A mechanics-based perspective on the function of the esophagogastric junction during functional luminal imaging probe manometry

Abstract

The esophagogastric junction (EGJ) is located at the distal end of the esophagus and acts as a valve allowing swallowed food to enter the stomach and preventing acid reflux. Irregular weakening or stiffening of the EGJ muscles results in changes to its opening and closing patterns which can progress into esophageal disorders. Therefore, understanding the physics of the opening and closing cycle of the EGJ can provide mechanistic insights into its function and can help identify the underlying conditions that cause its dysfunction. Using clinical functional lumen imaging probe (FLIP) data, we plotted the pressure-cross-sectional area loops at the EGJ location and distinguished two major loop types -a pressure dominant loop (PDL) and a tone dominant loop (TDL). In this study, we aimed to identify the key characteristics that define each loop type and determine what causes the inversion from one loop to another. To do so, the clinical observations are reproduced using 1D simulations of flow inside a FLIP device located in the esophagus, and the work done by the EGJ wall over time is calculated. This work is decomposed into active and passive components, which reveal the competing mechanisms that dictate the loop type. These mechanisms are esophagus stiffness, fluid viscosity, and the EGJ relaxation pattern.

Enhancing Chicago Classification diagnoses with functional lumen imaging probe—mechanics (FLIP‐MECH)

“…Additionally, the variability within each cluster is revealed providing a better comparison between HRM and FLIP. In preliminary work, the mechanics of esophageal transport have been analyzed [22][23][24][25][26][27][28][29][30] and mechanics-based parameters developed to quantify esophageal function. [31][32][33][34] Furthermore, MI-VAE has been shown to identify and cluster esophageal disorders based on a set of mechanics-based parameters including wall stiffness, active relaxation, and contraction strength that define the mechanical health of the esophagus.…”