ACVIM consensus statement: Guidelines for the identification, evaluation, and management of systemic hypertension in dogs and cats

Bridging the gap-Rethinking the role of the adrenal gland in chronic kidney disease from the feline perspective

Chronic kidney disease (CKD) is the most common metabolic disease in domestic cats. Unlike humans and dogs, CKD in cats seems to have a highly complex and multifactorial etiology. Despite great effort being poured into research trying to elucidate possible pathways for the pathogenesis of CKD, there is still a lack of understanding regarding its initiating and progression factors. There is also a lack of therapeutic options for these patients, with most treatment plans relying on a low-phosphate diet, dietary protein modification and medical management of complications (e.g. hypertension) as they arise. In this review, we propose the hypothalamic-pituitary-adrenal (HPA) axis plays a central role in the development, pathophysiology and progression of feline chronic kidney disease. The adrenal glands and the hormones they secrete, in particular, may act as lynchpins in chronic kidney disease, mediating virtually every aspect of the disease: from the establishment of fibrosis and kidney damage to the development of hypertension and a pro-inflammatory status. By compiling the available research regarding the influence of adrenal hormones and the HPA axis, we hope to highlight possible future areas of scientific interest regarding feline CKD as well as possible aspects in which the cat may act as a model for research in human medicine.

Systemic Arterial Hypertension and Factors Associated with Blood Pressure Dysregulation in Companion Animals

Systemic arterial hypertension (SAH), characterised by a persistent increase in BP beyond the reference values for the species, is a concerning and detrimental clinical condition. The aim of this manuscript is to present the state of the art on SAH in companion animals, including the different types of hypertension, diagnostic and therapeutic approaches, and the factors associated with its occurrence, such as the role of stress. It also discusses the benefits and challenges related to the measurement process. SAH is categorised into types based on the underlying cause: situational, secondary, and idiopathic (the least frequently observed). The situational type occurs when stress is the primary factor, such as during veterinary visits, contact with other animals, or in cases of 'white coat syndrome'. If the stressor is removed, BP values tend to normalise. The most common type of SAH is the secondary form, which is associated with an underlying condition, such as renal, cardiac, endocrine, or neurological diseases, or a combination of these. Diagnosing SAH is a challenging task for many veterinarians due to factors related to handling the animal, managing the equipment, and interpreting the results. Consequently, many professionals either take inaccurate measurements or misinterpret the results, often prescribing antihypertensive medications prematurely or unnecessarily. Despite being a well-standardised and well-documented process, challenges persist. Treatment often involves antihypertensive drugs, either alone or in combination, alongside management of the underlying causes, when present. Therefore, BP values should be obtained correctly, with clinical-therapeutic decisions carefully aligned with the factors that may influence them.

Longitudinal Study of Renal Health Screening in Apparently Healthy Aging Dogs

BACKGROUND

Combined measurement of functional, glomerular, and tubular markers in aging dogs is essential to detect early renal disease.

OBJECTIVES

Prospective longitudinal study to describe renal function and assess which biomarkers are associated with the development of early renal disease or death.

ANIMALS

One hundred and twenty-two apparently healthy senior and geriatric dogs.

METHODS

Prospective longitudinal study. Renal function was evaluated at baseline (T0) and every 6-12 months over 2 years, using systolic blood pressure measurements (SBP) and validated serum (creatinine, symmetric dimethylarginine, cystatin C [sCysC]), and urinary (specific gravity [USG], protein:creatinine [UPC], albumin:creatinine, retinol-binding protein:creatinine [uRBPcr]) biomarkers. Glomerular filtration rate (GFR) was measured in a subgroup. Survival models were used to assess the predictive value of measured biomarkers at baseline for the onset of azotemic chronic kidney disease (CKD) or death, respectively.

RESULTS

A total of 122 dogs were included; follow-up was available in 106 (T12) and 92 (T24); and GFR was estimated in 18 (T0), 11 (T12), and 10 (T24) dogs. Throughout the study, 15/122 (12%) dogs showed evidence of non-azotemic CKD, and in 11/106 (10%) dogs, azotemic CKD developed. Proteinuria was not associated with azotemic CKD, in contrast to muscle condition score, functional markers, and uRBPcr. Death was weakly associated with USG, UPC, and sCysC.

CONCLUSIONS AND CLINICAL IMPORTANCE

Over a 2-year period, 20% (26/122) of older dogs developed CKD, mostly persistent renal proteinuria (15/122). Muscle wasting and functional markers combined with uRBPcr had the best predictive value for the onset of azotemic CKD in these older, previously apparently healthy dogs.

Diagnostic Value of Echocardiography in Cats With and Without Ultrasonographic Evidence of Renal Infarction

BACKGROUND

Revisiting the association between heart disease and renal infarction (RI) in cats is relevant to determine whether those with RI should undergo echocardiographic screening.

OBJECTIVE

Compare the relative frequency of echocardiographically detectable heart disease and other comorbidities in cats with and without ultrasonographic evidence of RI.

ANIMALS

A total of 826 cats that underwent concurrent abdominal ultrasonography and transthoracic echocardiography and were assigned a cardiac diagnosis.

METHODS

Two-center cross-sectional study with a study population recruitment period from January 1, 2011 to June 15, 2021. Demographic, clinical, clinicopathologic, and ultrasonographic data were recorded. Available echocardiographic images were reviewed to assign a standardized cardiac diagnosis. Occult heart disease was defined as structural heart disease without clinical signs of congestive heart failure. Risk factors for RI were evaluated by univariable or multivariable logistic regression.

RESULTS

The relative frequency of structural heart disease in cats with and without RI was 63% (114/181) and 46% (297/645), respectively (adjusted odds ratio [OR] 95% confidence interval [CI], 1.6; 1.2-2.3). Older age (p = 0.03), higher maximum end-diastolic left ventricular wall thickness (p = 0.02), higher systolic blood pressure (p = 0.02), auscultable cardiac abnormalities other than murmur (p = 0.04), and diagnosis of acute kidney injury (p = 0.002), chronic kidney disease (p = 0.005), and occult heart disease (OR [95% CI], 2.4 [1.7-3.4]; p ≤ 0.001) were associated with increased risk of RI. Strength and statistical significance of associations varied by site.

CONCLUSIONS AND CLINICAL IMPORTANCE

Occult heart disease is more frequent in cats with RI, and echocardiographic screening of these cats should be considered.

Effect of the Vascular Endothelial Growth Factor Inhibitor Toceranib on Cardiac Function and Endothelial Dysfunction Biomarkers in Dogs With Cancer

BACKGROUND

Hypertension is documented in dogs with cancer receiving toceranib, but no studies have evaluated left ventricular (LV) systolic function and biomarkers of endothelial function.

OBJECTIVES

To characterize changes in echocardiographic variables and biomarkers of endothelial function in dogs treated with toceranib.

ANIMALS

Twenty-six client-owned dogs with no evidence of pre-existing cardiac disease or systemic hypertension are receiving a single agent toceranib for cancer treatment.

METHODS

Dogs were enrolled in this prospective observational study with study visits at baseline, 1, 3, and 5 months after starting toceranib for echocardiographic exams, blood and urine collection, and blood pressure measurements, with an additional blood pressure obtained 2 weeks after starting toceranib. Serum markers of vascular endothelial function (VEGF, endothelin-1, platelet derived growth factor [PDGF], prostacyclin, cyclic guanosine monophosphate [cGMP]) and urinary nitrate were evaluated with ELISA.

