Spatial and structural characteristics of the ecological network of carbon metabolism of cultivated land based on land use and cover change: a case study of Nanchang, China.

This paper explored the ecological network of CMCL (carbon metabolism of cultivated land) of Nanchang City from 2000 to 2020 to promote the low-carbon land management and China's dual carbon goals. We found that vertical and horizontal net carbon flow of cultivated land was negative during 2000-2020, and harmful carbon flow was mainly generated by the conversion of cultivated land to transportation and industrial land. Cultivated land contributed the most of the total carbon throughflow, accounting for 56.16%. Furthermore, exploitation and control relationships made maximal contribution to ecological relationships (45.83%), followed by competition relationships and mutualism relationships. In addition, ecological utility index showed the ecological network of CMCL is unhealthy. We suggest that it is necessary to achieve healthy and orderly operation of the ecological network of CMCL to reduce carbon emissions.

Remediation characteristics of surfactant-enhanced air sparging (SEAS) technology on volatile organic compounds contaminated soil with low permeability.

Surfactant-enhanced air sparging (SEAS) is an effective technology for the remediation of volatile organic compounds contamination of medium and high-permeability soil, though applying SEAS to low-permeability soil contamination has rarely been explored. In this study, a series of two-dimensional physical model tests were designed to explore the feasibility and remediation characteristics of SEAS on low-permeability soil. In the test results, the incorporation and increase in surfactant concentration promoted air channel formation in the low-permeability soil, finally reduced the capillary breakthrough pressure and improved the airflow rate. The majority of the exhausted gaseous contaminants were distributed along the horizontal direction, differing from the results observed in medium and high-permeability soils. The exhausted gaseous contaminant concentration changed slightly when the sparging pressure and surfactant concentration increased at relatively low levels and increased as the sparging pressure and surfactant concentration increased further. Increasing the air sparging pressure without surfactant incorporation or with a low surfactant concentration cannot effectively remove the contaminant, while the removal efficiency can be enhanced with further increases in surfactant concentration. The discrete remediation characteristics had been confirmed during SEAS application on low-permeability soil, then the relationships between the ratios of remediation area and remediation extent under different surfactant concentrations and sparging pressures were established for remediation efficiency evaluation. Using this method, the discrete remediation characteristics can be recreated once the surfactant concentration and the sparging pressure were chosen. On the other side, targeted improvements in the remediation area or extent can be achieved by controlling the surfactant concentration and sparging pressure. Through this study, SEAS technology and the proposed evaluation method were successfully implemented in soil with hydraulic conductivity around 9E-7 m/s, which expanded the application scope of SEAS technology for contaminant removal.

Chaotic peak propagation in patients with Jackhammer esophagus.

BACKGROUND: The contractile activity of Jackhammer esophagus(JE) is heterogeneous and abnormalities in the balance of pre- and post-peak contractile activity has been reported. We observed that the progression of the peak contraction is disordered in JE patients, which reflect underlying abnormalities in the inhibitory and excitatory influence in esophageal contraction. In order to better define this abnormality, we developed novel time metrics to define trajectory of the pressure wave peak and assessed it in healthy controls and JE patients. METHODS: 38 patients with JE (ages 43-70, 19 females) and 71 asymptomatic controls (ages 19-48; 33 females) were retrospectively evaluated. High resolution manometry was performed in all subjects with 10 supine liquid swallows. The first 5 intact supine swallows and supine swallow with the greatest DCI were analyzed using ManoView™ software and customized MATLAB program. The time distance, negative time distance sum and chaotic ratio were calculated. JE patients were subcategorized by the Brief Esophageal Dysphagia Questionnaire (BEDQ) with cut-off of 6. KEY RESULTS: Jackhammer patients had longer time distance, longer negative time distance, and higher chaotic ratio than controls( p < 0.001). The distribution of the number of negative time distances differed between JE patients with BEDQ>6 and BEDQ≤6. CONCLUSIONS & INFERENCES: The trajectory of the pressure wave peak propagation commonly occurred in an unordered fashion in JE, but rarely in controls. Additionally, differences in pressure propagation trajectory was associated with higher symptom scores thus trajectory of the pressure wave peak may be an important marker of abnormal esophageal motor function.

Esophageal motility classification can be established at the time of endoscopy: a study evaluating real-time functional luminal imaging probe panometry.

