Glomerular filtration rate and renal volume in dogs with congenital portosystemic vascular anomalies before and after surgical ligation

Glomerular filtration rate (GFR) and renal volume were evaluated in dogs wi th confirmed portosystemic vascular anomalies (PSVA) before and after surgi cal ligation of their PSVA. Pre- and postligation CBC, serum biochemistry, urinalysis, abdominal ultrasonography with measurement of renal volume, and per rectal scintigraphy were performed to document resolution of abnormali ties consistent with portosystemic shunting. GFR was estimated by plasma Tc -99m-diethylenetriaminepentaacetic acid (Tc-99m-DTPA) clearance before (n = 21) and after (n = 12) surgical correction of PSVA. Preligation Tc-99m-DTP A 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. Postli gation Tc-99m-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 evaluate d, respectively. Right renal volume decreased significantly (n = 5; median change, -45%; P = .03) after surgical ligation of PSVA. These findings docu ment increased GFR and renal volume in dogs with PSVA, which may explain in part the low blood urea nitrogen and serum creatinine concentrations encou ntered in these dogs. Knowledge of changes in GFR associated with PSVA liga tion may prove helpful in the anesthetic, drug, and dietary management of a ffected dogs.