RESULTS

Dogs were enrolled between 2019 and 2023. Systolic blood pressure increased 2 weeks after initiating toceranib treatment (p = 0.009). Serum prostacyclin concentration was lower after 1 month of treatment (mean 98.8 pg/mL vs. 140.0 pg/mL at baseline, p = 0.03), and serum VEGF concentration was higher after 3 months of treatment (mean of 247.8 pg/mL vs. 135.4 pg/mL at baseline, p = 0.01). Global longitudinal strain (GLS) decreased at the five-month time point (mean -14.5% vs. -15.7% at baseline, p = 0.048) with no significant change in LV fractional shortening by M-mode or ejection fraction by Simpson's method of discs.

CONCLUSIONS

Dogs treated with toceranib might have higher systemic blood pressure associated with changes in VEGF and prostacyclin and decreased systolic function.

Effects of Hydrolysed Poultry Byproduct Meal on Metabolic, Inflammatory and Oxidative Parameters in Cats

Hydrolysed proteins are of interest owing to their potential effects on metabolic and physiological responses, low allergenicity and high digestibility. This study aimed to evaluate the use of hydrolysed poultry byproduct meal (HPM) as a replacement for conventional poultry byproduct meal (PBM) as a protein source and to study its effects on serum cytokines, angiotensin-converting enzyme (ACE) activity, serum antioxidant parameters, blood pressure, and urinary parameters in cats. The replacement of PBM with HPM was evaluated using five formulations with similar chemical compositions: control (PBM as the sole protein source) and the inclusion of 5%, 10%, 20%, and 30% HPM (on an as-fed basis). Thirty cats were distributed into two randomised blocks of 15 cats, with 3 cats per diet in each block, totalling 6 cats per food. After 10 days of diet adaptation, the urine of the cats was quantitatively collected from Days 11 to 15, and on the day 21 blood samples were collected and blood pressure was evaluated. Data were subjected to analysis of variance and the means were compared by polynomial contrasts. Non-parametrically distributed variables were compared using the Kruskal-Wallis test (p < 0.05). All the cats remained healthy throughout the study period. Diet did not affect urine volume; intake and excretion of sodium, potassium, and chloride; blood pressure; ACE plasma activity; or serum triglyceride and cholesterol levels (p > 0.05). Among the oxidative parameters, there was a quadratic increase in lipid peroxidation and glutathione S-transferase (higher values at 10% HPM) (p < 0.05). A quadratic increase was observed for steam cell factor, interferon-γ, IL-4, and IL-8 (p < 0.05), with higher values for cats fed 5% and 10% HPM diets. A nonparametric distribution with higher values for cats fed the 5% HPM diet was observed for monocyte chemoattractant protein-1; tumour necrosis factor-α; IL-2; and regulated upon activation, normal T cell expressed and secreted (RANTES) (p < 0.05). In conclusion, we observed that the intake of diets containing 5% and 10% HPM stimulated the antioxidant system and the secretion of several cytokines involved in the preparation and function of the immune system, suggesting potential biological functions with implications for cat health deserving further investigation.

Fundoscopy in cats: a practical guide and common findings

PRACTICAL RELEVANCE

Comprehensive examination of the feline fundus should be in every clinician's arsenal. It is an integral part of both the physical and ophthalmic examination, especially in senior cats and in the presence of intraocular inflammation and visual impairment. Fundoscopy provides critical insight into a wide range of systemic diseases, often leading to quicker diagnoses and better treatment outcomes.

CLINICAL CHALLENGES

Practice is needed to become proficient and take high-quality photos of the retina. Distinguishing between normal variants and pathological findings can be challenging initially.

EVIDENCE BASE

This review includes information from published references of common retinal pathologies in cats, as well as the authors' extensive experience on performing fundoscopy.

EQUIPMENT

The essential tools for fundoscopy include a direct and indirect ophthalmoscope, condensing lens and a focal light source. High-quality images of the fundus can be achieved with any smartphone.

AUDIENCE

This review is aimed at veterinary clinicians and outlines all the steps and equipment needed to confidently perform fundoscopy. It also provides tips on how to capture photos of the fundus using a smartphone. Common findings are discussed in relation to different retinal pathologies.

Description of unilateral kidney embolism and contralateral nephrectomy as a less invasive remnant kidney model in cats; a proof-of-concept study

BACKGROUND

Refined models of kidney disease are critical to better understand disease processes and study novel treatments while minimizing discomfort in research animals. The objective of this study was to report a technique for minimally invasive partial kidney embolism in cats and describe outcomes following transcatheter administration of embolic microspheres with subsequent contralateral nephrectomy.

METHODS

Eleven, apparently healthy, male, purpose-bred cats underwent unilateral kidney embolism with 0.25 or 0.5 mL of embolic microparticle (40-120 μm) suspension (0.2 mL microspheres/mL) delivered into the right renal artery under fluoroscopic guidance, followed 5 months later by contralateral nephrectomy. One month after nephrectomy, blood and urinary markers of kidney function were evaluated, and embolized kidneys were harvested for histopathology evaluation.

RESULTS

Renal artery embolization was possible in all cats. Two cats did not complete the study, one after experiencing congestive heart failure (n = 1) and the other following evidence of complete kidney embolism precluding nephrectomy (n = 1) post-embolization. At study end, compared to baseline, cats had significant increases in median (range) serum creatinine (159.1 μmol/L [141.4-530.4] versus 128.2 μmol/L [92.8-150.3]; p = 0.0004), urea nitrogen (15.71 mmol/L [9.29-47.85] versus 7.50 mmol/L [6.07-8.57]; p < 0.0001), and symmetric dimethylarginine (0.74 μmol/L [0.59-3.12] versus 0.67 μmol/L [0.54-0.72]; p = 0.0288) concentrations. No differences in markers of kidney function were documented between dose groups.

CONCLUSIONS

Minimally invasive kidney embolism is a promising technique for modeling kidney disease in cats. Understanding optimal dose, timing of nephrectomy, and longer-term consequences requires additional work.

Efficacy of Urine Asymmetric Dimethylarginine Concentration to Predict Azotemia in Hyperthyroid Cats After Radio-Iodine Treatment

BACKGROUND

Hyperthyroidism can mask concurrent chronic kidney disease in cats, and no accurate biomarkers are available to predict which cats will develop renal azotemia after radioiodine (131I) treatment.

HYPOTHESIS/OBJECTIVES

To evaluate the potential of serum and urinary metabolites and metabolite ratios to predict post-131I renal azotemia in hyperthyroid cats.

ANIMALS

Hyperthyroid cats (n = 31), before and (3-12 months) after treatment with 131I at the Faculty of Veterinary Medicine (Ghent University, Belgium).

METHODS

Retrospective study. Optimized and validated feline extraction and analysis protocols were employed for metabolic profiling of urine and serum samples using ultra-high performance liquid chromatography-high-resolution mass spectrometry. A dual strategy of cross-validated univariate and penalized multivariate logistic regression was applied to determine predictivity (i.e., area under the curve [AUC], accuracy, sensitivity, and specificity) of individual biomarkers and panels.

RESULTS

All hyperthyroid cats were non-azotemic before 131I administration. After 131I treatment, 7 cats became persistently (≥ 2 timepoints) azotemic while 24 remained non-azotemic. Urinary asymmetric dimethylarginine (ADMA) was identified as a pivotal predictor of post-131I azotemia in both univariate and multivariate modeling. When employed as a standalone biomarker, an AUC of 0.851, accuracy of 0.903, sensitivity of 0.714, and specificity of 0.958 were achieved. While pre-treatment USG was significantly different (P = 0.002) between both groups, it did not show enhanced prediction over ADMA, nor in multivariate modeling.

CONCLUSIONS AND CLINICAL IMPORTANCE

Urinary ADMA can accurately predict post-131I azotemia in hyperthyroid cats becoming euthyroid after 131I treatment. These findings can aid clinicians in managing owner expectations and modify treatment plans.

