Clinicopathological Findings and Prognosis in Canine Cases Diagnosed As Primary Hypoplasia of the Portal Vein

Abstract

Canine primary hypoplasia of the portal vein (PHPV) is a microscopic malformation of the hepatic vasculature. The prevalence, clinical signs, and clinicopathological findings of PHPV in dogs are unclear, because there are few reports concerning PHPV in the veterinary literature. This retrospective study reviewed clinical records and liver biopsy data from 48 dogs with hepatic disease that were examined at a private veterinary hospital in Japan between April 2011 and March 2014 to determine the prevalence of PHPV among dogs that underwent liver biopsy and to determine the clinical and clinicopathological findings of PHPV in dogs. Records for all 48 dogs that underwent liver biopsy were investigated. Collected data included signalment, clinical signs, physical examination findings, complete blood cell count, chemistry results, pre-and postprandial serum total bile acid concentrations, coagulation profiles (prothrombin time, activated partial thromboplastin time, fibrinogen, and antithrombin), and abdominal ultrasonography findings at the first medical examination. The diagnosis of PHPV was made on the basis of histological examination of hepatic biopsy specimens and portography or CT angiography. Among the 48 canine cases, 28 dogs (58.3%) were diagnosed with PHPV, which was the most common diagnosis. The most frequent clinical sign in dogs with PHPV was asymptomatic persistently increased liver enzymes (57.1%). Toy poodles were at a significantly higher risk of PHPV than other breeds among dogs that underwent liver biopsy (P < 0.001). The median survival time of dogs with PHPV was more than 5 years. Plasma fibrinogen concentration below the reference range was an indicator of PHPV in this study. Dogs with PHPV frequently had mild clinical signs and a favorable prognosis.

Histopathological frequency of canine hepatobiliary disease in the United Kingdom

“…Young Yorkshire terriers presented most frequently along with Pugs, shih-tzu and schnauzers as predisposed to disorders of impaired hepatic perfusion; previous studies have not associated this with a gender predisposition (Van den Bossche et al 2012, Akiyoshi et al 2017. A limitation of this category is that it is histologically not possible to differentiation between cPSS from primary portal vein hypoplasia.…”

Lobular diameters of autopsied dog livers give clues for an appropriate liver biopsy methodology

“…PPVH is essentially a veterinary disease while other congenital vascular disorders affecting circulation of the liver, such as PSS, have been reported with precise histologic description in human medicine [ 10 ]. Discussing the existence (underdiagnosis) of PPVH in people is beyond the scope of our study; however, the authors speculate that idiopathic non-cirrhotic intrahepatic portal hypertension of humans could be a potential counterpart of PPVH of animals due to their common gross and histological findings as well as the relatively benign clinical course in both diseases [ 1 , 5 , 21 , 25 ]. The reason PPVH is often diagnosed in dogs in their adolescence seems to be related to a regular (mostly annual) health check in canine medicine.…”

“…As an example of an animal-specific condition, there has been little research published in the literature dealing with primary portal vein hypoplasia (PPVH, alias hepatic microvascular dysplasia [ 6 ]) in humans. Briefly PPVH is mainly a canine (rarely a feline) congenital vascular disorder, that is recognized by an elevation of liver-related values such as alanine aminotransferase and bile acid, manifested by a decreased portal vein to aorta ratio on computed tomography (CT) imaging and various hepatic histologic alterations quite similar to those found in the liver of human and animal patients with a portosystemic shunt (PSS) [ 1 , 9 , 16 , 20 , 26 , 27 ]. Though most animals with PPVH show mild or no clinical signs and only require modest medical treatment [ 1 ], this disease is not amenable to surgery and there have been rare cases that developed portal hypertension and ascites [ 27 ].…”

“…Briefly PPVH is mainly a canine (rarely a feline) congenital vascular disorder, that is recognized by an elevation of liver-related values such as alanine aminotransferase and bile acid, manifested by a decreased portal vein to aorta ratio on computed tomography (CT) imaging and various hepatic histologic alterations quite similar to those found in the liver of human and animal patients with a portosystemic shunt (PSS) [ 1 , 9 , 16 , 20 , 26 , 27 ]. Though most animals with PPVH show mild or no clinical signs and only require modest medical treatment [ 1 ], this disease is not amenable to surgery and there have been rare cases that developed portal hypertension and ascites [ 27 ]. This seemingly indolent canine PPVH is gaining scientific attention regarding its application to the development of a hepatocyte growth factor treatment for more aggressive liver diseases of other types, such as chronic hepatitis or cirrhosis [ 22 ].…”

“…Fine-needle aspiration or the biopsy gun technique are unsuitable for the diagnosis of PPVH because one has to evaluate a change in the size and number of interlobular arteries and interlobular veins in multiple portal tracts [ 27 ]. Hepatocellular atrophy is also an important histologic feature of canine congenital hepatic vascular anomalies such as PPVH or PSS likely because of a decreased supply of nutrition and oxygen via the attenuated (extrahepatic) portal vein or by-passing of the liver by shunt vessels [ 1 , 13 ]. Consequently, as long as the risks of anesthesia can be adequately managed, an excisional biopsy (partial hepatectomy) during laparotomy or laparoscopy, in spite of the requirement for general anesthesia, is preferred to the fine-needle aspiration or biopsy gun method because the former method can yield a larger sample which provides more information for the diagnosis of PPVH or PSS [ 27 ].…”