Tu1088 Distal and Proximal Esophageal Impedance Basal Values in Patients With Non-Erosive Reflux Disease and Functional Heartburn

Abstract

Background and aim: Several studies have shown that proximal extent of reflux episodes plays an important role in gastro-esophageal reflux symptom perception. The relative hypersensitivity of the proximal esophagus is most evident in patients with non-erosive reflux disease (NERD). Recent studies demonstrated that low distal basal impedance values may reflect impaired mucosal integrity and increased acid sensitivity. The aim was to compare distal and proximal basal impedance values in patients with NERD and functional heartburn (FH). Methods: According to impedance and pH (MII-pH) monitoring off-therapy, we selected patients with NERD (i.e. pathological acid exposure time, AET) and FH (i.e. normal AET and reflux number; negative symptom association). FH patients did not show any symptom relief after acid suppression therapy. For each patient, we evaluated basal impedance values at the distal (3 cm) and proximal (17 cm) channel, during the overnight rest, at three different times: 1, 2, 3 am. Results: Male/female ratio was 23/23 in NERD and 13/33 in FH patients. Mean age was 52.3±13.2 in NERD and 49.2±11.3 in FH. Mean AET was higher in NERD (6.1%±3.8%) than in FH (0.6%±0.7%) (p<0.05). NERD group recorded higher total reflux number (67.8±18.2) than FH group (23.7±9.4) (p<0.05). Basal impedance values were significantly (p<0.05) lower in NERD than in FH, both at the distal (1294.3±529.9 Ohm vs 3502.1±809.2 Ohm) and proximal (3480.7 ±1322.6 Ohm vs 4344.9±976.2 Ohm) channels. Distal basal values were significantly lower than proximal basal values, both in NERD and FH group (p<0.05). Moreover, in NERD group, 24/46 patients (52.2%) had an abnormal number of proximal refluxes. These NERD patients with pathological proximal refluxes did not show lower basal impedance values than NERD patients with normal number of proximal refluxes even if distal (1226.7±453 vs 1243.1±497.1; P=0.5239) or proximal channels (2670.8±1163.4 vs 2849.2±1434.2; p=0.5046) were compared. Summary and conclusion: Patients with NERD showed lower basal impedance values both at the distal and proximal esophagus. Consistently with the concept that low basal impedance may reflect impaired mucosal integrity, our results might be helpful to better investigate the pathophysiological role of proximal refluxes.