BACKGROUND AND AIMS: A novel device that provides real-time depiction of functional luminal image probe (FLIP) panometry (ie, esophagogastric junction [EGJ] distensibility and distension-induced contractility) was evaluated. We aimed to compare real-time FLIP panometry interpretation at the time of sedated endoscopy with high-resolution manometry (HRM) in evaluating esophageal motility. METHODS: Forty consecutive patients (aged 24-81 years; 60% women) referred for endoscopy with a plan for future HRM from 2 centers were prospectively evaluated with real-time FLIP panometry during sedated upper endoscopy. The EGJ distensibility index and contractility profile were applied to derive a FLIP panometry classification at the time of endoscopy and again (post-hoc) using a customized program. HRM was classified according to the Chicago classification. RESULTS: Real-time FLIP panometry motility classification was abnormal in 29 patients (73%), 19 (66%) of whom had a subsequent major motility disorder on HRM. All 9 patients with an HRM diagnosis of achalasia had abnormal real-time FLIP panometry classifications. Eleven patients (33%) had normal motility on real-time FLIP panometry and 8 (73%) had a subsequent HRM without a major motility disorder. There was excellent agreement (κ = .939) between real-time and post-hoc FLIP panometry interpretation of abnormal motility. CONCLUSIONS: This prospective, multicentered study demonstrated that real-time FLIP panometry could detect abnormal esophageal motility, including achalasia, at the endoscopic encounter. Additionally, normal motility on FLIP panometry was predictive of a benign HRM. Thus, real-time FLIP panometry incorporated with endoscopy appears to provide a suitable and well-tolerated point-of-care esophageal motility assessment.

Normal Values of Esophageal Distensibility and Distension-Induced Contractility Measured by Functional Luminal Imaging Probe Panometry.

BACKGROUND & AIMS: Functional luminal imaging probe (FLIP) panometry provides a comprehensive evaluation of esophageal functional at the time of endoscopy, including assessment of esophageal distensibility and distension-induced esophageal contractility. However, the few and inconsistent findings from healthy individuals pose challenges to the application of FLIP to research and clinical practice. We performed FLIP panometry in asymptomatic volunteers. METHODS: We performed a prospective study of 20 asymptomatic volunteers (ages, 23-44; 14 women) who were evaluated with 16-cm FLIP positioned across the esophagogastric junction (EGJ) and distal esophagus (and in 8 subjects also repositioned at the proximal esophagus) during sedated upper endoscopy. FLIP data were analyzed with a customized program that generated FLIP panometry plots and calculated the EGJ-distensibility index (DI) and distensibility plateaus (DP) of distal and proximal esophageal body. Distension-induced esophageal contractility was also assessed. RESULTS: The median EGJ-DI was 5.8 mm2/mm Hg (interquartile range [IQR], 4.9-6.7 mm2/mm Hg); all 20 subjects had an EGJ-DI greater than 2.8 mm2/mm Hg. The median DP values from all subjects tested were 20.2 mm (IQR, 19.8-20.8 mm) at the distal body, 21.1 mm (IQR, 20.3-22.9 mm) at the proximal body, and greater than 18 mm at both locations. Repetitive antegrade contractions (RACs) were observed in all 20 subjects; in 19 of 20 (95%) subjects, the RAC pattern persisted for 10 or more consecutive antegrade contractions. CONCLUSIONS: Normal parameters of FLIP panometry are EGJ-DI greater than 2.8 mm2/mm Hg, DP greater than 18 mm, and antegrade contractions that occur in a repetitive pattern (RACs)-these can be used as normal findings for esophageal distensibility and distension-induced contractility. These values can be used in comparative studies of esophageal diseases, such as achalasia and eosinophilic esophagitis, and will facilitate application of FLIP panometry to clinical practice.

High-resolution impedance manometry parameters in the evaluation of esophageal function of non-obstructive dysphagia patients.

BACKGROUND: High-resolution impedance manometry (HRIM) allows evaluation of esophageal bolus retention, flow, and pressurization. We explored novel HRIM measures and assessed their temporal relationship to dysphagia symptoms for boluses of different volume and consistency in non-obstructive dysphagia (NOD) patients. METHODS: Thirty-three NOD patients (n = 19 minor or no disorder of peristalsis ("Normal") and n = 14 esophagogastric junction outflow obstruction ("EGJOO")) were evaluated with HRIM. Patients were administered 5 and 10 mL liquid, semisolid, and 2 and 4 cm solid boluses and indicated bolus perception during individual swallows using a 5-point Likert scale. HRIM was analyzed to assess Chicago Classification and pressure flow metrics, esophageal impedance integral (EII) ratio, and bolus flow time (BFT). KEY RESULTS: Overall, bolus perception increased with increasing bolus consistency (P < 0.001), but did not differ significantly between EGJOO and Normal patients. EGJOO patients had higher IRP4, higher levels of bolus residual (ie, EII ratio and IR), and restricted esophageal emptying. The results for linking semisolid bolus perception to semisolid-derived measures revealed more biomechanically plausible and consistent patterns when compared to those derived for liquid boluses. In Normal patients, perception of boluses of heavier viscosity was related to higher bolus flow resistance during transport, whilst in EGJOO, perception was related to restriction of esophageal emptying. CONCLUSION & INFERENCES: These novel pressure-impedance measures may aid in the evaluation of NOD patients by revealing abnormal motor patterns, which may explain symptom generation. Future studies are needed to evaluate which of these measures are worthy of calculation and to establish protocol settings that allow for their meaningful interpretation.

