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

The Esophageal Response to Distension on Functional Lumen Imaging Probe Panometry Is Minimally Changed by Conscious Sedation in Healthy Asymptomatic Subjects

Background/Aims

Functional lumen imaging probe (FLIP) Panometry has demonstrated utility in the assessment of esophageal motility as a complement to existing methodologies like high-resolution manometry. However, as FLIP is typically performed with sedation during routine endoscopy, there is potential for impact of sedation agents on esophageal motility. We aim to examine the effects of conscious sedation with midazolam and fentanyl on FLIP Panometry metrics and classification.

Methods

A cross-over study was conducted on 12 healthy, asymptomatic volunteers that completed FLIP while sedated with intravenous fentanyl and midazolam and while awake on a separate day. FLIP was performed in the same manner in both conditions with transoral placement of the FLIP and stepwise FLIP filling. During awake FLIP, subjects also rated the presence and intensity of esophageal perception.

Results

In both experimental conditions, all subjects demonstrated normal motility. The esophagogastric junction distensibility index was lower (median [interquartile range]: 5.8 [5.15-6.85] vs 8.9 [7.68-9.38] mm2/mmHg; P = 0.025), and the FLIP pressure was higher (46.5 [38.125-52.5] vs 33 [26-36.8] mmHg; P = 0.010) in the sedated condition compared to the awake condition. Maximum esophagogastric junction diameter and body distensibility plateau were no different between conditions (P = 0.999 and P = 0.098, respectively). Perception of esophageal sensation during awake FLIP was reported in 7/12 (58%) subjects.

Conclusions

While numeric differences in FLIP Panometry metrics were observed between sedated and awake FLIP in healthy subjects, these differences did not change the FLIP Panometry diagnosis. Sedated FLIP offers a well-tolerated method to assess esophageal motility during endoscopy.

Disorders of secondary peristalsis are associated with the development of esophagitis

BACKGROUND

Disorders of primary peristalsis are associated with a higher percent time pH <4 in the esophagus suggesting poor acid clearance. However, there are no studies of secondary peristalsis and its relationship to microscopic or erosive esophagitis. The goal of this study was to determine the relationship between secondary peristalsis using functional luminal imaging probes (EndoFLIP) and the presence or absence of esophagitis.

METHODS

We reviewed the endoscopic and EndoFLIP 2.0 tracings for 103 consecutive patients including those with a history of upper gastrointestinal surgery undergoing upper endoscopy. Esophagogastric junction (EGJ) distensibility and diameter, repetitive antegrade contraction (RACs) presence and frequency, and occlusive diameters were measured. Measurements were then compared between patients with and without microscopic and/or erosive esophagitis. Means were compared using t-tests. Proportions were compared using Chi-Squared analyses.

KEY RESULTS

One hundred and three patients were included (mean age: 14.4 + 6.4 years). Ten patients had erosive esophagitis and 28 patients had microscopic esophagitis. Erosive and microscopic esophagitis were associated with abnormal or absent of RACs (p < 0.001). Occlusive diameters were higher in patients with esophagitis compared to those without (p < 0.001). There was no relationship between EGJ distensibility and the presence of erosive or microscopic esophagitis (p = 0.4). The absence of RACs was the only independent predictor of esophagitis (erosive and microscopic), after controlling for age, proton pump inhibitors (PPI) use and EGJ distensibility (p < 0.001).

CONCLUSIONS & INFERENCES

Abnormal secondary peristalsis is associated with microscopic and gross esophagitis, suggesting that EndoFLIP should be part of the diagnostic algorithm for esophagitis.

Functional lumen imaging probe use in a high-volume practice: Practical and technical implications

BACKGROUND

The functional lumen imaging probe (FLIP) is a Food and Drug Administration approved tool to aid the diagnosis and management of esophageal disorders. However, widespread adoption of FLIP remains limited and its utility in high-volume practices remains unclear.

AIM

To analyze large sample data on clinical use of FLIP and provide insight on several technical aspects when performing FLIP.

METHODS

We conducted a retrospective comparative and descriptive analysis of FLIP procedures performed by a single provider at an academic medical center. There was a total of 398 FLIP procedures identified. Patient medical records were reviewed and data regarding demographics and procedural details were collected. Statistical tests, including chi-squared, t-test, and multivariable logistic and linear regression, were performed.

RESULTS

There was an increase in FLIP cases with each successive time period of 13 months (n = 68, 146, 184, respectively) with notable rises specifically for indications of dysphagia and gastroesophageal reflux disease. There was a shift toward use of the longer FLIP balloon catheter for diagnostic purposes (overall 70.4% vs 29.6%, P < 0.01). Many cases (42.8%) were performed in conjunction with other diagnostics/interventions, such as dilation and wireless pH probe placement. Procedures were nearly equally performed with anesthesia vs moderate sedation (51.4% anesthesia), with no major complications. Patients who had anesthesia were less likely to have recurrent antegrade contractions [odds ratio (OR) = 0.4, 95%CI: 0.3-0.8] and were also more likely to have absent contractility (OR = 2.4, 95%CI: 1.3-4.4).

CONCLUSION

FLIP cases have increased in our practice with expanding indications for its use. Given limited normative data, providers should be aware of several potential technical issues, including the possible impact of sedation choice when assessing esophageal motility patterns.

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

BACKGROUND

Functional lumen imaging probe (FLIP) panometry evaluates esophageal motility, including the contractile response to distension, that is, secondary peristalsis. Impaired/disordered contractile response (IDCR) is an abnormal, but nonspecific contractile response that can represent either hypomotility or spastic motor disorders on high-resolution manometry (HRM). We hypothesized that FLIP pressure could be incorporated to clarify IDCR and aimed to determine its utility in a cohort of symptomatic esophageal motility patients.

METHODS

173 adult patients that had IDCR on FLIP panometry and HRM with a conclusive Chicago Classification v4.0 (CCv4.0) diagnosis were included and analyzed as development (n = 118) and validation (n = 55) cohorts. FLIP pressure values were assessed for prediction of either hypomotility or spasm, defined on HRM/CCv4.0.

KEY RESULTS

HRM/CCv4.0 diagnoses were normal motility in 48 patients (28%), "hypomotility" (ineffective esophageal motility, absent contractility, or Type I or II achalasia) in 89 (51%), and "spasm" (Type III achalasia, distal esophageal spasm, or hypercontractile esophagus) in 36 (21%). The pressure at esophagogastric junction-distensibility index (DI) (60 mL) was lower in hypomotility (median [interquartile range] 34 [28-42] mmHg) than in spasm (49 [40-62] mmHg; p < 0.001) and had an area under the receiver operating characteristic curve of 0.80 (95% CI 0.73-0.88) for hypomotility and 0.76 (0.69-0.83) for spasm. For "spasm" on HRM, a threshold FLIP pressure of >35 mmHg provided 90% sensitivity (47% specificity) while >55 mmHg provided 93% specificity (40% sensitivity).

CONCLUSION & INFERENCES

Pressure on FLIP panometry can help clarify the significance of IDCR, with low-pressure IDCR associated with hypomotility and high-pressure IDCR suggestive of spastic motor disorders.

