Esophageal clearance assessed by high-resolution impedance manometry in achalasia: a prospective study with 1-year follow-up

Background and Aims: 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 esophageal clearance following 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 pre- and post-procedure 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% male; median age 62 yrs) 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 cut-offs, the diagnostic performance for predicting treatment failure for EC-HRiM and EC-TBE were respectively: sensitivity 66% vs. 100%, specificity 82% vs. 59%, PPV 30% vs. 19%, and NPV 95% vs. 100%. Similar results were obtained in the external validation cohort Conclusion: HRiM is a reliable, reproducible tool for assessment of esophageal clearance post-POEM.(Clinicaltrial.gov, NCT06230536).