Assessment of serum symmetric dimethylarginine and creatinine concentrations in cats with urethral obstruction.

Abstract

OBJECTIVES: The aims of this study were to evaluate serum symmetric dimethylarginine (SDMA) and creatinine concentrations in cats with urethral obstruction pre- and post-decompression of the obstruction, and to determine if pre-decompression values were predictive of post-decompression renal function, as measured by SDMA and creatinine. METHODS: This was a prospective observational study. Twenty-five client-owned cats with urethral obstruction were hospitalized for decompression of the obstruction. Serum SDMA and creatinine were prospectively assessed at presentation, 24&#x2009;h post-decompression and 5-20 days post-decompression. Urinalysis and culture were assessed at presentation and at the final follow-up. Exclusion criteria included positive urine culture, reobstruction or failure to obtain required samples. RESULTS: Mean SDMA concentration dropped by 41.8% from an initial pre-decompression concentration of 17.6&#x2009;&#xb5;g/dl to 10.3&#x2009;&#xb5;g/dl 24&#x2009;h post-decompression (&#x2009;<0.001). The mean creatinine value dropped by 38.4% from an initial pre-decompression concentration of 2.5&#x2009;mg/dl to 1.5&#x2009;mg/dl 24&#x2009;h post-decompression (&#x2009;<0.001). There was no association between SDMA concentration at initial presentation and SDMA concentration 5-20 days after urethral catheterization (Spearman's &#x3c1;&#x2009;=&#x2009;0.205,&#x2009;=&#x2009;0.314). Creatinine concentration upon initial presentation was associated with the 5-20 day values after urethral catheterization (Spearman's &#x3c1;&#x2009;=&#x2009;0.583,&#x2009;<0.002). Twenty percent of cases were excluded due to bacterial growth on initial urine culture. SDMA and creatinine concentrations were significantly higher in these cases (median 59&#x2009;&#xb5;g/dl and 10.9&#x2009;mg/dl, respectively) compared with those with negative cultures (median 14&#x2009;&#xb5;g/dl and 1.6&#x2009;mg/dl [&#x2009;<0.002 and&#x2009;<0.001], respectively). CONCLUSIONS AND RELEVANCE: Both SDMA and creatinine decreased significantly after urethral catheterization, suggesting that renal function post-decompression cannot be predicted by the pre-decompression concentrations of these values.