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Published on: March 11, 2016
Normal Doppler velocimetry of renal vasculature in Persian cats
Cibele F Carvalho1, Maria C Chammas
1School of Veterinary Medicine of Universidade Cruzeiro do Sul, Sao Paulo, Brazil. cibelefcarvalho@terra.com.br
Insights
This study establishes normal Doppler flowmetric parameters for renal arteries in healthy Persian cats, introducing a new ratio to detect renal vascular changes. These findings provide a baseline for diagnosing feline kidney disease earlier.
Area of Science:
- Veterinary Medicine
- Cardiovascular Physiology
- Diagnostic Imaging
Background:
- Renal diseases are prevalent in aging cats, with decreased renal blood flow often being an early indicator.
- Resistive index (RI) has shown limited sensitivity in detecting early renal dysfunction.
- Doppler waveforms can reveal reduced blood flow in renal arteries before RI changes occur.
Purpose of the Study:
- To determine normal Doppler flowmetric parameters for renal arteries (RAs), interlobar arteries (IAs), and the abdominal aorta (AO) in healthy adult Persian cats.
- To establish reference values for peak systolic velocity (PSV), resistive index (RI), and early systolic acceleration (ESA).
- To introduce and evaluate novel ratio indices for assessing renal vasculature.
Main Methods:
- B-mode ultrasonography and color mapping were used to examine the renal vasculature of 25 healthy Persian cats.
- Pulsed Doppler assessed PSV, RI, and ESA in RAs, IAs (cranial, middle, caudal), and the AO.
- Ratio indices including RA/AO and IA/RA velocities were calculated.
Main Results:
- Mean AO values: PSV 53.17±13.46 cm/s, diameter 0.38±0.08 cm.
- Mean RA values: diameter 0.15±0.02 cm, PSV 41.17±9.40 cm/s, RI 0.54±0.07, ESA 1.12±1.14 m/s(2).
- Mean IA values: PSV 32.16±9.33 cm/s, RI 0.52±0.06, ESA 0.73±0.61 m/s(2).
- Mean renal-aortic ratio was 0.828±0.296; mean renal-interlobar artery ratio was 1.45±0.57.
Conclusions:
- This study provides essential reference values for Doppler parameters in the renal vasculature of healthy Persian cats.
- Early systolic acceleration (ESA) and novel ratio indices offer potential for earlier detection of renal hemodynamic changes than RI alone.
- Further research is needed to validate these parameters in pathological conditions and across different feline populations.
Abstract:
Renal diseases are common in older cats. Decreased renal blood flow may be the first sign of dysfunction and can be evaluated by Doppler ultrasound. But previous studies suggest that the resistive index (RI) has a low sensitivity for detecting renal disease. Doppler waveforms of renal and intrarenal arteries demonstrate decreased blood flow before there are any changes in the RI. The purpose of this study was to evaluate the normal Doppler flowmetrics parameters of renal arteries (RAs), interlobar arteries (IAs) and abdominal aorta (AO) in adult healthy, Persian cats. Twenty-five Persian cats (13 females and 12 males with mean age of 30 months and an age range 12-60 months) with normal clinical examinations and biochemical tests and normal systemic blood pressure were given B-mode ultrasonographies in order to exclude all nephropathies, including polycystic kidney disease. All measurements were performed on both kidneys. Both kidneys (n=50) were examined by color mapping of the renal vasculature. Pulsed Doppler was used to examine both RAs, the IAs at cranial, middle and caudal sites, and the AO. The RI was calculated for all of the vessels. Early systolic acceleration (ESA) of RA and IA was obtained with Doppler spectral analysis. Furthermore, the ratio indices between RA/AO, and IA/RA velocities were calculated. The mean values of peak systolic velocity (PSV) and the diameter for AO were 53.17±13.46 cm/s and 0.38±0.08 cm, respectively. The mean RA diameter for all 50 kidneys was 0.15±0.02 cm. Considering the velocimetric values in both RAs, the mean PSV and RI that were obtained were 41.17±9.40 cm/s and 0.54±0.07. The RA had a mean ESA of 1.12±1.14 m/s(2) and the calculated upper limit of the reference value was 3.40 m/s(2). The mean renal-aortic ratio was 0.828±0.296. The IA showed PSV and RI values of 32.16±9.33 cm/s and 0.52±0.06, respectively. The mean ESA of all IAs was 0.73±0.61 m/s(2). The calculated upper limit of the reference value was 2.0m/s(2). The mean renal-interlobar artery ratio was 1.45±0.57. The RI values obtained in this study were similar to values reported in the literature. Some conditions that lead to a decrease in compliance and to an increase in vascular resistance can affect the Doppler spectral waveforms without changes in RI. To our knowledge, there are no studies that were directed toward to the normal ESA values of the renal vasculature in Persian cats. This study introduced a new ratio between the PSV of the RA and the IA. This index was developed based on the well-known effects of Doppler on the detection of stenosis, regardless of the cause. Further studies are necessary to verify the hemodynamic behavior of this index under pathological conditions in cats as well as the effect of aging, nephropathies and systemic pressure on Doppler velocimetric parameters.
