An analysis of distal esophageal impedance in individuals with and without esophageal motility abnormalities

Background: Combined multichannel intraluminal impedance and manometry provides simultaneous evaluation of bolus transit and pressure changes within the esophagus. The aim of this study was to analyze and to compare distal esophageal impedance values between healthy volunteers and patients with normal and abnormal esophageal manometry. Materials and Methods: We analyzed multichannel intraluminal impedance and manometry studies in 130 individuals (79 women, mean age 53 y, age range 17 to 85 y). There were 20 healthy volunteers and 20 patients with normal manometry. Patients with abnormal manometry were separated into nutcracker esophagus (n=20), distal esophageal spasm (n=20), ineffective esophageal motility (IEM, n=20), achalasia (n=20), and scleroderma esophagus (n=10). Manometric and MII parameters were assessed during 10 liquid and 10 viscous swallows. MII findings included esophageal impedance values and number of complete and incomplete bolus transits (CBTs). Esophageal impedance values from 2 distal impedance measuring segments (5 and 10-cm above lower esophageal sphincter) were assessed over a 2 to 3 seconds interval before the first liquid and the first viscous swallow, and 2 to 3 seconds after the tenth viscous swallow. The average values of esophageal impedance measured at 5 and 10-cm above lower esophageal sphincter (distal esophageal impedance) were calculated before liquid [distal baseline impedance (DBI)] and after 10 liquid swallows [distal liquid impedance (DLI)] and after 10 viscous swallows [distal viscous impedance (DVI)]. The correlations between DLI and DVI and number of CBT for liquid and viscous as well as distal esophageal amplitude (DEA) for liquid and viscous were also assessed using Pearson correlation coefficient. Results: Patients with achalasia or scleroderma esophagus had significantly lower DBI, DLI, and DVI than healthy volunteers, patients with normal manometry, nutcracker esophagus, or distal esophageal spasm. Patients with IEM had significantly lower DBI, DLI, and DVI than healthy volunteers or patients with nutcracker esophagus. Patients with IEM had significantly lower DLI and DVI than patients with normal manometry and significantly higher DVI than patients with achalasia. Overall, there was a significant correlation between DLI and CBTs during 10 liquid swallows (r=0.7, P<0.0001), DVI and CBTs during 10 viscous swallows (r=0.6, P<0.0001), DLI and DEA during 10 liquid swallows (r=0.5, P<0.0001), and DVI and DEA during 10 viscous swallows (r=0.5, P<0.0001). Conclusions: Our results suggest that evaluation of distal esophageal impedance may assist in recognition and diagnosis of esophageal motility abnormalities.