Measuring and improving quality in esophageal care and swallowing disorders

Evaluating clinical care through quality-related metrics is increasingly common. There are now numerous quality statements and indicators related to the medical management of benign and pre-malignant esophageal diseases. Expert consensus leveraging evidence-based recommendations from published society guidelines has been the most frequently used basis for developing esophageal quality statements. While surgical care of patients with esophageal malignancies, including squamous cell carcinoma, has also been developed, those related to benign esophageal disease now include domains of diagnosis, treatment, and monitoring for gastroesophageal reflux disease, eosinophilic esophagitis (EoE), achalasia, and Barrett's esophagus (BE). Several recent studies evaluating adherence to quality metrics affirm substantial variation in practice patterns with opportunities for improvement in care across esophageal diseases. In particular, patient education regarding treatment options in achalasia, frequency of esophageal biopsies among patients with dysphagia to evaluate for EoE, and endoscopic evaluation within a BE segment are areas identified to have need for improvement. As the management of esophageal diseases becomes more complex and interdisciplinary, adherence to quality metrics may be a source of standardization and improvement in delivery and ultimately patient outcomes. Indeed, the development of national quality databases has resulted in a significant growth in the use of these metrics for quality improvement activities and may form the basis for future inclusion in quality reporting and payment programs.

Endoscopic impedance planimetry versus high-resolution manometry (HRM) for pre-operative motility evaluation in anti-reflux surgery

INTRODUCTION

Pre-operative evaluation of patients with gastroesophageal reflux disease (GERD) includes assessment of esophageal motility. High-resolution manometry (HRM) is the gold standard; endoscopic impedance planimetry (IP) with Endoflip 2.0 is increasingly utilized in esophageal disorders of motility. We hypothesized that normal IP motility would correlate with normal HRM motility and tested this in a prospective cohort study.

METHODS

Patients presenting for surgical evaluation of GERD between 9/2020 and 10/2021 were prospectively enrolled under an IRB-approved protocol. Patients with prior esophageal/gastric surgery, known motility disorders, or large paraesophageal hernias were excluded. All underwent HRM and IP, with normal motility defined by Chicago 3.0 classification for HRM and the presence of repetitive antegrade contractions for IP. Logistic regression and t test were used to analyze the data; p value < 0.05 was considered significant.

RESULTS

Of 63 patients enrolled, 48 completed both IP and HRM testing. The cohort was 50% male with a median age of 52.5 [42.0, 66.0] years, mostly ASA class 1-2 (75.1%, n = 36) and had an average BMI of 31.4 ± 6.3 kg/m2. Normal motility tracings were in 62.5% of IP and 75% of HRM tests. Using HRM as the gold standard, IP detected normal motility with a sensitivity of 65.8% and a specificity of 50% (positive predictive value 83.3%, negative predictive value 27.8%). Normal IP was not statistically significant in predicting normal HRM (OR 3.182, 95% CI 0.826-12.262, p = 0.0926). Tolerability of IP was significantly better than HRM with lower rates of discomfort (10.9% vs. 93.4%, p < 0.0001) and higher willingness to repeat testing (100% vs. 47.8%, p < 0.0001).

CONCLUSION

Esophageal motility testing with Endoflip 2.0 is well tolerated by patients. The low specificity (50%), poor negative predictive value (27.8%), and lack of statistically significant concordance between IP and HRM raises concern for the reliability of this test as a stand-alone replacement for HRM in the pre-operative evaluation for GERD.

Impedance planimetry and panometry (EndoFLIP™) can replace manometry in preoperative anti-reflux surgery assessment

BACKGROUND

Endoluminal functional impedance planimetry and panometry assesses secondary peristalsis in response to volumetric distention under sedation. We hypothesize that impedance planimetry and panometry can replace high-resolution manometry in the preoperative assessment prior to anti-reflux surgery.

METHODS

Single institution prospective data were collected from patients undergoing anti-reflux surgery between 2021 and 2023. A 16-cm functional luminal imaging probe (FLIP) assessed planimetry and panometry prior to surgery under general anesthesia at the start of each case. Panometry was recorded and esophageal contractile response was classified as normal (NCR), diminished or disordered (DDCR), or absent (ACR) in real time by a single panometry rater, blinded to preoperative HRM results. FLIP results were then compared to preoperative HRM.

RESULTS

Data were collected from 120 patients, 70.8% female, with mean age of 63 ± 3 years. There were 105 patients with intraoperative panometry, and 15 with panometry collected during preoperative endoscopy. There were 60 patients (50%) who had peristaltic dysfunction on HRM, of whom 57 had FLIP dysmotility (55 DDCR, 2 ACR) resulting in 95.0% sensitivity. There were 3 patients with normal secondary peristalsis on FLIP with abnormal HRM, all ineffective esophageal motility (IEM). No major motility disorder was missed by FLIP. A negative predictive value of 91.9% was calculated from 34/37 patients with normal FLIP panometry and normal HRM. Patients with normal HRM but abnormal FLIP had larger hernias compared to patients with concordant studies (7.5 ± 2.8 cm vs. 5.4 ± 3.2 cm, p = 0.043) and higher preoperative dysphagia scores (1.5 ± 0.7 vs. 1.1 ± 0.3, p = 0.021).

CONCLUSION

Impedance planimetry and panometry can assess motility under general anesthesia or sedation and is highly sensitive to peristaltic dysfunction. Panometry is a novel tool that has potential to streamline and improve patient care and therefore should be considered as an alternative to HRM, especially in patients in which HRM would be inaccessible or poorly tolerated.

Interventional functional diagnostics in gastrointestinal endoscopy: Combining diagnostic and therapeutic tools in the endoscopy suite with the functional lumen imaging probe

With technical progress of gastrointestinal functional testing, there has been a demand for more comprehensive examination of esophageal physiology and pathophysiology beyond high-resolution manometry. A new interventional technology based on impedance planimetry, the functional lumen imaging probe (FLIP), enables intraluminal measurement of distensibility and compliance of hollow organs. EndoFLIP uses balloon catheters to measure diameter and distension pressure to calculate cross-sectional area and distensibility in different organs (mostly esophagus, stomach, anorectal region) and can be used in wide variety of indications (diagnostics, pre- and post-treatment evaluation) and currently serves as a helpful adjunctive tool in ambiguous clinical cases. EsoFLIP is a therapeutic variation that uses a stiffer balloon catheter allowing for dilation. The trend to simplify the clinical process from diagnosis to treatment tends to a one-session procedure combining diagnostics and therapeutic interventions. In specified conditions like e.g. achalasia or gastroparesis, a combination of EndoFLIP and EsoFLIP procedures may therefore be useful. The aim of this narrative review is to introduce the clinical use of FLIP and its potential benefit in combined diagnostic-therapeutic procedures.

Assessing mechanical function of peristalsis with functional lumen imaging probe panometry: Contraction power and displaced volume

BACKGROUND AND AIMS

The distal contractile integral (DCI) quantifies the contractile vigor of primary peristalsis on high-resolution manometry (HRM), whereas no such metric exists for secondary peristalsis on functional lumen imaging probe (FLIP) panometry. This study aimed to evaluate novel FLIP metrics of contraction power and displaced volume in asymptomatic controls and a patient cohort.