Amlodipine improves symmetric dimethylarginine in dogs with chronic kidney disease

Introduction

In canines, chronic kidney disease (CKD) is frequently associated with high blood pressure. Amlodipine is used to treat hypertension in dogs, and we anticipated that amlodipine administration might improve renal function in dogs. However, the effect of amlodipine on canine renal function is unknown. Therefore, this study evaluated changes in symmetric dimethylarginine (SDMA) levels before and after amlodipine administration in pet dogs that had been diagnosed with CKD based on persistently elevated SDMA levels and were being treated with amlodipine alone for any reason. We also conducted a comparative investigation of whether there were any differences in SDMA changes depending on whether these dogs with CKD had hypertension.

Methods

This study employed a retrospective design. The study subjects were pet dogs that exhibited persistently elevated SDMA (≥14 μg/dL), were diagnosed with CKD, and were treated with amlodipine. Profile data such as breed, sex, and age, as well as data on blood chemistry tests, blood pressure, heart rate, and echocardiograms before and after amlodipine administration, were collected. Forty-five dogs were included in the study, of which 20 were hypertensive (HT: systolic arterial pressure ≥160 mmHg) and 25 were non-hypertensive (Non-HT: systolic arterial pressure <160 mmHg).

Results

Mean SDMA was significantly lower after drug administration compared with before administration in both the HT and Non-HT groups. Moreover, we found that cardiac output (CO) increased in all dogs with CKD treated with amlodipine. Blood pressure measurements showed that the blood pressure decreased in both the HT and Non-HT groups.

Discussion

It is believed that the increase in CO due to amlodipine administration increases glomerular filtration rate, which may have led to a decrease in SDMA levels. Based on the rate of decrease in systolic arterial pressure, we considered that amlodipine might decrease blood pressure by a greater amount in patients with higher levels of hypertension. In this study, we showed that amlodipine administration improved SDMA in dogs with CKD regardless of whether they were hypertension. We also showed that amlodipine could be safely used to treat normotensive dogs.

Evaluation of serum insulin-like growth factor 1 concentrations in non-diabetic cats with chronic kidney disease

Feline hypersomatotropism (HST) can develop in both diabetic and non-diabetic cats, but studies evaluating the prevalence of HST in cats without diabetes mellitus (DM) are lacking. The aims of the study were to evaluate circulating insulin-like growth factor 1 (IGF-1) in non-diabetic cats with chronic kidney disease (CKD), to assess whether there is a correlation between general test of renal function and IGF-1 concentration in cats with CKD, and to screen this population for the presence of HST. In this prospective study, one hundred fifty-four non-diabetic cats (n = 154) with CKD from referral centers in Buenos Aires (Argentina) were evaluated. Serum IGF-1 concentration was measured as part of the routine tests for CKD and compared with a healthy control group of 50 cats without CKD. The median serum IGF-1 concentration in the total population of cats with CKD was 500 ng/mL (range 34-1593 ng/mL). Median serum IGF-1 concentrations of cats with IRIS stage 1 (n = 13), stage 2 (n = 86), stage 3 (n = 40) and stage 4 (n = 15) of CKD were 230 ng/mL (range 58-951 ng/mL), 473 ng/mL (range 34-1456 ng/mL), 597 ng/mL (range 123-1593 ng/mL), 569 ng/mL (range 123-1045 ng/mL), respectively. None of the cats in the control group had IGF-1 concentration >1000 ng/mL (median 505 ng/mL, range 114-720 ng/mL). There was a positive linear correlation between serum IGF-1 and creatinine concentrations in cats with CKD (r= 0.22, 95% confidence interval 0.06-0.37 P=0.005). A proportion of 5.8% (95% confidence interval 2.7-10.8%) of non-diabetic cats with CKD had markedly increased IGF-1 concentrations (cut-off IGF-1 >1000 ng/mL). Pituitary enlargement was detected on computed tomography in 3/4 of these cases. Eighteen cats (11.6%) had serum IGF-1 concentrations in the "grey zone" between 800 and 1000 ng/mL. A small proportion of non-diabetic cats with CKD had an IGF-1 concentration in a range that is consistent with HST in diabetic cats. Likewise, the progression of CKD in cats without DM correlates with increases in serum IGF-1 concentrations.

Evaluation of enzymatically hydrolyzed poultry byproduct meal effects on fecal microbiota and pressure variables in elderly obese cats

Arterial hypertension is influenced by the intestinal microbiota and its metabolites, which play a crucial role in host health. Dietary peptides are multifunctional molecules with therapeutic potential for managing hypertension. This study aimed to evaluate the impact of incorporating enzymatically hydrolyzed poultry byproduct meal (EHPM-c) into extruded dry diets on the fecal microbiota and blood pressure parameters of elderly obese cats. Eighteen owners of neutered, clinically healthy male and female cats of various breeds were randomly assigned to two groups: control (30.8%, conventional poultry byproduct meal-CPM-c) and test (17.07%, CPM-c + 12.0% EHPM-c). Clinical values of systolic blood pressure, serum aldosterone concentrations, angiotensin-converting enzyme I activity, and fecal microbiota using 16S rRNA were measured. Data were processed using SAS software (PROC MIXED, PROC GLIMMIX, and PROC CORR; p < 0.05). Both groups exhibited high microbial alpha diversity, with no significant differences in beta diversity. Although the inclusion of 12.0% EHPM-c had no measurable effect on blood pressure, both diets promoted beneficial modulation of the fecal microbiota, improving intestinal health. These findings underscore the importance of diet in maintaining gut homeostasis in obese senior cats. While the inclusion of 12.0% EHPM-c did not significantly alter blood pressure parameters, the modulation of the fecal microbiota suggests a potential role in maintaining intestinal health. These results highlight the need for further studies to explore different inclusion levels and longer intervention periods.

Study of the Arrhythmogenic Profile in Dogs with Acute and Chronic Monocytic Ehrlichiosis

Canine monocytic ehrlichiosis (CME) is a globally prevalent disease transmitted by the tick Rhipicephalus sanguineus and caused by the Gram-negative bacterium Ehrlichia spp. Following an incubation period, the infection is categorized based on the progression of the disease into acute, subclinical, and chronic stages. Besides hematological alterations, the cardiovascular system is significantly impacted by the hemodynamic effects of the disease, as persistent anemia can lead to myocardial hypoxia and the activation of inflammatory processes, potentially causing myocarditis. It is known that in dogs infected with Ehrlichia canis, there is a higher occurrence of arrhythmias and a predominance of sympathetic activity. This study assessed arrhythmogenic parameters, including P wave dispersion (Pd), QT dispersion (QTd), and QT instability, along with heart rate variability (HRV) analysis from 24 h Holter monitoring in naturally infected dogs during the acute phase (n = 10) and chronic phase (n = 10) compared to a control group (n = 10). The Pd and QTd values were higher in the infect group, confirming the arrhythmogenic character. Instability parameters (TI, LTI, and STI) were higher in sick animals, but no worsening was observed in the chronic phase. All HRV metrics in the time domain were higher in the control group, indicating a balanced sympathovagal activity throughout the day in healthy dogs. Additionally, parameters linked to parasympathetic activity (rMSSD and pNN50) were reduced in the sick groups, confirming the dominance of sympathetic activity. These findings indicate a decrease in HRV in sick individuals and reinforce this useful marker for assessing the influence of the autonomic nervous system on the cardiovascular system. In conclusion, CME exhibits arrhythmogenic activity characterized by the deterioration of predictive parameters for ventricular arrhythmias and increased activity of the sympathetic autonomic nervous system in the heart. This is likely secondary to myocarditis, myocardial hypoxia, and structural damage to cardiomyocytes.

