A pilot study investigating renal biomarkers in dogs with pulmonary hypertension: a comparison between cystatin-C, symmetric dimethylarginine, and creatinine.

Pulmonary hypertension (PH) can affect renal function, yet renal dysfunction in canine PH is relatively underexplored. Cystatin C (CYS-C), a useful marker for evaluating renal function in humans with PH, has not been studied in dogs. This study aimed to compare seventeen dogs with PH to a control group, evaluating the relationship between PH and renal parameters such as symmetric dimethylarginine (SDMA), creatinine, and CYS-C. The mean tricuspid regurgitation maximal velocity (TRmax) and systolic pulmonary arterial pressure (SPAP) in dogs with PH was 4.24 m/sec and 74.48 mmHg, respectively. Dogs with PH exhibited significantly higher SDMA (15.47 μg/dL vs. 10.55 μg/dL) and CYS-C (1.36 mg/L vs. 0.88 mg/L) compared to controls. SDMA showed moderate positive correlations with SPAP (r=0.682) and TRmax (r=0.662), and a negative moderate correlation with mean arterial pressure (r=-0.590). CYS-C moderately correlated with SPAP (r=0.529), TRmax (r=0.485), heart rate (r=0.506), and body weight (r=0.691). Creatinine did not vary significantly between PH group (122.21 μmol/L) and controls (93.70 μmol/L), nor did it correlate with any parameters. Multivariate analysis revealed that CYS-C was significantly influenced by PH severity, while SDMA and creatinine were not. These findings suggest that renal dysfunction is prevalent in dogs with PH. CYS-C may be a more sensitive marker for detecting early renal changes linked to PH severity, while SDMA appears to be more specific to true renal dysfunction and creatinine was the least informative biomarker.