Mechanisms of repetitive retrograde contractions in response to sustained esophageal distension: a study evaluating patients with postfundoplication dysphagia.

Repetitive retrograde contractions (RRCs) in response to sustained esophageal distension are a distinct contractility pattern observed with functional luminal imaging probe (FLIP) panometry that are common in type III (spastic) achalasia. RRCs are hypothesized to be indicative of either impaired inhibitory innervation or esophageal outflow obstruction. We aimed to apply FLIP panometry to patients with postfundoplication dysphagia (a model of esophageal obstruction) to explore mechanisms behind RRCs. Adult patients with dysphagia after Nissen fundoplication ( n = 32) or type III achalasia ( n = 25) were evaluated with high-resolution manometry (HRM) and upper endoscopy with FLIP. HRM studies were assessed for outflow obstruction and spastic features: premature contractility, hypercontractility, and impaired deglutitive inhibition during multiple-rapid swallows. FLIP studies were analyzed to determine the esophagogastric junction (EGJ)-distensibility index and contractility pattern, including RRCs. Barium esophagram was evaluated when available. RRCs were present in 8/32 (25%) fundoplication and 19/25 (76%) achalasia patients ( P < 0.001). EGJ outflow obstruction was detected in 21 (67%) fundoplication patients by HRM, FLIP, or esophagram [6 (29%) had RRCs]. On HRM, none of the fundoplication patients had premature contractility, whereas 3/4 with defective inhibition on multiple-rapid swallows and 2/4 with hypercontractility had RRCs. Regression analysis demonstrated HRM with spastic features, but not esophageal outflow obstruction, as a predictor for RRCs. RRCs in response to sustained esophageal distension appear to be a manifestation of spastic esophageal motility. Although future study to further clarify the significance of RRCs is needed, RRCs on FLIP panometry should prompt evaluation for a major motor disorder. NEW & NOTEWORTHY Repetitive retrograde contractions (RRCs) are a common response to sustained esophageal distension among spastic achalasia patients when evaluated with the functional luminal imaging probe. We evaluated patients with postfundoplication dysphagia, i.e., patients with suspected mechanical obstruction, and found that RRCs occasionally occurred among postfundoplication patients, but often in association with manometric features of esophageal neuromuscular imbalance. Thus, RRCs appear to be a manifestation of spastic esophageal dysmotility, likely from neural imbalance resulting in excess excitation.

Improved Assessment of Bolus Clearance in Patients With Achalasia Using High-Resolution Impedance Manometry.

BACKGROUND & AIMS: Esophageal retention is typically evaluated by timed-barium esophagram in patients treated for achalasia. Esophageal bolus clearance can also be evaluated using high-resolution impedance manometry. We evaluated the associations of conventional and novel high-resolution impedance manometry metrics, esophagram, and patient-reported outcomes (PROs) in achalasia. METHODS: We performed a prospective study of 70 patients with achalasia (age, 20-81 y; 30 women) treated by pneumatic dilation or myotomy who underwent follow-up evaluations from April 2013 through December 2015 (median, 12 mo after treatment; range, 3-183 mo). Patients were assessed using timed-barium esophagrams, high-resolution impedance manometry, and PROs, determined from Eckardt scores (the primary outcome) and the brief esophageal dysphagia questionnaire. Barium column height was measured from esophagrams taken 5 minutes after ingestion of barium (200 mL). Impedance-manometry was analyzed for bolus transit (dichotomized) and with a customized MATLAB program (The MathWorks, Inc, Natick, MA) to calculate the esophageal impedance integral (EII) ratio. RESULTS: Optimal cut points to identify a good PRO (defined as Eckardt score of ≤3) were esophagram barium column height of 3 cm (identified patients with a good PRO with 63% sensitivity and 75% specificity) and an EII ratio of 0.41 (identified patients with a good PRO with 83% sensitivity and 75% specificity). Complete bolus transit identified patients with a good PRO with 28% sensitivity and 75% specificity. Of the 25 patients who met these cut points for both esophagram barium column height and EII ratio, 23 (92%) had a good PRO. Of the 17 patients who met neither cut point, 14 (82%) had a poor PRO (Eckardt score above 3). CONCLUSIONS: In a prospective study of 70 patients with achalasia, we found EII ratio identified patients with good PROs with higher levels of sensitivity (same specificity) than timed-barium esophagram or impedance-manometry bolus transit assessments. The EII ratio should be added to achalasia outcome evaluations that involve high-resolution impedance manometry as an independent measure and to complement timed-barium esophagram.

