Impact of ineffective esophageal motility on chemical clearance in patients with gastroesophageal reflux symptoms

Ineffective esophageal motility (IEM) is the most common manometric abnormality in gastroesophageal reflux disease (GERD). However, the impact of IEM on esophageal chemical clearance has not been fully investigated. This study aimed to determine the impact of IEM on esophageal chemical clearance in patients with GERD. A total of 369 patients with GERD symptoms who underwent upper endoscopy and high-resolution manometry (HRM) test were retrospectively analyzed. The relationship between IEM and erosive esophagitis was examined. In addition, the impact of IEM on chemical clearance was examined in patients who underwent an additional combined multichannel intraluminal impedance-pH (MII-pH) test. Esophageal chemical clearance capability was evaluated via postreflux swallow-induced peristaltic wave (PSPW) index and acid clearance time (ACT). Of 369 patients, 181 (49.1%) had esophageal motility disorders, of which 78 (21.1%) had IEM. The proportion of IEM patients in those with erosive esophagitis and those without were 16.2% and 21.7%, respectively, and no significant difference was observed (P=0.53). After excluding patients other than those with IEM and normal esophageal motility, 64 subsequently underwent MII-pH test. The median values of the PSPW index in the IEM and normal esophageal motility group were 11.1% (4.2%-20.0%) and 17.1% (9.8%-30.6%), respectively. The PSPW index was significantly lower in the IEM group than in the normal esophageal motility group (P<0.05). The median ACT values in the IEM group and normal esophageal motility group were 125.5 (54.0-183.5) seconds and 60.0 (27.2-105.7) seconds, respectively. The ACT was significantly longer in the IEM group than in the normal esophageal motility group (P<0.05). In conclusion, IEM was found to be associated with chemical clearance dysfunction as measured against the PSPW index and ACT. As this condition could be a risk factor for GERD, future treatments should be developed with a focus on chemical clearance.