Simplified methods for estimating glomerular filtration rate in cats and for detection of cats with low or borderline glomerular filtration rate

Journal of Feline Medicine and Surgery

Ghys

et al. 2016

Self Cite

Objectives Hypertension is a common cause of proteinuria in HIV-infected people. In cats, feline immunodeficiency virus (FIV) infection appears to be associated with proteinuria. Therefore, the results from systolic blood pressure (SBP) measurements in naturally infected FIV-positive cats were reviewed to assess whether hypertension contributes to the observed proteinuria in these cats. Ultrasonographic findings in FIV-positive cats were reviewed to complete renal assessment and to extend the scant knowledge on renal ultrasonography in cats. Methods Data from client-owned, naturally infected FIV-positive cats were retrospectively reviewed. To obtain a control group, records were reviewed from age-matched, privately owned, FIV-negative cats. Results Data from 91 FIV-infected and 113 control cats were compared. FIV-infected cats showed a significantly lower SBP ( P <0.0001) and significantly fewer FIV-infected cats were hypertensive (⩾160 mmHg) compared with control cats ( P = 0.025). The prevalence of renal azotaemia did not significantly differ between groups, although FIV-infected cats had significantly lower urine specific gravity (USG) ( P = 0.0273) and a higher incidence of USG below 1.035 ( P = 0.043). Urinary protein:creatinine ratio (UPC) was significantly higher in FIV-infected cats ( P = 0.0005) and proteinuria (UPC >0.4) occurred more frequently in FIV-infected cats ( P <0.001). Renal ultrasonography showed abnormalities in 60/91 FIV-infected cats, with hyperechogenic cortices in 39/91 and enlarged kidneys in 31/91. Conclusions and relevance Hypertension can be excluded as a common cause of renal damage leading to proteinuria in FIV-infected cats. Proteinuria and poorly concentrated urine are common in naturally infected FIV-positive cats, in contrast to azotaemia. Clinicians should cautiously interpret ultrasonographic abnormalities as these occur in over half of FIV-infected cats.

Section: Discussionsupporting

confidence: 87%

Systolic blood pressure, routine kidney variables and renal ultrasonographic findings in cats naturally infected with feline immunodeficiency virus

Taffin

Journal of Feline Medicine and Surgery

Ghys

et al. 2016

Self Cite

“…This test was performed 1 day before radioiodine treatment and repeated 1 day before the post‐treatment examination. A limited sampling strategy, minimally impacting the reliability of the GFR estimate, was used, as previously described . Briefly, 40 mg/kg creatinine was administered IV and blood samples were taken in EDTA tubes before and 5, 30, 60, 120, 180, 360, and 600 minutes after injection.…”

Section: Methodsmentioning

confidence: 99%

“…Briefly, 40 mg/kg creatinine was administered IV and blood samples were taken in EDTA tubes before and 5, 30, 60, 120, 180, 360, and 600 minutes after injection. The borderline GFR cutoff value was defined as 1.7 mL/min/kg, the lower GFR cutoff value as 1.2 mL/min/kg …”

Section: Methodsmentioning

confidence: 99%

Evaluation of Renal Perfusion in Hyperthyroid Cats before and after Radioiodine Treatment

Stock

Daminet

Veterinary Internal Medicne

et al. 2017

BackgroundHyperthyroidism and chronic kidney disease (CKD) are common in elderly cats. Consequently, both diseases often occur concurrently. Furthermore, renal function is affected by thyroid status. Because changes in renal perfusion play an important role in functional renal changes in hyperthyroid cats, investigation of renal perfusion may provide novel insights.ObjectivesTo evaluate renal perfusion in hyperthyroid cats with contrast‐enhanced ultrasound (CEUS).AnimalsA total of 42 hyperthyroid cats was included and evaluated before and 1 month after radioiodine treatment.MethodsProspective intrasubject clinical trial of contrast‐enhanced ultrasound using a commercial contrast agent (SonoVue) to evaluate renal perfusion. Time‐intensity curves were created, and perfusion parameters were calculated by off‐line software. A linear mixed model was used to examine differences between pre‐ and post‐treatment perfusion parameters.ResultsAn increase in several time‐related perfusion parameters was observed after radioiodine treatment, indicating a decreased blood velocity upon resolution of the hyperthyroid state. Furthermore, a small post‐treatment decrease in peak enhancement was present in the renal medulla, suggesting a lower medullary blood volume.Conclusions and Clinical ImportanceContrast‐enhanced ultrasound indicated a higher cortical and medullary blood velocity and higher medullary blood volume in hyperthyroid cats before radioactive treatment in comparison with 1‐month post‐treatment control.

“…We also studied if sCysC could distinguish cats with normal, borderline, or low GFR, based on PexICT, compared with sCr. The cut‐off concentrations for normal GFR were defined as GFR ≥1.7 mL/min/kg, for borderline GFR as GFR 1.2–1.7 mL/min/kg and for low GFR as GFR <1.2 mL/min/kg, as determined previously by our group …”

Section: Methodsmentioning

confidence: 99%

Evaluation of Cystatin C for the Detection of Chronic Kidney Disease in Cats

Ghys

Veterinary Internal Medicne

Lefebvre

et al. 2016

BackgroundSerum cystatin C (sCysC) and urinary cystatin C (uCysC) are potential biomarkers for early detection of chronic kidney disease (CKD) in cats. An in‐depth clinical validation is required.ObjectivesTo evaluate CysC as a marker for CKD in cats and to compare assay performance of the turbidimetric assay (PETIA) with the previously validated nephelometric assay (PENIA).AnimalsNinety cats were included: 49 CKD and 41 healthy cats.MethodsSerum CysC and uCysC concentrations were prospectively evaluated in cats with CKD and healthy cats. Based on plasma exo‐iohexol clearance test (PexICT), sCysC was evaluated to distinguish normal, borderline, and low GFR. Sensitivity and specificity to detect PexICT < 1.7 mL/min/kg were calculated. Serum CysC results of PENIA and PETIA were correlated with GFR. Statistical analysis was performed using general linear modeling.ResultsCats with CKD had significantly higher mean ± SD sCysC (1.4 ± 0.5 mg/L) (P < .001) and uCysC/urinary creatinine (uCr) (291 ± 411 mg/mol) (P < .001) compared to healthy cats (sCysC 1.0 ± 0.3 and uCysC/uCr 0.32 ± 0.97). UCysC was detected in 35/49 CKD cats. R 2 values between GFR and sCysC or sCr were 0.39 and 0.71, respectively (sCysC or sCr = μ + GFR + ε). Sensitivity and specificity were 22 and 100% for sCysC and 83 and 93% for sCr. Serum CysC could not distinguish healthy from CKD cats, nor normal from borderline or low GFR, in contrast with sCr.ConclusionSerum CysC is not a reliable marker of reduced GFR in cats and uCysC could not be detected in all CKD cats.