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.

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.

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.

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.

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.

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.

Lack of correlation between HRM metrics and symptoms during the manometric protocol.

OBJECTIVES: Although esophageal motor disorders are associated with chest pain and dysphagia, minimal data support a direct relationship between abnormal motor function and symptoms. This study investigated whether high-resolution manometry (HRM) metrics correlate with symptoms. METHODS: Consecutive HRM patients without previous surgery were enrolled. HRM studies included 10 supine liquid, 5 upright liquid, 2 upright viscous, and 2 upright solid swallows. All patients evaluated their esophageal symptom for each upright swallow. Symptoms were graded on a 4-point likert score (0, none; 1, mild; 2, moderate; 3, severe). The individual liquid, viscous or solid upright swallow with the maximal symptom score was selected for analysis in each patient. HRM metrics were compared between groups with and without symptoms during the upright liquid protocol and the provocative protocols separately. RESULTS: A total of 269 patients recorded symptoms during the upright liquid swallows and 72 patients had a swallow symptom score of 1 or greater. Of the 269 patients, 116 recorded symptoms during viscous or solid swallows. HRM metrics were similar between swallows with and without associated symptoms in the upright, viscous, and solid swallows. No correlation was noted between HRM metrics and symptom scores among swallow types. CONCLUSIONS: Esophageal symptoms are not related to abnormal motor function defined by HRM during liquid, viscous or solid bolus swallows in the upright position. Other factors beyond circular muscle contraction patterns should be explored as possible causes of symptom generation.

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.

Esophageal distensibility as a measure of disease severity in patients with eosinophilic esophagitis.

BACKGROUND & AIMS: The aim of this study was to assess whether measurements of esophageal distensibility, made by high-resolution impedance planimetry, correlated with important clinical outcomes in patients with eosinophilic esophagitis. METHODS: Seventy patients with eosinophilic esophagitis (50 men; age, 18-68 y) underwent endoscopy with esophageal biopsy collection and high-resolution impedance planimetry using the functional lumen-imaging probe. The patients were followed up prospectively for an average of 9.2 months (range, 3-14 mo), and the risk of food impaction, requirement for dilation, and symptom severity during the follow-up period was determined from medical records. Esophageal distensibility metrics and the severity of mucosal eosinophilia at baseline were compared between patients presenting with and without food impaction and those requiring or not requiring esophageal dilation. Logistic regression and stratification assessments were used to assess the predictive value of esophageal distensibility metrics in assessing risk of food impaction, the need for dilation, and continued symptoms. RESULTS: Patients with prior food impactions had significantly lower distensibility plateau (DP) values than those with solid food dysphagia alone. In addition, patients sustaining food impaction and requiring esophageal dilation during the follow-up period had significantly lower DP values than those who did not. The severity of mucosal eosinophilia did not correlate with risk for food impaction, the requirement for dilation during follow-up evaluation, or DP values. CONCLUSIONS: Reduced esophageal distensibility predicts risk for food impaction and the requirement for esophageal dilation in patients with eosinophilic esophagitis. The severity of mucosal eosinophilia was not predictive of these outcomes and had a poor correlation with esophageal distensibility.

Comparison of esophagogastric junction distensibility changes during POEM and Heller myotomy using intraoperative FLIP.

BACKGROUND: Peroral endoscopic myotomy (POEM) is a novel endoscopic surgical procedure for the treatment of achalasia. The comparative effects of POEM and laparoscopic Heller myotomy (LHM) on esophagogastric junction (EGJ) physiology are unknown. A novel measurement catheter, the functional lumen imaging probe (FLIP), allows for intraoperative evaluation of EGJ compliance by measuring luminal geometry and pressure during volume-controlled distensions. METHODS: Distensibility index (DI) (defined as the minimum cross-sectional area at the EGJ divided by pressure) was measured with FLIP intraoperatively in patients undergoing LHM and POEM. Separate measurements were taken after each operative step. During LHM, measurements were performed after: (1) induction of anesthesia, (2) insufflation of pneumoperitoneum, (3) hiatal dissection and esophageal mobilization, (4) myotomy, (5) partial fundoplication, and (6) deinsufflation. During POEM, they were performed after: (1) induction of anesthesia, (2) submucosal tunnel creation, and (3) myotomy. RESULTS: Eleven LHM and 14 POEM patients underwent intraoperative FLIP. Baseline DI was similar between groups. LHM resulted in an overall increase in mean DI (pre 1.4 vs. post 7.6 mm(2)/mmHg, using a 40-ml distension volume; p < 0.001). Insufflation of pneumoperitoneum and hiatal dissection did not affect DI. Myotomy caused an increase in DI. Partial fundoplication (6 Toupet, 5 Dor) caused a decrease in DI, and deinsufflation caused an increase in DI. POEM also resulted in an overall increase in mean DI (pre 1.4 vs. post 7.9 mm(2)/mmHg; p < 0.001). Measured individually, both submucosal tunnel creation and myotomy caused increases in DI. When overall changes were compared, there were no differences in the amount of DI increase between LHM and POEM. CONCLUSIONS: POEM and LHM result in a similar improvement in EGJ distensibility intraoperatively. Further study is needed to correlate intraoperative FLIP measurements with postoperative symptomatic and physiologic outcomes.

