Pilot study to evaluate the potential use of the renal resistive index as a preliminary diagnostic tool for chronic kidney disease in cats

Abstract

Objectives Chronic kidney disease (CKD) is the most common renal pathology diagnosed in geriatric cats, and its prevalence increases with age. The arterial resistive index (RI) is important when evaluating vascular resistance and compliance, and can be applied in the kidney (renal RI [RRI]), allowing the evaluation of its vascular haemodynamics. The present study aimed to: (1) investigate in cats with CKD the relationships between the RRI and the following parameters: age, sex, body weight, plasmatic creatinine, blood urea nitrogen, potassium, urine specific gravity, urine protein:creatinine ratio and systolic arterial pressure; and (2) evaluate the potential use of the RRI as a preliminary diagnostic tool in cats with CKD. Methods The present study involved 24 cats of both sexes. Six were healthy cats (control group [CG]) and 18 had CKD, but did not have any concomitant diseases and were not being treated with any medications (study group [SG]). For RRI measurement we used colour Doppler ultrasound (CDUS). Results RRI differed significantly between the CG and SG ( P <0.01) and was higher in the SG. A statistically significant correlation was only achieved between the RRI and the body weight of the patients and it was negative. A strong and positive correlation was noted between the mean RRI of both kidneys (r = 0.66). Receiver-operating curve analysis allowed us to establish an admissible cut-off for the RRI value of 0.639 for a preliminary diagnosis of CKD for both kidneys. Conclusions and relevance No differences were found for the RRI between the left and right kidneys, suggesting that evaluation of only one kidney is sufficient to provide an estimate of the RRI value for both organs. RRI measurement, which can be achieved with CDUS, is an easy-to-use diagnostic tool that, with a cut-off value of 0.639 for both kidneys, is useful in establishing a preliminary diagnosis of CKD.

Renal Doppler Ultrasound in the Evaluation of Renal Function in Patients with Sepsis

“…AKI can slowly develop into chronic renal failure and eventually become an independent risk factor for death. There are many factors that can trigger AKI such as hypovolemia, shock, major surgery, trauma, and heart failure [ 16 ], of which the most common factor is sepsis. According to some research, the mortality rate of patients with septic AKI is much higher than that of patients with AKI of other causes [ 17 ].…”

Renal shear wave elastography and urinary procollagen type III amino-terminal propeptide (uPIIINP) in feline chronic kidney disease

“…SWE was performed in this study because it is the newest USE technique [44]; it also provides better information on elasticity than SE, in which the result is highly dependent upon operator experience [45]. Other imaging techniques have also been used to facilitate an early CKD diagnosis in cats, such as: contrast-enhanced ultrasound examination in domestic and purebred cats [46], and renal resistive index (RRI) in domestic cats [47]. However, methods such as RRI are difficult to evaluate, especially in CKD cats with renal vascular impairment and decreased renal blood flow [47].…”

“…Other imaging techniques have also been used to facilitate an early CKD diagnosis in cats, such as: contrast-enhanced ultrasound examination in domestic and purebred cats [46], and renal resistive index (RRI) in domestic cats [47]. However, methods such as RRI are difficult to evaluate, especially in CKD cats with renal vascular impairment and decreased renal blood flow [47]. Peng and colleagues [25] reported that human patients with CKD had stiffer kidneys than healthy people, when using SWE.…”

Resistivity and pulsatility indexes in feline kidney disease: a systematic review

“…Despite the values of RI and PI for the kidneys of healthy cats and animals with kidney disease being previously reported, 6,8,11,21–26 their clinical utility remains unclear. This doubt is probably related to diverse upper limits proposed for felines.…”