Evaluation of the incidence of haematuria following the placement of subcutaneous ureteral bypass devices in 18 cats (2016-2022).

ObjectivesThe aim of the present study was to evaluate the incidence of postoperative haematuria in cats treated with a subcutaneous ureteral bypass (SUB) device for the management of benign ureteral obstruction.MethodsMedical records from a single referral institute were retrospectively searched for cats that underwent placement of a SUB device for the management of benign ureteral obstruction between June 2016 and June 2022. Signalment, history, diagnostic imaging findings, surgery duration, and pre- and postoperative clinicopathological data were recorded.ResultsIn total, 18 cats presented with placement of de novo SUB devices: 14 unilateral SUBs and four bilateral SUBs. All 18 (100%) cats developed microscopic haematuria postoperatively. Median time to detection of microscopic haematuria was 1 month (range 1-11), with 16/18 (89%) detected on the first postoperative urinalysis. In total, 14 (78%) cats had persistent microscopic haematuria, two (11%) had recurrent microscopic haematuria and a further two (11%) cats had recurrent persistent microscopic haematuria. Severe haematuria (⩾50 red blood cells per high-power field) was identified in 13 (72%) cats; however, gross haematuria as a clinical sign was infrequently reported (n = 2/18, 11%). The median time to first detection of severe haematuria was 1 month (range: 1-31 months). Persistent severe haematuria was documented in seven cats, with a median duration of persistence of 17 months (range 5-31). Haematuria without a positive urine culture at any time point was present in 11/18 (61%) cats.Conclusions and relevanceIn this study population, postoperative persistent microscopic haematuria was a frequent finding in cats after SUB device placement. Further studies are necessary to understand if microscopic haematuria is a clinically relevant finding, and to further understand the aetiology of haematuria in such patients.