Improvement in Esophageal Distensibility in Response to Medical and Diet Therapy in Eosinophilic Esophagitis.

OBJECTIVES: We aimed to evaluate the effect of medical and diet therapies on esophageal distensibility assessed using the functional lumen imaging probe (FLIP) and the association of changes in esophageal distensibility with clinical outcomes in eosinophilic esophagitis (EoE). METHODS: Patients with EoE were evaluated with FLIP during endoscopy at baseline and following therapy without interval dilatation. Evaluation also included a validated patient-reported outcome (PRO; a positive PRO was considered at a 30% score improvement), mucosal biopsies, and scoring of endoscopic features of EoE. FLIP data were analyzed to calculate the distensibility plateau (DP). RESULTS: In all, 18 patients (ages 19-54 years; 4 female) treated with topical steroid (8), elimination diet (6), and/or proton-pump inhibitor (4 only treated with proton-pump inhibitor) were included. Follow-up testing occurred at a mean (range) of 14.6 (8-28) weeks. Improvement was observed in DP (13.9 (12.2-19.2) to 16.8 mm (15.8-19.2), P=0.007) and peak eosinophil count (45 (29-65) to 23 per high-power field (h.p.f.) (5-53), P=0.042). Nine patients had a positive symptomatic outcome. Six of 8 (75%) patients with a DP increase ≥2 mm had a positive PRO (P=0.077), while 2 of 7 (29%) patients that achieved an eosinophil count <15/h.p.f. had a positive PRO (P=0.167). CONCLUSIONS: Improvement in esophageal body distensibility can be achieved with medical and diet therapies without dilation in EoE. Improved DP appeared to be better indicator of symptomatic improvement than eosinophil count, supporting FLIP as a valuable outcome measure in EoE.

Novel 3D high-resolution manometry metrics for quantifying esophagogastric junction contractility.

BACKGROUND: The esophagogastric junction (EGJ) is a complex sphincter composed of both the crural diaphragm (CD) and lower esophageal sphincter (LES). Three dimensional high-resolution manometry (3D-HRM) provides a dynamic 360° representation of EGJ pressure in which the CD has a distinct pressure signature. We aimed to develop 3D-HRM metrics to: (i) quantify the vigor of CD contractility, (ii) best eliminate the CD contribution and thereby isolate the LES component of EGJ contractility, and (iii) compare these metrics with conventional HRM metric of EGJ contractility. METHODS: Twenty healthy subjects underwent 3D-HRM studies. Two novel 3D-HRM EGJ metrics, 3D-DHA , and 3D-LES pressure (3D-LESP) were devised and calculated to best approximate the CD and LES components of the composite EGJ pressure topography. These values were then compared to conventional HRM metrics of EGJ contractility, the EGJ contractile integral (EGJ-CI), inspiratory EGJ pressure and expiratory EGJ pressure. KEY RESULTS: Mean 3D-DHA correlated most strongly with EGJ-CI (r=.82, P<.001), while the 3D-LESP correlated most strongly with inspiratory EGJ pressure (r=.91 P<.001) and expiratory EGJ pressure (r=.85, P<.001). CONCLUSIONS & INFERENCES: We devised novel 3D-HRM metrics to quantify the CD (3D-DHA ) and LES (3D-LESP) elements of EGJ contractility. Both measures correlated strongly with conventional HRM metrics of EGJ contractility. The 3D-DHA , in particular, correlated strongly with the EGJ-CI suggesting that both are largely determined by CD contractility. It is hoped that future studies will show these new metrics useful in quantifying elements of the antireflux barrier in mechanistically defined subsets of gastro-esophageal reflux disease (GERD) patients.

Developments in Gastrointestinal Electrical Stimulation.

