Peristaltic regimes in esophageal transport

Elisha, Guy; Acharya, Shashank; Halder, Sourav; Carlson, Dustin A.; Kou, Wenjun; Kahrilas, Peter J.; Pandolfino, John E.; Patankar, Neelesh A.

doi:10.1007/s10237-022-01625-x

Cited by 4 publications

(32 citation statements)

References 38 publications

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“…In our previous studies, we developed a one dimensional (1D) model of a flow inside an elastic tube closed on both ends to imitate a flow inside a FLIP device ( Elisha et al, 2022a ; Elisha et al, 2021 ; Acharya et al, 2021c ; Halder et al, 2022c ). Our goal was to study the relation between tube properties, fluid properties, muscle activation pattern, and their effect on pressure and CSA of the tube.…”

Section: Methodsmentioning

confidence: 99%

“…To complete the system, we relate pressure and CSA by a linear constitutive equation of the form

This relation, also known as the “Tube Law,” was derived by Whittaker et al (2010) and validated experimentally by Kwiatek et al (2011) . In the equation above, P o is the outside pressure, K e is tube stiffness, and A o is the undeformed reference area (CSA of the tube when P = P o ) ( Elisha et al, 2022a ; Elisha et al, 2021 ; Elisha et al, 2022b ; Acharya et al, 2021c ). Lastly, to mimic muscle peristaltic contraction, we vary the reference area sinusoidally by multiplying A o by an activation function θ ( x , t ) ( Ottesen, 2003 ; Manopoulos et al, 2006 ; Bringley et al, 2008 ; Acharya et al, 2021c ; Elisha et al, 2022a ).…”

Section: Methodsmentioning

confidence: 99%

“…In the equation above, P o is the outside pressure, K e is tube stiffness, and A o is the undeformed reference area (CSA of the tube when P = P o ) ( Elisha et al, 2022a ; Elisha et al, 2021 ; Elisha et al, 2022b ; Acharya et al, 2021c ). Lastly, to mimic muscle peristaltic contraction, we vary the reference area sinusoidally by multiplying A o by an activation function θ ( x , t ) ( Ottesen, 2003 ; Manopoulos et al, 2006 ; Bringley et al, 2008 ; Acharya et al, 2021c ; Elisha et al, 2022a ). As Eq.…”

Section: Methodsmentioning

confidence: 99%

“…We non-dimensionalize the dynamic system using

to reduce the number of independent variables. The terms α , τ , U , p , and χ are the non-dimensional variables of area, time, velocity, pressure, and position, respectively ( Acharya et al, 2021c ; Elisha et al, 2022a ). The dimensional wave speed and tube length are

and L , respectively.…”

Section: Methodsmentioning

confidence: 99%

“…Thus, understanding esophageal motor function and investigating the contractile behavior of esophageal smooth muscles can help in identifying esophageal disease progression and develop diagnostic tools. Extensive computational studies have been performed in recent years on the mechanics of esophageal transport ( Kou et al, 2017a ; Kou et al, 2017b ; Kou et al, 2018 ; Kou et al, 2017c ; Acharya et al, 2022 ; Halder et al, 2021 ; Elisha et al, 2022a ; Acharya et al, 2021c ; Acharya et al, 2021a ; Elisha et al, 2021 ; Liao et al, 2020 ) and emptying as well as the state of various esophageal diseases ( Acharya et al, 2021b ; Halder et al, 2022a ; Halder et al, 2022c ; Halder et al, 2022b ).…”

Section: Introductionmentioning

confidence: 99%

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A mechanics-based perspective on the pressure-cross-sectional area loop within the esophageal body

et al. 2023

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Introduction: Plotting the pressure-cross-sectional area (P-CSA) hysteresis loops within the esophagus during a contraction cycle can provide mechanistic insights into esophageal motor function. Pressure and cross-sectional area during secondary peristalsis can be obtained from the functional lumen imaging probe (FLIP). The pressure-cross-sectional area plots at a location within the esophageal body (but away from the sphincter) reveal a horizontal loop shape. The horizontal loop shape has phases that appear similar to those in cardiovascular analyses, whichinclude isometric and isotonic contractions followed by isometric and isotonic relaxations. The aim of this study is to explain the various phases of the pressurecross-sectional area hysteresis loops within the esophageal body.Materials and Methods: We simulate flow inside a FLIP device placed inside the esophagus lumen. We focus on three scenarios: long functional lumen imaging probe bag placed insidethe esophagus but not passing through the lower esophageal sphincter, long functional lumen imaging probe bag that crosses the lower esophageal sphincter, and a short functional lumen imaging probe bag placed in the esophagus body that does not pass through the lower esophageal sphincter.Results and Discussion: Horizontal P-CSA area loop pattern is robust and is reproduced in all three cases with only small differences. The results indicate that the horizontal loop pattern is primarily a product of mechanical conditions rather than any inherently different function of the muscle itself. Thus, the distinct phases of the loop can be explained solely based on mechanics.

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Section: Methodsmentioning

confidence: 99%

“…To complete the system, we relate pressure and CSA by a linear constitutive equation of the form

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…We non-dimensionalize the dynamic system using

and L , respectively.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A mechanics-based perspective on the pressure-cross-sectional area loop within the esophageal body

et al. 2023

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

Elisha

Halder

Acharya

et al. 2023

Biomech Model Mechanobiol

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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.

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

Halder,

Yamasaki,

Liu

et al. 2024

Neurogastroenterology Motil

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BackgroundEsophageal motility disorders can be diagnosed by either high‐resolution manometry (HRM) or the functional lumen imaging probe (FLIP) but there is no systematic approach to synergize the measurements of these modalities or to improve the diagnostic metrics that have been developed to analyze them. This work aimed to devise a formal approach to bridge the gap between diagnoses inferred from HRM and FLIP measurements using deep learning and mechanics.MethodsThe “mechanical health” of the esophagus was analyzed in 740 subjects including a spectrum of motility disorder patients and normal subjects. The mechanical health was quantified through a set of parameters including wall stiffness, active relaxation, and contraction pattern. These parameters were used by a variational autoencoder to generate a parameter space called virtual disease landscape (VDL). Finally, probabilities were assigned to each point (subject) on the VDL through linear discriminant analysis (LDA), which in turn was used to compare with FLIP and HRM diagnoses.ResultsSubjects clustered into different regions of the VDL with their location relative to each other (and normal) defined by the type and severity of dysfunction. The two major categories that separated best on the VDL were subjects with normal esophagogastric junction (EGJ) opening and those with EGJ obstruction. Both HRM and FLIP diagnoses correlated well within these two groups.ConclusionMechanics‐based parameters effectively estimated esophageal health using FLIP measurements to position subjects in a 3‐D VDL that segregated subjects in good alignment with motility diagnoses gleaned from HRM and FLIP studies.

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Peristaltic regimes in esophageal transport

Cited by 4 publications

References 38 publications

A mechanics-based perspective on the pressure-cross-sectional area loop within the esophageal body

A mechanics-based perspective on the pressure-cross-sectional area loop within the esophageal body

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

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

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