Background: Tetra EDTA (tEDTA), used as a locking solution in people with intravenous catheters decreases luminal obstruction and infection rates and may have similar effects following routine SUB flushes in cats. Hypothesis/
Objective: To compare the rate of positive urine culture, luminal obstruction and outcome in cats with SUBs undergoing routine flushing with sterile saline or tEDTA. Animals: Cats with benign ureteral obstruction treated with a SUB between 2012-2024.
Methods: Retrospective study. Cats were evaluated every 3-4 months to monitor SUB patency by ultrasound-guided flushes. Saline (2012-2017) or tEDTA 4% (2017-2024) was used as a locking solution.
Results: 81 cats with 116 bypassed ureters (BU) were included. 36 cats with 47 BU received saline and 45 cats with 69 BU received tEDTA. No significant difference was found for luminal obstruction between the saline (11/47, 23%) and tEDTA groups (25/69, 36%; p= 0.112). Median time to obstruction (418 and 469 days, respectively; p=0.798) and rate of positive urine culture (12/36, 33% and 11/45, 24%, respectively; p= 0.67) were similar among the two groups. Total median follow-up was 581 days for saline and 898 days for tEDTA (p= 0.068). In cats with luminal obstruction, an increase in serum creatinine was observed in 7/30 (23%) and a dilated renal pelvis in 10/36 (28%).
Conclusions: Routine use of tEDTA as a locking solution in cats with SUBs did not significantly decrease the rate of luminal obstruction nor positive urine cultures. Luminal obstruction was uncommonly associated with an increased creatinine or dilated renal pelvis.
