Esophageal Baseline Impedance Reflects Mucosal Integrity and Predicts Symptomatic Outcome With Proton Pump Inhibitor Treatment

Background/Aims Esophageal baseline impedance, which is decreased in gastroesophageal reflux disease (GERD) patients, is related to the severity of acid reflux and the integrity of the esophageal mucosa. The study aims to compare the baseline impedance and the dilated intercellular spaces (DIS) within patients with typical reflux symptoms and to evaluate the correlation of baseline impedance with DIS, esophageal acid exposure, as well as the efficacy of proton pump inhibitor (PPI) treatment. Methods Ninety-two patients and 10 healthy controls were included in the study. Erosive esophagitis (EE) was defined by esophageal mucosal erosion under upper endoscopy. Patients without mucosa erosion were divided into groups with pathologic acid reflux (non-erosive reflux disease [NERD]) or with hypersensitive esophagus. The biopsies of esophageal mucosa were taken 2-4 cm above the gastroesophageal junction Z-line during upper endoscopy for DIS measurement. All the patients received esomeprazole 20 mg twice-daily treatment for 8 weeks. The efficacy of esomeprazole was evaluated among all patients. Results The intercellular spaces were dilated in both EE and NERD patients (P < 0.05). The value 0.73 µm could be used as the cut-off DIS value to distinguish patients from controls (area under the curve [AUC] = 0.849, P < 0.01). One thousand seven hundred sixty-four ohms could be used as the cut-off impedance values to distinguish patients from controls (AUC = 0.794, P < 0.01). The baseline impedance was decreased in both EE patients and NERD patients, and negatively correlated to the acid exposure time (r = -0.527, P < 0.05). There was a weak correlation between DIS and baseline impedance (r = -0.230, P < 0.05). "Baseline impedance > 1764 Ω" was an independent predictor for PPI failure (OR, 11.9; 95% CI, 2.4-58.9; P < 0.01). Conclusions The DIS and decreased baseline impedance was observed in patients with mucosa erosion or pathological acid reflux. The baseline impedance reflected the mucosal integrity, it was more sensitive to esophageal acid exposure. Patients with high impedance might not benefit from the PPI treatment.