Characteristics of achalasia subtypes in untreated Chinese patients: a high-resolution manometry study.

Objective To evaluate and compare the clinical characteristics, manometric results and treatment outcomes of different subtypes of achalasia in untreated Chinese patients using high-resolution esophageal manometry. Methods A total of 75 achalasia patients and 34 healthy controls were enrolled in the study, and three achalasia subtypes were determined based on the Chicago classification. Clinical characteristics, manometric and treatment outcomes were compared. Results In all, 25 patients were classified as type I, 46 as type II and 4 as type III. The mean overall length of lower esophageal sphincter (LES) in type III was significantly longer than those in the controls and type I patients (P < 0.05), and abdominal LES length was significantly longer in type III than those in controls, type I and type II patients. All subtypes of achalasia had higher resting and residual LES pressures than those found in healthy controls (P < 0.05). Resting upper esophageal sphincter (UES) pressure in type III patients was significantly lower than those in healthy controls and type I patients, whereas types I and II patients had higher residual UES pressures compared with healthy controls (P < 0.05). Type II patients had a better response to the treatment than type I and III patients. Conclusions Type II is more common in untreated Chinese achalasia patients, and type II patients had better treatment outcomes than other types of patients. Large-sample multicenter trials are necessary in the future.