Gas-Bloat Syndrome after Magnetic Sphincter Augmentation: Incidence, Natural History, Risk Factors, and Impact on Surgical Outcomes Over Time.

Background: The notion that gas-bloat syndrome (GBS) after magnetic sphincter augmentation (MSA) is less detrimental has not been substantiated by data. This study aimed to identify the incidence, natural history, risk factors, and impact on outcomes of GBS after MSA.

Study Design: Records of patients who underwent MSA at our institution were reviewed. GBS was defined as a score of 4 or more on the gas bloat-specific item within the GERD health-related quality-of-life (GERD-HRQL) questionnaire. Preoperative clinical and objective testing data were compared between those with and without GBS at 1 year using univariate followed by multivariable analysis. GBS evolution over time and its impact on outcomes were assessed in those with 1- and 2-year follow-up.

Results: A total of 489 patients underwent MSA. At a mean (SD) follow-up of 12.8 (2.1) months, patient satisfaction was 88.8%, 91.2% discontinued antisecretory medications, and 74.2% achieved DeMeester score normalization.At 1 year, 13.3% of patients developed GBS, and had worse GERD-HRQL scores and antisecretory medication use and satisfaction (p < 0.0001). DeMeester score normalization was comparable (p = 0.856). Independent predictors of GBS were bloating (odds ratio [OR] 1.8, p = 0.043), GERD-HRQL score greater than 30 (OR 3, p = 0.0010), and MSA size 14 or less beads (OR 2.5, p = 0.004). In a subgroup of 239 patients with 2-year follow-up, 70.4% of patients with GBS at 1 year had resolution by 2 years. The GERD-HRQL total score improved when GBS resolved from 11 (7 to 19) to 7 (4 to 10), p = 0.016. Patients with persistent GBS at 2 years had worse 2-year GERD-HRQL total scores (20 [5 to 31] vs 5 [3 to 12], p = 0.019).

Conclusions: GBS affects 13.3% of patients at 1 year after MSA and substantially diminishes outcomes. However, GBS resolves spontaneously with quality-of-life improvement. Patients with preoperative bloating, high GERD-HRQL scores, or small MSA devices are at greatest risk of this complication.