The clinical anatomy of congenital portosystemic venous shunts

Abstract

Congenital portosystemic venous shunts are rare. Their gross anatomy has not been well defined. Four different varieties of congenital portosystemic venous shunts are described in six children seen during a 10-year period, focusing on the anatomy of the shunt as determined by imaging studies and surgery. A detailed review of the literature indicates that congenital portosystemic venous shunts are best classified as: extrahepatic or intrahepatic. Extrahepatic shunts may be further subdivided into portocaval shunts (type 1 end-to-side and type 2 side-to-side) and others. Intrahepatic shunts are due to an abnormal intrahepatic connection between the portal vein and hepatic vein/inferior vena cava or a persistent patent ductus venosus. Additional congenital anomalies, particularly cardiac malformations, may be associated with any type. Some congenital intrahepatic portosystemic venous shunts close spontaneously in infancy; all other congenital portosystemic venous shunts tend to remain patent. To a variable extent, depending largely on the volume and duration of the shunt, affected individuals are at risk of developing hepatic encephalopathy and/or an intrahepatic tumor. The key to understanding the pathogenesis of these shunts lies in the normal developmental mechanisms underlying the formation of the portal vein and inferior vena cava in the embryo.

Role of per-rectal portal scintigraphy in long-term follow-up of congenital portosystemic shunt

“…Various imaging modalities and blood tests indicated that the natural histories of intrahepatic and extrahepatic CPSSs differed. Intrahepatic CPSS without hepatic tumor has been reported to spontaneously close or regress, whereas extrahepatic CPSS does not spontaneously regress (3,7,8,(16)(17)(18). Ultrasonography and dynamic contrast-enhanced CT evaluation showed spontaneous reductions in the shunt size in all of our patients with intrahepatic CPSS but in none with extrahepatic CPSS, strengthening the previous findings.…”

“…Surgical repair or embolization may be recommended for extrahepatic CPSS without closure because of the high risk of hepatopulmonary syndrome, pulmonary hypertension, and hepatic encephalopathy (4,7,8,(13)(14)(15)(16). Stringer (8) described that CPSS-affected individuals are at risk of developing hepatic encephalopathy and/or an intrahepatic tumor depending largely on the volume and duration of the shunt.…”

“…Stringer (8) described that CPSS-affected individuals are at risk of developing hepatic encephalopathy and/or an intrahepatic tumor depending largely on the volume and duration of the shunt. The risk of hepatic encephalopathy is related to the degree of portosystemic shunting, as measured by PRPS (3); therefore, it is rational to take the SI into consideration when deciding whether surgical treatment or embolization is indicated.…”

“…c ongenital portosystemic shunt (CPSS), which is a major cause of neonatal hypergalactosemia without galactosemetabolizing-enzyme deficiency (1), causes brain manganese deposition, pulmonary hypertension, and hyperammonemia leading to hepatic encephalopathy (2)(3)(4)(5)(6)(7)(8). CPSS is generally suspected if serum total bile acid (TBA) and ammonia levels are elevated, and it is diagnosed by using color Doppler ultrasonography, dynamic contrast-enhanced computed tomography (CT), and per-rectal portal scintigraphy (PRPS) (7,(9)(10)(11)(12).…”

“…CPSS is generally suspected if serum total bile acid (TBA) and ammonia levels are elevated, and it is diagnosed by using color Doppler ultrasonography, dynamic contrast-enhanced computed tomography (CT), and per-rectal portal scintigraphy (PRPS) (7,(9)(10)(11)(12). Some shunts close spontaneously, whereas others need to be closed surgically or with embolization because of hyperammonemia leading to severe hepatic encephalopathy (7,8,(13)(14)(15). Therefore, it is important to follow up CPSS patients carefully with color Doppler ultrasonography, dynamic contrast-enhanced CT, and blood tests.…”