Esophageal Clearance Assessed by High-Resolution Impedance Manometry in Achalasia: A Prospective Study With 1-Year Follow-up

Introduction: Timed barium esophagram (TBE) is widely used to evaluate esophageal clearance (EC) after peroral endoscopic myotomy (POEM) in achalasia. Our aim was to compare high-resolution impedance manometry (HRiM) and TBE for assessment of EC after POEM in achalasia. Methods: We conducted a monocentric prospective study with external validation to compare EC assessed by HRiM (EC-HRiM) in response to a 200 mL rapid drink challenge and TBE (EC-TBE) after POEM for achalasia, and to evaluate their diagnostic performance, reproducibility, and predictive value for long-term clinical success. Consecutive patients undergoing POEM were assessed preprocedure and postprocedure at 3 months using Eckardt score, HRiM, and TBE. Treatment failure was defined by an Eckardt score >3 at 12 months. Results: In the prospective cohort (n = 103; 65% men; median age 62 years), 97 patients completed the 12-month follow-up, with a POEM success rate of 90%. EC significantly improved post-POEM using both HRiM and TBE. Interobserver reproducibility and correlation with Eckardt score were high for both EC-HRiM and EC-TBE. Meaningful thresholds for prediction of failure at 12 months were any residual bolus (>0 cm) for EC-HRiM and 9-cm bolus height for EC-TBE at 3 months. Using these cutoffs, the diagnostic performance for predicting treatment failure for EC-HRiM and EC-TBE were, respectively: sensitivity 66% vs 100%, specificity 82% vs 59%, positive predictive value (PPV) 30% vs 19%, and negative predictive value (NPV) 95% vs 100%. Similar results were obtained in the external validation cohort. Discussion: HRiM is a reliable, reproducible tool for assessment of EC post-POEM.