Tu1413 Relationship Between Esophageal Pressure Changes in Different Body Positions and Bolus Dynamics at the Esophago-Gastric Junction

Background: The Chicago classification is useful to classify esophageal motility disorders; however, the clinical importance of some diagnoses such as esophago-gastric junction (EGJ) outflow obstruction should be clarified. There are several cases in which it is difficult to determine if a high integral relaxation pressure (IRP) value in the supine position (supine IRP) has causes dysphagia because IRP in the sitting position (sitting IRP) is lower. Although the relationship between EGJ pressure and bolus dynamics at the EGJ has been assessed, the relationship between esophageal pressure and bolus dynamics at the EGJ is not fully understood.Aim: To clarify the relationship between esophageal pressure changes in different body positions and bolus dynamics at the EGJ. Material and Methods: High resolution manometry (HRM) was performed using ManoScan® in 43 patients with esophageal symptoms such as dysphagia, chest pain or heartburn. Ten 5-ml water swallows were performed in the supine position to evaluate esophageal motility, followed by at least five 5-ml water swallows were repeated in the sitting position. Moreover, an esophagogram in the upright position was performed in all patients. Pressure values were calculated by ManoView® and esophageal motility disorders were diagnosed by the Chicago classification criteria. Barium bolus dynamics were classified into 4 types: i) bolus passed smoothly at the EGJ (type 1), ii) bolus was pooled in the esophagus and then cleared by peristalsis (type 2), iii) bolus passed at the EGJ with minor pooling in the esophagus (type 3), and iv) most of bolus was pooled in the esophagus (type 4). The Mann-Whitney test or the Kruskal-Wallis test was used to compare pressure values.Results: The patient diagnoses, IRP, and intrabolus pressure (IBP) values in different body positions, and the bolus dynamics at the EGJ are shown in the Table. Although the IRP was similar in different body positions in patients with achalasia, the sitting IRP was significantly lower than the supine IRP in patients with other abnormalities or normal peristalsis. Bolus dynamics varied according to esophageal motility abnormalities. The bolus was pooled in the esophagus (type 3 or 4) in all patients with achalasia and absent peristalsis, and in some patients with weak or frequent failed peristalsis. The type 2 bolus dynamics were observed in all, but one patients with EGJ outflow obstruction. The sitting IRP in patients with type 2 or 4 bolus dynamics was significantly higher than that in patients with type 1 or 3 bolus dynamics (median 9.4 vs. 4.4 mmHg, respectively, p<0.01). Conclusions: Both EGJ relaxation and esophageal peristalsis are important for esophageal