The effects of congenital heart disease and cardiac surgery on liver blood flow in children.

Children with congenital heart disease may have some degree of hepatic impairment, with further impairment developing shortly after surgical correction of the cardiac defect. The redistribution of organ blood flow that occurs during cardiopulmonary bypass implicates ischaemia as one of the principal causes of injury. The aim of this study was to measure liver blood flow in children with congenital heart disease and to determine both the effects of cardiopulmonary bypass and the consequences of corrective surgery. Indocyanine green clearance and auricular densitometry, were used in 31 children. In 83% we demonstrated a reduced liver blood flow, with a mean percentage disappearance rate (PDR) of 12.9% (SEM +/- 1.2). This finding was unrelated to the patient's age, the type of congenital heart defect or the presence or absence of cyanosis. During cardiopulmonary bypass, hepatic perfusion was further reduced in 77% of children, by an average of 67%, out of proportion with the iatrogenic reduction in total body flow. Six hours after surgery, liver blood flow had increased significantly above preoperative levels (p < 0.001; t-test) to approximately normal values with a mean PDR of 20.4% (SEM +/- 1.5).