Idiopathic spontaneous intracardiac microbubbles in an adult dog

A four-year-old, female neutered English springer spaniel presented for evaluation of exercise intolerance, panting and lingual cyanosis. Echocardiography revealed a structurally and functionally normal heart with the presence of spontaneous intracardiac microbubbles entering the right side of the heart from the caudal vena cava. A cause for the clinical signs could not be identified; routine blood work, urinalysis and electrocardiography were unremarkable. Testing for tick-borne diseases, clotting times, cardiac biomarkers, thyroid function and basal cortisol were all within normal limits. Faecal samples tested for Clostridium perfringens alpha, beta and epsilon toxins were negative. Genetic conditions including malignant hyperthermia and phosphofructokinase deficiency were excluded. Computed tomography and angiography of the abdomen and thorax revealed no abnormalities or shunting vessels that could explain the origin of the spontaneous intracardiac microbubbles. Previously, microbubbles have only been visualised when intravenous access is present or when purposeful contrast studies are performed. As far as the authors are aware, this is the first case of spontaneous intracardiac microbubbles visualised in the right heart of a dog with no identifiable underlying systemic conditions.

Stem Cell Therapies in Canine Cardiology: Comparative Efficacy, Emerging Trends, and Clinical Integration

Cardiovascular diseases are a leading cause of morbidity and mortality in dogs, with limited options available for reversing myocardial damage. Stem cell therapies have shown significant potential for cardiac repair, owing to their immunomodulatory, antifibrotic, and regenerative properties. This review evaluates the therapeutic applications of mesenchymal stem cells (MSCs) derived from bone marrow, adipose tissue, and Wharton's jelly with a focus on their role in canine cardiology and their immunoregulatory properties. Preclinical studies have highlighted their efficacy in enhancing cardiac function, reducing fibrosis, and promoting angiogenesis. Various delivery methods, including intracoronary and intramyocardial injections, are assessed for their safety and efficacy. Challenges such as low cell retention, differentiation efficiency, and variability in therapeutic responses are also discussed. Emerging strategies, including genetic modifications and combination therapies, aim to enhance the efficacy of MSCs. Additionally, advances in delivery systems and regulatory frameworks are reviewed to support clinical translation. This comprehensive evaluation underscores the potential of stem cell therapies to revolutionize canine cardiovascular disease management while identifying critical areas for future research and clinical integration.

Splenic Doppler Resistance Index for Detection of Circulatory Shock in Dogs

OBJECTIVE

To assess the splenic flow resistance index (RI) and its response to a fluid bolus in dogs showing circulatory abnormalities upon hospital admission.

DESIGN

Prospective clinical study.

SETTING

Veterinary referral hospital.

ANIMALS

Nine dogs with circulatory shock and nine dogs without circulatory abnormalities.

INTERVENTIONS

Dogs with circulatory abnormalities received an IV bolus of 30 mL/kg of balanced isotonic crystalloid fluid.

MEASUREMENTS AND MAIN RESULTS

The splenic flow RI and the baseline aortic velocity-time integral of both groups of dogs were evaluated upon hospital admission. Measurements were repeated after the fluid bolus in dogs with circulatory shock. The Mann-Whitney U-test or the Wilcoxon rank sign test was used as appropriate. The median RI in dogs with circulatory shock was higher than that in dogs without hemodynamic disorders (median [interquartile range]: 0.64 [0.62-0.77] vs. 0.54 [0.51-0.54], P < 0.001). The best cutoff value to discriminate between the two groups was 0.61, with an area under the receiver operating characteristic curve of 1.00 (95% confidence interval [CI]: 1.00-1.00), a sensitivity of 100% (95% CI: 66.4-100), a specificity of 100% (95% CI: 66.4-100), a positive predictive value of 100% (95% CI: 66.4-100), and a negative predictive value of 100% (95% CI: 66.4-100). After fluid expansion, a significant decrease in the median splenic flow RI was observed (0.57 [0.54-0.71], P = 0.007 vs. basal).

CONCLUSIONS

The splenic flow RI may be a dependable tool for identifying circulatory shock in dogs and assessing their response to fluid therapy. Additional studies are required to evaluate the use of this index for the monitoring of organ perfusion, changes in cardiac output, and fluid responsiveness in critically ill dogs.

Early detection of feline chronic kidney disease via 3-hydroxykynurenine and machine learning

Feline chronic kidney disease (CKD) is one of the most frequently encountered diseases in veterinary practice, and the leading cause of mortality in cats over five years of age. While diagnosing advanced CKD is straightforward, current routine tests fail to diagnose early CKD. Therefore, this study aimed to identify early metabolic biomarkers. First, cats were retrospectively divided into two populations to conduct a case-control study, comparing the urinary and serum metabolome of healthy (n = 61) and CKD IRIS stage 2 cats (CKD2, n = 63). Subsequently, longitudinal validation was conducted in an independent population comprising healthy cats that remained healthy (n = 26) and cats that developed CKD2 (n = 22) within one year. Univariate, multivariate, and machine learning-based (ML) approaches were compared. The serum-to-urine ratio of 3-hydroxykynurenine was identified as a single biomarker candidate, yielding a high AUC (0.844) and accuracy (0.804), while linear support vector machine-based modelling employing metabolites and clinical parameters enhanced AUC (0.929) and accuracy (0.862) six months before traditional diagnosis. Furthermore, analysis of variable importance indicated consistent key serum metabolites, namely creatinine, SDMA, 2-hydroxyethanesulfonate, and aconitic acid. By enabling accurate diagnosis at least six months earlier, the highlighted metabolites may pave the way for improved diagnostics, ultimately contributing to timely disease management.

Test of Rapamycin in Aging Dogs (TRIAD): study design and rationale for a prospective, parallel-group, double-masked, randomized, placebo-controlled, multicenter trial of rapamycin in healthy middle-aged dogs from the Dog Aging Project

Companion dogs are a powerful model for aging research given their morphologic and genetic variability, risk for age-related disease, and habitation of the human environment. In addition, the shorter life expectancy of dogs compared to human beings provides a unique opportunity for an accelerated timeline to test interventions that might extend healthy lifespan. The Test of Rapamycin In Aging Dogs (TRIAD) randomized clinical trial is a parallel-group, double-masked, randomized, placebo-controlled, multicenter trial that will test the ability of rapamycin to prolong lifespan and improve several healthspan metrics in healthy, middle-aged dogs recruited from Dog Aging Project participants. Here, we describe the rationale, design, and goals of the TRIAD randomized clinical trial, the first rigorous test of a pharmacologic intervention against biological aging with lifespan and healthspan metrics as endpoints to be performed outside of the laboratory in any species.

Blood pressure and proteinuria in older cats and cats with chronic kidney disease

Background and Aim

Systemic hypertension and proteinuria are key prognostic indicators in cats with chronic kidney disease (CKD). However, their interrelationship in older cats and those with CKD remains unclear. This study aimed to investigate the association between systolic blood pressure (SBP) and proteinuria in older cats and cats with CKD and evaluate the correlation of these parameters with hematological and biochemical markers.

Materials and Methods

A cross-sectional observational study was conducted on 51 cats divided into three groups: 19 young adult cats (1-6 years, G1), 19 older cats (>10 years, G2), and 13 cats with CKD (creatinine >1.6 mg/dL, G3). Cats underwent clinical evaluations, blood pressure measurements using the oscillometric method, electrocardiography, and hematological, serum, and urine biochemical analyses. Statistical analyses included bootstrapped t-tests and Spearman's correlation, with significance set at p < 0.05.

