772. EVALUATING OUTCOMES OF LES OBSTRUCTION AND REFLUX IN PATIENTS UNDERGOING PERORAL ENDOSCOPIC MYOTOMY GUIDED BY THE 16CM IMPEDANCE PLANIMETRY CATHETER

Abstract Background Peroral endoscopic myotomy (POEM) is a standard treatment option in achalasia. The endoluminal functional lumen imaging probe (FLIP) system utilizes impedance planimetry to measure diameter and distensibility at the esophagogastric junction (EGJ) in real-time. Most reports of the intraoperative FLIP experience focus on the 8 cm balloon, but the 16 cm balloon catheter also provides topographical assessments in addition to EGJ metrics. The aim of this study is to determine the clinical outcomes after a tailored myotomy using the 16 cm balloon during POEM. Methods We conducted a retrospective review of consecutive patients who underwent POEM with intraoperative FLIP with the 16 cm balloon catheter between January 2020 and September 2023. Operative reports were reviewed, and data including FLIP metrics and topographical assessments and myotomy length, which was guided by FLIP panometry, were recorded. Clinical parameters for lower esophageal sphincter (LES) obstruction (defined by FLIP-EGJ metrics, BEDQ/Eckardt scores and/or need for LES re-intervention) and reflux (defined by GERD-HRQL/RSI scores, +pH testing, LA B/C/D reflux esophagitis, PPI use and/or need for anti-reflux surgery) were collected during the 6-36 month follow up time period. Results Of 100 patients (57 female, mean 56.1y), 82 had Achalasia, 15 EGJOO, and 3 hypercontractile esophagus. Myotomy length was tailored (mean 8.2cm, range 3 – 15) by FLIP, and 10% had a short myotomy (≤4cm). Among 16 patients with previous Heller, the myotomy targeted contractile activity proximal to the previous myotomy in 10 cases. On follow up of 71 patients (median time 14mo), clinical outcomes are noted in Table 1. Obstructive symptoms and FLIP metrics showed significant improvement. Repeat myotomy was required in 5.6%. While reflux symptom scores improved, 37.5% had abnormal %AET, 4.7% had reflux esophagitis, and 7.0% required anti-reflux surgery. Conclusion A tailored myotomy with guidance of a 16 cm FLIP catheter to assess EGJ metrics and topographical assessments during POEM appears to be safe and effective at 6-36 month follow up. A tailored myotomy allows for a shorter myotomy than traditional surgical lengths and can be extended to capture residual disease noted with the 16 cm FLIP catheter in patients with previous surgery. Use of the 16 cm balloon during POEM results in overall low rates of LES re-intervention and post-myotomy reflux.