Esophagogastric Junction Opening Research Articles

Four-Dimensional Impedance Manometry in Esophageal Motility Disorders.

Four-dimensional high-resolution impedance manometry (4D HRM) uses impedance to estimate esophageal luminal cross-sectional area and track nadir impedance to measure intrabolus pressure (IBP). We aimed to determine whether 4D HRM metrics could define abnormal esophagogastric junction (EGJ) opening between Chicago Classification version 4.0 motility disorders and compare 4D HRM with functional lumen imaging probe (FLIP) metrics. Symptomatic adult patients who completed high-resolution impedance manometry and FLIP were included and compared with an asymptomatic control group. 4D HRM analysis used custom-built software to measure IBP, maximum EGJ diameter, and distensibility index on supine test swallows. 4D HRM metrics were compared with FLIP EGJ metrics. Ninety patients (31 normal motility, 16 ineffective esophageal manometry, 9 absent contractility, 8 conclusive EGJ outflow obstruction [EGJOO], 12 type I achalasia, 14 type II achalasia, 12 type III achalasia, and 34 asymptomatic controls) were included. Phase 2 and 3 IBP was higher in type II and III achalasia compared with controls and normal motility groups ( P < 0.03). Maximum EGJ diameter and EGJ-distensibility index in the conclusive EGJOO and achalasia groups were significantly lower than in controls and normal motility groups ( P < 0.03). 4D HRM identified 37 of 44 (84%) subjects with normal EGJ opening and 29 of 39 (74%) subjects with reduced EGJ opening on FLIP. 4D HRM metrics correlated with expected clinical observations across a spectrum of esophageal motility disorders and defined EGJ obstruction. 4D HRM metrics may have value in defining EGJ obstruction in equivocal cases related to EGJOO or absent peristalsis.

Impact of Body Composition on Esophagogastric Junction Opening Measures: Discordant FLIP and Manometric Findings Are More Common With Increased Body Mass Index.

Increased intra-abdominal pressure in patients with elevated body mass index (BMI) may affect measurements of esophagogastric junction (EGJ) opening. Findings from adult patients who underwent both impedance planimetry with functional luminal imaging probe (FLIP) and high-resolution manometry (HRM) were compared by BMI. Among patients with no EGJ outflow obstruction on HRM, abnormal EGJ classifications on FLIP were more common among those with elevated than normal BMI (61.1% vs 31.6%, P = 0.037). Discordant results between FLIP and HRM on EGJ opening are more common in patients with elevated BMI. Body composition may impact EGJ function and measures on current testing modalities.

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

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. 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. 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. 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.

Relaxation of the lower esophageal sphincter in response to reduced volume distension during FLIP Panometry.

The esophageal response to stepwise distension during the functional lumen imaging probe (FLIP) Panometry study often parallels high-resolution manometry (HRM) motility diagnoses. This study aimed to describe the changes in FLIP metrics during FLIP emptying, that is, reduced volume distension. Adult patients who completed FLIP and HRM for esophageal motility evaluation were included. Esophagogastric junction (EGJ) opening parameters were assessed during stepwise FLIP filling to volumes of 60 mL ("filling 60 mL"), then 70 mL, and then back to 60 mL ("emptying 60 mL"). HRM studies were analyzed per Chicago classification version 4.0 (CCv4.0). Among 265 patients included, HRM/CCv4.0 diagnoses included achalasia in 80 patients (30%), normal motility in 70 (26%), and ineffective esophageal motility (IEM) in 43 (16%). EGJ-distensibility index (DI) and EGJ diameter were greater during emptying 60 mL than filling 60 mL in achalasia, normal motility, and IEM (p values <0.002). If applying the emptying 60 mL EGJ-DI (vs. filling 60 mL EGJ-DI), EGJ opening classification changed from reduced EGJ opening to borderline EGJ opening in 31% of achalasia patients and in 2% of patients with normal motility or IEM. EGJ opening classification was unchanged in 69% achalasia and 96% of normal motility/IEM. This study suggests that isotonic or auxotonic relaxation of the lower esophageal sphincter occurs with reduced volume distension in patients with achalasia and normal motility. The study also supports the importance of utilizing a standardized FLIP motility study protocol (i.e., controlled, stepwise filling to 50 mL, 60 mL, then 70 mL) to provide reliable and generalizable FLIP metrics to facilitate diagnosis of esophageal motility disorders.