Results

SBP values did not significantly differ among groups, but absolute SBP values were higher in older cats (G2), suggesting a potential age-related trend. No significant correlations were found between SBP and proteinuria, creatinine, urea, or urine density in G2 and G3. However, kidney injury biomarkers (urinary protein-to-creatinine ratio, creatinine, and urea) were strongly correlated with weight, body score, and total plasma protein in CKD cats (G3), indicating disease progression. Furthermore, G3 exhibited significant reductions in hematocrit, hemoglobin, and red blood cell counts, which were associated with kidney dysfunction.

Conclusion

This study did not find a direct correlation between SBP and proteinuria in older cats or cats with CKD. However, the higher SBP values in older cats highlight the importance of monitoring hypertension in aging felines. In addition, proteinuria was significantly associated with declining body condition and biochemical markers of kidney dysfunction, reinforcing its value as a prognostic indicator in CKD. Further studies are needed to explore the role of proteinuria and hypertension in advanced CKD stages.

Efficacy and safety of different antiarrhythmic protocols used for rate control in dogs with secondary atrial fibrillation

INTRODUCTION/OBJECTIVES

Studies comparing the effects of antiarrhythmic protocols used for rate control in dogs with secondary atrial fibrillation (AF) are currently limited; therefore, this study aimed to report detailed data on the efficacy and therapy-related side-effects (TRSEs) of different antiarrhythmic protocols in dogs with secondary AF.

ANIMALS, MATERIALS, AND METHODS

Dogs with secondary AF treated with combination therapy with diltiazem and digoxin (CTDilt+Digox), diltiazem monotherapy (MTDilt), digoxin monotherapy (MTDigox), or amiodarone monotherapy (MTAmiod) were retrospectively evaluated. Signalment, clinical, diagnostic, therapeutic, and outcome data were retrieved. Electrocardiographically, antiarrhythmic efficacy was defined by a reduction in the mean heart rate on Holter monitoring ≤125 beats/minutes. Statistical analysis was performed to compare selected data, including the rate of efficacy and TRSEs as well as the median survival time, between dogs treated with different antiarrhythmic protocols.

RESULTS

Fifty-four dogs were included, with 28 receiving the CTDilt+Digox and 26 receiving monotherapies (MTDigox = 16; MTDilt = 5; MTAmiod = 5). The efficacy rate documented in dogs treated with CTDilt+Digox was significantly higher than that observed in dogs from the composite monotherapy group (i.e., MTDilt+MTDigox+MTAmiod) (P=0.048). The rate of TRSEs documented in dogs treated with CTDilt+Digox was similar to that observed in dogs from the composed monotherapy group (P=0.129). The median survival time documented in dogs treated with CTDilt+Digox was significantly longer than that observed in dogs of the MTDigox group (P=0.01).

DISCUSSION

In dogs with secondary AF we included, CTDilt+Digox was well tolerated and provided clinically relevant benefits compared to the use of a single antiarrhythmic drug.

LIMITATIONS

Retrospective design; heterogeneous sample size of categories analyzed; clinicopathological data available for many, but not all, dogs.

CONCLUSIONS

Our findings support the indication to generally consider CTDilt+Digox as a first-line antiarrhythmic treatment in dogs with secondary AF.

Canine obesity, overweight, and adipokine serum concentration are associated with hematological, biochemical, hormonal, and cardiovascular markers

Background

Canine obesity is an increasingly concerning issue that negatively impacts dogs' health, quality of life, and lifespan.

Aim

This study aimed to evaluate the adipokine profiles of overweight (OW) and obese (OB) dogs and their associations with various hematological, biochemical, hormonal, and cardiovascular markers.

Methods

A total of 84 dogs were classified according to their body condition scores as normal weight (NW), OW, or OB, and were subsequently subjected to blood pressure measurement, blood testing, and urine sampling.

Results

The findings revealed that OB dogs had higher serum concentrations of leptin and resistin while exhibiting lower levels of adiponectin when compared to NW dogs. Additionally, they showed higher systolic blood pressure. Serum creatinine levels were lower in OB dogs, and urinary specific gravity was reduced in both OW and OB dogs compared to their NW counterparts. Furthermore, total leukocyte counts and neutrophil counts were elevated in OW and OB dogs. The study also found that serum insulin levels were positively correlated with triglycerides, cholesterol, and C-reactive protein.

Conclusion

Canine obesity is reflected in altered adipokine concentrations and is associated with insulin resistance, as well as changes in renal function, protein metabolism, and hematological markers.

Corticosteroid-Induced Sinus Bradycardia in a Dog with Systemic Lupus Erythematosus: A Case Report

A 3-year-old, 10.2 kg, spayed, female mixed-breed dog was diagnosed with systemic lupus erythematosus. The patient was administered intravenous methylprednisolone at a dose of 2 mg/kg twice daily. Over the next 24 h, the dog's heart rate dropped to 42-48 bpm, while other vital signs remained stable. A 12-lead electrocardiogram revealed sinus bradycardia without any other arrhythmia. Notably, the dog was not receiving any beta-blockers or undergoing other therapies commonly associated with sinus bradycardia. After tapering the corticosteroid dose, no further episodes of bradycardia were observed. Herein, we report the first case of sinus bradycardia in a dog following intravenous methylprednisolone therapy to improve veterinarians' understanding of corticosteroid-induced cardiac arrhythmias.

Orally administered prednisolone decreases plasma arginine vasopressin and serum copeptin concentrations in healthy dogs

BACKGROUND

The pathophysiology of polyuria and polydipsia secondary to exogenous glucocorticoid excess is incompletely understood.

OBJECTIVE

Investigate plasma AVP (pAVP) and serum CoP (sCoP) concentrations in healthy dogs before, during, and after abrupt discontinuation of a long-term course of orally administered prednisolone.

ANIMALS

Eight healthy neutered young adult research Beagles.

METHODS

In our prospective longitudinal study, Beagles were treated with a placebo PO q24h for 15 days (baseline), followed by a 35-day course of prednisolone (2.35-2.75 mg/kg PO q24h) and then abrupt discontinuation of prednisolone. Serial pAVP and sCoP concentrations, urine specific gravity (USG) and calculated plasma osmolality (pOsmcalculated) were determined during placebo and prednisolone administration, and up to 4 weeks after prednisolone discontinuation. Paired plasma samples for pAVP measurement were obtained in EDTA tubes with (pAVPP800) and without (pAVPEDTA) a proprietary combination of protease, esterase, and dipeptidyl peptidase-IV inhibitors (BD Biosciences P800).

RESULTS

Mean pAVPP800 and sCoP concentrations were significantly lower at the end of the prednisolone course (25.8 ± 8.1 pg/mL and 166 pg/mL, range, 131-223) vs baseline (34.1 ± 5.4 pg/mL and 243 pg/mL, range, 157-336; P = .02, P = .02, respectively). Correlations between pAVPP800 and sCoP (r = .77, P = .001) and pAVPP800 and USG (r = .61, P = .02) were positive, despite no correlation between pAVPP800 and pOsmcalculated, sCoP and pOsmcalculated, and sCoP and USG. On paired samples, mean pAVPEDTA was significantly lower (5.0 ± 2.5 pg/mL) than mean pAVPP800 (34.1 ± 5.4 pg/mL; P < .0001).

CONCLUSIONS AND CLINICAL IMPORTANCE

Orally administered prednisolone led to markedly decreased plasma AVP and serum CoP concentrations despite increased calculated plasma osmolality and stable systolic blood pressure.

Prevalence of cardiomyopathy and cardiac mortality in a colony of non-purebred cats in New Zealand

AIMS

To evaluate the prevalence of subclinical cardiomyopathy and cardiac mortality in a research colony of non-purebred cats, established as a model of the wider cat population in New Zealand.

