Distribution of extrahepatic congenital portosystemic shunt morphology in predisposed dog breeds

Abstract

BackgroundAn inherited basis for congenital extrahepatic portosystemic shunts (EHPSS) has been demonstrated in several small dog breeds. If in general both portocaval and porto-azygous shunts occur in breeds predisposed to portosystemic shunts then this could indicate a common genetic background. This study was performed to determine the distribution of extrahepatic portocaval and porto-azygous shunts in purebred dog populations.ResultsData of 135 client owned dogs diagnosed with EHPSS at the Faculty of Veterinary Medicine of Utrecht University from 2001 – 2010 were retrospectively analyzed. The correlation between shunt localization, sex, age, dog size and breed were studied. The study group consisted of 54 males and 81 females from 24 breeds. Twenty-five percent of dogs had porto-azygous shunts and 75% had portocaval shunts. Of the dogs with porto-azygous shunts only 27% was male (P = 0.006). No significant sex difference was detected in dogs with a portocaval shunt. Both phenotypes were present in almost all breeds represented with more than six cases. Small dogs are mostly diagnosed with portocaval shunts (79%) whereas both types are detected. The age at diagnosis in dogs with porto-azygous shunts was significantly higher than that of dogs with portocaval shunts (P < 0.001).ConclusionThe remarkable similarity of phenotypic variation in many dog breeds may indicate common underlying genes responsible for EHPSS across breeds. The subtype of EHPSS could be determined by a minor genetic component or modulating factors during embryonic development.

Genome‐wide based model predicting recovery from portosystemic shunting after liver shunt attenuation in dogs

“…A correlation between shunt localization, weight, age at time of surgery, and clinical outcome is suggested in several studies . In general, IHPSS leads to an earlier development of clinical signs when compared to EHPSS, although geographical differences are reported. Such a difference also is observed within the EHPSS subtypes, where extrahepatic portocaval shunts seem to be diagnosed at an earlier age compared to extrahepatic portoazygos shunts.…”

Determination of Porto‐Azygos Shunt Anatomy in Dogs by Computed Tomography Angiography

“…In 25% of dogs with an extrahepatic portosystemic shunt, an abnormal communication between the portal system and the azygos vein is present . Based on CT angiography images of 25 dogs, Nelson and Nelson identified 4 porto‐caval and 2 porto‐azygos shunt types .…”

“…A portosystemic shunt is an anomalous vessel that bypasses the liver, diverting blood drainage from the venous gastrointestinal tract directly into the systemic circulation . Porto‐azygos shunts account for 25% of all congenital extrahepatic portosystemic shunts in dogs . Computed tomography (CT) angiography provides accurate details on the shunting vessels and their tributaries .…”

Transdiaphragmatic Approach to Attenuate Porto‐Azygos Shunts Inserting in the Thorax

“…Nearly one fourth of all extrahepatic PSSs in dogs are porto‐azygos shunts . Although the majority of those shunts traverse the diaphragm to insert in the thoracic section of the azygos vein, most surgeons attenuate porto‐azygos shunts intra‐abdominally rather than intrathoracically .…”