Electrical stimulation of the gastrointestinal (GI) tract, analogous to pacing the human heart, is an attractive idea. This is because these organs, like the heart, have their own natural pacemakers, and the electrical signals they generate can be altered by externally delivering certain types of electric currents via intraluminal or serosal electrodes to certain areas of the GI tract. A number of studies on animals have been accomplished successfully to treat a variety of disease models, including gastroparesis, dumping, and short bowel syndrome. Over the past 10 years or so, electrical stimulation of the GI tract has received increasing attention among researchers and clinicians because of new techniques, such as implantable devices, and promising results achieved in treatment of gastroparesis and morbid obesity. The objective of this article is to review the advances in electrical stimulation of the gastrointestinal tract. First the electrophysiology of the GI tract and history of GI electrical stimulation are introduced. Then various methods of electrical stimulation of the stomach and small bowel in healthy animals and models of GI diseases are reviewed. Finally clinical applications of electrical stimulation to GI disorders and their possible mechanisms are discussed.

Evaluation of Esophageal Motility Utilizing the Functional Lumen Imaging Probe.

OBJECTIVES: Esophagogastric junction (EGJ) distensibility and distension-mediated peristalsis can be assessed with the functional lumen imaging probe (FLIP) during a sedated upper endoscopy. We aimed to describe esophageal motility assessment using FLIP topography in patients presenting with dysphagia. METHODS: In all, 145 patients (aged 18-85 years, 54% female) with dysphagia that completed upper endoscopy with a 16-cm FLIP assembly and high-resolution manometry (HRM) were included. HRM was analyzed according to the Chicago Classification of esophageal motility disorders; major esophageal motility disorders were considered "abnormal". FLIP studies were analyzed using a customized program to calculate the EGJ-distensibility index (DI) and generate FLIP topography plots to identify esophageal contractility patterns. FLIP topography was considered "abnormal" if EGJ-DI was <2.8 mm2/mm Hg or contractility pattern demonstrated absent contractility or repetitive, retrograde contractions. RESULTS: HRM was abnormal in 111 (77%) patients: 70 achalasia (19 type I, 39 type II, and 12 type III), 38 EGJ outflow obstruction, and three jackhammer esophagus. FLIP topography was abnormal in 106 (95%) of these patients, including all 70 achalasia patients. HRM was "normal" in 34 (23%) patients: five ineffective esophageal motility and 29 normal motility. In all, 17 (50%) had abnormal FLIP topography including 13 (37%) with abnormal EGJ-DI. CONCLUSIONS: FLIP topography provides a well-tolerated method for esophageal motility assessment (especially to identify achalasia) at the time of upper endoscopy. FLIP topography findings that are discordant with HRM may indicate otherwise undetected abnormalities of esophageal function, thus FLIP provides an alternative and complementary method to HRM for evaluation of non-obstructive dysphagia.

High-Resolution Impedance Manometry Metrics of the Esophagogastric Junction for the Assessment of Treatment Response in Achalasia.

OBJECTIVES: We aimed to evaluate the value of novel high-resolution impedance manometry (HRIM) metrics, bolus flow time (BFT), and esophagogastric junction (EGJ) contractile integral (CI), as well as EGJ pressure (EGJP) and the integrated relaxation pressure (IRP), as indicators of treatment response in achalasia. METHODS: We prospectively evaluated 75 patients (ages 19-81, 32 female) with achalasia during follow-up after pneumatic dilation or myotomy with Eckardt score (ES), timed-barium esophagram (TBE), and HRIM. Receiver-operating characteristic (ROC) curves for good symptomatic outcome (ES≤3) and good radiographic outcome (TBE column height at 5 min<5 cm) were generated for each potential predictor of treatment response (EGJP, IRP, BFT, and EGJ-CI). RESULTS: Follow-up occurred at a median (range) 12 (3-291) months following treatment. A total of 49 patients had good symptomatic outcome and 46 had good radiographic outcome. The area-under-the-curves (AUCs) on the ROC curve for symptomatic outcome were 0.55 (EGJP), 0.62 (IRP), 0.77 (BFT) and 0.56 (EGJ-CI). The AUCs for radiographic outcome were 0.64 (EGJP), 0.48 (IRP), 0.73 (BFT), and 0.65 (EGJ-CI). Optimal cut-points were determined as 11 mm Hg (EGJP), 12 mm Hg (IRP), 0 s (BFT), and 30 mm Hg•cm (EGJ-CI) that provided sensitivities/specificities of 57%/46% (EGJP), 65%/58% (IRP), 78%/77% (BFT), and 53%/62% (EGJ-CI) to predict symptomatic outcome and 57%/66% (EGJP), 57%/41% (IRP), 76%/69% (BFT), and 57%/66% (EGJ-CI) to predict radiographic outcome. CONCLUSIONS: BFT, a novel HRIM metric, provided an improved functional assessment over manometric measures of EGJP, IRP, and EGJ-CI at follow-up after achalasia treatment and may help direct clinical management.

