Vascular Anomalies of the Pediatric Liver

Abstract

The liver is a unique organ as it receives afferent blood supply from the umbilical vein, portal vein, and hepatic artery in the developing embryo but has only one efferent drainage method, through the hepatic veins. In the postnatal period, about 70% of the afferent blood flow into the liver is from the portal venous system, unique vessels that begin and end in a capillary system. Vascular anomalies of the hepatic artery, hepatic veins, portal vein, and/or umbilical vein can be congenital or acquired secondary to inflammation and/or infection, trauma, systemic disorders, or iatrogenic causes. The vascular anomalies can be incidental findings at imaging, or the infant or child can present with symptoms such as abdominal pain and ascites, be diagnosed with gastrointestinal bleeding, and have abnormal liver function test results. Imaging can demonstrate vascular findings such as shunts, thrombosis, or collaterals; secondary parenchymal findings such as diffuse or focal abnormal enhancement patterns; and parenchymal lesions such as regenerative nodules. This article discusses and illustrates vascular disorders of the liver that may be encountered in the pediatric population. These include (a) normal vascular variants; (b) congenital anomalies (preduodenal portal vein and infradiaphragmatic total anomalous pulmonary venous return); (c) acquired thromboses (extrahepatic portal venous thrombosis); (d) inflammatory vascular conditions, which can result in hepatic artery aneurysms or pseudoaneurysms; (e) hepatic venous outflow disorders (veno-occlusive disease); and shunt lesions. Liver transplantation and associated vascular complications are a large topic and will not be reviewed in this article. Knowledge of the vascular and parenchymal changes seen with these entities can aid imaging diagnosis and guide appropriate management. ©

Assessment of the incidence of accessory hepatic arteries: a literature review

“…Most often such a shunt is asymptomatic. (4,13) In the literature, there is no evidence proving an association between the presence of arterioportal shunts and the occurrence of aHA. However, this condition of aHA is probably possible.…”

“…(13,26,29) Interestingly, arterioportal shunts which are a pathologic anastomosis between the hepatic artery and PV may occur. (4,13) The aim of this study is to systematize the current knowledge on occurrence of accessory hepatic arteries and their variations. We also focus on clinical syndromes related to arterial hepatic vascularization.…”

Percutaneous transhepatic treatment of a unique portal vein malformation with portal hypertension in a pediatric patient

“…Portal vein thrombosis (PVT) must be distinguished from CAPV: in particular when thrombosis occurs gradually, or during embryologic development, this can be very difficult. Differential diagnosis in favor of PVT is the presence of venous collaterals or secondary signs of portal hypertension, such as splenomegaly or ascites (Albers and Khanna 2019). Imaging provides a very accurate representation of the actual anatomic situation, but cannot always assess the evolution of events and establish an exact diagnosis.…”

A new classification of congenital abnormalities of UPVS: sonographic appearances, screening strategy and clinical significance

“…Atresia of a major branch of the PV can have the associated absence of the corresponding hepatic lobe. Congenital complete atresia of the PV may involve extrahepatic portosystemic shunt of splenomesenteric vein system [ 20 ].…”

“…PV hypoplasia in the setting of biliary atresia has an incidence of 26% [ 21 ]. This increases the risk of complications associated with liver transplantation, strongly linked to the risk of thrombosis [ 20 , 21 ].…”