Ineffective esophageal motility: clinical, manometric, and outcome characteristics in patients with and without abnormal esophageal acid exposure.

The etiology and clinical impact of ineffective esophageal motility (IEM) remain poorly understood. Unless gastroesophageal acid reflux (GERD) is identified, symptomatic patients with IEM are challenging to treat. We sought to determine whether any clinical or functional characteristics could distinguish those patients with IEM and either normal or abnormal esophageal acid exposure.In this retrospective cohort study, we identified 46 consecutive patients presenting with heartburn, and other GER symptoms who underwent clinical, endoscopic, and functional evaluation that included high-resolution manometry (HRM) and ambulatory pH monitoring. IEM was defined using the Chicago Classification criteria (v.3) as ≥50% ineffective swallows (DCI ≤ 450 mmHg.s.cm). Esophageal acid exposure by ambulatory pH monitoring was considered abnormal when total time with esophageal pH < 4 exceeded 4.2%.Of the 46 IEM patients identified, 19 (mean age: 42 years, 37% female), had normal esophageal acid exposure and 27 patients, mean age 54 years, 33% female, evidence of pathologic acid reflux. There was a 12 years age difference between the groups, with those with normal acid exposure being significantly younger (P < 0.01); the mean body mass index (BMI) was 22.6 ± 0.6 in the normal group and 25.4 ± 0.7 in the abnormal group (P < 0.001); otherwise the groups were endoscopically and histologically similar. Symptoms were not discriminatory and heartburn and regurgitation were the most prevalent in both groups. HRM did not discriminate symptomatic patients with IEM and either normal or abnormal esophageal acid exposure. Proton pump inhibition (PPI) therapy was significantly more effective (74% vs. 10%) in patients with pathologic acid reflux (P < 0.001). As pH exposure becomes abnormal in the context of IEM, there is dominance for supine reflux.IEM appears to be an early, primary event, eventually associated with pathologic acid exposure, particularly supine. Higher BMI is also associated with abnormal esophageal acid exposure in such patients. GER symptoms are not discriminatory in patients with IEM with and without underlying pathologic acid reflux. Clinical response to PPI in such patients depends on the presence of esophageal pathologic acid exposure. Those with IEM and normal acid exposure remain symptomatic and mostly resistant to therapy.