Severity of endoscopically identified esophageal rings correlates with reduced esophageal distensibility in eosinophilic esophagitis.

BACKGROUND/AIMS: A grading system for the endoscopic features of eosinophilic esophagitis (EoE) has recently been validated. The EoE Endoscopic Reference Score (EREFS) incorporates both inflammatory and remodeling features of EoE. High resolution impedance planimetry using the functional luminal imaging probe (FLIP) is a technique for quantification of esophageal remodeling. The aim of this study was to evaluate the association between endoscopic severity with EREFS and esophageal distensibility as measured with the FLIP. METHODS: Upper gastrointestinal endoscopy with biopsies and FLIP were performed in 72 adults with EoE. Endoscopic features of edema, rings, exudates, furrows, and stricture were evaluated using the EREFS system. Esophageal distensibility metrics obtained by FLIP, including the distensibility slope and distensibility plateau, were compared with EREFS parameters. Bivariate associations between EREFS parameters and histologic eosinophil density were assessed. RESULTS: Higher ring scores were associated with a lower distensibility plateau (rs = -0.46; P < 0.0001). An association was found between severity of exudates and eosinophil density (rs = 0.27; P = 0.02), as well as between furrows and eosinophil density (rs = 0.49; P < 0.0001). Severity of exudates and furrows, and degree of eosinophilia were not associated with the distensibility parameters. CONCLUSIONS: Endoscopic assessment of ring severity can serve as a marker for esophageal remodeling and may be useful for food impaction risk stratification in EoE. Eosinophil count was not significantly associated with esophageal distensibility, consistent with previous reports of dissociation between inflammatory activity and fibrostenosis in EoE. Endoscopic inflammatory features show a weak correlation with histopathology but should not replace histologic indices of inflammation.

The effect of incremental distal gastric myotomy lengths on EGJ distensibility during POEM for achalasia.

BACKGROUND: During peroral esophageal myotomy (POEM) for the treatment of achalasia, the optimal distal gastric myotomy length is unknown. In this study, we used a functional lumen imaging probe (FLIP) to intraoperatively measure the effect of variable distal myotomy lengths on esophagogastric junction (EGJ) distensibility. METHODS: EGJ distensibility index (DI) (minimum cross-sectional area divided by intrabag pressure) was measured with FLIP after each operative step. Each patient's myotomy was performed in four increments from proximal to distal: (1) an esophageal myotomy (from 6 cm proximal to the EGJ to 1 cm proximal to it), (2) a myotomy ablating the lower esophageal sphincter (LES) complex (from 1 cm proximal to the EGJ to 1 cm distal to it), (3) an initial gastric extension (from 1 cm distal to the EGJ to 2 cm distal), and (4) a final gastric extension (from 2 cm distal to the EGJ to 3 cm distal). RESULTS: Measurements were taken in 16 achalasia patients during POEM. POEM resulted in an overall increase in DI (pre 1.2 vs. post 7.2 mm(2)/mmHg, p < .001). Initial creation of the submucosal tunnel resulted in a threefold increase in DI (1.2 vs. 3.6 mm(2)/mmHg, p < .001). When the myotomy was then performed in a stepwise fashion from proximal to distal, the initial esophageal myotomy component had no effect on DI. Subsequent myotomy extension across the LES complex resulted in an increase in DI, as did the initial gastric myotomy extension (to 2 cm distal to the EGJ). The final gastric myotomy extension (to 3 cm distal) had no further effect. CONCLUSIONS: During POEM, creation of the submucosal tunnel prior to myotomy resulted in a marked improvement in EGJ physiology. Myotomy extension across the LES complex and to 2 cm onto the gastric wall resulted in the normalization of EGJ distensibility, whereas subsequent extension to 3 cm distal to the EGJ did not increase compliance further.

The Functional Lumen Imaging Probe Detects Esophageal Contractility Not Observed With Manometry in Patients With Achalasia.

