Esophageal High-Resolution Manometry Can Unravel the Mechanisms by Which Different Bariatric Techniques Produce Different Reflux Exposures

Introduction: Bariatric surgery is increasingly performed. Since there are numerous surgical techniques, the effects of these on the esophageal function are still poorly understood. We aimed at assessing the effect of different techniques on esophagogastric junction (EGJ), esophageal peristalsis and reflux exposure using high-resolution manometry (HRM), and impedance-pH monitoring (MII-pH). Methods: All obese patients underwent symptomatic questionnaires, endoscopy, HRM, and MII-pH before and 1 year after surgery. Esophageal function and EGJ were classified according to Chicago Classification V. 3.0. Intragastric pressure (IGP) and gastroesophageal pressure gradient (GEPG) were assessed. Total acid exposure time (AET %), total number of refluxes, and symptom association probability (SAP) were assessed. A group of healthy volunteers (HVs) served as control. Results: One hundred and twelve obese subjects and 15 HVs (normal weight) were studied. Thirteen underwent endoscopic balloon placement (BIB), 12 gastric banding (GB), 26 sleeve gastrectomy (SG), 18 Roux-en-Y gastric bypass (RYGB), 15 mini-gastric bypass (MGB), 16 biliointestinal bypass (BIBP), and 12 biliopancreatic diversion (BPD). IGP and GEPG significantly decreased after RYGP, BPD, and BPBP, whereas they significantly increased after GB and SG. Post-operative greater AET (p < 0.05) and increased total number of reflux (p < 0.001) were present after GB and SG. RYGB and MGB showed a significant decrease in AET (p < 0.05) and total number of reflux (p < 0.001). Conclusions: HRM verified that different bariatric techniques produced different modification of IGP and GEPG, leading to different reflux exposure. Only GB and SG can negatively impact on esophageal function and reflux exposure.