S846 Functional Lumen Imaging Probe Measurement Post-Pneumatic Dilation in Patients With Achalasia

Introduction: Pneumatic dilation (PD) is a well-established therapeutic option for achalasia. Functional lumen impedance planimetry (FLIP) offers real-time assessment of lower esophageal sphincter (LES) distensibility and diameter. This retrospective cohort study aimed to assess whether FLIP measurements changed with symptom improvement post-PD in patients with achalasia. A secondary aim was to evaluate whether post-PD FLIP measurements correlated with the need for repeat dilation. Methods: Patients with a confirmed diagnosis of achalasia based on manometry, timed barium esophagram (TBE), and FLIP who underwent PD were included. Pre- and post-dilation FLIP parameters, including distensibility index (DI) and diameter were recorded. Post-PD FLIP was performed during the same endoscopy session following PD. Clinical response was assessed with Eckardt scores pre-PD and post-PD. Patients were stratified based on the need for repeat PD during the follow-up period. Additional stratification was performed based on achalasia subtypes. Per guidelines for post-procedural follow-up, post-PD Eckardt scores were obtained at 6-8 week follow-up visits. Results: A total of 21 patients were included in the study. After PD, average DI increased from 1.5 mm²/mmHg to 4.3 mm²/mmHg (P < 0.001), and diameter improved from 9.04 mm to 15.9 mm (P < 0.001). Similar post-PD changes were observed among each achalasia subtype. The average post-PD Eckardt score was 1.78, which decreased from an average pre-PD score of 4.66. Among patients requiring repeat PD, average post-PD DI and diameter were 4.03 mm²/mmHg and 14.74 mm, respectively, which were not significantly different compared to those who did not require repeat dilation (P = 0.45, 0.14, respectively). Average Eckardt scores at 6-8 weeks were not statistically different from patients who did not require repeat dilation (P = 0.278). Conclusion: In patients with achalasia, PD is associated with improved DI and diameter as measured by FLIP, which is consistent with symptomatic improvement shown by Eckardt score. However, post-PD FLIP parameters did not identify a correlation with the need for subsequent dilation. Further investigation is warranted to establish FLIP-based thresholds that may guide treatment and follow-up planning.