Preoperative MNBI as a predictor of ESD-G efficacy in GERD treatment

Background: Although ESD-G, an endoscopic treatment for refractory GERD, has been approved for health insurance in Japan, the preoperative predictors of its efficacy remain unclear. While mean nocturnal baseline impedance (MNBI) has been reported as a predictor of acid suppression therapy efficacy in GERD, its role in predicting ESD-G outcomes have not been established. Methods: We conducted a retrospective study in 9 patients who underwent ESD-G from 2022 to 2024. Patients were stratified into low and normal MNBI groups using a 1967Ω cut-off. Postoperative outcomes, patient demographics (sex, age, BMI), acid exposure time (AET), DeMeester score, and lower esophageal sphincter (LES) pressure were compared. Treatment efficacy was defined as an improvement of ≥9 points in the FSSG. Results: ESD-G was effective in 5 of 6 patients with low MNBI and 1 of 3 with normal MNBI. Compared to the normal MNBI group, the low MNBI group had more males (4 and 1) and older median age (71 and 47 years) and higher mean BMI (23.2 and 20.7), AET (12.7% and 3.8%), DeMeester score (47.4 and 7.1) and lower mean LES pressure (15.2 and 23.9 mmHg). Conclusion: Refractory GERD patients with low MNBI exhibited a higher response rate to ESD-G, with trends toward older age, male, higher BMI, higher AET, and lower LES pressure. These findings suggest MNBI could serve as a potential predictor of the efficacy of ESD-G.