Interrater Reliability of Functional Lumen Imaging Probe Panometry and High-Resolution Manometry for the Assessment of Esophageal Motility Disorders.

High-resolution manometry (HRM) and functional lumen imaging probe (FLIP) are primary and/or complementary diagnostic tools for the evaluation of esophageal motility. We aimed to assess the interrater agreement and accuracy of HRM and FLIP interpretations. Esophageal motility specialists from multiple institutions completed the interpretation of 40 consecutive HRM and 40 FLIP studies. Interrater agreement was assessed using intraclass correlation coefficient (ICC) for continuous variables and Fleiss' κ statistics for nominal variables. Accuracies of rater interpretation were assessed using the consensus of 3 experienced raters as the reference standard. Fifteen raters completed the HRM and FLIP studies. An excellent interrater agreement was seen in supine median integral relaxation pressure (ICC 0.96, 95% confidence interval 0.95-0.98), and a good agreement was seen with the assessment of esophagogastric junction (EGJ) outflow, peristalsis, and assignment of a Chicago Classification version 4.0 diagnosis using HRM (κ = 0.71, 0.75, and 0.70, respectively). An excellent interrater agreement for EGJ distensibility index and maximum diameter (0.91 [0.90-0.94], 0.92 [0.89-0.95]) was seen, and a moderate-to-good agreement was seen in the assignment of EGJ opening classification, contractile response pattern, and motility classification (κ = 0.68, 0.56, and 0.59, respectively) on FLIP. Rater accuracy for Chicago Classification version 4.0 diagnosis on HRM was 82% (95% confidence interval 78%-84%) and for motility diagnosis on FLIP Panometry was 78% (95% confidence interval 72%-81%). Our study demonstrates high levels of interrater agreement and accuracy in the interpretation of HRM and FLIP metrics and moderate-to-high levels for motility classification in FLIP, supporting the use of these approaches for primary or complementary evaluation of esophageal motility disorders.

Estimating Probability for Esophageal Obstruction: A Diagnostic Decision Support Tool Applying Machine Learning to Functional Lumen Imaging Probe Panometry.

Background/AimsThis study aimed to develop a diagnostic tool using machine learning to apply functional luminal imaging probe (FLIP) panometry data to determine the probability of esophagogastric junction (EGJ) obstruction as determined using the Chicago Classification version 4.0 (CCv4.0) and high-resolution manometry (HRM).MethodsFive hundred and fifty-seven adult patients that completed FLIP and HRM (with a conclusive CCv4.0 assessment of EGJ outflow) and 35 asymptomatic volunteers (“controls”) were included. EGJ opening was evaluated with 16-cm FLIP performed during sedated endoscopy via EGJ-distensibility index and maximum EGJ diameter. HRM was classified according to the CCv4.0 as conclusive disorders of EGJ outflow or normal EGJ outflow (timed barium esophagram applied when required and available). The probability tool utilized Bayesian additive regression treesBART, which were evaluated using a leave-one-out approach and a holdout test set.ResultsPer HRM and CCv4.0, 243 patients had a conclusive disorder of EGJ outflow while 314 patients (and all 35 controls) had normal EGJ outflow. The model accuracy to predict EGJ obstruction (based on leave-one-out/holdout test set, respectively) was 89%/90%, with 87%/85% sensitivity, 92%/97% specificity, and an area under the receiver operating characteristic curve of 0.95/0.97. A free, open-source tool to calculate probability for EGJ obstruction using FLIP metrics is available at https://www.wklytics.com/nmgi/prob_flip.html.ConclusionsApplication of FLIP metrics utilizing a probabilistic approach incorporates the diagnostic confidence (or uncertainty) into the clinical interpretation of EGJ obstruction. This tool can provide clinical decision support during application of FLIP Panometry for evaluation of esophageal motility disorders.