BACKGROUND & AIMS: The functional lumen imaging probe (FLIP) could improve the characterization of achalasia subtypes by detecting nonocclusive esophageal contractions not observed with standard manometry. We aimed to evaluate esophageal contractions during volumetric distention in patients with achalasia using FLIP topography. METHODS: Fifty-one treatment-naive patients with achalasia, defined and subclassified by high-resolution esophageal pressure topography, and 10 asymptomatic individuals (controls) were evaluated with the FLIP during endoscopy. During stepwise distension, simultaneous intrabag pressures and 16 channels of cross-sectional areas were measured; data were exported to software that generated FLIP topography plots. Esophageal contractility was identified by noting periods of reduced luminal diameter. Esophageal contractions were characterized further by propagation direction, repetitiveness, and based on whether they were occluding or nonoccluding. RESULTS: Esophageal contractility was detected in all 10 controls: 8 of 10 had repetitive antegrade contractions and 9 of 10 had occluding contractions. Contractility was detected in 27% (4 of 15) of patients with type I achalasia and in 65% (18 of 26, including 9 with occluding contractions) of patients with type II achalasia. Contractility was detected in all 10 patients with type III achalasia; 8 of these patients had a pattern of contractility that was not observed in controls (repetitive retrograde contractions). CONCLUSIONS: Esophageal contractility not observed with manometry can be detected in patients with achalasia using FLIP topography. The presence and patterns of contractility detected with FLIP topography may represent variations in pathophysiology, such as mechanisms of panesophageal pressurization in patients with type II achalasia. These findings could have implications for additional subclassification to supplement prediction of the achalasia disease course.

Esophagogastric junction distensibility measurements during Heller myotomy and POEM for achalasia predict postoperative symptomatic outcomes.

BACKGROUND: The functional lumen imaging probe (FLIP) is a novel diagnostic tool that can be used to measure esophagogastric junction (EGJ) distensibility. In this study, we performed intraoperative FLIP measurements during laparoscopic Heller myotomy (LHM) and peroral esophageal myotomy (POEM) for treatment of achalasia and evaluated the relationship between EGJ distensibility and postoperative symptoms. METHODS: Distensibility index (DI) (defined as the minimum cross-sectional area at the EGJ divided by distensive pressure) was measured with FLIP at two time points during LHM and POEM: (1) at baseline after induction of anesthesia, and (2) after operation completion. RESULTS: Measurements were performed in 20 patients undergoing LHM and 36 undergoing POEM. Both operations resulted in an increase in DI, although this increase was larger with POEM (7 ± 3.1 vs. 5.1 ± 3.4 mm(2)/mmHg, p < .05). The two patients (both LHM) with the smallest increases in DI (1 and 1.6 mm(2)/mmHg) both had persistent symptoms postoperatively and, overall, LHM patients with larger increases in DI had lower postoperative Eckardt scores. In the POEM group, there was no correlation between change in DI and symptoms; however, all POEM patients experienced an increase in DI of >3 mm(2)/mmHg. When all patients were divided into thirds based on final DI, none in the lowest DI group (<6 mm(2)/mmHg) had symptoms suggestive of reflux (i.e., GerdQ score >7), as compared with 20 % in the middle third (6-9 mm(2)/mmHg) and 36 % in the highest third (>9 mm(2)/mmHg). Patients within an "ideal" final DI range (4.5-8.5 mm(2)/mmHg) had optimal symptomatic outcomes (i.e., Eckardt ≤ 1 and GerdQ ≤ 7) in 88 % of cases, compared with 47 % in those with a final DI above or below that range (p < .05). CONCLUSIONS: Intraoperative EGJ distensibility measurements with FLIP were predictive of postoperative symptomatic outcomes. These results provide initial evidence that FLIP has the potential to act as a useful calibration tool during operations for achalasia.

The four phases of esophageal bolus transit defined by high-resolution impedance manometry and fluoroscopy.

We aimed to model esophageal bolus transit based on esophageal pressure topography (EPT) landmarks, concurrent intrabolus pressure (IBP), and esophageal diameter as defined with fluoroscopy. Ten healthy subjects were studied with high-resolution impedance manometry and videofluoroscopy. Data from four 5-ml barium swallows (2 upright, 2 supine) in each subject were analyzed. EPT landmarks were utilized to divide bolus transit into four phases: phase I, upper esophageal sphincter (UES) opening; phase II, UES closure to the transition zone (TZ); phase III, TZ to contractile deceleration point (CDP); and phase IV, CDP to completion of bolus emptying. IBP and esophageal diameter were analyzed to define functional differences among phases. IBP exhibited distinct changes during the four phases of bolus transit. Phase I was associated with filling via passive dilatation of the esophagus and IBP reflective of intrathoracic pressure. Phase II was associated with auxotonic relaxation and compartmentalization of the bolus distal to the TZ. During phase III, IBP exhibited a slow increase with loss of volume related to peristalsis (auxotonic contraction) and passive dilatation in the distal esophagus. Phase IV was associated with the highest IBP and exhibited isometric contraction during periods of nonemptying and auxotonic contraction during emptying. IBP may be used as a marker of esophageal wall state during the four phases of esophageal bolus transit. Thus abnormalities in IBP may identify subtypes of esophageal disease attributable to abnormal distensibility or neuromuscular dysfunction.

