Prospective analysis of endoscopic impedance planimetry pyloric measurements and its association with clinical outcomes with gastric peroral endoscopic myotomy

Background and Aims: Functional luminal imaging probe (FLIP) assesses pyloric sphincter physiology. We aimed to prospectively use FLIP to evaluate the association between pyloric measurements and clinical outcomes of gastric peroral endoscopic myotomy (G-POEM) in patients with refractory gastroparesis. Methods: Single-center prospective trial of patients who underwent G-POEM between January 2022 and March 2024. FLIP was performed pre-G-POEM, immediately post-G-POEM and at follow-up (median 6 months). Clinical response was defined as an improvement of ≥ 1 point on the Gastroparesis Cardinal Symptom Index (GCSI). Receiver operating characteristic curve was constructed to evaluate the relationship between FLIP measurements and response to G-POEM. Results: Clinical response was achieved in 64 out of 90 (71.1%) at a median of 6-months. Pre-G-POEM FLIP mean distensibility index (DI) was significantly lower among responders vs. non-responders (7.1±2.8 vs. 9.2±3.1 mm2/mm Hg; p=0.002). Mean DI increased significantly in both groups immediately after G-POEM, but this remained persistently elevated only among responders (10.4±4.4 mm2/mm Hg; p=0.02), while returning towards baseline among non-responders (9.7±4.7 mm2/mm Hg; p=0.69) at 6-month follow-up. Pre-G-POEM DI with an area under the curve of 0.72 yielded a specificity of 80.8% and sensitivity of 60.6% at a cut-off point of 7.35 mm2/mm Hg. Conclusion: Sustained improvement in pyloric FLIP measurements was seen in patients who endorsed a clinical response to G-POEM. Patients who responded to G-POEM had a lower baseline DI when compared to non-responders. Additional studies optimizing and standardizing FLIP protocols in patients undergoing G-POEM are needed.