Introduction

Chronic kidney disease (CKD) is common in older cats, and it is an important cause of morbidity and mortality. Conditions like advanced age, congenital diseases, inappropriate nutrition, use of nephrotoxic drugs, intoxications, and infectious disease may lead to parenchymal lesions.

Objectives

The aim of this study was to analyze the contribution of ultrasonography color Doppler for staging chronic kidney disease in felines, classified according to the International Renal Interest Society (IRIS).

Methods

Forty-five cats with CKD were enrolled. The control group was composed of 16 clinically normal cats with no clinical signs of upper and lower urinary tract disease and serum creatinine levels less than 1.6 mg/dL. Four cats were classified in stage I (serum creatinine < 1.6 mg/dL), 17 cats were in stage II (creatinine between 1.6 and 2.8 mg/dL) and 8 cats in stage III/IV (creatinine > 2.9 mg/dL). Kidney parenchymal evaluations were performed by B-mode, and the investigation of vascular filling of interlobar, arcuate, and interlobular arteries by the color Doppler.

Results

None of the cats of the control group showed renal vascular alteration by color Doppler. In chronic kidney disease cats, hypovascularization of 50%, 53%, and 87.5% were detected in stages I, II, and III/IV, respectively, by color Doppler procedure.

Conclusion

The evaluation of the filling of intrarenal vessels by color Doppler might be a useful technique in order to add more information for staging renal disease, mainly in those patients that show slight or no specific changes by B-mode ultrasound.