Age Affects Esophageal Secondary Peristalsis More Than Primary as Assessed by FLIP Panometry and High-resolution Manometry.

Age-related changes in esophageal function involve increased rates of dysmotility with advancing age (sometimes described as presbyesophagus).1-4 Specifically, advanced age has been associated with increased lower esophageal sphincter (LES) pressure and decreased peristaltic vigor.1-4 However, the mechanisms underlying these changes, including the relative relationship of primary peristalsis and secondary peristalsis over the lifespan, remain incompletely understood. Current approaches assess primary peristalsis using high-resolution manometry (HRM), with esophageal motility disorders defined using the Chicago Classification version 4.0 (CCv4.0), and secondary peristalsis using functional lumen imaging probe (FLIP) panometry.5,6 Although HRM and FLIP panometry motility diagnoses are often analogous, they can sometimes differ. For example, abnormal secondary peristalsis can occur when primary peristalsis is normal, which has been associated with reflux and non-obstructive dysphagia.7,8 This study aimed to examine the effect of age on primary peristalsis and secondary peristalsis.

Rapid Development of Achalasia After SARS-CoV-2 Infection: Polymerase Chain Reaction Analysis of Esophageal Muscle Tissue.

INTRODUCTION: Achalasia has been linked to viruses. We have observed cases of rapid-developing achalasia post-coronavirus disease 2019 (COVID-19). METHODS: We aimed to prospectively evaluate esophageal muscle for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) from patients with rapid-onset achalasia post-COVID-19 and compare them with achalasia predating COVID-19 and achalasia with no COVID-19. RESULTS: Compared with long-standing achalasia predating COVID-19 and long-standing achalasia with no COVID-19, the subjects with achalasia post-COVID-19 had significantly higher levels of messenger RNA for the SARS-CoV-2 nucleocapsid (N) protein, which correlated with a significant increase in the inflammatory markers NOD-like receptor family pyrin domain-containing 3 and tumor necrosis factor. DISCUSSION: SARS-CoV-2, the virus responsible for COVID-19, is a possible trigger for achalasia.

A Mechanics-Based Perspective on the Function of Human Sphincters During Functional Luminal Imaging Probe Manometry.

Functional luminal imaging probe (FLIP) is used to measure cross-sectional area (CSA) and pressure at sphincters. It consists of a catheter surrounded by a fluid filled cylindrical bag, closed on both ends. Plotting the pressure-CSA hysteresis of a sphincter during a contraction cycle, which is available through FLIP testing, offers information on its functionality, and can provide diagnostic insights. However, limited work has been done to explain the mechanics of these pressure-CSA loops. This work presents a consolidated picture of pressure-CSA loops of different sphincters. Clinical data reveal that although sphincters have a similar purpose (controlling the flow of liquids and solids by opening and closing), two different pressure-CSA loop patterns emerge: negative slope loop (NSL) and positive slope loop (PSL). We show that the loop type is the result of an interplay between (or lack thereof) two mechanical modes: (i) neurogenic mediated relaxation of the sphincter muscle or pulling applied by external forces, and (ii) muscle contraction proximal to the sphincter which causes mechanical distention. We conclude that sphincters which only function through mechanism (i) exhibition NSL whereas sphincters which open as a result of both (i) and (ii) display a PSL. This work provides a fundamental mechanical understanding of human sphincters. This can be used to identify normal and abnormal phenotypes for the different sphincters and help in creating physiomarkers based on work calculation.

Effects of Cholecystokinin on Esophageal Motor Response to Distension in Asymptomatic Volunteers.