The Predictive Value of Intraoperative Esophageal Functional Luminal Imaging Probe Panometry in Patients With Achalasia Undergoing Peroral Endoscopic Myotomy: A Single-center Experience.

Background/AimsWe evaluated the clinical significance and prognostic power of functional luminal imaging probe (FLIP) panometry in patients with achalasia treated with peroral endoscopic myotomy (POEM), and examined the clinical parameters associated with symptomatic improvement and the presence of contractility (POC) following POEM.MethodsWe reviewed the electronic medical records of patients with achalasia treated with FLIP panometry and POEM at a tertiary teaching hospital in Seoul, Republic of Korea. Follow-up examination was composed of esophageal manometry and questionnaires on symptoms. We analyzed the FLIP data by interpolating using the cubic spline method in MATLAB.ResultsWe retrospectively analyzed 33 men and 35 women (mean age 52 ± 17 years), of whom 14, 39, and 15 patients were diagnosed with achalasia types I, II, and III, respectively. The FLIP panometry diagnoses were reduced esophagogastric junction opening (REO) with a retrograde contractile response (n = 43); REO with an absent contractile response (n = 5); REO with a normal contractile response (n = 11); and a retrograde contractile response (n = 9). Overall, the patients showed improvements in Eckardt scores following POEM from 6.48 ± 2.20 to 1.16 ± 1.15 (P < 0.01). Post-POEM symptomatic improvement was not significantly associated with any of the clinical parameters, including panometry diagnosis. Conversely, post-POEM POC was significantly associated with the presence of repetitive antegrade contractions and achalasia subtypes (both P < 0.01).ConclusionWhile FLIP panometry was not significantly associated with the clinical course of achalasia, FLIP panometry was associated with POC following POEM and may complement manometry in the functional evaluation of esophageal motility disorders.

Normative values of intra-bolus pressure and esophageal compliance based on 4D high-resolution impedance manometry.

This study aimed to quantify normative values of phase-specific intra-bolus pressure (IBP) and esophageal distensibility using 4D analysis of high-resolution-impedance manometry (HRIM). HRIM studies of supine swallows from 34 normal controls were analyzed with respect to the four phases of bolus transit: (1) accommodation, (2) compartmentalization, (3) peristalsis/esophageal emptying, and (4) ampullary emptying. Phase-specific IBP, bolus volume, and distensibility index (DI) in the esophageal body and esophagogastric junction (EGJ) during phases 1-3 were extracted. The median (5-95th/IQR) IBP values were as follows: phase 1: 4.0 (-2.0-10.4/1.9-5.8)mmHg, phase 2: 5.7 (0.2-14.1/3.6-8.9)mmHg, and phase 3: 11.2 (2.9-19.4/7.7-15.1)mmHg. The median bolus volume calculated by integrating impedance planimetry cross-sectional areas was 4.1ml during the compartmentalization phase. The EGJ-DI at max EGJ diameter during phase 2 and 3 was 2.8 (1.1-9.5/1.8-3.7)mm2 /mmHg and 6.0 (3.2-20.3/5.1-7.8)mm2 /mmHg, respectively. The phase 3 EGJ-DI values (6.0 (3.2-20.3/5.1-7.8)mm2 /mmHg) were similar to those calculated using functional lumen imaging probe (FLIP) at the 60 ml volume on the same subjects (5.8 [3.5-7.2/5.0-6.4]mm2 /mmHg). 4D-HRIM provides a standardized methodology to track the nadir impedance and provide measurements of IBP during maximal distention across phases 1-3 of bolus transit. Median IBP and delta IBP were different across the phases, supporting the need to define IBP by phase. Additionally, the EGJ-DI calculated during phase 3 was similar to the 60-ml EGJ-DI from FLIP in the same subjects suggesting that 4D-HRIM can quantify EGJ opening during primary peristalsis.

