Tu1170 DIAGNOSTIC PERFORMANCE OF AN ENDOSCOPIC PRESSURE INTEGRATED SYSTEM (EPSIS): A NOVEL DIAGNOSTIC TOOL FOR GASTROESOPHAGEAL REFLUX DISEASE

Abstract

Lower esophageal sphincter (LES) dysfunction is known to be the main cause of gastroesophageal reflux disease (GERD). Although esophageal pH monitoring is considered the gold standard for the diagnosis of GERD, it is laborious and time consuming. Currently, there is no diagnostic method that can directly assess the function of LES endoscopically. We have recently developed a new diagnostic tool: endoscopic pressure study integrated system (EPSIS) that enables us to evaluate LES function endoscopically. The aim of this study was to evaluate the diagnostic performance of this novel diagnostic system. We conducted a retrospective study of patients who underwent both EPSIS and 24-hour impedance-pH monitoring at a single tertiary referral center from April 2016 to October 2017. EPSIS was performed at the time of gastroscopy by using a through-the-scope catheter connected to the system to measure intra-gastric pressure (IGP). Carbon dioxide was insufflated until LES loosens to evacuate the pressure by belching. The maximum IGP and waveform pattern of IGP (uphill or flat pattern) were recorded (Figure 1). On 24-hour impedance-pH monitoring, percentage of total time pH < 4 over 4.2%, DeMeester composite score over 14.7, and distal reflux event over 48 times on impedance monitoring were considered positive for GERD. We hypothesized as follows: (i) maximum IGP below 20mmHg and (ii) flat waveform pattern would correlate with GERD based upon a previously conducted preliminary study performed at our institution. The diagnostic performance of these findings was evaluated based on aforementioned positive findings on esophageal pH monitoring. A total of 54 patients with PPI-refractory acid reflux symptoms underwent both EPSIS and esophageal pH monitoring. The additional time of gastroscopy needed to perform EPSIS was less than 5 minutes in all cases. Both maximum IGP < 20mmHg and flat waveform pattern significantly correlated with percent total time pH < 4 over 4.2% (p < 0.01) and DeMeester composite score over 14.7 (p < 0.01). Twenty-five patients (44%) were diagnosed positive for GERD on pH monitoring. Forty patients (74.0%) were considered positive with maximum IGP < 20mmHg or flat waveform pattern recorded on EPSIS. Sensitivity, specificity, overall accuracy of positive EPSIS findings were 91.7% (95% CI, 0.73-0.99), 40.0% (95% CI, 0.23-0.59), 62.9% (95% CI, 0.49-0.76), respectively in the diagnosis of GERD by pH monitoring. EPSIS may be a promising detection tool that can be utilized to determine the pretest probability of esophageal pH monitoring in less than 5 minutes during gastroscopy. With this rapid and easily performed examination, EPSIS could be performed prior to proceeding with other diagnostic investigations for GERD.