Clinical Presentation and Outcome of Cats with Circumcaval Ureters Associated with a Ureteral Obstruction

Abstract

Background: Circumcaval ureters (CU) are a rare embryological malformation resulting in ventral displacement of the caudal vena cava, which crosses the ureter, potentially causing a ureteral stricture. Objectives: To evaluate cats with obstructed CU(s) and report the presenting signs, diagnostics, treatment(s), and outcomes. Cats with obstructed CU(s) were compared to ureterally obstructed cats without CU(s). Animals: 193 cats; 22 circumcaval obstructed (Group 1); 106 non-circumcaval obstructed (Group 2); 65 non-obstructed necropsy cases (Group 3). Methods: Retrospective study, review of medical records for cats treated for benign ureteral obstructions from AMC and University of Pennsylvania between 2009 and 2013. Inclusion criteria: surgical treatment of benign ureteral obstruction, complete medical record including radiographic, ultrasonographic, biochemistry, and surgical findings. Results: Seventeen percent (22/128) of obstructed cats had a CU (80% right-sided) compared to 14% (9/65) non-obstructed necropsy cats (89% right-sided). Clinical presentation, radiographic findings, and creatinine were not statistically different between Groups 1 and 2. Strictures were a statistically more common (40%) cause of ureteral obstruction in Group 1 compared to Group 2 (17%) (P = .01). The MST for Groups 1 and 2 after ureteral decompression was 923 and 762 days, respectively (P = .62), with the MST for death secondary to kidney disease in both groups being >1,442 days. Re-obstruction was the most common complication in Group 1 (24%) occurring more commonly in ureters of cats treated with a ureteral stent(s) (44%) compared to the subcutaneous ureteral bypass (SUB) device (8%) (P = .01). Conclusions and Clinical Importance: Ureteral obstructions in cats with a CU(s) have a similar outcome to those cats with a ureteral obstruction and normal ureteral anatomy. Long-term prognosis is good for benign ureteral obstructions treated with a double pigtail stent or a SUB device. The SUB device re-obstructed less commonly than the ureteral stent, especially when a ureteral stricture was present.