Hepatic Histology and Morphometric Measurements in Idiopathic Extrahepatic Portal Vein Thrombosis in Children, Correlated to Clinical Outcome of Meso-Rex Bypass

Wedged hepatic vein portovenography for assessment of Rex vein patency in children with extrahepatic portal venous obstruction

BACKGROUND

Meso-Rex bypass is the surgical intervention of choice for children with extrahepatic portal vein obstruction (EHPVO). Patency of Rex vein, umbilical recessus of the portal vein, is a prerequisite for this surgery. Conventional diagnostic modalities poorly detect patency, while transjugular wedged hepatic vein portography (WHVP) accurately detects patency in 90%.

OBJECTIVES

We aimed to assess Rex vein patency and portal vein branching pattern in children with EHPVO using transjugular WHVP and to identify factors associated with Rex vein patency.

METHODS

Transjugular WHVP was performed in 31 children with EHPVO by selective cannulation of left and right hepatic veins. Rex vein patency, type of intrahepatic portal venous anatomy (Types A-E), and factors associated with patency of Rex vein were studied.

RESULTS

The patency of Rex recess on transjugular WHVP was 29%. Complete obliteration of intrahepatic portal venous radicles was the commonest pattern (Type E, 38.7%) while Type A, the favorable anatomy for meso-Rex bypass, was seen in only 12.9%. Patency of the Rex vein, but not the anatomical pattern, was associated with younger age at evaluation (patent Rex: 6.6 ± 4.9 years vs. nonpatent Rex: 12.7 ± 3.9 years, p = 0.001). Under-5-year children had a 12 times greater chance of having a patent Rex vein (odds ratio: 12.22, 95% confidence interval: 1.65-90.40, p = 0.004). Patency or pattern was unrelated to local factors like umbilical vein catheterization, systemic thrombophilia, or disease severity.

CONCLUSION

Less than one-third of our pediatric EHPVO patients have a patent Rex vein. Younger age at evaluation is significantly associated with Rex vein patency.

Optimal Treatment for Patients With Cavernous Transformation of the Portal Vein

Cavernous transformation of the portal vein (CTPV) is a sequela of extrahepatic and/or intrahepatic portal vein obstruction caused by a combination of local and risk factors. It was ever taken as a relatively rare disease due to its scant literature, which was mainly based on clinical series and case reports. CTPV often manifests as gastroesophageal variceal bleeding, splenomegaly, and portal biliopathy after the long-term insidious presentation. It is unable for CTPV to be recanalized with anticoagulation because it is a complete obstruction of the mesentericoportal axis. Endoscopic therapy is mainly used for temporary hemostasis in acute variceal bleeding. Meso-Rex shunting characterized by portal-flow-preserving shunts has been widely performed in children with CTPV. The multitude of complications associated with CTPV in adults can be effectively addressed by various interventional vascular therapies. With the ubiquity of radiological examinations, optimal treatment for patients with CTPV becomes important. Multivisceral transplantation, such as liver-small intestinal transplantation, may be lifesaving and should be considered for patients with diffuse mesenteric venous thrombosis.

Liver histopathology in patients with hepatic masses and the Abernethy malformation

BACKGROUND/PURPOSE

The Abernethy malformation (AM) is a congenital venous malformation in which the splanchnic venous return bypasses the liver and drains directly into the systemic circulation. This deprives the liver of hepatotrophic growth factors and allows metabolic products of digestion to enter the systemic veins without the benefit of passing through the liver. The histologic features of liver biopsies in children with an AM were reviewed.

METHODS

A retrospective review of liver biopsies in patients with AM between 1997 and 2017 was performed. Patients were divided into two groups for comparison of histologic features: presence (M+) or absence (M-) of a coexistent liver mass on imaging. Biopsies were reviewed by a pediatric pathologist. Chi-square test was used for statistical analysis between groups. Significance was assigned to p values <0.05.

RESULTS

Eighteen liver biopsies were reviewed. Masses were present in only 6 patients who had a liver biopsy. Masses were observed with similar frequencies in either type of the Abernethy malformation (I or II). Nine of 12 M- patients and 3/6 M+ patients had the type I AM. Histologically, all patients were noted to have small or absent portal veins. Isolated capillaries were seen more frequently in patients with a known liver mass (p = 0.045), while crowding of portal tracts was more commonly seen in patients without a liver mass (p = 0.019).

CONCLUSION

Liver biopsies in patients with AM demonstrate abnormal vascular and parenchymal histologic features. Livers with coexistent masses were more commonly found to have features suggesting an increased dependence on arterial blood supply.

LEVEL OF EVIDENCE

III.