METHODS

Thirty-five asymptomatic controls and adult patients (with normal esophagogastric junction outflow/opening and without spasm) who completed HRM and FLIP panometry were included. The patient group also completed timed barium esophagram (TBE). Contraction power (estimate of esophageal work over time) and displaced volume (estimate of contraction-associated fluid flow) were computed from FLIP. HRM was analyzed per Chicago Classification v4.0.

KEY RESULTS

In controls, median (5th-95th percentile) contraction power was 27 mW (10-44) and displaced volume was 43 mL (17-66). 95 patients were included: 72% with normal motility on HRM, 17% with ineffective esophageal motility (IEM), and 12% with absent contractility. Among patients, DCI was significantly correlated with both contraction power (rho = 0.499) and displaced volume (rho = 0.342); p values < 0.001. Both contraction power and displaced volume were greater in patients with normal motility versus IEM or absent contractility, complete versus incomplete bolus transit, and normal versus abnormal retention on TBE; p values < 0.02.

CONCLUSIONS

FLIP panometry metrics of contraction power and displaced volume appeared to effectively quantify peristaltic vigor. These novel metrics may enhance evaluation of esophageal motility with FLIP panometry and provide a reliable surrogate to DCI on HRM.

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

BACKGROUND

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.

METHODS

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).

KEY RESULTS

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.

CONCLUSIONS AND INFERENCES

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.

Role of short interval FLIP panometry in predicting long-term outcomes after per-oral endoscopic myotomy

BACKGROUND

The Eckardt score (ES) is used to assess symptom response to Per-Oral Endoscopic Myotomy (POEM), but reliable methods to assess physiologic success are needed. Functional lumen imaging probe (FLIP) panometry has a potential role in post-POEM follow-up to predict long-term outcomes. The aim of this study was to assess the correlation between clinical success and FLIP parameters following POEM to determine if short interval FLIP could predict long-term outcomes.

METHODS

This was a prospective study of adult patients who underwent POEM with short interval follow-up FLIP between 11/2017 and 3/2020. Clinical success was defined as post-procedure ES ≤ 3. Physiologic success was based on an esophago-gastric junction distensibility index (EGJ-DI) > 2.8 mm2/mmHg on FLIP.

RESULTS

47 patients (55% female, mean age 55 years) were included in the study. Clinical success after POEM was seen in 45 (96%) patients (mean ES 6.5 ± 2.2 pre and 0.83 ± 1.0 post-POEM, p < 0.001). Physiologic success was noted in 43 (91.5%) patients (mean EGJ-DI 6.1 mm2/mmHg ± 2.5). Among 4 patients not meeting criteria for physiologic success, EGJ-DI was 2.5-2.6. There was no correlation between post-POEM EGJ-DI and ES in the short term or long term. Significant reflux esophagitis was seen in 6 (12.8%) patients with no difference in mean EGJ-DI with vs without esophagitis (5.9 vs 6.1, p = 0.44).

CONCLUSION

Post-POEM endoscopy with FLIP is useful to both assess EGJ physiology and to examine for reflux esophagitis. Short interval FLIP has limited utility to predict long-term patient outcomes or risk of acid reflux.

The impact of primary peristalsis, contractile reserve, and secondary peristalsis on esophageal clearance measured by timed barium esophagogram

BACKGROUND

Primary and secondary peristalsis facilitate esophageal bolus transport; however, their relative impact for bolus clearance remains unclear. We aimed to compare primary peristalsis and contractile reserve on high-resolution manometry (HRM) and secondary peristalsis on functional lumen imaging probe (FLIP) Panometry with emptying on timed barium esophagogram (TBE) and incorporate findings into a comprehensive model of esophageal function.

METHODS

Adult patients who completed HRM with multiple rapid swallows (MRS), FLIP, and TBE for esophageal motility evaluation and without abnormal esophagogastric junction outflow/opening or spasm were included. An abnormal TBE was defined as a 1-min column height >5 cm. Primary peristalsis and contractile reserve after MRS were combined into an HRM-MRS model. Secondary peristalsis was combined with primary peristalsis assessment to describe a complementary neuromyogenic model.

KEY RESULTS

Of 89 included patients, differences in rates of abnormal TBEs were observed with primary peristalsis classification (normal: 14.3%; ineffective esophageal motility: 20.0%; absent peristalsis: 54.5%; p = 0.009), contractile reserve (present: 12.5%; absent: 29.3%; p = 0.05), and secondary peristalsis (normal: 9.7%; borderline: 17.6%; impaired/disordered: 28.6%; absent contractile response: 50%; p = 0.039). Logistic regression analysis (akaike information criteria, area under the receiver operating curve) demonstrated that the neuromyogenic model (80.8, 0.83) had a stronger relationship predicting abnormal TBE compared to primary peristalsis (81.5, 0.82), contractile reserve (86.8, 0.75), or secondary peristalsis (89.0, 0.78).

CONCLUSIONS AND INFERENCES

Primary peristalsis, contractile reserve, and secondary peristalsis were associated with abnormal esophageal retention as measured by TBE. Added benefit was observed when applying comprehensive models to incorporate primary and secondary peristalsis supporting their complementary application.

An artificial intelligence platform provides an accurate interpretation of esophageal motility from Functional Lumen Imaging Probe Panometry studies

BACKGROUND

Functional lumen imaging probe (FLIP) Panometry is performed at the time of sedated endoscopy and evaluates esophageal motility in response to distension. This study aimed to develop and test an automated artificial intelligence (AI) platform that could interpret FLIP Panometry studies.

METHODS

The study cohort included 678 consecutive patients and 35 asymptomatic controls that completed FLIP Panometry during endoscopy and high-resolution manometry (HRM). "True" study labels for model training and testing were assigned by experienced esophagologists per a hierarchical classification scheme. The supervised, deep learning, AI model generated FLIP Panometry heatmaps from raw FLIP data and based on convolutional neural networks assigned esophageal motility labels using a two-stage prediction model. Model performance was tested on a 15% held-out test set (n = 103); the remainder of the studies were utilized for model training (n = 610).

KEY RESULTS

"True" FLIP labels across the entire cohort included 190 (27%) "normal," 265 (37%) "not normal/not achalasia," and 258 (36%) "achalasia." On the test set, both the Normal/Not normal and the achalasia/not achalasia models achieved an accuracy of 89% (with 89%/88% recall, 90%/89% precision, respectively). Of 28 patients with achalasia (per HRM) in the test set, 0 were predicted as "normal" and 93% as "achalasia" by the AI model.

CONCLUSIONS

An AI platform provided accurate interpretation of FLIP Panometry esophageal motility studies from a single center compared with the impression of experienced FLIP Panometry interpreters. This platform may provide useful clinical decision support for esophageal motility diagnosis from FLIP Panometry studies performed at the time of endoscopy.

