The Subcutaneous Ureteral Bypass 3.0 device shows improved short-term outcomes compared to the 2.0 device for treatment of benign ureteral obstructions in cats.

Abstract

Objective: The Subcutaneous Ureteral Bypass (SUB) 3.0 device was designed to treat ureteral obstructions to circumvent kinking found with prior versions where the nephrostomy and cystostomy catheters traversed the body wall. The authors hypothesized that new adaptations would reduce procedure times and kinking without negatively impacting other short-term complication rates.

Methods: The medical records of cats with SUBs for benign ureteral obstructions flushed routinely with tetrasodium EDTA were reviewed. Cats with a SUB 2.0 (group 1), SUB 3.0 (group 2), and unilateral SUB 2.0/unilateral SUB 3.0 (group 3) were compared.

Results: 80 cats (121 renal units [71 SUB 2.0, 50 SUB 3.0]) were included. Most ureteral obstructions were caused by ureterolithiasis ± stricture (89 of 121 [74%]), stricture alone (17 of 121 [14%]), or pyonephrosis (8 of 121 [7%]). Survival rates to 90 days were 75%, 85%, and 94% in groups 1, 2, and 3, respectively. Median procedure times for unilateral 2.0, bilateral 2.0, unilateral 3.0, bilateral 3.0, and bilateral 2.0/3.0 were 75, 120, 55, 73.5, and 102.5 minutes, respectively. Kinks were reported in 11 of 71 SUB 2.0s (15.5%) and 0 of 50 SUB 3.0s (0%), blood clot occlusion was reported in 10 of 71 SUB 2.0s (14%) and 2 of 50 SUB 3.0s (4%), and obstruction from mineralization was documented in 1 SUB 3.0 (2%). One cat in group 1, and one in group 2 developed ≥ 1 infection during this follow-up period.

Conclusions: The results support that the SUB 3.0 is associated with fewer short-term complications and shorter surgical times than the SUB 2.0 over a 90-day follow-up period.

Clinical relevance: The SUB 3.0 requires shorter anesthetic times and results in less kinking than previous versions. Follow-up studies to assess long-term complications, like chronic infections or mineralization, are underway.