Evaluation of esophageal distensibility in eosinophilic esophagitis: an update and comparison of functional lumen imaging probe analytic methods

Abstract

Background Distensibility evaluation of the esophageal body using the functional lumen imaging probe (FLIP) offers an objective measure to characterize patients with eosinophilic esophagitis (EoE), though this analysis may be limited by unrecognized catheter movement and esophageal contractility. The aims of this study were to report novel FLIP analytic methods of esophageal distensibility measurement in EoE and to assess the effect of contractility. Methods Nine healthy controls (6 female; ages 20 – 49) and 20 EoE patients (4 female; ages 19 – 64; grouped by degree of distension-mediated contractility identified on FLIP) were evaluated with a 16-cm FLIP device during step-wise balloon distension during upper endoscopy. A distensibility plateau (DP) was generated using multiple methods to identify the narrowest esophageal body diameter: 1) Wavelet decomposition (WD) 2) Maximal diameter (MD), and 3) FLIP Analytics software. Results Distensibility was reduced in EoE patients compared with controls using the WD (p = 0.002) and MD (p = 0.001) methods; a trend was detected using the FLIP Analytics method (p = 0.055). Significant intra-subject differences were detected between methods among both patients and controls (p-values <0.001 – 0.025); the difference was more pronounced among subjects with a greater degree of contractility. DP was < 19 mm among 7/9 controls with FLIP Analytics, 6/9 controls with WD, and 0/9 controls using the MD-method. Conclusion Distension-mediated contractility affects distensibility measurement with the FLIP. Using software-based algorithms, particularly with a method that identifies the maximal achieved diameters (MD), may improve objective distensibility measurement for clinical research and practice.

Influence of Age and Eosinophilic Esophagitis on Esophageal Distensibility in a Pediatric Cohort

“…Previously published studies in EoE have used both catheter lengths but have not compared the two. [11, [17] Until this observed trend can be directly studied, we recommend that when following patients longitudinally that the same catheter type be used and propose that consideration be given to using the 8 cm catheter in children with an estimated esophageal length less than 16 cm but that in other children and adults, the longer 16 cm catheter be used in the evaluation of lumen distensibility in EoE.…”

“…This value was chosen based on previous work by others as it is considered to be slightly above typical swallow-associated pressure and determined to be a value sensitive enough to detect EoE associated stiffness. [10,11,17]…”

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

“…Thus, various methods using the FLIP Analytics software (Crospon) or other external software methods (e.g. MATLAB, The Math Works, Natick, MA) have been developed to counteract these effects using various filtering techniques and analysis paradigms 8–10 .…”

“…This analysis may also be hampered by catheter movement and esophageal contractility being misinterpreted as a fixed luminal narrowing and thus, various analysis approaches have been used, such as wavelet decomposition (WD), maximal diameter (MD), and FLIP Analytics software filtering. A recent study comparing these three approaches suggests that the MD approach using the maximal diameter attained at each axial location may be the most accurate 10 . Additionally, FLIP topography can also be utilized to assess areas of narrowing along the body over the entire study to assess the distensibility plateau.…”

“…Thus post-processing the FLIP data using software programs to filter out the contraction-associated changes in esophageal luminal diameter is necessary 8–10 . Software enhancements are being developed that improve the current analysis paradigms and should broaden the clinical utility of FLIP in the evaluation of EoE.…”