Background/Aims: Cholecystokinin (CCK) administration has been shown to reduce lower esophageal sphincter (LES) pressure in normal subjects in manometric studies. Functional luminal imaging probe (FLIP) panometry offers a method to assess esophageal motility in response to sustained distension though mechanisms related to this response remain unexplored. The aim of this study is to evaluate the effect of CCK-8 on the esophageal response to distension in asymptomatic volunteers using FLIP. Methods: Esophageal response to distension was studied in 7 asymptomatic volunteers (mean age ± SD [27 ± 2]; 86% female) before and after CCK-8 administration in a crossover study design. During sedated endoscopy, FLIP was performed twice with CCK-8 administered via intravenous push in one of 2 protocols: during filling (n = 4) or during emptying (n = 3). Esophagogastric junction distensibility index (EGJ-DI) at 60 mL fill volume and esophageal body contractile response patterns were analyzed. Results: During the baseline FLIP study, all subjects had a contractile response with repetitive antegrade contractions both before and after CCK-8 administration. However, a sustained LES contraction or a sustained occluding contraction with esophageal shortening was observed in all subjects in the filling protocol, but in none during the emptying protocol. EGJ-DI was similar before and after CCK-8 during both filling (4.7 ± 1.9 mm2/mmHg vs 4.3 ± 1.8 mm2/mmHg) and emptying protocol (7.5 ± 1.4 mm2/mmHg vs 6.9 ± 0.6 mm2/mmHg). Conclusion: While EGJ-DI appeared unaffected by CCK-8 administration in asymptomatic volunteers, CCK induced spastic-reactive contractions of the LES during distention suggesting that exogenous CCK interferes with normal LES relaxation during secondary peristalsis.

Presence of esophageal contractility after achalasia treatment is associated with improved esophageal emptying.

BACKGROUND AND AIMS: Some achalasia patients exhibit esophageal contractile activity on follow-up after treatment, yet its importance remains unclear. We aimed to identify factors associated with presence of contractility after treatment and to assess its impact on timed barium esophagram (TBE) and clinical outcomes. METHODS: Patients with type I or II achalasia on baseline high-resolution manometry (HRM) who completed HRM, TBE, and functional lumen imaging probe (FLIP) after treatment were retrospectively identified. Contractility was defined on post-treatment HRM as presence of at least 1 supine swallow with DCI ≥100 mmHg s cm. KEY RESULTS: One hundred twenty-two patients were included (mean age 48 ± 17 years, 50% female). At follow-up evaluation after treatment (54% peroral endoscopic myotomy, 24% pneumatic dilation, 22% laparoscopic Heller myotomy), 61 (50%) patients had contractility on HRM. Patients with contractility (compared to those without) more frequently had type II achalasia (84% vs 57%, p = 0.001) and a post-treatment normal EGJ opening classification on FLIP (69% vs 49%; p < 0.001). In the subgroup of patients with post-treatment integrated relaxation pressure <15 mmHg and normal EGJ opening on FLIP (n = 53), those with contractility had a lower median column height on TBE at 1 min (4 vs 7 cm, p = 0.002) and 5 min (0 vs 5 cm, p = 0.001). In patients with "abnormal" EGJ metrics, patients with contractility showed lower symptom scores (median Eckardt score 2 vs 3, p = 0.03). CONCLUSIONS & INFERENCES: Occurring more frequently in type II achalasia, and if adequate EGJ opening is achieved after treatment, esophageal contractility may contribute to improved esophageal emptying and improved symptoms in non-spastic achalasia. Preservation of esophageal body muscle could improve outcomes in these patients.

Discriminating "impaired" from "disordered" contractile response on FLIP panometry by utilizing pressure measurement.

BACKGROUND: Functional lumen imaging probe (FLIP) panometry evaluates esophageal motility, including the contractile response to distension, that is, secondary peristalsis. Impaired/disordered contractile response (IDCR) is an abnormal, but nonspecific contractile response that can represent either hypomotility or spastic motor disorders on high-resolution manometry (HRM). We hypothesized that FLIP pressure could be incorporated to clarify IDCR and aimed to determine its utility in a cohort of symptomatic esophageal motility patients. METHODS: 173 adult patients that had IDCR on FLIP panometry and HRM with a conclusive Chicago Classification v4.0 (CCv4.0) diagnosis were included and analyzed as development (n = 118) and validation (n = 55) cohorts. FLIP pressure values were assessed for prediction of either hypomotility or spasm, defined on HRM/CCv4.0. KEY RESULTS: HRM/CCv4.0 diagnoses were normal motility in 48 patients (28%), "hypomotility" (ineffective esophageal motility, absent contractility, or Type I or II achalasia) in 89 (51%), and "spasm" (Type III achalasia, distal esophageal spasm, or hypercontractile esophagus) in 36 (21%). The pressure at esophagogastric junction-distensibility index (DI) (60 mL) was lower in hypomotility (median [interquartile range] 34 [28-42] mmHg) than in spasm (49 [40-62] mmHg; p < 0.001) and had an area under the receiver operating characteristic curve of 0.80 (95% CI 0.73-0.88) for hypomotility and 0.76 (0.69-0.83) for spasm. For "spasm" on HRM, a threshold FLIP pressure of >35 mmHg provided 90% sensitivity (47% specificity) while >55 mmHg provided 93% specificity (40% sensitivity). CONCLUSION & INFERENCES: Pressure on FLIP panometry can help clarify the significance of IDCR, with low-pressure IDCR associated with hypomotility and high-pressure IDCR suggestive of spastic motor disorders.

