Original article
Alimentary tract
Normal Values of Esophageal Distensibility and Distension-Induced Contractility Measured by Functional Luminal Imaging Probe Panometry

https://doi.org/10.1016/j.cgh.2018.07.042Get rights and content

Background & Aims

Functional luminal imaging probe (FLIP) panometry provides a comprehensive evaluation of esophageal functional at the time of endoscopy, including assessment of esophageal distensibility and distension-induced esophageal contractility. However, the few and inconsistent findings from healthy individuals pose challenges to the application of FLIP to research and clinical practice. We performed FLIP panometry in asymptomatic volunteers.

Methods

We performed a prospective study of 20 asymptomatic volunteers (ages, 23–44; 14 women) who were evaluated with 16-cm FLIP positioned across the esophagogastric junction (EGJ) and distal esophagus (and in 8 subjects also repositioned at the proximal esophagus) during sedated upper endoscopy. FLIP data were analyzed with a customized program that generated FLIP panometry plots and calculated the EGJ-distensibility index (DI) and distensibility plateaus (DP) of distal and proximal esophageal body. Distension-induced esophageal contractility was also assessed.

Results

The median EGJ-DI was 5.8 mm2/mm Hg (interquartile range [IQR], 4.9–6.7 mm2/mm Hg); all 20 subjects had an EGJ-DI greater than 2.8 mm2/mm Hg. The median DP values from all subjects tested were 20.2 mm (IQR, 19.8–20.8 mm) at the distal body, 21.1 mm (IQR, 20.3–22.9 mm) at the proximal body, and greater than 18 mm at both locations. Repetitive antegrade contractions (RACs) were observed in all 20 subjects; in 19 of 20 (95%) subjects, the RAC pattern persisted for 10 or more consecutive antegrade contractions.

Conclusions

Normal parameters of FLIP panometry are EGJ-DI greater than 2.8 mm2/mm Hg, DP greater than 18 mm, and antegrade contractions that occur in a repetitive pattern (RACs)—these can be used as normal findings for esophageal distensibility and distension-induced contractility. These values can be used in comparative studies of esophageal diseases, such as achalasia and eosinophilic esophagitis, and will facilitate application of FLIP panometry to clinical practice.

Section snippets

Subjects

Healthy, asymptomatic (ie, free of esophageal symptoms including dysphagia, heartburn, and chest pain), adult volunteers were enrolled. Potential subjects were excluded for a previous diagnosis of esophageal, autoimmune, or eating disorders. Additional exclusion criteria included use of antacids or proton pump inhibitors, body mass index greater than 30 kg/m2, or a history of tobacco use or alcohol abuse. The study protocol was approved by the Northwestern University Institutional Review Board.

Subjects

Twenty-two asymptomatic volunteers were evaluated, but 1 was excluded because of a technical limitation and another because of frequent retching during the endoscopy/FLIP that limited interpretation, thus 20 subjects, with a mean age of 30 years (range, 23–44 y), were included (14 [70%] were women). Endoscopic examinations were normal in all 20 subjects. Sedation dosages were an average of 9 mg (range, 7–10 mg) midazolam and 193 mcg (range, 150–200 mcg) fentanyl.

Distensibility of the Esophagogastric Junction

The median EGJ-DI was 5.8 mm2/mm

Discussion

This study described the esophageal response to volumetric distention in 20 asymptomatic normal subjects and generated normative data focused on EGJ distensibility, esophageal body distensibility, and the contractile response to sustained volumetric distention. Focusing on EGJ-DI as the primary metric of EGJ opening function, our results support a previously defined cut-off value for normal of 2.8 mm2/mm Hg because 100% of our asymptomatic normal subjects exceeded this threshold.1, 3, 6

References (16)

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Conflicts of interest These authors disclose the following: Dustin A. Carlson, Zhiyue Lin, Peter J. Kahrilas, and John E. Pandolfino hold shared intellectual property rights and ownership surrounding functional luminal imaging probe panometry systems, methods, and apparatus with Medtronic, Inc; and John E. Pandolfino holds stock options in Crospon, Inc, has served as a consultant for Given Imaging, Sandhill Scientific, Medtronic, Torax, and Ironwood, has received grants from Given Imaging and Impleo, and has served as a speaker for Given Imaging, Sandhill Scientific, Takeda, Astra Zeneca, Medtronic, and Torax. The remaining authors disclose no conflicts.

Funding Supported by grant R01 DK079902 (J.E.P.) from the Public Health Service and grants from the Scleroderma Research Foundation (M.H.).

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