METHODS

All apparently healthy, compliant, non-pregnant, non-neonatal cats in the colony at the Centre for Feline Nutrition (Massey University, Palmerston North, NZ) underwent physical examination and echocardiography using a 4.4-6.2-MHz probe by a board-certified veterinary cardiologist. Cardiac phenotype was classified following current guidelines. Hypertrophic cardiomyopathy (HCM) phenotype was defined as an end-diastolic left ventricular wall thickness ≥ 6 mm. Colony mortality data from February 2012 to February 2022 was reviewed to determine cardiac mortality.

RESULTS

Cats (n = 132; 65 females and 67 males) included in the study had a median age of 4.1 (IQR 3.0-8.0) years. Thirty-two (24%) cats had a heart murmur, and three (2%) cats had an arrhythmia. Echocardiography revealed heart disease in 24 (18.2%) cats, including 23 with an HCM phenotype and one with a restrictive cardiomyopathy phenotype. Of the cats with the HCM phenotype, 3/23 had systemic hypertension or hyperthyroidism or both, and these cats were excluded from the final diagnosis of HCM (20/132; 15.2 (95% CI = 9.5-22.4)%).Between 2012 and 2022, 168 colony cats died, with 132 undergoing post-mortem examination. Heart disease was considered the cause of death in 7/132 (5.3%; 95% CI = 2.2-10.6%) cats; five had HCM, one a congenital heart defect, and one myocarditis. The overall prevalence of death related to HCM in the colony during this period was 3.8% (95% CI = 1.2-8.6%). Three cats with HCM and the cat with a congenital heart defect died unexpectedly without prior clinical signs, while congestive heart failure was observed prior to death in two cats with HCM and the cat with myocarditis. Additionally, 30/132 (22.7%) cats had cardiac abnormalities but died for non-cardiac reasons.

CONCLUSIONS

Subclinical cardiomyopathy, specifically HCM, was common in cats in the colony. Given that the colony originated as a convenience selection of non-purebred cats in New Zealand, the true prevalence of HCM in the wider New Zealand population is likely to fall within the 95% CI (9.5-22%). The proportion of deaths of colony cats due to HCM was lower (3.8%) supporting the conclusion that subclinical cardiomyopathy may not progress to clinical disease causing death.

CLINICAL RELEVANCE

Veterinarians should be aware of the high prevalence of subclinical HCM when treating cats.

ABBREVIATIONS

CAM: Systolic anterior motion of the chordae tendineae; CFN: Centre for Feline Nutrition; HCM: Hypertrophic cardiomyopathy; LA/Ao: Left atrial to aortic ratio; LV FS: Left ventricular fractional shortening; LVIDd: Left ventricular internal diameters in end-diastole; LVIDs: Left ventricular internal diameter in end-systole; LVWT: Max Maximum left ventricular wall thickness; SAM: Systolic anterior motion of the mitral valve; 2D: Two-dimensional.

Retrospective evaluation of risk factors for worsening renal function after angiotensin-converting enzyme inhibitor treatment in dogs

BACKGROUND

Angiotensin-converting enzyme inhibitors (ACEi) have the potential to cause worsening renal function (WRF). Therefore, reevaluation of renal function is recommended 1-2 weeks after starting ACEi therapy.

OBJECTIVES

To identify risk factors for WRF in dogs receiving ACEi for cardiac diseases, proteinuria, or systemic hypertension.

ANIMALS

A total of 156 client-owned dogs that received ACEi were included.

METHODS

Serum creatinine concentration was determined at the initial presentation and first reevaluation to detect and grade WRF (increase in sCr ≥ 0.3 mg/dL). Grade 1 (nonazotemic), 2 (mild), and 3 (moderate to severe) WRF were characterized by sCr remaining ≤1.6 mg/dL, 1.7-2.5 mg/dL increase, and 2.6-5.0 mg/dL increase, respectively. Demographic and serum chemistry data, such as total protein, albumin, blood urea nitrogen, creatinine, symmetric dimethylarginine, glucose, triglyceride, total cholesterol concentrations, and serum electrolyte concentrations at first presentation, were evaluated. Multivariable modeling was performed to identify risk factors for WRF after treatment with ACEi.

RESULTS

Worsening renal function was identified in 27/156 (17%, 95% confidence interval [CI], 0.11-0.23) dogs after ACEi treatment. It was classified as Grades 1, 2, and 3 in 17, 2, and 8 dogs, respectively. The only significant factors associated with WRF in dogs receiving ACEi were concurrent administration of furosemide (odds ratio, 5.05; 95% CI, 2.05-12.4; P < .001) and pre-existing azotemia (odds ratio, 3.21; 95% CI, 1.28-8.03; P = .01).

CONCLUSIONS AND CLINICAL IMPORTANCE

Although WRF is uncommon and mild, ACEi should be cautiously prescribed in dogs receiving furosemide or those with pre-existing azotemia.

Alterations in gut-derived uremic toxins before the onset of azotemic chronic kidney disease in cats

BACKGROUND

Although gut-derived uremic toxins are increased in azotemic chronic kidney disease (CKD) in cats and implicated in disease progression, it remains unclear if augmented formation or retention of these toxins is associated with the development of renal azotemia.

OBJECTIVES

Assess the association between gut-derived toxins (ie, indoxyl-sulfate, p-cresyl-sulfate, and trimethylamine-N-oxide [TMAO]) and the onset of azotemic CKD in cats.

ANIMALS

Forty-eight client-owned cats.

METHODS

Nested case-control study, comparing serum and urine gut-derived uremic toxin abundance at 6-month intervals between initially healthy cats that developed azotemic CKD (n = 22) and a control group (n = 26) that remained healthy, using a targeted metabolomic approach.

RESULTS

Cats in the CKD group had significantly higher serum indoxyl-sulfate (mean [SD], 1.44 [1.06] vs 0.83 [0.46]; P = .02) and TMAO (mean [SD], 1.82 [1.80] vs 1.60 [0.62]; P = .01) abundance 6 months before the detection of azotemic CKD. Furthermore, logistic regression analysis indicated that indoxyl-sulfate (odds ratio [OR]: 3.2; 95% confidence interval [CI]: 1.2-9.0; P = .04) and TMAO (OR: 3.9; 95% CI: 1.4-11; P = .03) were predictors for the onset of azotemia 6 months before diagnosis. However, renal function biomarkers creatinine, symmetric dimethylarginine, and urinary specific gravity were significantly correlated with indoxyl-sulfate and TMAO abundance, causing a loss in predictive significance after correction for these factors.

CONCLUSIONS

Impaired gut-derived uremic toxin handling is apparent at least 6 months before the diagnosis of azotemia, likely reflecting an already ongoing decrease in GFR, tubular function, or both. A direct causal relationship between gut-derived uremic toxicity and the initiation of CKD in cats is still lacking.

Cardiovascular changes in Persian cats with polycystic kidney disease: a study of cardiac troponin I, echocardiography and blood pressure

OBJECTIVES

Cardiovascular complications are well known in humans with autosomal dominant polycystic kidney disease (PKD), but limited data exist for cats. This study aimed to assess echocardiographic changes, cardiac troponin I (cTnI) levels and systolic blood pressure (SBP) in Persian cats with PKD to detect early cardiac abnormalities.

METHODS

In total, 52 Persian and mixed-Persian cats were enrolled, with 26 cats in the control group and 26 diagnosed with PKD via ultrasound due to the unavailability of genetic testing. Although genetic testing is the gold standard for definitive diagnosis, this study utilised high-sensitivity ultrasound as an alternative diagnostic tool. This method aligns with existing literature supporting its effectiveness in detecting PKD, particularly in regions where genetic testing is not accessible. Echocardiographic examinations employed M-mode and two-dimensional echocardiography to measure the diastolic thickness of the interventricular septum and the left ventricular free wall. Doppler ultrasonography was used to measure SBP and cTnI serum levels were determined using a Monobind-ELISA kit.

