The hepatic vasculature and its response to hepatic injury: a working hypothesis.

The hepatic circulation is unique in that high volumes of low pressure blood flow are supplied through a dual venous and arterial circulation. This vascular supply is modulated both by the gastrointestinal vascular bed and an intrahepatic microcirculation. This complex vascular system is influenced by pathologic processes within the liver. Alterations in the hepatic circulation reflect hepatic metabolic adaptation and injury. It seems reasonable to assume that in some circumstances hepatic circulatory alterations are inappropriate, exaggerated or inadequate and contribute to the initiation or perpetuation of hepatic injury. This paper attempts to focus on evidence derived from studies of the normal and abnormal hepatic circulation that provide insights into hepatic circulatory responses and their role in the initiation and perpetuation of hepatic injury. A possible relationship of these vascular changes to pathologic processes within the liver is proposed. Ultimately, precise measurement and understanding of hepatic vasculature changes may allow appropriate intervention to offset injury or stimulate maximum effective repair.