Significant Contribution of the Portal Vein to Blood Flow Through the Common Bile Duct

Objective: The aim of this study was to determine the contribution of the hepatic artery, gastroduodenal artery, and portal vein to the microvascular blood flow in the common bile duct (CBD). Background: Biliary complications are a common cause of graft loss after liver transplantation. The occurrence is, partly, attributed to hepatic artery thrombosis, which is considered to be the sole provider of blood flow to the bile ducts. However, the contribution of the portal vein and the gastroduodenal artery to the bile ducts is unknown. Methods: Microvascular blood flow in the CBD was determined in 15 patients who underwent a pancreaticoduodenectomy with a combination of laser Doppler flowmetry and reflectance spectrophotometry. Microvascular blood flow was measured at baseline, during clamping the portal vein, during clamping the hepatic artery, and during clamping both. After transection of the CBD, these 4 measurements were repeated. Results: Compared with baseline measurements, the microvascular blood flow through the CBD decreased to 62% after clamping the portal vein, 51% after clamping the hepatic artery, and 31% after clamping both. After the CBD was transected, these 3 measurements were 60%, 31%, and 20%, respectively. Conclusions: Historically, the hepatic artery has been considered mainly responsible for biliary blood flow. We show that after transection of the CBD, mimicking the situation after liver transplantation, the contribution of the portal vein to the microvascular blood flow through the CBD is 40%. This study emphasizes the importance of the portal vein, and disturbances in portal venous blood flow could contribute to the formation of biliary complications after liver transplantation