Classifying Esophageal Motility by FLIP Panometry: A Study of 722 Subjects With Manometry.

Functional luminal imaging probe (FLIP) panometry can evaluate esophageal motility in response to sustained esophageal distension at the time of sedated endoscopy. This study aimed to describe a classification of esophageal motility using FLIP panometry and evaluate it against high-resolution manometry (HRM) and Chicago Classification v4.0 (CCv4.0). Five hundred thirty-nine adult patients who completed FLIP and HRM with a conclusive CCv4.0 diagnosis were included in the primary analysis. Thirty-five asymptomatic volunteers ("controls") and 148 patients with an inconclusive CCv4.0 diagnosis or systemic sclerosis were also described. Esophagogastric junction (EGJ) opening and the contractile response (CR) to distension (i.e., secondary peristalsis) were evaluated with a 16-cm FLIP during sedated endoscopy and analyzed using a customized software program. HRM was classified according to CCv4.0. In the primary analysis, 156 patients (29%) had normal motility on FLIP panometry, defined by normal EGJ opening and a normal or borderline CR; 95% of these patients had normal motility or ineffective esophageal motility on HRM. Two hundred two patients (37%) had obstruction with weak CR, defined as reduced EGJ opening and absent CR or impaired/disordered CR, on FLIP panometry; 92% of these patients had a disorder of EGJ outflow per CCv4.0. Classifying esophageal motility in response to sustained distension with FLIP panometry parallels the swallow-associated motility evaluation provided with HRM and CCv4.0. Thus, FLIP panometry serves as a well-tolerated method that can complement, or in some cases be an alternative to HRM, for evaluating esophageal motility disorders.

Validation of Clinically Relevant Thresholds of Esophagogastric Junction Obstruction Using FLIP Panometry

This study aimed to assess the accuracy of functional luminal imaging probe (FLIP) panometry to detect esophagogastric junction (EGJ) obstruction assigned by high-resolution manometry (HRM) and the Chicago Classification version 4.0 (CCv4.0). Six hundred eighty-seven adult patients who completed FLIP and HRM for primary esophageal motility evaluation and 35 asymptomatic volunteers (controls) were included. EGJ opening was evaluated with 16-cm FLIP during sedated endoscopy via EGJ-distensibility index (DI) and maximum EGJ diameter. HRM was classified according to CCv4.0 and focused on studies with a conclusive disorder of EGJ outflow (ie, achalasia subtypes I, II, or III; or EGJ outflow obstruction with abnormal timed barium esophagogram) or normal EGJ outflow. All 35 controls had EGJ-DI >3.0 mm2/mmHg and maximum EGJ diameter >16 mm. Per HRM and CCv4.0, 245 patients had a conclusive disorder of EGJ outflow, and 314 patients had normal EGJ outflow. Among the 241 patients with reduced EGJ opening (EGJ-DI <2.0 mm2/mmHg and maximum EGJ diameter <12 mm) on FLIP panometry, 86% had a conclusive disorder of EGJ outflow per CCv4.0. Among the 203 patients with normal EGJ opening (EGJ-DI ≥2.0 mm2/mmHg and maximum EGJ diameter ≥16 mm) on FLIP panometry, 99% had normal EGJ outflow per CCv4.0. FLIP panometry accurately identified clinically relevant conclusive EGJ obstruction as defined by CCv4.0 in patients evaluated for esophageal motor disorders. Thus, FLIP panometry is a valuable tool for both independent and complementary evaluation of esophageal motility.

