasia spectrum disorders, while increased frequency of transient lower esophageal sphincter relaxations and/or EGJ disruption are seen in gastroesophageal reflux disease. High resolution manometry (HRM) is the modern day gold standard for assessment of EGJ morphology and function, with better performance characteristics compared with endoscopy and barium esophagography. Conventional LES metrics defining EGJ function include resting LES pressure as well as postswallow residual pressures. Newer HRM-based metrics include EGJ contractile integral, which measures static barrier function at rest, and EGJ morphology, which characterizes the relationship between LES and crural diaphragm. Provocative maneuvers assess dynamic EGJ function during physiological or pharmacologic stress. The most useful of these maneuvers, the rapid drink challenge, assesses for latent obstruction, while multiple rapid swallows evaluate adequacy of deglutitive inhibition. Amyl nitrate and cholecystokinin administration can segregate motor from structural obstruction. Newer provocative tests (straight leg raise maneuver, abdominal compression) and novel diagnostic tools (functional lumen imaging probe) complement HRM evaluation of the EGJ. Although current HRM metrics and maneuvers show promise in identifying clinically relevant EGJ abnormalities, future investigations evaluating management outcomes will improve segregation of normal from abnormal EGJ morphology and function.

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

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

Esophageal 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.

Clinical Functional Lumen Imaging Probe Testing in Esophageal Disorders: A Need for Better Quality Evidence

In their article "Use of the Functional Lumen Imaging Probe in Clinical Esophagology," Savarino et al. report the outcomes of a Grading of Recommendations Assessment, Development, and Evaluation analysis performed by experts in the use of functional lumen imaging probe (FLIP) evaluation of esophageal disorders. For essentially all clinical indications, the recommendation for use was conditional with a very low quality of evidence. FLIP is an expensive, invasive technology examining limited aspects of esophageal function. Its role in complementing or replacing existing technology is uncertain, particularly when compared with manometric testing with additional provocative studies. Performing properly designed studies to demonstrate FLIP's true effectiveness and cost-effectiveness will be costly.