Utility of esophageal mucosal impedance as a diagnostic test for esophageal disease

Purpose of reviewThe aim of this review is to summarize the use of direct mucosal impedance (MI) for the evaluation and management of esophageal diseases.Recent findingsEsophageal multichannel intraluminal impedance with pH (MII-pH) monitoring has been considered the most sensitive test for gastroesophageal reflux disease (GERD), but recent studies have failed to establish impedance parameters that reliably predict treatment response to medical and surgical GERD therapies. MII-pH uses a catheter passed through the nose, which is uncomfortable for patients, and the test is compromised by the day-to-day variability of reflux patterns. Recently, an MI device has been developed that can be passed through the working channel of an endoscope to measure esophageal epithelial conductivity as a marker of chronic GERD. The MI values so obtained are available within seconds, correlate with histological findings of epithelial barrier dysfunction, normalize with effective treatment, and show promise for diagnosing eosinophilic esophagitis and for distinguishing it from GERD.SummaryMI can differentiate esophageal disorders instantly during endoscopy, and can monitor treatment responses in GERD and eosinophilic esophagitis.