Gastroesophageal flap valve reflected EGJ morphology and correlated to acid reflux

Objective: The anatomy of esophagogastric junction (EGJ) serves as the anti-reflux barrier. The gastroesophageal flap valve (GEFV) is a component of EGJ. The aim of the current study was to assess its correlation with the esophageal acid exposure and the impact on anti-reflux barrier function by using the metrics of EGJ contraction. Methods: Eighty three patients with typical GERD symptoms were included in the study. Upper endoscopy, high-resolution manometry (HRM) and 24 h multichannel intraluminal impedance-pH (MII-pH) monitoring were performed in all patients. GEFV was determined as four grades during endoscopic examination based on the Hill classification. The esophageal pressure topography (EPT) metrics defined in the updated Chicago Classification were measured by HRM, including integrated relaxation pressure (IRP), EGJ contractile index (EGJ-CI), expiratory EGJ pressure(EGJP-exp) and inspiratory EGJ pressure (EGJP-insp). Results: The GEFV grade III and IV was more commonly found in patients with esophagitits (p < 0.05). The acid exposure time (AET%) and supine AET% were lower in patients with GEFV grade I (p < 0.01). There was weak correlation between AET% and GEFV grades (r = 0.27, p = 0.013). There were more EGJ morphology type III in patients with GEFV grade IV (p < 0.05). There were no significant differences on the values of four HRM metrics among the patients with different GEFV grades (p > 0.05). Conclusion: The GEFV grades were associated with acid reflux positively and could be a good reflection of EGJ morphology in HRM. But it had no impact on the four HRM metrics. Our research revealed that GEFV may play an assistant role in the anti-reflux barrier.