Evaluating esophageal motility beyond primary peristalsis: Assessing esophagogastric junction opening mechanics and secondary peristalsis in patients with normal manometry.

Functional luminal imaging probe (FLIP) Panometry assesses the esophageal response to distention and may complement the assessment of primary peristalsis on high-resolution manometry (HRM). We aimed to investigate whether FLIP Panometry provides complementary information in patients with normal esophageal motility on HRM. Adult patients that completed FLIP and had an HRM classification of normal motility were retrospectively identified for inclusion. 16-cm FLIP studies performed during endoscopy were evaluated to assess EGJ distensibility, secondary peristalsis, and identify an abnormal response to distention involving sustained LES contraction (sLESC). Clinical characteristics and esophagram were assessed when available. Of 164 patients included (mean(SD) age 48(16) years, 75% female), 111 (68%) had normal Panometry with EGJ-distensibility index (DI) ≥2.0 mm2 /mmHg, maximum EGJ diameter ≥16mm and antegrade contractions. Abnormal EGJ distensibility was observed in 44/164 (27%), and 38/164 (23%) had an abnormal contractile response to distension. sLESC was observed in 11/164 (7%). Among 68 patients that completed esophagram, abnormal EGJ distensibility was more frequently observed with an abnormal esophagram than normal EGJ opening: 14/23 (61%) vs 10/45 (22%); P=0.003. Epiphrenic diverticula were present in 3/164 patients: 2/3 had sLESC. Symptomatic patients with normal esophageal motility on HRM predominantly have normal FLIP Panometry; however, abnormal FLIP findings can be observed. While abnormal Panometry findings appear clinically relevant via an association with abnormal bolus retention, complementary tests, such as provocative maneuvers with HRM and timed barium esophagram, are useful to determine clinical context.

Esophagogastric Junction Opening Parameters Are Consistently Abnormal in Untreated Achalasia

Achalasia is a disorder of impaired lower esophageal sphincter (LES) relaxation and failed peristalsis traditionally characterized by manometry.1 As impaired LES relaxation is a mechanism of reduced esophagogastric junction (EGJ) opening, abnormally reduced EGJ distensibility assessed with functional luminal imaging probe (FLIP) was reported among patients with untreated achalasia.2-5 Therefore, we aimed to describe the performance characteristics of EGJ opening parameters on FLIP panometry among a large cohort of treatment-naïve achalasia patients.

Morphologic Restoration After Peroral Endoscopic Myotomy in Sigmoid-type Achalasia

Background/AimsAchalasia is a chronic, progressive motility disorder of the esophagus. The sigmoid-type achalasia is an advanced stage of achalasia characterized by severe dilatation and tortuous angulation of the esophageal body. Peroral endoscopic myotomy (POEM) has been reported to provide excellent clinical outcomes for achalasia, including the sigmoid type, but the restoration of esophageal morphology and function remain poorly described. The aim of our study is to investigate esophageal restoration after POEM for sigmoid-type achalasia.MethodsFrom 98 patients with achalasia who underwent POEM in the Yonsei University Health System from 2013 to 2018, we recruited 13 patients with sigmoid-type achalasia (7 male; mean age 53.3 years) and assessed morphological and manometric changes in the esophagus.ResultsClinical success (Eckardt score < 3) was achieved in all cases. After POEM, the average angle of esophageal tortuosity became more obtuse (91.5° vs 114.6°, P = 0.046), esophageal body diameter decreased (67.6 vs 49.8 mm, P = 0.002), and esophagogastric junction opening widened (6.4 vs 9.5 mm, P = 0.048). Patients whose esophageal tortuosity did not improve had longer durations of symptoms than patients with improvement (80.2 vs 636 months, P < 0.001). An absence of peristalsis was observed in all patients pre- and post-POEM.ConclusionsPOEM resulted in excellent clinical outcomes and morphologic improvement in sigmoid-type achalasia. These results suggest that the improvement of esophageal tortuosity through POEM reflects a reduced esophageal burden.

