Glomerular Filtration Rate and Renal Volume in Dogs with Congenital Portosystemic Vascular Anomalies before and after Surgical Ligation

Abstract

Glomerular filtration rate (GFR) and renal volume were evaluated in dogs with confirmed portosystemic vascular anomalies (PSVA) before and after surgical ligation of their PSVA. Pre‐ and postligation CBC, serum biochemistry, urinalysis, abdominal ultraso‐nography with measurement of renal volume, and per rectal scintigraphy were performed to document resolution of abnormalities consistent with portosystemic shunting. GFR was estimated by plasma99mTc‐diethylenetriaminepentaacetic acid (99mTc‐DTPA) clearance before (n = 21) and after (n = 12) surgical correction of PSVA. Preligation99mTc‐DTPA GFR was increased (median, 5.64 mL/minute/kg; range, 3.53–8.49 mL/minute/kg; reference range, 2.83–4.47 mL/minute/kg) in 81% (17/21) of dogs. Postligation99mTc‐DTPA GFR decreased in all 12 evaluated dogs (median change =—42%;P< .001). Preligation renal volume was above the reference range for the left and right kidneys in 71% (10/14) and 69% (11/16) of dogs evaluated, respectively. Right renal volume decreased significantly (n = 5; median change, —45%;P= .03) after surgical ligation of PSVA. These findings document increased GFR and renal volume in dogs with PSVA, which may explain in part the low blood urea nitrogen and serum creatinine concentrations encountered in these dogs. Knowledge of changes in GFR associated with PSVA ligation may prove helpful in the anesthetic, drug, and dietary management of affected dogs.