Long-term outcomes of peroral endoscopic myotomy for Chicago classification type I vs type III achalasia in treatment-naive patients.

The efficacy of peroral endoscopic myotomy (POEM) for achalasia has potential associations with Chicago classification by high-resolution manometry (HRM). Type II achalasia demonstrates the best response to POEM of all subtypes, while there remain controversies between type I and type III. Moreover, previous treatment history might cause discrepancy in direct comparison. We aimed to compare the clinical outcome of POEM for type I vs type III in treatment-naive patients. In total, 82 patients with type I or type III achalasia (45 type I, 37 type III) from February 2015 to December 2018 were enrolled and POEM was carried out as the initial treatment. Clinical success, change of Eckardt scores and HRM parameters were analyzed and compared between type I and type III group. About, 43 (95.6%) patients and 34 (91.9%) patients in type I and type III group acquired the clinical success (P = 0.821). Eckardt score and HRM results after POEM treatment decreased significantly in either group (P<0.01). Compared to type III group, higher reduction rates of Eckardt score (type I vs type III, 78.6 vs 66.9%, P = 0.034) and basal LES pressure (type I vs type III, 58.9 vs 40.4%, P = 0.040) were observed in type I group. Type I achalasia patients showed better response to POEM with more favorable clinical remission in Eckardt score and HRM outcomes than type III.