Esophagogastric Junction Distensibility on Functional Lumen Imaging Probe Topography Predicts Treatment Response in Achalasia-Anatomy Matters!

To compare the utility of the distensibility index (DI) on functional lumen imaging probe (FLIP) topography to other esophagogastric junction (EGJ) metrics in assessing treatment response in achalasia in the context of esophageal anatomy. We prospectively evaluated 79 patients (at ages 17-81 years; 47% female patients) with achalasia during follow-up after pneumatic dilation, Heller myotomy, or per-oral endoscopic myotomy with timed barium esophagram, high-resolution impedance manometry, and FLIP. Anatomic deformities were identified based on consensus expert opinion. Patients were classified based on anatomy and EGJ opening to determine the association with radiographic outcome and Eckardt score (ES). Twenty-seven patients (34.1%) had an anatomic deformity-10 pseudodiverticula at myotomy, 7 epiphrenic diverticula, 5 sigmoid, and 5 sinktrap. A 5-minute column area of >5 cm was best associated with an ES of >3, with a sensitivity of 84% (P = 0.0013). Area under the curve for EGJ metrics in association with retention was as follows: DI, 0.90; maximal EGJ diameter, 0.76; integrated relaxation pressure, 0.64; and basal esophagogastric junction pressure, 0.53. Only FLIP metrics were associated with retention given normal anatomy (DI 2.4 vs 5.2 mm/mm Hg and maximal EGJ diameter 13.1 vs 16.6 mm in patients with and without retention, respectively; P values < 0.0001 and 0.002). Using a DI cutoff of <2.8 as abnormal, 40 of 45 patients with retention (P = 0.0001) and 23 of 25 patients with an ES of >3 (P = 0.02) had a low DI and/or anatomic deformity. With normal anatomy, 21 of 22 patients with retention had a low or borderline low DI. The FLIP DI is most useful metric for assessing the effect of achalasia treatment on EGJ opening. However, abnormal anatomy is an important mediator of outcome and treatment success will be modulated by anatomic defects that impede bolus emptying.

Novel Pressure‐Impedance Parameters for Evaluating Esophageal Function in Pediatric Achalasia

In achalasia, absent peristalsis and reduced esophagogastric junction (EGJ) relaxation and compliance underlie dysphagia symptoms. Novel high-resolution impedance manometry variables, that is, bolus presence time (BPT) and trans-EGJ-bolus flow time (BFT) have been developed to estimate the duration of EGJ opening and trans-EGJ bolus flow. The aim of this study was to evaluate esophageal motor function and bolus flow in children diagnosed with achalasia using these variables. High-resolution impedance manometry recordings from 20 children who fulfilled the Chicago Classification (V3) criteria for achalasia were compared with recordings of 15 children with normal esophageal high-resolution manometry findings and no other evidence suggestive of achalasia. Matlab-based analysis software was used to calculate BPT and BFT. Both BPT and BFT were significantly reduced in achalasia patients compared with children with normal esophageal motility (BPT 3.3 s vs 5.1 s P < 0.01; BFT 1.4 s vs 4.3 s P < 0.001). BFT was significantly lower than BPT (achalasia difference 1.9 s ± 1.3 s, P = 0.001 and normal difference 0.9 ± 0.3 s, P = 0.001). Overall, there was a significant correlation between BPT and BFT (r = 0.825, P < 0.001). We observed a 2-way differentiation of achalasia patients; those in whom the BPT and BFT were proportional, but significantly lower than in patients with normal peristalsis, and those in whom BFT was disproportionately lower than BPT. Calculation of BPT and BFT may help determine whether esophageal bolus transport to the EGJ and/or esophageal emptying through the EGJ are aberrant. For achalasia, this may detect flow resistance at the EGJ, potentially improving both diagnosis and objective assessment of therapeutic effects.

