Staff Surgeon, Director of Interventional Radiology Service The Animal Medical Center New York, New York
Objective: To describe the prevalence of each of the anatomically based classifications/subtypes of canine congenital extrahepatic portosystemic shunts (EHPSS). Study
Design: Retrospective, multi-institutional study. Animals: Canine patients <12kgs with a diagnostic quality CT scan demonstrating a congenital EHPSS without previous shunt surgery.
Methods: The SVSTS and VIRIES list-serves were used to recruit cases. Data collected included patient DOB, gender, breed, weight, CT date, and reported diagnosis. A single author (CW) viewed all CT scans and anatomically classified shunts based upon (1) the shunt portal vessel of origin, (2) the shunt systemic vessel of insertion, and (3) any substantial portal vessels contributing to the shunt. Additionally, hepatic portal perfusion was subjectively scored between 0 (poor) and 4 (good/normal) based upon caliber of the intrahepatic PVs.
Results: 1210 CT scans were submitted from 14 different institutions. Due to exclusion criteria, 82 (6.8%) were removed leaving 1128 CT scans to be included. 45 different EHPSS anatomies were identified with 5 classifications accounting for 85% of all shunts (LGP [28%], LGA [19%], LGC [15%], aLGC +RGV [12%], and aLGC +RGV +SGV [11%]). Shunt origin involved the left gastric vein (LGV) in over 95% of the described classifications. The most common shunt (LGP) had good (4/4) portal perfusion in 62% of cases, while the third most common shunt (LGC) had poor (0/4) portal perfusion in 71%.
Conclusions: An anatomical classification system for canine EHPSS may enable improved understanding, treatment comparisons, and outcome prediction for patients with these anomalies.
