Background The functional lumen imaging probe (Endoflip™) is increasingly used for evaluation of patients with esophageal symptoms. To improve the interpretation of Endoflip™ in clinical practice, normative values with appropriate cut‐off values are required. Methods Original clinical studies describing Endoflip™ use for measurements of esophageal motility in healthy adults were considered. Meta‐analysis was performed based on published values. Results A total of 17 articles were included in the systematic review, 15 of which were included in the meta‐analysis, representing 154 unique subjects. At 40 ml distention, the 5th–95th and 10th–90th percentiles for esophagogastric junction distensibility index (EGJ‐DI) were 1.96–10.95 mm2/mmHg and 2.36–8.95 mm2/mmHg, respectively. An EGJ‐DI below 2 mm2/mmHg was found in 5.4%, and below 3 mm2/mmHg in 20.1% of healthy subjects. At 50 ml distention, the 5th–95th and 10th–90th percentiles for EGJ‐DI are 2.86–10.66 mm2/mmHg and 3.28–9.12 mm2/mmHg, respectively (below 2 mm2/mmHg: 0.6%, 3 mm2/mmHg: 6.3%). The 5th–95th and 10th–90th percentiles for EGJ‐DI at 60 ml distention were 3.06–8.14 mm2/mmHg and 3.33–7.18 mm2/mmHg, respectively (below 2 mm2/mmHg: 0.0%, 3 mm2/mmHg: 7%). A clear cut‐off for lower values was identified while a large spread in values was observed for upper limits of normal for EGJ‐DI for all filling volumes. Conclusions Given these observations, we recommend using a cut‐off of 2 mm2/mmHg for clinical practice, values below can be considered abnormal. Given that 5.4% of the healthy subjects will have an EGJ‐DI below 2 mm2/mmHg at 40 ml, we recommend using the 50 and 60 ml distention volumes. The clinical use of an upper limit for normality of EGJ‐DI seems questionable.

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. Goodto-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 mm 2 /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.