Achalasia Subtypes Have Different Motility Response of Esophagus to Per-Oral Endoscopic Myotomy (POEM): High-Resolution Manometry Approach With Chicago Classification

Abstract

Introduction: To investigate the motility response after POEM in subtypes of achalasia according to Chicago classification. Methods: Achalasia patients who received POEM were included for analysis. Eckardt score was used to assess symptom improvement. High-resolution manometry was applied for studying motility. Main parameters analyzed were (i) LES: resting pressure (restP), 4-second integrated relaxation pressure (4s-IRP); (ii) esophageal body (EB): contraction amplitude (CA); contraction duration (CD), distal contraction integral (DCI); (iii) upper esophageal sphincter (UES): relaxation pressure (relaxP). Results: There were 11 type I, 23 type II patients included for analysis. There were no type III achalasia patients because of scarcity. Results were shown in Figure 1. (i) Eckardt score decreased more in type II than type I achalasia [-6.00(3-10) vs -5.00(3-9), p=0.046]. (ii) LES tone was reduced significantly in both subtypes. (iii) Motility parameters of EB (CA, CD and DCI) were all lowered in type II achalasia, but were not in type I. (iv) UES relaxP was reduced only in type II achalasia (13.49±6.58 vs 5.17±6.48 mmHg, p<0.001). (vi) Proximal segment of esophagus without myotomy changed with distal segment with myotomy correlatively in both subtypes.Figure 1: Different motility response patterns of achalasia subtypes to POEM. (A) Eckardt score change; (B)-(D) LES motility parameters; (E)-(I) EB motility parameters; (J)-(L) UES motility parameters. Δ Change after POEM. Level of significance: * p<0.050, ** p<0.010, *** p<0.001.Conclusion: Type I and type II achalasia had different proximal esophageal motility response to POEM, which could lead to different clinical outcome. This change was mediated by inhibition feedback of myotomy on distal esophagus.