Role of Esophageal Mean Nocturnal Baseline Impedance and Post-reflux Swallow-induced Peristaltic Wave Index in Discriminating Chinese Patients With Heartburn.

Background/Aims Recently, esophageal mean nocturnal baseline impedance (MNBI) and post-reflux swallow-induced peristaltic wave (PSPW) index have been proposed, which can increase the diagnostic role of multichannel intraluminal impedance and pH recording (MII/pH) for differentiating patients with heartburn. Therefore, our aim is to investigate the role of esophageal proximal MNBI, distal MNBI, and PSPW index in differentiating Chinese patients with heartburn. Methods Patients with heartburn from the Beijing Anzhen Hospital, who underwent upper gastrointestinal endoscopy and 24-hour MII/pH, were enrolled in this study. Results In all, 24 erosive esophagitis (EE), 46 non-erosive reflux disease (NERD), 52 reflux hypersensitivity (RH), and 78 functional heartburn (FH) patients were recruited. The respective median values for the EE, NERD, RH, and FH groups were as follows: proximal MNBI 1858.0, 2147.5, 2374.3, and 2329.0 Omega (P = 0.053); distal MNBI 1243.4, 1506.5, 2451.2, and 2477.3 Omega (P < 0.001); and PSPWI 15.0%, 25.0%, 25.0%, and 45.0% (P < 0.001). Spearman correlation analysis showed that distal MNBI and PSPW index were significantly negatively correlated with acid and bolus exposure time and acid reflux events. Receiver operating characteristic analyses showed that distal MNBI and PSPW index significantly discriminated FH from EE, NERD, and RH (P < 0.001), with cut-off values of 1890.6 Omega and 27.5% and areas under the curve of 0.721 and 0.779, respectively. Conclusion Esophageal distal MNBI and PSPW index could increase the diagnostic role of MII/pH, especially for differentiating Chinese patients with heartburn.