Inter- and intra-rater agreement of interpretation of functional lumen imaging probe in healthy subjects

BACKGROUND

The functional lumen imaging probe (FLIP) evaluates esophagogastric junction (EGJ) opening and esophageal contractility. Both post hoc and real-time analyses are possible, but reproducibility and reliability of analysis remain undefined. This study assesses inter- and intra-rater agreement of normative FLIP measurements among novice and experienced users.

METHODS

Eight motility experts from different institutions independently evaluated de-identified video recordings from 27 asymptomatic healthy subjects using FLIP. Interpretation methods simulating a post-procedure and a live procedure setting were tested. Novice FLIP users (n = 3) received training prior to post-procedure interpretation. Experienced FLIP users (n = 5) interpreted using both methods. Users recorded maximum EGJ and distal esophageal body diameter, distensive pressure, and EGJ distensibility index (EGJ-DI), at balloon fill volumes of 50-, 60-, and 70 ml, as well as repetitive antegrade contractions (RACs). Inter- and intra-rater agreements of diameters, distensive pressure and EGJ-DI were assessed by intra-class correlation coefficient (ICC) and Pearson's correlation coefficient (PCC). Percentage agreement evaluated inter- and intra-rater reliability for RACs.

KEY RESULTS

Novice and experienced users acquired normative FLIP metrics. Good-to-excellent inter- and intra-rater reliability were achieved for all variables at 60 ml balloon fill volumes. Median parameters at 60 ml balloon fill volume were as follows: EGJ-DI 5.5 mm2 /mmHg, maximum EGJ diameter 18.6 mm, distensive pressure at maximum EGJ diameter 48.1 mmHg, and distal esophageal body diameter 19.5 mm.

CONCLUSIONS AND INFERENCES

Normative FLIP parameters can be reliably extracted from FLIP videos using both real-time and post hoc analyses, with high reliability between experienced and novice users.

The broad impact of functional lumen imaging probe panometry in addition to high-resolution manometry in an esophageal clinical practice

High-resolution manometry (HRM) with the Chicago Classification (CC) is the standard paradigm to define esophageal motility disorders. Functional lumen imaging probe (FLIP) panometry utilizes impedance planimetry to characterize esophageal compliance and secondary peristalsis. The aim of this study was to explore the clinical impact of FLIP panometry in addition to HRM. A retrospective chart review was performed on FLIP panometry cases utilizing the 322N catheter. Cases with prior foregut surgeries or botulinum injection within 6 months of FLIP panometry were excluded. EGJ-diameter and distensibility index (DI) and secondary contraction patterns at increasing balloon volumes were recorded. An EGJ-DI of ≥2.8 mm2/mm Hg at 60 mL was considered as a normal EGJ distensibility. CC diagnosis, Eckhardt score, Brief Esophageal Dysphagia Questionnaire, and clinical outcomes were obtained for each FLIP case. A total of 186 cases were included. Absent contractility and achalasia types 1 and 2 showed predominantly absent secondary contraction patterns, while type 3 had a variety of secondary contractile patterns on FLIP panometry. Among 77 cases with EGJ outflow obstruction (EGJOO), 60% had a low EGJ-DI. Among those with no motility disorder or ineffective esophageal motility on HRM, 27% had a low DI and 47% had sustained contractions on FLIP, raising concern for an esophageal dysmotility process along the achalasia and/or spastic spectrum. FLIP panometry often confirmed findings on HRM in achalasia and absent contractility. FLIP panometry is useful in characterizing EGJOO cases. Spastic features on FLIP panometry may raise concern for a motility disorder on the spastic spectrum not captured by HRM. Further studies are needed on FLIP panometry to determine how to proceed with discrepancy with HRM and explore diagnoses beyond the CC.

Identifying hiatal hernia with impedance planimetry during esophageal distension testing

INTRODUCTION

Functional luminal imaging probe (FLIP) Panometry evaluates the esophageal response to distension involving biomechanics and motility. We have observed that hiatus hernia (HH) is evident during FLIP studies as a separation between the crural diaphragm (CD) and lower esophageal sphincter (LES) like what is seen with high-resolution manometry (HRM). The aim of this study was to compare FLIP findings to endoscopy and HRM in the detection of HH.

METHODS

A total of 100 consecutive patients that completed FLIP during sedated endoscopy and HRM were included. LES-CD separation was assessed on FLIP and HRM with the presence of HH defined as LES-CD ≥1 cm. The agreement was evaluated using the kappa (κ) statistic.

RESULTS

Hiatal hernia was detected in 32% of patients on HRM and 44% of patients on FLIP with a substantial agreement between studies (84% agreement; κ = 0.667). On FLIP, a 'new' HH (i.e. HH not observed on HRM) occurred in 14 patients and an "enlarged" HH (i.e., LES-CD ≥2 cm larger than on HRM) occurred in 11 patients. Among patients that also completed, timed barium esophagogram (TBE), delayed esophageal emptying on TBE was more common in patients with new or enlarged HH on FLIP than those without: 7/11 (64%) versus 2/12 (17%); p = 0.017.

CONCLUSION

FLIP can detect HH with a substantial agreement with HRM, though esophageal distension with FLIP testing appeared to elicit and/or enlarge a HH in an additional 25% of patients. Although this unique response to esophageal distension may represent a mechanism of dysphagia or susceptibility to reflux, additional study is needed to clarify its significance.

Functional Lumen Imaging Probe Panometry Helps Identify Clinically Relevant Esophagogastric Junction Outflow Obstruction per Chicago Classification v4.0

INTRODUCTION

Esophagogastric junction (EGJ) outflow obstruction (EGJOO) per Chicago Classification v4.0 (CCv4.0) represents a high-resolution manometry (HRM) diagnosis with uncertain clinical significance. This study aimed to evaluate functional lumen imaging probe (FLIP) panometry among patients with EGJOO on HRM/CCv4.0 to assess clinical/manometric associations and treatment outcomes.

METHODS

An observational cohort study was performed on patients who completed FLIP during endoscopy and had an HRM/CCv4.0 diagnosis of EGJOO, i.e., HRM-EGJOO (inconclusive). Abnormal FLIP panometry motility classifications were applied to identify FLIP-confirmed conclusive EGJOO. Rapid drink challenge on HRM and timed barium esophagram were also assessed. Clinical management plan was determined by treating physicians and assessed through chart review. Clinical outcome was defined using the Eckardt score (ES) during follow-up evaluation: ES < 3 was considered a good outcome.

RESULTS

Of 139 adult patients with manometric EGJOO (inconclusive per CCv4.0), a treatment outcome ES was obtained in 55 after achalasia-type treatment (i.e., pneumatic dilation, peroral endoscopic myotomy, laparoscopic Heller myotomy, or botulinum toxin injection) and 36 patients after other nonachalasia-type treatment. Among patients with conclusive EGJOO by HRM-FLIP complementary impression, 77% (33/43) had a good outcome after achalasia-type treatment, whereas 0% (0/12) of patients had a good outcome after nonachalasia-type treatment. Of patients with normal EGJ opening on FLIP, one-third of patients treated with achalasia-type treatment had a good outcome, while 9 of the 10 treated conservatively had a good outcome.