RESULTS

Median SBP and cTnI levels in PKD cats were 155 mmHg and 85.80 ng/l, respectively, which was significantly higher than the control group (P ⩽0.001). Interventricular septum in systole, as well as diastolic thickness of the interventricular septum and the left ventricular free wall, was significantly elevated in PKD cats compared with controls (P ⩽0.001). No significant differences were observed in other echocardiographic parameters.

CONCLUSIONS AND RELEVANCE

Asymptomatic PKD-affected Persian cats exhibited elevated SBP and cardiac structural changes; however, the clinical significance of these findings remains uncertain due to a lack of long-term follow-up. While early cardiac changes may be present, further research is necessary to establish their clinical relevance and guide appropriate management strategies. Monitoring PKD cats is advised, but a direct clinical impact is not confirmed at this stage.

Clinical importance of borderline proteinuria in nonazotemic cats and evaluation of other risk factors for the development of chronic kidney disease

BACKGROUND

Borderline proteinuria is associated with decreased survival in cats with azotemic chronic kidney disease (CKD).

OBJECTIVES

Determine the clinical importance of borderline proteinuria in nonazotemic cats.

ANIMALS

A total of 201 healthy client-owned cats ≥7 years of age; 150 nonproteinuric (urinary protein : creatinine ratio [UPC] <0.2) and 51 borderline proteinuric (UPC 0.2-0.4).

METHODS

Prospective study. Cats were thoroughly screened and subsequently examined every 6 months for 2 years. Kaplan-Meier curves were compared between nonproteinuric and borderline proteinuric cats. Univariable and multivariable Cox models were fit to determine the relationship between development of renal disease and potential risk factors such as age, sex, breed, weight, dental disease, blood pressure, serum creatinine concentration (sCrea), serum symmetric dimethylarginine concentration (sSDMA), blood urea nitrogen concentration, urine specific gravity (USG), and UPC.

RESULTS

Significantly more cats with borderline proteinuria at inclusion developed renal disease (International Renal Interest Society [IRIS] ≥ stage 2 CKD or renal proteinuria; log-rank P = .004) or died (log-rank P = .02) within 2 years, compared with nonproteinuric cats. In the multivariate analysis, IRIS stage 1 CKD (persistent USG <1.035 or sSDMA >14 μg/dL; hazard ratio [HR], 4.2; 95% confidence interval [CI], 2.0-8.8; P < .001), sCrea ≥1.6 mg/dL (≥140 μmol/L; HR, 2.6; 95% CI, 1.1-6.4; P = .04), borderline proteinuria (HR, 2.5; 95% CI, 1.2-5.2; P = .01), and age at inclusion (HR, 1.3; 95% CI, 1.2-1.5; P < .001) were significantly associated with diagnosis of renal disease 6 months later.

CONCLUSIONS AND CLINICAL IMPORTANCE

Borderline proteinuria should receive more attention in healthy mature adult and senior cats because it is associated with renal disease and death.

Comorbidities, long-term outcome and poststroke epilepsy associated with ischemic stroke - A multicenter observational study of 125 dogs

BACKGROUND

Little is known regarding the comorbidities and prognostic factors associated with the long-term outcome of ischemic stroke in dogs. Although poststroke epilepsy is a well-recognized syndrome in people, it is unclear if this phenomenon also occurs in dogs.

HYPOTHESIS/OBJECTIVE

Document comorbidities, long-term outcome (survival and stroke recurrence), and occurrence of epileptic seizures associated with ischemic stroke.

ANIMALS

One hundred and twenty-five client-owned dogs.

METHODS

Multicenter observational study including dogs diagnosed with ischemic stroke between 2000 and 2021. Associations between comorbidities, stroke location and extent, poststroke epileptic seizures, and long-term outcome were investigated. Referring veterinarians and owners were contacted to obtain follow-up information.

RESULTS

Fifty-two dogs (41.6%) had a comorbidity. The most common comorbidities were hypertension (20%) and proteinuria (8%). Eight dogs (6.4%) that did not survive to discharge had a territorial ischemic stroke. Overall median survival time for dogs with a comorbidity was 482 days (range, 1-3013) and 907 days (range, 1-3027) in dogs without comorbidities (Kaplan-Meier survival analysis P = .602). Twenty-four dogs (19.2%) had a suspected stroke recurrence and a total of 8/109 dogs (7.3%) developed poststroke epilepsy. No association was found between suspected stroke recurrence or development of poststroke epilepsy and survival (P = .812, P = .487).

CONCLUSIONS AND CLINICAL IMPORTANCE

Despite no significant difference in survival of dogs diagnosed with ischemic stroke, with or without comorbidities, investigations for underlying causes are recommended to provide appropriate treatment. Poststroke epilepsy is uncommon.

Assessment of shock index in healthy cats and in cats presenting to an emergency room with shock

OBJECTIVE

To prospectively compare the shock index (SI) in a population of healthy cats with a population of cats presenting to the emergency room (ER) deemed to be in a state of shock.

DESIGN

Prospective cohort study of cats.

SETTING

University teaching hospital.

ANIMALS

Twenty-seven healthy control cats were enrolled to establish a reference interval, and 27 cats were enrolled that were presented to the ER with clinical signs of shock. Shock was defined as abnormalities in at least 2 of the following inclusion criteria: plasma lactate concentration > 2.5 mmol/L; peripheral vasoconstriction (at least 2 of the following parameters: capillary refill time >3 s, rectal-interdigital temperature gradient [RITG] >8°C, femoral pulse not palpable, pale mucous membranes); or systolic blood pressure (SBP) < 100 mm Hg.

INTERVENTIONS

Upon presentation, SI (SI = heart rate [HR]/SBP), HR, SBP, and RITG were recorded in both groups, along with peripheral venous blood sampling for lactate measurement.

MEASUREMENTS AND MAIN RESULTS

The mean SI in the control group was 1.47 ± 0.2 and was 1.87 ± 0.47 in the shock group (P = 0.001). Using equality in sensitivity and specificity of 0.7, an SI cutoff point of 1.54 (95% confidence interval [CI]: 0.49-0.86) was determined with an estimated area under the receiver operating characteristic curve of 0.78 (95% CI: 0.65-0.90). HR, plasma lactate concentration, and RITG did not differ between the groups. Systolic arterial blood pressure (P = 0.01), rectal temperature (P = 0.02), and interdigital temperature (P = 0.04) differed significantly.

CONCLUSIONS

The SI is a noninvasive, easy, and reliable parameter for distinguishing cats in shock from normal cats.

