Differences in upper esophageal sphincter function and clinical characteristics among the three subtypes of Japanese patients with esophageal achalasia

BACKGROUND The rarity of esophageal achalasia has resulted in little being known about the characteristics of its three subtypes. The upper esophageal sphincter is considered one key factor to prevent aspiration pneumonia, a serious complication of esophageal achalasia. This study aimed to reveal the subtype characteristics of esophageal achalasia and how the upper esophageal sphincter functions and relates to other clinical parameters of the disease. METHODS We retrospectively investigated the clinical records of patients diagnosed with esophageal achalasia. All participants underwent esophagogastroduodenoscopy and then, within 2 weeks, high-resolution manometry. Gastrointestinal symptoms were assessed using a previously validated self-reported questionnaire. RESULTS A total of 110 patients with esophageal achalasia were enrolled: 50 with type I, 40 with type II, and 20 with type III. Mean age at diagnosis was 54.5, 50.4, and 66.1 years for types I, II, and III, respectively. Mean resting upper esophageal sphincter pressure was 28.0, 51.8, and 43.6 mmHg for patients with types I, II, and III, respectively (p