Flow time through esophagogastric junction derived during high-resolution impedance-manometry studies: a novel parameter for assessing esophageal bolus transit.

This study aimed to develop and validate a method to measure bolus flow time (BFT) through the esophagogastric junction (EGJ) using a high-resolution impedance-manometry (HRIM) sleeve. Ten healthy subjects were studied with concurrent HRIM and videofluoroscopy; another 15 controls were studied with HRIM alone. HRIM studies were performed using a 4.2-mm-outer diameter assembly with 36 pressure sensors at 1-cm intervals and 18 impedance segments at 2-cm intervals (Given Imaging, Los Angeles, CA). HRIM and fluoroscopic data from four barium swallows, two in the supine and two in the upright position, were analyzed to create a customized MATLAB program to calculate BFT using a HRIM sleeve comprising three sensors positioned at the crural diaphragm. Bolus transit through the EGJ measured during blinded review of fluoroscopy was almost identical to BFT calculated with the HRIM sleeve, with the nadir impedance deflection point used as the signature of bolus presence. Good correlation existed between videofluoroscopy for measurement of upper sphincter relaxation to beginning of flow [R = 0.97, P < 0.001 (supine) and R = 0.77, P < 0.01 (upright)] and time to end of flow [R = 0.95, P < 0.001 (supine) and R = 0.82, P < 0.01 (upright)]. The medians and interquartile ranges (IQR) of flow time though the EGJ in 15 healthy subjects calculated using the virtual sleeve were 3.5 s (IQR 2.3-3.9 s) in the supine position and 3.2 s (IQR 2.3-3.6 s) in the upright position. BFT is a new metric that provides important information about bolus transit through the EGJ. An assessment of BFT will determine when the EGJ is open and will also provide a useful method to accurately assess trans-EGJ pressure gradients during flow.

An extended proximal esophageal myotomy is necessary to normalize EGJ distensibility during Heller myotomy for achalasia, but not POEM.

BACKGROUND: For laparoscopic Heller myotomy (LHM), the optimal myotomy length proximal to the esophagogastric junction (EGJ) is unknown. In this study, we used a functional lumen imaging probe (FLIP) to measure EGJ distensibility changes resulting from variable proximal myotomy lengths during LHM and peroral esophageal myotomy (POEM). METHODS: Distensibility index (DI) (defined as the minimum cross-sectional area at the EGJ divided by pressure) was measured with FLIP after each operative step. During LHM and POEM, each patient's myotomy was performed in two stages: first, a myotomy ablating only the EGJ complex was created (EGJ-M), extending from 2 cm proximal to the EGJ, to 3 cm distal to it. Next, the myotomy was lengthened 4 cm further cephalad to create an extended proximal myotomy (EP-M). RESULTS: Measurements were performed in 12 patients undergoing LHM and 19 undergoing POEM. LHM resulted in an overall increase in DI (1.6 ± 1 vs. 6.3 ± 3.4 mm(2)/mmHg, p < 0.001). Creation of an EGJ-M resulted in a small increase (1.6-2.3 mm(2)/mmHg, p < 0.01) and extension to an EP-M resulted in a larger increase (2.3-4.9 mm(2)/mmHg, p < 0.001). This effect was consistent, with 11 (92%) patients experiencing a larger increase after EP-M than after EGJ-M. Fundoplication resulted in a decrease in DI and deinsufflation an increase. POEM resulted in an increase in DI (1.3 ± 1 vs. 9.2 ± 3.9 mm(2)/mmHg, p < 0.001). Both creation of the submucosal tunnel and performing an EGJ-M increased DI, whereas lengthening of the myotomy to an EP-M had no additional effect. POEM resulted in a larger overall increase from baseline than LHM (7.9 ± 3.5 vs. 4.7 ± 3.3 mm(2)/mmHg, p < 0.05). CONCLUSIONS: During LHM, an EP-M was necessary to normalize distensibility, whereas during POEM, a myotomy confined to the EGJ complex was sufficient. In this cohort, POEM resulted in a larger overall increase in EGJ distensibility.