Functional Lumen Imaging Probe for the Management of Esophageal Disorders: Expert Review From the Clinical Practice Updates Committee of the AGA Institute.

The functional luminal imaging probe is a Food and Drug Administration-approved measurement tool used to measure simultaneous pressure and diameter to guide management of various upper gastrointestinal disorders. Additionally, this tool is also approved to guide therapy during bariatric procedures and specialized esophageal surgery. Although it has been commercially available since 2009 as the endolumenal functional lumen imaging probe (EndoFLIP), the functional luminal imaging probe has had limited penetrance into clinical settings outside of specialized centers. This is primarily because of a paucity of data supporting its utility in general practice and a lack of standardized protocols and data analysis methodology. However, data are accumulating that are providing guidance regarding emerging applications in the evaluation and management of foregut disorders. This clinical practice update describes the technique and reviews potential indications in achalasia, eosinophilic esophagitis, and gastroesophgeal reflux disease. Best Practice Advice 1: Clinicians should not make a diagnosis or treatment decision based on functional lumen imaging probe (FLIP) assessment alone. Best Practice Advice 2: FLIP assessment is a complementary tool to assess esophagogastric junction opening dynamics and the stiffness of the esophageal wall. Best Practice Advice 3: Utilization should follow distinct protocols and analysis paradigms based on the disease state of interest. Best Practice Advice 4: Clinicians should not utilize FLIP in routine diagnostic assessments of gastroesophageal reflux disease. Best Practice Advice 5: FLIP should not be used to diagnose eosinophilic esophagitis but may have a role in severity assessment and therapeutic monitoring.

Esophagogastric junction distensibility measurements during hydraulic dilation therapy in achalasia patients

SUMMARYIncreasing evidence suggests that esophagogastric junction (EGJ) distensibility is predictive of long-term clinical success after achalasia treatment. A new commercially available hydraulic dilation balloon is capable of measuring EGJ opening diameters whilst simultaneously dilating the EGJ. Deployed alongside the endoscope under direct visualization, it is used for dilation of the lower esophageal sphincter in patients with achalasia. Impedance measurement electrodes are incorporated in the catheter shaft in the dilation balloon, which allows measuring the diameter of the EGJ and displaying it in real time before, during and after dilation. This obviates the need for fluoroscopy during the dilation procedure. The extent of recoil of the EGJ after dilation potentially provides a measurement that could be incorporated into a clinical rule for predicting therapeutic success after dilation.

Abnormal Structure and Function of the Esophagogastric Junction and Proximal Stomach in Gastroesophageal Reflux Disease

This study applies concurrent magnetic resonance imaging (MRI) and high-resolution manometry (HRM) to test the hypothesis that structural factors involved in reflux protection, in particular, the acute insertion angle of the esophagus into the stomach, are impaired in gastroesophageal reflux disease (GERD) patients. A total of 24 healthy volunteers and 24 patients with mild-moderate GERD ingested a test meal. Three-dimensional models of the esophagogastric junction (EGJ) were reconstructed from MRI images. Measurements of the esophagogastric insertion angle, gastric orientation, and volume change were obtained. Esophageal function was assessed by HRM. Number of reflux events and EGJ opening during reflux events were assessed by HRM and cine-MRI. Statistical analysis applied mixed-effects modeling. The esophagogastric insertion angle was wider in GERD patients than in healthy subjects (+7° ± 3°; P=0.03). EGJ opening during reflux events was greater in GERD patients than in healthy subjects (19.3 mm vs. 16.8 mm; P=0.04). The position of insertion and gastric orientation within the abdomen were also altered (both P<0.05). Median number of reflux events was 3 (95% CI: 2.5-4.6) in GERD and 2 (95% CI: 1.8-3.3) in healthy subjects (P=0.09). Lower esophageal sphincter (LES) pressure was lower (-11 ± 2 mm Hg; P<0.0001) and intra-abdominal LES length was shorter (-1.0 ± 0.3 cm, P<0.0006) in GERD patients. GERD patients have a wider esophagogastric insertion angle and have altered gastric morphology; structural changes that could compromise reflux protection by the "flap valve" mechanism. In addition, the EGJ opens wider during reflux in GERD patients than in healthy volunteers: an effect that facilitates volume reflux of gastric contents.

