964 A Novel Device Measuring Esophageal Mucosal Consequences of Chronic GERD

Abstract

INTRODUCTION: Gastroesophageal reflux disease (GERD) afflicts more than 100 million US adults, significantly impacts quality of life and imposes >$9 billion/yr in total cost upon our healthcare system. Current GERD diagnostics are suboptimal due to limited sensitivity and specificity, and they are constrained by measurement of esophageal reflux during a single time point at a specified location. They measure presence of reflux but do not measure the long-term mucosal consequences of GERD, a significant limitation of existing platforms. Thus, the aim of our study was to develop and test a novel, minimally invasive technology to assess esophageal mucosal conductivity changes as a result of chronic mucosal exposure to gastroduodenal reflux. METHODS: A single channel mucosal impedance(MI) measuring rings separated by 0.4mm with a 360 degree circumferential design were mounted on a catheter, which could be easily traversed through the working channel of an upper endoscope. 53 patients along the spectrum of GERD were enrolled: Barrett's esophagus (BE) (n=12); Erosive Esophagitis (E+) (n=16); pH+/Non-erosive GERD (pH+) (n=11) and pH-/non-erosive subjects (pH-) (n=14). All pts underwent endoscopy and wireless 48-hour pH monitoring 10-days off PPI tx. During index endoscopy, MI were measured from the site of injury (Barrett's epithelium or esophagitis) as well as 2-, 5and 10-cm above squamocolumnar junction (SCJ). In those without mucosal injury, measurements were taken from 2-, 5and 10-cm above the SCJ. MI measurements (ohms) were obtained continuously for 5 seconds at each location by direct application of the impedance rings to the mucosal surface and the mean of the 5-second measurements for each location was used for analysis. RESULTS: Median (IQ) mucosal measurements were significantly (p=0.001) lower at the site of Barrett's [765 (512-953)] and erosive esophageal mucosa [1147 (530-1307)] than non-erosive regions at the same level [3654 (2315-6146)]. There was a significant (p=0.004) and graded increase in median (IQ) MI axially along the esophagus from distal (2 cm above the SCJ) to proximal (10 cm above the SCJ) (Figure 1). Importantly, there was a graded increase in MI axially along the esophagus in pts with BE, E+ and pH+, which was not present in subjects with visually normal esophageal mucosa and normal acid exposure (E-) (non-GERD) (Figure2). CONCLUSIONS: 1) Esophageal mucosal erosion due to GERD, on average has 81% lower MI than normal tissue. 2) Non-erosive GERD patients show similar pattern of MI along the axial distribution of esophagus as those with erosive disease. 3) This pattern does not exist in those without GERD. 4) These encouraging data show feasibility of the MI concept in providing an alternative and innovative method for detecting chronic consequence of GERD on esophageal mucosal.