Flow time through esophagogastric junction derived during high-resolution impedance-manometry studies: a novel parameter for assessing esophageal bolus transit

Abstract

This study aimed to develop and validate a method to measure bolus flow time (BFT) through the esophagogastric junction (EGJ) using a high-resolution impedance-manometry (HRIM) sleeve. Ten healthy subjects were studied with concurrent HRIM and videofluoroscopy; another 15 controls were studied with HRIM alone. HRIM studies were performed using a 4.2-mm-outer diameter assembly with 36 pressure sensors at 1-cm intervals and 18 impedance segments at 2-cm intervals (Given Imaging, Los Angeles, CA). HRIM and fluoroscopic data from four barium swallows, two in the supine and two in the upright position, were analyzed to create a customized MATLAB program to calculate BFT using a HRIM sleeve comprising three sensors positioned at the crural diaphragm. Bolus transit through the EGJ measured during blinded review of fluoroscopy was almost identical to BFT calculated with the HRIM sleeve, with the nadir impedance deflection point used as the signature of bolus presence. Good correlation existed between videofluoroscopy for measurement of upper sphincter relaxation to beginning of flow [R = 0.97, P < 0.001 (supine) and R = 0.77, P < 0.01 (upright)] and time to end of flow [R = 0.95, P < 0.001 (supine) and R = 0.82, P < 0.01 (upright)]. The medians and interquartile ranges (IQR) of flow time though the EGJ in 15 healthy subjects calculated using the virtual sleeve were 3.5 s (IQR 2.3-3.9 s) in the supine position and 3.2 s (IQR 2.3-3.6 s) in the upright position. BFT is a new metric that provides important information about bolus transit through the EGJ. An assessment of BFT will determine when the EGJ is open and will also provide a useful method to accurately assess trans-EGJ pressure gradients during flow.

Advances in the management of oesophageal motility disorders in the era of high-resolution manometry: a focus on achalasia syndromes

“…4). Conversely, in other instances, diagnosis might be achieved via minimal bolus flow time ascertained during high-resolution impedance mano metry 28,29 , a timed barium oesophagram 26 , or a rapid drink challenge 30,31 . However, in most cases an IRP >15 mmHg will suffice to detect impaired EGJ relaxation.…”

The Chicago Classification of Motility Disorders

“…In the future, additional findings will likely be incorporated that further improve accuracy and utility. The use of combined impedance-HRM might be helpful to assess pharyngeal motility and upper esophageal sphincter function 28 and may also complement the analysis of esophageal function 2930 . Performing HRM in alternative conditions such as upright posture 911 may also be considered as this may improve diagnostic yield.…”

High-Resolution Impedance Manometry Metrics of the Esophagogastric Junction for the Assessment of Treatment Response in Achalasia

“…(13) Based on this concept, we developed and validated a novel HRIM metric to specifically assess flow across the EGJ: the bolus flow time (BFT). (15) Utilizing simultaneous videofluoroscopy with HRIM, bolus flow across the EGJ was observed on fluoroscopy when two criteria were met: 1) bolus was present, which was associated with a decrease in impedance and 2) a preferential pressure gradient existed across the EGJ such that pressure in the distal esophagus was greater than at the crural diaphragm. Both of these criteria were incorporated into a computer-based algorithm for automated calculation of the BFT.…”