title: Correlation between hypersensitivity induced by esophageal acid infusion and the baseline impedance level in patients with suspected gastroesophageal reflux.
abstract: OBJECTIVE
  To evaluate the relevance between the pH parameters and baseline impedance level or esophageal hypomotility in patients with suspected gastroesophageal reflux.
  
  
  METHODS
  The recordings of 51 patients with heartburn, acid regurgitation, globus or noncardiac chest pain were analyzed. Evaluation included a 24-h multichannel intraluminal impedance-pH test while on off-proton pump inhibitor therapy over 1 week, high-resolution manometry and Bernstein test. Mean baseline impedance level at the most distal portion of the impedance channel was assessed manually. Esophageal hypomotility was evaluated using transitional zone defect (TZD) and distal break (DB) length measurement.
  
  
  RESULTS
  In the study subjects (n = 51), 6 had a DeMeester score of more than 14.7 and 14 had a positive symptom index. The Bernstein test was positive in ten patients. The baseline impedance level was inversely correlated with the acid exposure time % (r = -0.660, P < 0.001). Also, all reflux and weakly acid reflux time % measured by impedance monitoring showed a weak correlation with TZD + DB length (r = 0.327 and 0.324, P = 0.019 and 0.020, respectively). Although a positive Bernstein test has no relevance for the acid exposure time or acid-related symptoms as represented by the DeMeester score or symptom index, the baseline impedance level was significantly lower in patients with a positive Bernstein test than in those with a negative one (2,628.4 ± 862.7 vs. 1,752.2 ± 611.1 Ω, P = 0.004).
  
  
  CONCLUSIONS
  A lower baseline impedance level is closely related to increased esophageal acid exposure. Hypersensitivity induced by esophageal acid infusion might be attributed to acid-induced mucosal changes of the esophagus.
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, 173-82, Gumi-ro, Bundang-gu, Seongnam, Gyeonggi-do, 463-707, South Korea.
authors.forename: A Young
authors.initials: AY
authors.lastname: Seo
authors.forename: Cheol Min
authors.initials: CM
authors.lastname: Shin
authors.forename: Nayoung
authors.initials: N
authors.lastname: Kim
authors.forename: Hyuk
authors.initials: H
authors.lastname: Yoon
authors.forename: Young Soo
authors.initials: YS
authors.lastname: Park
authors.forename: Dong Ho
authors.initials: DH
authors.lastname: Lee
mesh_terms: D017097:Electric Impedance; D050782:Esophageal pH Monitoring; D004947:Esophagus / Q000378:metabolism* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D005744:Gastric Acid / Q000378:metabolism*; D005745:Gastric Acidity Determination; D005764:Gastroesophageal Reflux / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D008297:Male; D008365:Manometry; D008875:Middle Aged; D054328:Proton Pump Inhibitors / Q000627:therapeutic use; D012189:Retrospective Studies
chemical_list: D054328:Proton Pump Inhibitors