Use of the Functional Lumen Imaging Probe in Clinical Esophagology

Abstract

The functional lumen imaging probe (FLIP) measures luminal dimensions using impedance planimetry, performed most often during sedated upper endoscopy. Mechanical properties of the esophageal wall and opening dynamics of the esophagogastric junction (EGJ) can be objectively evaluated in esophageal motor disorders, eosinophilic esophagitis, esophageal strictures, during esophageal surgery and in postsurgical symptomatic states. Distensibility index, the ratio of EGJ cross sectional area to intraballoon pressure, is the most useful FLIP metric. Secondary peristalsis from balloon distension can be displayed topographically as repetitive anterograde or retrograde contractile activity in the esophageal body, similar to high-resolution manometry. Real-time interpretation and postprocessing of FLIP metadata can complement the identification of esophageal outflow obstruction and achalasia, especially when findings are inconclusive from alternate esophageal tests in symptomatic patients. FLIP can complement the diagnosis of achalasia when manometry and barium studies are inconclusive or negative in patients with typical symptoms. FLIP can direct adequacy of disruption of the EGJ in achalasia when used during and immediately after myotomy and pneumatic dilation. Lumen diameter measured using FLIP in eosinophilic esophagitis and in complex strictures can potentially guide management. An abbreviated modification of the Grading of Recommendations Assessment, Development, and Evaluation was used to determine the quality of available evidence and recommendations regarding FLIP utilization. FLIP metrics that are diagnostic or suggestive of an abnormal motor pattern and metrics that define normal esophageal physiology were developed by consensus and are described in this review.

Chicago Classification update (version 4.0): Technical review on diagnostic criteria for achalasia

“…A TBE is a simple test, with relatively low cost and radiation exposure, in evaluating degree of esophageal emptying after a patient drinks 15 The FLIP is a novel tool used during upper endoscopy to simultaneously assess luminal diameter along with pressure in the esophagus during planned volumetric distension. 16 The apparatus can assess the cross-sectional area of the EGJ divided by the pressure in the 20 and there is evidence that FLIP panometry can accurately identify achalasia physiology and identify patients most likely to benefit from achalasia-type therapy. [21][22][23][24] Supportive manometric measurements in the standard HRM protocol of CCv4.0 can also assist with an inconclusive diagnosis of achalasia in the setting of an IRP at the upper limit of normal.…”

Prospective evaluation of the efficacy of peroral endoscopic myotomy in patients with achalasia

“…[ 12 ] It provides useful information for estimating the optimal extent of myotomy during POEM and predicting treatment outcomes. [ 27 , 28 ] FLIP estimates were correlated with symptoms as well as esophageal emptying, and patients with inadequate responses after treatment showed significantly lower EGJ-DI than those who experienced clinical successes. [ 13 ] In addition, there were significant correlations between EGJ-DI and Eckardt score, integrated relaxation pressure, and bolus retention on timed barium esophagogram.…”

EndoFLIP: una nueva tecnología

“…En el extremo más distal del balón se ubica un electrodo de estado sólido que mide la presión y en el segmento proximal hay un puerto de infusión a través del cual se perfunde un líquido conductor. El catéter EF-325 proporciona información sobre la distensibilidad de la UGE y CSA, mientras que el catéter EF-322 proporciona patrones de peristaltismo secundario del cuerpo esofágico, además de las métricas de UGE (Tabla 1) (3,4,9,10).…”

“…A partir de la medición simultánea de la presión y las CSA se calcula la distensibilidad. Estos datos se muestran como una representación tridimensional de la luz esofágica (Figura 2) (3,4,10).…”

“…La FLIP se basa en el principio de planimetría de impedancia y permite la medición directa de áreas transversales intraluminales (CSA), la evaluación de diámetros intraluminales, perfiles geométricos del lumen y cambios de presión, volumen y distensibilidad; es decir, propiedades biomecánicas de la pared, y brinda una imagen tridimensional de la luz esofágica y de la UGE (1,2). Entonces, la EndoFLIP (sonda de imagen endoluminal funcional) es un sistema que mide en tiempo real el índice de distensibilidad de la unión gastroesofágica (UGE-ID) y el peristaltismo esofágico secundario a través de planimetría de impedancia de alta resolución (3)(4)(5). La evaluación inicial de la planimetría de impedancia como prueba se realizó a finales de la década de 1980 y los primeros estudios se realizaron con los dispositivos en la década de los 1990 (6).…”