DISCUSSION

FLIP panometry provides a useful complement to clarify the clinical significance of an HRM/CCv4.0 EGJOO diagnosis and help direct management decisions.

Chronic opioid users with dysphagia are indistinguishable from symptomatic nonusers on functional lumen imaging probe evaluation

BACKGROUND

Opioid-induced esophageal dysmotility (OIED) includes spastic esophageal motility disorders, increasingly recognized in the contemporary opioid epidemic. We assessed functional lumen imaging probe (FLIP) findings in diagnosing OIED.

METHODS

Symptomatic patients undergoing FLIP with no prior foregut surgery who completed validated questionnaires were identified and segregated into chronic opioid users and nonusers in this cohort study. Esophagogastric junction (EGJ) distensibility index (DI), EGJ diameter, and esophageal body contraction patterns were extracted. Symptom profiles were compared to FLIP findings between chronic opioid users and nonusers. Outcome was evaluated in a subset using the same validated questionnaires.

RESULTS

Over the 18-months study period, of 116 patients (median age 62 years, 70.7% female), 33 (28.4%) were chronic opioid users, with median morphine milligram equivalent of 30 mg. While presenting symptoms were similar, chronic opioid users reported higher perceptive symptoms (p = 0.008) and worse quality of life (p = 0.01) compared to nonusers. Median DI trended lower in chronic opioid users (p = 0.08), with more retrograde repetitive contractions (p < 0.001) and less absent contractility (p = 0.007), but final FLIP diagnoses were similar compared to nonusers. There was no correlation between opioid dose and FLIP metrics. In the subset with follow-up, perceptive symptoms trended higher in chronic opioid users (p = 0.08), but symptom improvement following therapy was similar in both groups.

CONCLUSIONS & INFERENCES

Symptomatic chronic opioid users have FLIP diagnoses that are similar to nonusers, despite higher perceptive symptoms and worse quality of life. Dominant symptoms improve both in chronic opioid users and nonusers following treatment directed by FLIP.

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

Background/Aims

This 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).

Methods

Five 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.

Results

Per 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.

Conclusions

Application 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/Aims

We 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.

Methods

We 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.

Results

We 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).

Conclusion

While 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.

Functional luminal imaging probe in the evaluation of esophago-gastric junction outflow obstruction

PURPOSE OF REVIEW

Esophagogastric junction outflow obstruction (EGJOO) comprises a heterogeneous group of conditions that demonstrate impaired deglutitive relaxation of the esophagogastric junction (EGJ) with intact esophageal peristalsis on high-resolution manometry. Functional luminal imaging probe (FLIP) panometry is a powerful tool that can help to clarify the etiology of this manometric diagnosis. The aim of this review is to summarize the use of FLIP for the evaluation and management of EGJOO.

RECENT FINDINGS

FLIP panometry provides measures of esophageal compliance at the EGJ and information on esophageal body contractile responses to balloon distention that have important implications for the management of patients with EGJOO. After excluding anatomic causes of impaired EGJ distensibility, FLIP panometry is useful in differentiating true lower esophageal sphincter dysfunction from manometric artifact. FLIP panometry has been shown to be useful in determining the need for invasive treatment in patients with EGJOO, and in intraoperative tailoring of myotomy procedures.

SUMMARY

FLIP panometry is easy to perform during endoscopy and provides useful information for characterizing the EGJOO population. FLIP panometry can be used to guide treatment and improve outcomes in the management of patients with EGJOO.

The Utility of Functional Luminal Imaging Probes Measurements to Diagnose Dysmotility and Their Relationship to Impaired Bolus Clearance

BACKGROUND

Functional luminal imaging probes (FLIP) have been used by multiple centers to assess esophagogastric junction (EGJ) function in patients at risk for esophageal obstruction but its role in diagnosing peristaltic disorders is less well studied. In particular, there are no studies comparing the sensitivity of FLIP to diagnose motility abnormalities and impaired bolus transit by high-resolution esophageal manometry with impedance.

METHODS

We prospectively recruited 42 patients undergoing high-resolution esophageal manometry with impedance (HRIM) who also underwent FLIP between 2018 and 2020. HRIM parameters were analyzed using Swallow Gateway software to determine peristaltic and lower esophageal sphincter pressure measurements as well as bolus flow parameters. FLIP tracings were analyzed for the presence of repetitive antegrade contractions (RACs), EGJ distensibility, and associated parameters.

RESULTS

Forty-two patients were included (11 controls, 7 achalasia, 16 fundoplication, 8 dysmotility). The mean age of patients was 10.1 ± 0.9 years. There were significant differences in bolus flow parameters across diagnosis with longer bolus presence (BPT) in control patients compared with fundoplication and dysmotility patients. There was a significant correlation between EGJ diameter, EGJ distensibility and bolus flow time (BFT) for solid foods (r2 > 0.518, P < 0.02). The presence of RACs and EGJ relaxation during RACs was associated with a greater BFT and BPT across textures (P < 0.05). Forty-two percentage of patients with absent RACs, however, had clear peristalsis by HRIM.

CONCLUSIONS

The presence of RACs and EGJ relaxation by FLIP correlate with improved bolus flow. Patients with an absence of RACs need HRIM to confirm any diagnoses of dysmotility.

Devices for esophageal function testing

BACKGROUND AND AIMS

Esophageal function testing is an integral component of the evaluation of refractory GERD and esophageal motility disorders. This review summarizes the current technologies available for esophageal function testing, including the functional luminal imaging probe (FLIP), high-resolution esophageal manometry (HRM), and multichannel intraluminal impedance (MII) and pH monitoring.

METHODS

We performed a MEDLINE, PubMed, and MAUDE database literature search to identify pertinent clinical studies through March 2021 using the following key words: esophageal manometry, HRM, esophageal impedance, FLIP, MII, and esophageal pH testing. Technical data were gathered from traditional and web-based publications, proprietary publications, and informal communications with pertinent vendors. The report was drafted, reviewed, and edited by the American Society for Gastrointestinal Endoscopy Technology Committee and approved by the Governing Board of the American Society for Gastrointestinal Endoscopy.

RESULTS

FLIP is a high-resolution impedance planimetry system used for pressure and dimension measurement in the esophagus, pylorus, and anal sphincter. FLIP provides complementary information to HRM for esophageal motility disorders, especially achalasia. The Chicago classification, based on HRM data, is a widely adopted algorithmic scheme used to diagnose esophageal motility disorders. MII detects intraluminal bolus movement and, combined with pH measurement or manometry, provides information on acid and non-acid gastroesophageal reflux and bolus transit in patients with refractory GERD and for preoperative evaluation for anti-reflux procedures.

CONCLUSIONS

Esophageal function testing techniques (FLIP, HRM, and MII-pH) have diagnostic and prognostic value in the evaluation of esophageal motility disorders and refractory GERD. Newer technologies and classification systems have enabled an increased understanding of these diseases.

Can FLIP guide therapy in idiopathic esophagogastric junction outflow obstruction?

