Gastroesophageal and bile reflux after one-anastomosis gastric bypass: long-term outcomes in a functionally evaluated cohort

Background: One-anastomosis gastric bypass (OAGB) is increasingly performed worldwide, but concerns persist regarding postoperative gastroesophageal reflux disease (GERD), bile reflux, and related complications. Objectives: To evaluate the incidence and clinical relevance of GERD and bile reflux after OAGB and to investigate whether preoperative esophageal functional parameters predict postoperative reflux-related complications. Setting: Department of General Surgery, Policlinico San Marco, Bergamo, Italy. Methods: This retrospective cohort study included 150 consecutive patients undergoing laparoscopic OAGB between 2016 and 2023. All patients underwent preoperative esophagogastroduodenoscopy and esophageal manometry, with selective pH-impedance monitoring when indicated. Postoperative GERD, esophagitis, bile reflux, anastomotic ulcers, and revisional surgery were assessed during a follow-up of 24-84 months. At last follow-up, 142 patients were available for evaluation, while 8 patients (5.3%) were lost to follow-up. Results: The mean preoperative body mass index was 48 kg/m2, decreasing to 27 kg/m2 at last follow-up. Postoperative GERD developed in 26 patients (17.3%), all of whom had a preoperative hypotensive lower esophageal sphincter (LES) (<16 mmHg). Bile reflux was diagnosed in 30 patients (20%) by pH-impedance monitoring and was refractory to medical therapy in all cases, leading to conversion to Roux-en-Y gastric bypass (RYGB) with complete symptom resolution. Anastomotic ulcers occurred in 15 patients (10%), including 3 perforations (2%). No patient with normal preoperative LES pressure developed GERD or esophagitis. Conclusions: OAGB is associated with clinically relevant and likely underestimated postoperative GERD and bile reflux. In this cohort, biliary reflux was frequent and uniformly required surgical conversion to RYGB. Preoperative LES hypotonia was associated with postoperative GERD and esophagitis, supporting the role of preoperative functional evaluation in patient selection.