Secondary peristalsis and esophagogastric junction distensibility in symptomatic post-fundoplication patients.

BACKGROUND: The impact of esophageal dysmotility among patients with post-fundoplication esophageal symptoms is not fully understood. This study aimed to investigate secondary peristalsis and esophagogastric junction (EGJ) opening biomechanics using functional lumen imaging probe (FLIP) panometry in symptomatic post-fundoplication patients. METHODS: Eighty-seven adult patients post-fundoplication who completed FLIP for symptomatic esophageal evaluation were included. Secondary peristaltic contractile response (CR) patterns and EGJ opening metrics (EGJ distensibility index (EGJ-DI) and maximum EGJ diameter) were evaluated on FLIP panometry and analyzed against high-resolution manometry (HRM), patient-reported outcomes, and fundoplication condition seen on esophagram and/or endoscopy. KEY RESULTS: FLIP CR patterns included 14 (16%) normal CR, 30 (34%) borderline CR, 28 (32%) impaired/disordered CR, 13 (15%) absent CR, and 2 (2%) spastic reactive CR. Compared with normal and borderline CRs (i.e., CR patterns with distinct, antegrade peristalsis), patients with impaired/disordered and absent CRs demonstrated significantly greater time since fundoplication (2.4 (0.6-6.8) vs. 8.9 (2.6-14.5) years; p = 0.002), greater esophageal body width on esophagram (n = 50; 2.3 (2.0-2.8) vs. 2.9 (2.4-3.6) cm; p = 0.013), and lower EGJ-DI (4.3 (2.7-5.4) vs. 2.6 (1.7-3.7) mm2/mmHg; p = 0.001). Intact fundoplications had significantly higher rates of normal CRs compared to anatomically abnormal (i.e., tight, disrupted, slipped, herniated) fundoplications (9 (28%) vs. 5 (9%); p = 0.032), but there were no differences in EGJ-DI or EGJ maximum diameter. CONCLUSIONS & INFERENCES: Symptomatic post-fundoplication patients were characterized by frequent abnormal secondary peristalsis after fundoplication, potentially worsening with time after fundoplication or related to EGJ outflow resistance.

Neurological disorders leading to mechanical dysfunction of the esophagus: an emergent behavior of a neuromechanical dynamical system.

An understanding how neurological disorders lead to mechanical dysfunction of the esophagus requires knowledge of the neural circuit of the enteric nervous system. Historically, this has been elusive. Here, we present an empirically guided neural circuit for the esophagus. It has a chain of unidirectionally coupled relaxation oscillators, receiving excitatory signals from stretch receptors along the esophagus. The resulting neuromechanical model reveals complex patterns and behaviors that emerge from interacting components in the system. A wide variety of clinically observed normal and abnormal esophageal responses to distension are successfully predicted. Specifically, repetitive antegrade contractions (RACs) are conclusively shown to emerge from the coupled neuromechanical dynamics in response to sustained volumetric distension. Normal RACs are shown to have a robust balance between excitatory and inhibitory neuronal populations, and the mechanical input through stretch receptors. When this balance is affected, contraction patterns akin to motility disorders are observed. For example, clinically observed repetitive retrograde contractions emerge due to a hyper stretch sensitive wall. Such neuromechanical insights could be crucial to eventually develop targeted pharmacological interventions.

Effect of esophageal body recoil on clinical outcomes in non-spastic achalasia.

