Common Bile Duct Dilation After Bariatric Surgery

Abstract

Introduction: Biliary dilation, even if incidentally noted, suggests distal obstruction and prompts further work up such as endoscopic ultrasound (EUS) and endoscopic retrograde cholangiopancreatography (ERCP). Our institution's clinical experience with EUS and ERCP in the symptomatic post-gastric bypass population has revealed many patients with radiographically dilated bile ducts, but endoscopically normal papilla without an obvious cause for obstruction. It is unclear if this finding is phenomenological and unrelated, or an effect of bariatric surgery. Additionally, it is unknown whether the type of bariatric surgery, based on technical conduct or efficacy, alters biliary pathophysiology. Thus, we studied whether a change occurs in biliary diameter following Roux-en-Y gastric bypass (RYGB) and longitudinal sleeve gastrectomy (LSG). Methods: This is a single center retrospective study assessing biliary diameter before and after RYGB or LSG based on ultrasound, computed tomography or magnetic resonance imaging. All patients undergoing RYGB or LSG from January 2010 to December 2013 who had imaging studies before and greater than 3 months after surgery were included. Those with choledocholithiasis, obstructive jaundice and those without post-operative imaging were excluded. Common bile duct (CBD) diameter was re-read by a radiologist at the same location in the CBD for pre- and post-operative imaging. Baseline clinical factors of age, gender, body mass index, co-morbid illnesses, alcohol use, narcotic use, and smoking history were additionally collected. Results: There were 269 patients who met inclusion criteria (193 RYGB; 76 LSG). The baseline characteristics are shown [Table 1].The average time from surgery to repeat imaging was 24.1 months. After adjusting for pre-operative factors, subjects who underwent an RYGB had an increase in CBD diameter of 1.4mm (95% CI: 0.096 - 0.18), which was greater than the change following LSG 0.5mm (95% CI: - 0.007, 0.11) [Table 2].Table: No Caption available.Table: No Caption available.Conclusion: Bariatric surgery results in common bile duct dilation, with changes more pronounced after gastric bypass. Biliary dilation occurs whether or not patients have previously undergone cholecystectomy. Further work is necessary to determine the cause and clinical implications of this phenomenon.