Transient Lower Esophageal Sphincter Relaxations and Reflux: Mechanistic Analysis Using Concurrent Fluoroscopy and High-Resolution Manometry

The aim of this study was to perform a detailed analysis of the mechanics leading to esophagogastric junction (EGJ) opening during transient lower esophageal sphincter relaxations (tLESRs) using high-resolution manometry coupled with simultaneous fluoroscopy. Six subjects without hiatus hernia had endoclips placed at the squamocolumnar junction and 10 cm proximal. A 36-channel solid-state manometric assembly was placed spanning from stomach to pharynx, and subjects were studied for 2 hours after a high-fat meal. An esophageal pH electrode also was placed and fluoroscopy was initiated at the onset of a tLESR. Axial clip movement was measured during replay of the videotaped fluoroscopy and was correlated with manometric data. Ninety-three tLESRs were recorded, 62 tLESRs of which had good fluoroscopic visualization. Seventy-eight tLESRs had manometric evidence of flow and the majority had evidence of a common cavity (88%), but few were detected by the pH electrode. Esophageal shortening and crural diaphragm inhibition always preceded EGJ opening and common cavity. A positive pressure gradient between the stomach and the EGJ lumen of 7.1 mm Hg (interquartile range, 4.1-9.1 mm Hg) preceded the EGJ opening. Key events leading to the EGJ opening during tLESRs were LES relaxation, crural diaphragm inhibition, esophageal shortening, and a positive pressure gradient between the stomach and the EGJ lumen. The manometric signature of opening was pressure equalization within the EGJ, but this only occasionally was associated with pH evidence of reflux. Future investigations will need to analyze how this delicately balanced anatomic-physiologic system is perturbed in subjects with reflux disease.

Impaired Bolus Transit Across the Esophagogastric Junction in Postfundoplication Dysphagia

This study assessed the effect of fundoplication on liquid and solid bolus transit across the esophagogastric junction (EGJ) in relation to EGJ dynamics and dysphagia. Twelve patients with gastro-esophageal reflux disease (GERD) were studied before and after fundoplication. Concurrent high-resolution EGJ manometry and fluoroscopy were performed whilst swallowing liquid barium and a solid bolus. The EGJ transit time, EGJ opening duration, transit efficacy, and EGJ relaxation were measured. During the test symptoms of dysphagia were scored using a visual analog scale. The minimal opening aperture at fluoroscopy was located at the manometric EGJ in all subjects. Fundoplication markedly reduced the EGJ opening diameter from 1.0 +/- 0.1 to 0.6 +/- 0.1 cm (p < 0.01) and rendered deglutative EGJ relaxation incomplete. After fundoplication, a higher intrabolus pressure was found (p < 0.05) associated with a reduced axial bolus length (p < 0.001). EGJ transit time increased from 6.9 +/- 0.9 to 9.8 +/- 1.0 s for liquids (p < 0.01) and from 2.8 +/- 0.5 to 5.8 +/- 0.8 s (p < 0.01) for solids after fundoplication. No relation between EGJ transit and dysphagia scores was observed before fundoplication. In contrast, EGJ transit time significantly correlated with dysphagia scores both during liquid (r = 0.84; p < 0.01) and solid (r = 0.69; p < 0.05) bolus transit following fundoplication. Fundoplication patients exhibit a restricted hiatal opening and an incomplete deglutative EGJ relaxation. To facilitate EGJ transit despite these altered EGJ dynamics a higher intrabolus pressure is created by augmented bolus compression. Fundoplication increases EGJ transit time, the degree of which is associated with postoperative dysphagia.