BACKGROUND

Esophagogastric junction outflow obstruction (EGJOO) has a variable disease course. Currently, barium swallow (BaS) and manometric parameters are used to characterize clinically significant EGJOO. The esophagogastric junction distensibility index (EGJ-DI) measured via functional lumen imaging probe (FLIP) can provide complementary information. Our aim was to assess symptom response in patients with EGJOO and an abnormal EGJ-DI after botulinum toxin (BT) treatment.

METHODS

A prospective cohort study of adults with idiopathic EGJOO was performed from September 2019 to March 2021. Patients with dysphagia underwent upper endoscopy with FLIP. If the EGJ-DI was abnormally low, BT was injected. Data examined included demographics, medical history, endoscopic and FLIP findings, BaS, manometry, and Eckardt score (ES). ES improvement was assessed via paired samples t-test. Pearson's chi-square tests were used to assess for associations.

RESULTS

Of the 20 patients, 75% had an abnormal EGJ-DI and underwent BT injections. Mean ES for patients with abnormal EGJ-DIs significantly improved from baseline to 1, 3, and 6 month follow-up (P-values: 0.01, 0.05, and 0.02, respectively). There was a significant association between an abnormal EGJ-DI with delayed bolus transit and presence of rapid drink challenge panesophageal pressurization on manometry: P = 0.03 and P = 0.03.

CONCLUSION

This prospective study revealed that an abnormal EGJ-DI can guide BT as assessed via symptomatic response. Additionally, abnormal EGJ-DI measurements were significantly associated with other parameters used previously to determine clinically relevant EGJOO. Larger follow-up studies are warranted to further elucidate guidance for therapy in EGJOO.

Dysphagia: Novel and Emerging Diagnostic Modalities

Among recent advances in diagnostics for dysphagia and esophageal motility disorders is the update to the Chicago Classification (version 4.0) for interpretation of high-resolution manometry (HRM) and diagnosis of esophageal motility disorders. The update incorporates application of complementary testing strategies during HRM, such as provocative HRM maneuvers, and recommendation for barium esophagram or functional luminal imaging probe (FLIP) panometry to help clarify inconclusive HRM findings. FLIP panometry also represents an emerging technology for evaluation of esophageal distensibility and motility at the time of endoscopy.

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

INTRODUCTION

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).

METHODS

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.

RESULTS

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.

DISCUSSION

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.

Predictors of Abnormal Functional Luminal Impedance Planimetry Findings in Non-mechanical Esophagogastric Junction Outflow Obstruction

BACKGROUND

Esophagogastric junction outflow obstruction (EGJOO) is a common but nonspecific motility pattern identified by esophageal high-resolution manometry (HRM). Functional luminal impedance planimetry (FLIP) provides information regarding lower esophageal sphincter (LES) mechanics, which can identify achalasia spectrum disorders and is useful in evaluating EGJOO. However, the relationship between HRM and FLIP parameters in EGJOO is not clearly defined.

AIMS

To identify predictors of abnormal FLIP findings in patients with non-mechanical EGJOO.

METHODS

This is a retrospective cohort study of patients with non-mechanical EGJOO who underwent FLIP between 10/1/16 and 7/1/19. Demographic data including age and gender, examination indication, concomitant medications, HRM parameters, symptom burden, and FLIP metrics of diameter and distensibility index (DI) were collected. DI was categorized as not low (DI > 2.8), borderline low (DI 1.1-2.8), and definitely low (DI ≤ 1). Kruskal-Wallis and Fisher's exact tests were used to assess the relationship between HRM and FLIP parameters and to identify predictors of abnormal FLIP.

RESULTS

Among the 44 patients studied, most were female (n = 33, 75%) and the median age was 63. The median IRP was 18.2, and 10 (23%) patients used chronic narcotics. Lower total heartburn and regurgitation scores, and LES diameter by FLIP are associated with definitely low DI.

CONCLUSIONS

In patients with non-mechanical EGJOO, reflux burden scores and FLIP diameters can aid in predicting DI. These results may provide useful adjunctive data to help in differentiating which patients have meaningful outflow obstruction.

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

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

Solid Swallow Examination During High Resolution Manometry and EGJ-Distensibility Help Identify Esophageal Outflow Obstruction in Non-obstructive Dysphagia

Single water swallow (SWS) high-resolution manometry (HRM) may miss relevant esophageal motility disorders. Solid test meal (STM) during HRM and lately the functional lumen imaging probe (FLIP) have been shown to be of diagnostic value in the assessment of motility disorders. We aimed to assess the diagnostic yield of STM and FLIP in non-obstructive dysphagia (NOD). Patients assessed for dysphagia with both HRM and FLIP between April 2016 and August 2019 were analyzed for signs of non-obstructive EGJ outflow obstruction (EGJOO) according to Chicago Classification 3.0 (CCv3) and CC adapted for the use with solid swallows (CC-S), followed by an individual group-specific analysis. Five subjects without dysphagia served as control group. Standard HRM- and FLIP-values as well as esophagograms and Eckardt Scores were analyzed. Forty-two patients were identified (male/female, 14/36, median age 62). Twenty-five (59.5%) were diagnosed with EGJOO during STM only (= SWS-negative patients; CC-S). The EGJ distensibility index (EGJ-DI) of symptomatic patients was significantly lower compared to the control group (p = 0.006). EGJ-DI was < 3mm²/mmHg in 67% and 88% of patients diagnosed according to CC-S and CCv3, respectively. The IRP during STM showed a significant association to the corresponding EGJ-DI values (p < 0.001). Seventy-six percent of patients received treatment because of additional STM evaluation with a favorable clinical response rate of 89%. STM and FLIP identify EGJOO in symptomatic patients with normal SWS during HRM. STM resembles an inexpensive and clinically meaningful option to diagnose motility disorders and helps to select patients for interventional treatment.

Normal Functional Luminal Imaging Probe Panometry Findings Associate With Lack of Major Esophageal Motility Disorder on High-Resolution Manometry

BACKGROUND & AIMS

A normal esophageal response to distension on functional luminal imaging probe (FLIP) panometry during endoscopy might indicate normal esophageal motor function. We aimed to investigate the correlation of normal FLIP panometry findings with esophageal high-resolution manometry (HRM) and outcomes of discrepant patients.

METHODS

We performed a retrospective study using data from a registry of patients who completed FLIP during sedated endoscopy. We identified 111 patients with normal FLIP panometry findings (mean age, 42 y; 69% female) and corresponding HRM data. A normal FLIP panometry was defined as an esophagogastric junction (EGJ) distensibility index greater than 3.0 mm2/mm Hg, an absence of repetitive retrograde contractions, and a repetitive antegrade contraction pattern that met the Rule-of-6s: ≥6 consecutive antegrade contractions of ≥6-cm in length, at a rate of 6 ± 3 contractions per minute. HRM findings were classified by the Chicago classification system version 3.0.

RESULTS

HRM results were classified as normal motility in 78 patients (70%), ineffective esophageal motility in 10 patients (9%), EGJ outflow obstruction in 20 patients (18%), and 3 patients (3%) as other. In patients with EGJ outflow obstruction based on HRM, the integrated relaxation pressure normalized on adjunctive swallows in 16 of 20 patients (80%), and in 8 of 9 patients (88%) who completed a barium esophagram and had normal barium clearance. Thus, although 23 of 111 patients (21%) with normal FLIP panometry had abnormal HRM findings, these HRMs often were considered to be false-positive or equivocal results. All patients with an abnormal result from HRM were treated conservatively.