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.

Adding a radial dimension to the assessment of esophagogastric junction relaxation: validation studies of the 3D-eSleeve.

High-resolution manometry (HRM) with esophageal pressure topography (EPT) allowed for the establishment of an objective quantitative measurement of esophagogastric junction (EGJ) relaxation, the integrated relaxation pressure (IRP). This study assessed whether or not a novel 3D-HRM assembly could improve on this measurement. Twenty-five normal subjects were studied with both a standard HRM assembly and a novel hybrid assembly (3D-HRM), including a 9.0 cm 3D-HRM segment composed of 96 radially dispersed independent pressure sensors. The standard IRP was computed using each assembly and compared with a novel paradigm, the 3D-IRP, an analysis premised on finding the axial maximum and radial minimum pressure at each sensor ring along the sleeve segment. Fourteen additional subjects underwent barium swallows with 3D-HRM and concurrent videofluoroscopy to compare the electronic sleeve (eSleeve) paradigm (circumferential average) to the 3D eSleeve paradigm (radial minimum) as a predictor of transphincteric flow. The 3D-IRP was significantly less than all other calculations of IRP with the upper limit of normal being 12 mmHg vs. 17 mmHg for the standard IRP. The sensitivity (0.78) and the specificity (0.88) of the 3D-eSleeve were also better than the standard eSleeve (0.55 and 0.85, respectively) for predicting flow permissive time verified fluoroscopically. The 3D-IRP and 3D-eSleeve calculated using the radial pressure minimum lowered the normative range of EGJ relaxation (upper limit of normal 12 mmHg) and yielded intraluminal pressure gradients that better correlated with bolus flow than did analysis paradigms based on circumferentially averaged pressure.

High-resolution manometry correlates of ineffective esophageal motility.

OBJECTIVES: There are currently no criteria for ineffective esophageal motility (IEM) and ineffective swallow (IES) in esophageal pressure topography (EPT). Our aims were to use high-resolution manometry metrics to define IEM within the Chicago Classification and to determine the distal contractile integral (DCI) threshold for IES. METHODS: The EPT of 150 patients with either dysphagia or reflux symptoms were reviewed. Peristaltic function in EPT was defined by the Chicago Classification; the corresponding conventional line tracing (CLT) were reviewed separately. Generalized linear mixed models were used to find thresholds for DCI corresponding to traditionally determined IES and failed swallows. An external validation sample was used to confirm these thresholds. RESULTS: In terms of swallow subtypes, IES in CLT were a mixture of normal, weak, and failed peristalsis in EPT. A DCI of 450 mm Hg-s-cm was determined to be optimal in predicting IES. In the validation sample, the threshold of 450 mm Hg-s-cm showed strong agreement with CLT determination of IES (positive percent agreement 83%, negative percent agreement 90%). The patient diagnostic level agreement between CLT and EPT was good (78.6% positive percent agreement and 63.9% negative percent agreement), with negative agreement increasing to 92.0% if proximal breaks were excluded. CONCLUSIONS: The manometric correlate of IEM in EPT is a mixture of failed swallows and weak swallows with breaks in the middle/distal troughs. A DCI value <450 mm Hg-s-cm can be used to predict IES previously defined in CLT. IEM can be defined by >5 swallows with weak/failed peristalsis or with a DCI <450 mm Hg-s-cm.

Treatment of high-frequency gastric electrical stimulation for gastroparesis.

BACKGROUND AND AIMS: The aim of this study was to assess the effects of gastric electrical stimulation (GES) on symptoms and gastric emptying in patients with gastroparesis, and the effects of GES on the three subgroups of gastroparesis. METHODS: A literature search of clinical trials using high-frequency GES to treat patients with gastroparesis from January 1995 to January 2011 was performed. Data on the total symptom severity score (TSS), nausea severity score, vomiting severity score, and gastric emptying were extracted and analyzed. The statistic effect index was weighted mean differences. RESULTS: Ten studies (n = 601) were included in this study. In the comparison to baseline, there was significant improvement of symptoms and gastric emptying (P < 0.00001). It was noted that GES significantly improved both TSS (P < 0.00001) and gastric retention at 2 h (P = 0.003) and 4 h (P < 0.0001) in patients with diabetic gastroparesis (DG), while gastric retention at 2 h (P = 0.18) in idiopathic gastroparesis (IG) patients, and gastric retention at 4 h (P = 0.23) in postsurgical gastroparesis (PSG) patients, did not reach significance. CONCLUSIONS: Based on this meta-analysis, the substantial and significant improvement of symptoms and gastric emptying, and the good safety we observed, indicate that high-frequency GES is an effective and safe method for treating refractory gastroparesis. DG patients seem the most responsive to GES, both subjectively and objectively, while the IG and PSG subgroups are less responsive and need further research.