A novel biliary-specific near-infrared fluorescent dye (BL-760) enhances visualization of the biliary tree in a swine inflammatory model of bile duct obstruction

Abstract Background Bile duct injury (BDI) is a morbid complication of laparoscopic cholecystectomy due to poor recognition of the anatomy and inadequate visualization of the extra-hepatic biliary ducts. Near-infrared indocyanine green (ICG) is the most commonly used non-invasive option to assist with identification of the extra-hepatic biliary structures. However ICG is limited by its slow onset of action and lack of specificity for the biliary tree. In light of these limitations our team previously reported bile-label 760 (BL-760), a pre-clinical near-infrared dye, as a novel tool for intraoperative identification of biliary structures. This study builds upon our previous work and assesses the intraoperative detection of the extra-hepatic biliary ducts in a swine model of biliary obstruction using intravenously administered BL-760. Methods A survival swine study utilizing BL-760 was performed in two 30 kg female Yorkshire swine. Each swine underwent two surgeries. In the initial surgeries, laparoscopic clipping of an extra-hepatic biliary duct was performed under BL-760 guidance. The cystic duct (CD) was clipped in Swine #1 and the common bile duct (CBD) was clipped in Swine #2. On the third postoperative day, a laparoscopic cholecystectomy was performed in each swine under BL-760 guidance. Target-to-background ratios (TBRs) of the extra-hepatic biliary ducts to the liver were measured using ImageJ. Results The surgeries were performed without complication. The TBR in the initial surgeries were 2.42 (Swine #1) and 3.22 (Swine #2) for the CBD, without the need for surrounding dissection. In the second surgeries, the gallbladders were clearly inflamed without perforation, and the CBDs were visualized with BL-760 with a TBR of 2.83 (Swine #1) and 2.60 (Swine #2). Conclusions BL-760 demonstrates high specificity for the biliary tree in an obstructive biliary model. BL-760’s rapid, enhanced visualization has the potential to improve the accuracy of identifying biliary anatomy and enhance cholecystectomy safety.