CONCLUSIONS

In a retrospective cohort study, we found that patients with normal FLIP panometry results did not have a clinical impression of a major esophageal motor disorder. Normal FLIP panometry results can exclude esophageal motility disorders at the time of endoscopy, possibly negating the need for HRM in select patients.

Efficacy and safety of peroral endoscopic myotomy after prior sleeve gastrectomy and gastric bypass surgery

BACKGROUND

Per-oral endoscopic myotomy (POEM) is safe and effective for the treatment of achalasia. There is limited data on performance of POEM in patients with altered upper gastrointestinal anatomy, especially after bariatric surgery. Outcomes in patients with prior sleeve gastrectomy have not been reported.

AIM

To assess the efficacy and safety of POEM in patients with prior bariatric surgery.

METHODS

A prospective POEM database was reviewed from 3/2017-5/2020 to identify patients who underwent POEM after prior bariatric surgery. Efficacy was assessed by technical success (defined as the ability to successfully complete the procedure) and clinical success [decrease in Eckardt score (ES) to ≤ 3 post procedure]. Safety was evaluated by recording adverse events.

RESULTS

Six patients (50% male, mean age 48 years) with a history of prior bariatric surgery who underwent POEM were included. Three had prior sleeve gastrectomy (SG) and three prior Roux-en-Y gastric bypass (RYGB). Four patients had achalasia subtype II and 2 had type I. Most (4) patients had undergone previous achalasia therapy. Technical success was 100%. Clinical success was achieved in 4 (67%) patients at mean follow-up of 21 mo. In one of the clinical failures, EndoFLIP evaluation demonstrated adequate treatment and candida esophagitis was noted as the likely cause of dysphagia. There were no major adverse events.

CONCLUSION

POEM is technically feasible after both RYGB and SG and offers an effective treatment for this rare group of patients where surgical options for achalasia are limited.

Use of the Functional Lumen Imaging Probe in Clinical Esophagology

The functional lumen imaging probe (FLIP) measures luminal dimensions using impedance planimetry, performed most often during sedated upper endoscopy. Mechanical properties of the esophageal wall and opening dynamics of the esophagogastric junction (EGJ) can be objectively evaluated in esophageal motor disorders, eosinophilic esophagitis, esophageal strictures, during esophageal surgery and in postsurgical symptomatic states. Distensibility index, the ratio of EGJ cross sectional area to intraballoon pressure, is the most useful FLIP metric. Secondary peristalsis from balloon distension can be displayed topographically as repetitive anterograde or retrograde contractile activity in the esophageal body, similar to high-resolution manometry. Real-time interpretation and postprocessing of FLIP metadata can complement the identification of esophageal outflow obstruction and achalasia, especially when findings are inconclusive from alternate esophageal tests in symptomatic patients. FLIP can complement the diagnosis of achalasia when manometry and barium studies are inconclusive or negative in patients with typical symptoms. FLIP can direct adequacy of disruption of the EGJ in achalasia when used during and immediately after myotomy and pneumatic dilation. Lumen diameter measured using FLIP in eosinophilic esophagitis and in complex strictures can potentially guide management. An abbreviated modification of the Grading of Recommendations Assessment, Development, and Evaluation was used to determine the quality of available evidence and recommendations regarding FLIP utilization. FLIP metrics that are diagnostic or suggestive of an abnormal motor pattern and metrics that define normal esophageal physiology were developed by consensus and are described in this review.

Utilizing functional lumen imaging probe in directing treatment for post-fundoplication dysphagia

BACKGROUND

Esophagogastric junction obstruction (EGJO) post-fundoplication (PF) is difficult to identify with currently available tests. We aimed to assess the diagnostic accuracy of EGJ opening on functional lumen imaging probe (FLIP) and dilation outcome in FLIP-detected EGJO in PF dysphagia.

METHODS

We prospectively collected data on PF patients referred to Esophageal Clinic over 18 months. EGJO diagnosis was made by (a) endoscopist's description of a narrow EGJ/wrap area, (b) appearance of wrap obstruction or contrast/tablet retention on esophagram, or (c) EGJ-distensibility index (DI) < 2.8 mm²/mmHg on real-time FLIP. In patients with EGJO and dysphagia, EGJ dilation was performed to 20 mm, 30 mm, or 35 mm in a stepwise fashion. Outcome was assessed as % dysphagia improvement during phone call or on brief esophageal dysphagia questionnaire (BEDQ) score.

RESULTS

Twenty-six patients were included, of whom 17 (65%) had a low EGJ-DI. No patients had a hiatal hernia greater than 3 cm. Dysphagia was the primary symptom in 17/26 (65%). In 85% (κ = 0.677) of cases, EGJ assessment (tight vs. open) was congruent between the combination of endoscopy (n = 26) and esophagram (n = 21) vs. EGJ-DI (n = 26) on FLIP. Follow-up data were available in 11 patients who had dilation based on a low EGJ-DI (4 with 20 mm balloon and 7 with ≥ 30 mm balloon). Overall, the mean % improvement in dysphagia was 60% (95% CI 37.7-82.3%, p = 0.0001). Nine out of 11 patients, including 6 out of 7 undergoing pneumatic dilation, had improvement ≥ 50% in dysphagia (mean % improvement 72.2%; 95% CI 56.1-88.4%, p = 0.0001).

CONCLUSIONS AND INFERENCES

Functional lumen imaging probe is an accurate modality for evaluating for EGJ obstruction PF. FLIP may be used to select patients who may benefit from larger diameter dilation.

EndoFLIP in the Esophagus: Assessing Sphincter Function, Wall Stiffness, and Motility to Guide Treatment

The functional luminal imaging probe (FLIP) uses high-resolution planimetry to provide a three-dimensional image of the esophageal lumen by measuring diameter, volume, and pressure changes. Literature surrounding use of FLIP has demonstrated its clinical utility as a diagnostic tool and as a device to guide and measure response to therapy. FLIP can assess and guide treatments for esophageal disease states including gastroesophageal reflux disease, achalasia, and eosinophilic esophagitis. FLIP may become the initial test for patients with undifferentiated dysphagia at their index endoscopy. This article summarizes use of FLIP in assessing sphincter function, wall stiffness, and motility to guide treatments.

Functional Luminal Imaging Probe Panometry Identifies Achalasia-Type Esophagogastric Junction Outflow Obstruction

BACKGROUND & AIMS

The etiologies of esophagogastric junction outflow obstruction (EGJOO) vary, as do their therapeutic implications. We aimed to identify patients with EGJOO most likely to benefit from achalasia-type treatment, based on findings from functional luminal imaging probe (FLIP) panometry.

METHODS

We performed a retrospective study of 34 patients who received a diagnosis of EGJOO from January 2015 through July 2017. Our analysis included patients who had been evaluated with timed barium esophagram, FLIP, or upper endoscopy.

