Alteration in Integrated Relaxation Pressure During Successive Swallows in Subjects With Normal Manometry Versus Those With Esophagogastric Junction Outflow Obstruction

BACKGROUND/AIMS: Integrated relaxation pressure (IRP) is defined as the average minimum esophagogastric junction pressure for 4 seconds of relaxation (contiguous or noncontiguous) within 10 seconds of swallowing. The durability of IRP values during successive swallows in the supine position remains to be elucidated. The aim is to determine alteration in IRP values during successive swallows among subjects with normal esophageal manometry versus those with esophagogastric junction outflow obstruction (EGJOO). METHODS: Consecutive subjects, who underwent high-resolution esophageal manometry (HREM) were included in the study. Individuals had to have either normal manometry or EGJOO. A total of 10 wet swallows of 5 mL water were performed after an adaptation period of a minimum of 3 minutes. Mean IRP was analyzed for both subject groups for each individual swallow. RESULTS: Thirty-one patients with EGJOO and seventy patients with normal manometry were included. As expected, the median IRP was higher in EGJOO patients compared to those with normal HREM (mean 23.92 vs 5.34, P < 0.001). The mean IRP of the last swallow was 40% lower than the mean IRP of the first swallow in the normal subjects (P = 0.015). In contrast, the difference in the mean IRP value in the EGJOO group between the first and the last swallow was 19% (P = 0.018). CONCLUSIONS: This study demonstrated that there is a significant decline in the mean IRP during successive swallows in subjects with normal esophageal manometry and those with EGJOO, despite adequate adaptation periods. This decline in IRP was less pronounced in EGJOO.