Is all ineffective esophageal motility the same? A clinical and high-frequency intraluminal US study

Background: Ineffective esophageal motility (IEM) is characterized by frequent hypotensive or failed peristaltic contractions; its pathophysiology is controversial. Objective: To evaluate whether patients with IEM because of GERD would differ from patients with other etiologies of IEM on the basis of esophageal-muscle thickness measured by high-frequency intraluminal US (HFIUS). Design: Single-center prospective study. Setting: Academic medical center; from January 2004 to June 2005. Subjects: A total of 46 patients who were newly diagnosed with IEM were classified into 2 groups: GERD-related IEM (group I, n = 26) and non-GERD-related IEM (group II, n = 20) on the basis of the presence of reflux esophagitis and/or pathologic acid exposure by 24-hour esophageal pH monitoring. In addition, 16 asymptomatic healthy volunteers with no reflux esophagitis, normal manometric finding, and normal level of acid exposure were included as controls. Main Outcome Measurements: We compared the clinical characteristics, including a predominant principal esophageal symptom and the results from HFIUS among the control, GERD-related IEM (group I), and non-GERD-related IEM (group II) groups. Results: The proportion of typical reflux symptom as a predominant symptom was higher in group I (66%) than in group II (25%). Muscle thickness was greater in group II than in group I and the control group during both the baseline rest period and the peak of contraction period at all levels of the middle of the lower esophageal sphincter (LES), and 3 cm and 9 cm above the LES (respectively) (P < .05). Limitation: The limitation was the small sample size. Conclusions: Patients with non-GERD-related IEM had increased muscle thickness on HFIUS compared with patients with GERD-related IEM and the controls. Based on this study, IEM is not necessarily indicative of GERD.