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

Abstract

BackgroundCircumcaval 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.ObjectivesTo 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).Animals193 cats; 22 circumcaval obstructed (Group 1); 106 non‐circumcaval obstructed (Group 2); 65 non‐obstructed necropsy cases (Group 3).MethodsRetrospective 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.ResultsSeventeen 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 ImportanceUreteral 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.

Radiographic distribution of ureteral stones in 78 cats

“…Anatomic variations such as a circumcaval ureter have been discussed in the literature to have a potential increased risk of ureteral obstruction . In our experience, the site of obstruction in cats with a circumcaval ureter does not seem to be correlated with the region of ureter passing ventral to the vena cava.…”

“…In our experience, the site of obstruction in cats with a circumcaval ureter does not seem to be correlated with the region of ureter passing ventral to the vena cava. Regardless, because circumcaval ureters cannot be diagnosed by radiographs and are difficult to diagnose by ultrasonography, any potential role of the circumcaval ureter in stone lodgement in cats could not be determined in our population.…”

Diagnostic imaging observations in cats treated with the subcutaneous ureteral bypass system

“…Perioperative, short‐ and long‐term complications have also been reported, usually device occlusion by calculi or debris, encrustation, leakage or kinking of the SUB tubing, sometimes necessitating repeat surgical intervention (Berent , Steinhaus et al . , Berent et al . , Deroy et al .…”

IMAGING DIAGNOSIS—RADIOGRAPHY AND ULTRASONOGRAPHY OF BILATERAL CONGENITAL URETEROVESICAL JUNCTION STENOSIS CAUSING HYDRONEPHROSIS AND HYDROURETER IN A FERRET (MUSTELA PUTORIUS FURO)

“…Causes of acquired strictures include ureterolithiasis, ureteral surgery, ureteritis, or idiopathic . Congenital anatomic anomalies have been rarely documented in veterinary patients, aside from ureteral ectopia, or circumcaval ureters . In ferrets, a single case report regarding ectopic, and circumcaval ureters have been published, and to the authors’ knowledge congenital ureteral stricture had not been previously described.…”

“…Disruptions of diverse factors and genetic pathways involved in the normal development processes of the urinary tract (induction of the metanephric kidney, establishment of the urinary conduit, or maturation of the pyeloureteral peristaltic machinery) have been linked with ureteral obstruction in humans . Patients suffering from this condition may remain asymptomatic, and can be diagnosed later in life, or may present with clinical signs such as dysuria, hematuria, abdominal pain, vomiting, anorexia, weight loss, and lethargy, or signs of severe anuric acute renal failure in bilateral ureteral obstruction …”