RESULTS

Among the 34 patients with idiopathic EGJOO, 7 (21%) had a normal esophagogastric junction distensibility index (EGJ-DI), based on FLIP panometry, and all had repetitive antegrade contractions. None of the patients had radiographic evidence of EGJOO (RAD-EGJOO), defined as liquid barium retention and/or barium tablet impaction. On the other hand, all 18 patients with RAD-EGJOO had an EGJ-DI less than 2 mm²/mm Hg. Nine of the 18 patients with RAD-EGJOO and EGJ-DI less than 2 mm²/mm Hg underwent achalasia-type treatment, and 77.8% of these (7 of 9) had improvements in Eckardt score. Of the 6 patients with a normal EGJ-DI (>3 mm²/mm Hg) who were treated conservatively and followed up, 100% had improvements in subsequent Eckardt scores.

CONCLUSIONS

We found that FLIP is useful in identifying patients with EGJOO who are most likely to benefit from achalasia-type therapy. Patients with a low EGJ-DI responded well to achalasia-type treatment, whereas patients with normal results from FLIP panometry had good outcomes from conservative management. FLIP panometry might help select management strategies for this difficult population of patients.

The use of impedance planimetry (Endoscopic Functional Lumen Imaging Probe, EndoFLIP® ) in the gastrointestinal tract: A systematic review

BACKGROUND AND PURPOSE

The EndoFLIP® system is a method of delineating impedance and was first designed to investigate the characteristics of the esophago-gastric junction. In the last decade, its use was widened to investigate other sphincteric and non-sphincteric systems of the gastrointestinal tract. The objective of the present systematic review was to summarize the available data in literature on the use of the EndoFLIP® system in the gastrointestinal tract, including sphincteric and non-sphincteric regions. We performed a systematic review in accordance with recommendations for systematic review using PRISMA guidelines without date restriction, until June 2020, using MEDLINE-PubMed, Cochrane Library, and Google Scholar databases. Only articles written in English were included in the present review. Five hundred and six unique citations were identified from all database combined. Of those, 95 met the inclusion criteria. There was a lack of standardization among studies in terms of anesthetic drugs use, probe placement, and inflation protocol. In most cases, only small cohorts of patients were included. Most studies investigated the EGJ, with a potential use of the EndoFLIP® to identify a subgroup of patients with achalasia and for intraoperative assessment of treatment efficacy in achalasia. However, the use of EndoFLIP® in the esophageal body (esophageal panometry), other esophageal diseases (gastro-esophageal reflux disease, eosinophilic esophagitis), and other sphincter regions (anal canal, pylorus) will need further confirmatory studies. The EndoFLIP® system provides detailed geometric data of the gastrointestinal lumen but further works are needed to determine its use in clinical practice.

Esophageal Functional Lumen Imaging Probe (FLIP): How Can FLIP Enhance Your Clinical Practice?

Recent innovations in esophageal diagnostic testing have enhanced gastroenterology clinical practice by facilitating more nuanced and advanced evaluation of esophageal symptoms. Among these pivotal advances is the FDA-approved functional lumen imaging probe (FLIP), which utilizes impedance planimetry via volumetric distension of a catheter-mounted balloon at the time of sedated upper endoscopy, to acquire esophageal dimensions and pressures. In real time, FLIP can display cross-sectional areas (CSA) and distensibility indices (ratios of CSA to intra-balloon pressures) throughout the esophagus, most notably at the esophagogastric junction, as well as secondary peristaltic esophageal body contractile patterns. As the use of FLIP has progressively spread and permeated into the practice of clinical gastroenterology since its introduction, increasing data on and experiences with its applications have accumulated to guide its utility in clinical practice. In this current review developed for gastroenterologists and foregut surgeons across clinical practice, we provide an introduction to FLIP technology and metrics and discuss the clinical scenarios in which performance of or referral for FLIP may be helpful in the evaluation and management of patients with commonly encountered esophageal symptoms and disorders. Specifically, we discuss the potential applications and limitations of FLIP as a complementary diagnostic modality in patients with non-obstructive dysphagia, established or suspected achalasia spectrum disorders, eosinophilic esophagitis, gastroesophageal reflux disease and those undergoing esophageal surgery.

Flip Technology for Assessing Esophageal Structural and Motor Disorders: a Skeptic's View

PURPOSE OF REVIEW

Functional lumen impedance (FLIP) technology has become commercially available to assess structural and motor abnormalities of the esophagus. Increasing numbers of papers have described novel findings with this technology. This review examines the validity of the FLIP technique, how it compares with existing diagnostic modalities, and evidence to date on diagnostic accuracy.

RECENT FINDINGS

FLIP studies require deep sedation at the time of endoscopy to complete. They assess a simulated state of esophageal obstruction in only a distal part of the esophagus rather than deglutitive motor function of the entire esophagus. The available normative dataset is small and not matched to the older age of patients typically being evaluated. The test-retest agreement in health and disease is unknown, as is the operator dependence on performing and interpreting findings. Studies to date have largely excluded patients with structural disorders, which FLIP cannot reliably distinguish from motor disorders. FLIP is an expensive technology that has been made clinically available without its true utility being established. For FLIP to be deemed a device ready for widespread clinical use, additional studies on validity, diagnostic accuracy, and outcomes need to be performed. Prospective clinical studies need to include all patients and assess the incremental cost-effectiveness of FLIP over more innovative use of existing technology, such as high-resolution manometry with provocative challenges.

Impedance in the evaluation of the esophagus

The aim of this paper is to review esophageal electrical impedance technologies and to discuss the use of these technologies for physiological measurements, diagnostics, and therapy of esophageal disease. In order to develop a better understanding of the pathophysiology of and improve the diagnosis of esophageal disorders, such as gastroesophageal reflux disease (GERD) and achalasia, several new diagnostic tests, including intraluminal impedance, esophageal mucosal impedance, and the functional luminal imaging probe, have been developed. These technologies have proven valuable for assessment of the esophagus in recent years. They provide information on esophageal flow properties, mucosal integrity, lumen shape, and distensibility in esophageal disorders, in particular for GERD and achalasia. Despite their promise and novel clinical studies, the potential of these technologies has been far from realized. New multidisciplinary approaches will contribute to our understanding and interpretation of esophageal impedance data and disease mechanisms.

Applying the Functional Luminal Imaging Probe to Esophageal Disorders

PURPOSE OF REVIEW

The functional luminal imaging probe (FLIP) uses high-resolution planimetry to provide a three-dimensional image of the esophageal lumen by measuring diameter, volume, and pressure changes. The goal of this review is to summarize the most recent advances in applying the (FLIP) to esophageal disorders.

RECENT FINDINGS

The FLIP has been studied in esophageal disease states including gastroesophageal reflux disease (GERD), achalasia, and eosinophilic esophagitis. It has also been used in the investigation of dysphagia. The FLIP is a valuable tool for the diagnosis of esophageal diseases as well as guiding treatments and predicting treatment response. As further research is done, the FLIP may become the initial test for the patient with undifferentiated dysphagia at the time of their index endoscopy.