S1020 Breaking the 15-mm Barrier: Liberal Ring Sizing and Index 30-mm Balloon Dilation Minimize Post-Magnetic Sphincter Augmentation Dysphagia in a 10-Year Retrospective Cohort

Introduction: Dysphagia is the most frequent early adverse event after magnetic sphincter augmentation (MSA) with the LINX® device. The package insert caps post-MSA dilation at 15 mm but it is unclear MSA size and index dilation diameter affects clinical outcomes. We analyzed retrospective data over 10 years to identify predictors of post-MSA dysphagia and compared initial 30 mm dilation (over-the-wire under fluoroscopic guidance) strategy vs conventional (<20 mm dilation) through the scope (TTS). Methods: Adults undergoing MSA for refractory gastroesophageal reflux disease at a single tertiary center (January 2014-January 2025) were reviewed. Demographics, MSA size, and postoperative endoscopic dilations were recorded. Multivariable logistic regression identified independent risk factors for dilation. Outcomes after first-line 30 mm dilation (inflated to 8 psi) were compared with <20 mm TTS dilations. Primary endpoints: repeat dilation and device explantation. Secondary endpoints: complications and time to first dilation. Absolute risk reduction (ARR), number-needed-to-treat (NNT) were calculated. Results: Of 304 MSA recipients (63% women, mean age 57 ± 14 years), 74 (24.3%) developed dysphagia requiring endoscopic dilation. Older age increased this risk (odds ratio [OR] 1.16 per 5 years; 95% confidence interval [CI] 1.03-1.29; P = 0.01), each increment in size of MSA reduced it (OR 0.73; 95% CI 0.56-0.98; P = 0.03). Forty-four patients underwent <20 mm dilation and 30 underwent 30 mm dilation. Repeat dilation was required in 20/44 (45.5%) vs 9/30 (20%), respectively; ARR 25.5%, NNT = 4. An initial 30 mm dilation independently lowered the repeat-dilation risk (OR 0.24; 95% CI 0.07-0.91; P = 0.03). Time to index dilation was longer in the 30 mm dilation group. (31.7 ± 24.2 vs 18.1 ± 14.4 months; P = 0.03). Device explantation occurred in 15 patients (4.9%), only 3 had received a 30 mm dilation. No perforations, erosions, or procedure-related hospitalizations were seen in either group. Conclusion: In this 10-year retrospective cohort, larger MSA size was significantly associated with lower post-MSA dysphagia, and treating dysphagia with a single 30 mm dilation (as opposed to step-up dilation per manufacturer’s recommendations) reduced the repeat-procedure rate by 76% without added morbidity (NNT = 4). Our data highlights 2 modifiable factors that can improve long-term dysphagia outcomes. Prospective multicenter data from physiologic manometric studies (such as esophageal functional luminal imaging probe) are needed to validate these findings and refine protocols for endoscopic therapy in post-MSA dysphagia.