Characterization and outcomes of cats with cardiomyopathy undergoing subcutaneous ureteral bypass device placement

Background Limited data exist on the characterization and outcomes of cats with cardiomyopathy and benign ureteral obstruction treated by subcutaneous ureteral bypass (SUB) placement. Hypothesis/Objectives Characterize cardiomyopathies, assess perioperative and long-term outcomes, and determine if an association exists between left atrial size and fluid overload (FO) or survival. Animals Ninety-four cats presented for SUB placement between 2010 and 2022 at the Veterinary Teaching Hospital of the University of Montreal. Methods Retrospective review of medical records including physical examination, serum creatinine concentration, echocardiography, and outcome. Cats were grouped as: cardiomyopathy present (CM+) or absent (CM−). Results Echocardiography was performed in 64/94 (68%) cats. Cardiomyopathy was diagnosed in 26/64 (40%) cats, including 85% (22/26) hypertrophic or hypertrophic obstructive cardiomyopathy. The majority of cats (22/26) had mild cardiomyopathy, with normal left atrial size (left atrial-to-aortic root diameter ratio in right parasternal short axis [LA:AoSAX] < 1.6). No significant difference in duration of hospitalization, survival time, renal recovery, or frequency of FO was found between CM+ and CM− cats. Fluid overload occurred in 45% (29/64) of the cats, and was associated with shorter survival (median [IQR]: 430 [40; 1260] days vs 1020 [494; 1668] days; P = .005). Admission serum creatinine concentration was higher in cats with FO (mean ± SD: 11.12 ± 5.93 mg/dL vs 6.16 ± 5.44 mg/dL; P < .001) and was associated with worse prognosis (P = .01). The LA:AoSAX was not associated with FO (P = .26) or survival (P = .39). Conclusions and clinical importance Mild cardiomyopathy was a common comorbidity but did not affect outcome and should not be considered a contraindication for SUB placement. However, the impact of more advanced cardiac disease remains unknown. In contrast, FO and higher serum creatinine concentration at admission predicted shorter survival.