BACKGROUND: Despite the established efficacy of achalasia treatments on symptomatic outcomes, there are limited data evaluating the treatment effect on esophageal dilatation. This study aimed to assess the effect achalasia treatment on esophageal dilatation and the effect of esophageal width reduction ("recoil") on clinical outcomes. METHODS: Patients with type I or type II achalasia that completed high-resolution manometry (HRM), functional lumen imaging probe (FLIP), and timed barium esophagram (TBE) pre and post treatment were included. Esophageal width was measured using TBE. Focused subgroup analysis was performed on patients with normal posttreatment EGJ opening on FLIP. Good clinical outcomes were defined as barium column height of <5 cm at 5 min and Eckardt Score ≤3. KEY RESULTS: Sixty-nine patients (41% type I and 59% type II) were included. Esophageal width decreased from pre to post treatment mean (SD) 4.2 (1.3) cm-2.8 (1.2) cm; p < 0.01. In the normal post treatment EGJ opening subgroup, esophageal width was less in patients with good TBE outcome compared to poor outcome mean (SD) 2.2 (0.7) cm versus 3.2 (1.4) cm (p < 0.01), but did not differ in good versus poor symptomatic outcome groups. Esophageal width recoil >25% posttreatment was associated with a greater rate of good TBE outcome (71% vs. 50%, p = 0.04) and good symptomatic outcome (88% vs. 50%; p = 0.04). CONCLUSIONS AND INFERENCES: Esophageal recoil was associated with good achalasia treatment outcome in patients without posttreatment EGJ obstruction. This suggests that mechanical properties of the esophageal wall, likely associated with tissue remodeling, play a role in clinical outcomes following achalasia treatment.

Enhancing Chicago Classification diagnoses with functional lumen imaging probe-mechanics (FLIP-MECH).

BACKGROUND: Esophageal motility disorders can be diagnosed by either high-resolution manometry (HRM) or the functional lumen imaging probe (FLIP) but there is no systematic approach to synergize the measurements of these modalities or to improve the diagnostic metrics that have been developed to analyze them. This work aimed to devise a formal approach to bridge the gap between diagnoses inferred from HRM and FLIP measurements using deep learning and mechanics. METHODS: The "mechanical health" of the esophagus was analyzed in 740 subjects including a spectrum of motility disorder patients and normal subjects. The mechanical health was quantified through a set of parameters including wall stiffness, active relaxation, and contraction pattern. These parameters were used by a variational autoencoder to generate a parameter space called virtual disease landscape (VDL). Finally, probabilities were assigned to each point (subject) on the VDL through linear discriminant analysis (LDA), which in turn was used to compare with FLIP and HRM diagnoses. RESULTS: Subjects clustered into different regions of the VDL with their location relative to each other (and normal) defined by the type and severity of dysfunction. The two major categories that separated best on the VDL were subjects with normal esophagogastric junction (EGJ) opening and those with EGJ obstruction. Both HRM and FLIP diagnoses correlated well within these two groups. CONCLUSION: Mechanics-based parameters effectively estimated esophageal health using FLIP measurements to position subjects in a 3-D VDL that segregated subjects in good alignment with motility diagnoses gleaned from HRM and FLIP studies.

Management advice for patients with reflux-like symptoms: an evidence-based consensus.

Patients with reflux-like symptoms (heartburn and regurgitation) are often not well advised on implementing individualised strategies to help control their symptoms using dietary changes, lifestyle modifications, behavioural changes or fast-acting rescue therapies. One reason for this may be the lack of emphasis in management guidelines owing to 'low-quality' evidence and a paucity of interventional studies. Thus, a panel of 11 gastroenterologists and primary care doctors used the Delphi method to develop consolidated advice for patients based on expert consensus. A steering committee selected topics for literature searches using the PubMed database, and a modified Delphi process including two online meetings and two rounds of voting was conducted to generate consensus statements based on prespecified criteria (67% voting 'strongly agree' or 'agree with minor reservation'). After expert discussion and two rounds of voting, 21 consensus statements were generated, and assigned strength of evidence and Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) rating. Eleven statements achieved the strongest (100%) agreement: five are related to diet and include identification and avoidance of dietary triggers, limiting alcohol, coffee and carbonated beverages, and advising patients troubled by postprandial symptoms not to overeat; the remaining six statements concern advice around smoking cessation, weight loss, raising the head-of-the-bed, avoiding recumbency after meals, stress reduction and alginate use. The aim of developing the consensus statements is that they may serve as a foundation for tools and advice that can routinely help patients with reflux-like symptoms better understand the causes of their symptoms and manage their individual risk factors and triggers.