Ambulatory 24-hour multichannel intraluminal impedance-pH monitoring and high resolution endoscopy distinguish patients with non-erosive reflux disease from those with functional heartburn

Aims To assess the contribution of 24-h esophageal multichannel intraluminal impedance and pH (MII-pH) monitoring and high resolution endoscopy (HRE) with i-scan imaging in differentiating non erosive reflux disease (NERD) from functional heartburn (FH). Methods This is a retrospective cohort study of patients with heartburn from the Endoscopy Unit. NERD patients and FH patients were defined by 24-h MII-pH monitoring and white light endoscopy. Minimal mucosal changes were assessed by HRE with i-scan imaging. Results Total of 156 consecutive patients with heartburn but without esophageal mucosal erosions were studied. Forty-eight of these subjects had NERD, with increased acid exposure time (AET) and positive SAP and/or SI. Eighteen had FH with normal AET and negative SAP and SI. When compared to FH patients and healthy controls, NERD patients had significantly increased number of total acid reflux episodes, as well as increased number of weakly acidic reflux episodes (p<0.01). The rate of proximal reflux episodes in NERD patients was higher than that of FH patients and healthy controls (p<0.01). Irregular or blurring of the Z-line (58.3%) and white mucosal turbidity (47.9%) were the most common endoscopic findings of minimal mucosal changes observed in this study. NERD patients had more prevalent minimal changes than FH patients and the controls (87.5% vs. 66.6% vs. 61.9%; p = 0.004) with sensitivity of 87.5%. Histopathological evaluation showed that NERD patients had significantly higher average scores of intercellular spaces dilation (2.82 +/- 0.9 vs. 1.2 +/- 0.6, p = 0.005) and papillae elongation (2.65 +/- 1.0 vs. 1.5 +/- 0.8, p = 0.014), but not for basal cell proliferation (1.6 +/- 1.3 vs. 1.0 +/- 0.9, p = 0.070). The histological scores of the NERD patients were 7.1 +/- 1.2, which were higher than those of FH patients (3.4 +/- 1.0, p = 0.004). Conclusions Minimal mucosal changes could be useful markers to support clinical diagnosis of NERD. Combination of 24-h MII-pH monitoring and i-scan high resolution endoscopy can distinguish patients with NERD from those with FH.