Cardiac pathology associated with hypertension and chronic kidney disease in aged cats

Hypertension is a common condition in older cats, often secondary to chronic kidney disease (CKD). Although the heart is one of the organs damaged by hypertension, the pathology of the feline hypertensive (HT) heart has been poorly studied. The aim of this retrospective study was to describe the gross and microscopic pathology of hearts obtained from cats at post-mortem examination and to compare cats diagnosed with hypertension with cats of similar age and kidney function for which antihypertensive treatment was not deemed clinically necessary. Hearts from 32 cats were examined‒18 from HT and 14 from normotensive (NT) cats. The prevalence of CKD was 72.2% vs. 78.6% in the HT and NT groups, respectively. The time-averaged blood pressure over the longitudinal follow-up from diagnosis was significantly higher in the HT group compared with the NT group (153.4 ± 20.8 vs. 133.9 ± 19.3 mmHg; P = 0.0106), respectively. HT cats, when compared with NT cats, had a thicker left ventricular free wall (7.67 [5.45-9.29] vs. 5.07 [4.72-7.16] mm; P = 0.001) and interventricular septum (6.92 [6.26-7.56] vs. 4.96 [4.15-6.46] mm; P = 0.008) and higher ventricular weight as a percentage of body weight (0.34 [0.29-0.36] vs. 0.28 [0.21-0.31]%; P = 0.02), respectively. Myocardial fibrosis was present in 72% of cases with no significant difference in the prevalence (P = 0.45) or score (P = 0.81) between the HT (1 [0.75-2]; 77.8% scoring one or above) and NT cats (1 [0-2]; 64.3% scoring one or above). Similarly, the population prevalence of myocyte hypertrophy, myofibre disarray and microvascular change was 71.9%, 50% and 43.7%, respectively, and did not differ significantly between groups. These results suggest that age-related cardiac pathology, exacerbated by azotaemic CKD, in cats is very common. The role that hypertension plays in mediating these pathological changes is uncertain.

Serum symmetric dimethylarginine concentrations in enalapril- or telmisartan-treated dogs with proteinuric chronic kidney disease

Introduction

Renin-angiotensin-aldosterone system inhibition (RAASi) reduces intraglomerular pressure and is a standard therapy for dogs with proteinuric chronic kidney disease (CKD). RAASi can acutely decrease glomerular filtration rate (GFR); however, its effects on the marker of GFR serum symmetric dimethylarginine (SDMA) concentration in dogs have not been specifically evaluated. The objective of this study was to evaluate changes, relative to pretreatment values, in serum SDMA concentrations in dogs with proteinuric CKD receiving RAASi therapy.

Methods

This retrospective study used banked samples from 29 dogs with proteinuric CKD treated with enalapril (0.5 mg/kg PO q12h; n = 16) or telmisartan (1 mg/kg PO q24h; n = 13) alone (n = 22) or in combination with amlodipine if severely hypertensive (n = 7). Serum SDMA, creatinine, and urea nitrogen (SUN) concentrations were measured before and 7 and 30 days after starting RAASi. Percentage and absolute changes in these biomarkers were calculated for each dog and time point. A linear mixed model was used to test whether changes significantly differed from zero (α < 0.05).

Results

Overall, mean ± SEM Day 7 and 30 percentage change in SDMA were  - 4.8 ± 3.6% and  - 3.2 ± 3.4%, respectively; in creatinine were 7.4 ± 3.3% and 3.0 ± 3.1%, respectively; and in SUN were 22.1 ± 6.8% and 16.7 ± 6.2%, respectively. Mean changes varied according to whether all dogs, those on RAASi alone, or those co-treated with amlodipine were evaluated. In dogs receiving RAASi alone, at day 7, there were significant mean percentual increases in creatinine (9%; p = 0.023) and SUN (23%; p = 0.005), but SDMA was unchanged. In dogs co-treated with amlodipine, a significant absolute decrease in mean SDMA (-2.29 μg/dL; p = 0.026) occurred at days 7 and 30, while mean creatinine was unchanged and mean SUN increased.

Discussion

Proteinuric dogs receiving RAASi had low-magnitude changes in serum SDMA and creatinine, and moderate-magnitude changes in SUN concentrations. The direction of change in SDMA did not consistently match that of creatinine and SUN.

Cardiac Autonomic Modulation in Domestic Cats with Obstructive Lower Urinary Tract Disease

Obstructive feline lower urinary tract disease (OFLUTD) is the most common complication of the urinary system, as metabolic and electrolyte changes can alter the functioning of the autonomic nervous system (ANS). The objective of this study was to describe the indices of heart rate variability (HRV) and their correlations with the observed alterations in Systolic Blood Pressure (SBP) and electrocardiographic, biochemical, and haemogasometric indices in cats diagnosed with OFLUTD. Sixty-five male cats up to 10 years of age were divided into two groups. The control group (CG) was composed of 25 healthy cats, and the obstructed group (OG) consisted of 40 cats with OFLUTD. The OG was evaluated by electrocardiography and blood pressure at four different time points. In the CG, electrocardiographic evaluation and SBP measurement were performed. A comparison of the HRV between the CG and OG (M0) revealed differences in the SDNN (standard deviation of all normal RR-NN) parameters (sympathetic and parasympathetic tone) and in the rMSSD (parasympathetic tone); there was a difference in the SBP, which was greater in the CG. There were higher rates in the CG. The HF and HR were greater in OG. The HRV serves as a preventive tool and predicts the severity of OFLUTD in patients due to an imbalance in the ANS.

Somatic GNAQ, CTNNB1, and CACNA1C Mutations in Cat Aldosterone-Secreting Tumors

BACKGROUND

Primary aldosteronism (PA) is a common cause of human hypertension. Somatic mutations in KCNJ5, CACNA1D, ATP1A1, and ATP2B3 are found in at least 80% of aldosterone-producing adenomas, which cause unilateral PA in humans. Somatic mutations have been identified infrequently in 7 other genes; few of these were known to play a role in aldosterone secretion before the discovery of their mutations. Interrogating somatic mutations in the domestic cat, in which spontaneous PA is also known to occur, might improve the understanding of normal adrenal gland physiology and the pathophysiology of PA.

METHODS

DNA and RNA extracted from tissue from 13 cats with unilateral aldosterone-secreting tumors, including 8 carcinomas and 5 adenomas, underwent whole genome sequencing, targeted Sanger sequencing, and RNA sequencing. Single-nucleotide substitution variants were filtered to select those with a predicted deleterious effect on protein function and a suspected role in aldosterone secretion.

RESULTS

Probable functional somatic single-nucleotide polymorphisms (n=8) were found in 3 adenomas and 2 carcinomas. Mutations with predicted significant effects were identified in 2 genes also mutated in human PA; GNAQ and CTNNB1, and in a residue of CACNA1C analogous to a common CACNA1D mutation. In contrast to humans, CACNA1C expression was much greater than CACNA1D in both feline tumor and nontumor adrenal tissue. No mutations were identified in KCNJ5, CACNA1D, ATP1A1, or ATP2B3.

CONCLUSIONS

Similar mutations were identified in cats to those found in humans. It is, therefore, likely that both species have shared underlying selection pressures for mutations that increase aldosterone secretion.

Evaluation of renal function in dogs using pulsed Doppler ultrasonography

Background

In human medicine, efforts have been made to evaluate venous blood flow in the kidneys to diagnose renal disease and estimate renal function. In dogs, previous studies have predicted renal function using the resistive index (RI) and pulsatility index (PI), which are derived from renal arterial blood flow velocity assessed via pulsed Doppler ultrasonography. However, to date, no study has been conducted on renal venous blood flow velocity in dogs.

Aim

To investigate the relationship between renal venous blood flow velocity and renal function.

Methods

Ten normal beagle dogs underwent blood tests and glomerular filtration rate (GFR) measurements. Pulsed Doppler ultrasonography was performed under sedation to measure the maximum venous flow velocity (Vmax), minimum venous flow velocity (Vmin), and venous impedance index in the renal and interlobular veins. The RI and PI were calculated from the renal and interlobular arteries.

Results

Vmax and Vmin of the renal vein were negatively correlated with GFR in both kidneys. No significant correlations were found between other measures and GFR. These results suggest a relationship between GFR and venous flow velocity in the renal veins assessed using pulsed Doppler ultrasonography.

Conclusion

These findings demonstrate the potential of this methodology as a new tool for predicting abnormalities in the renal venous blood flow and renal congestion in dogs. Further large-scale studies and comparisons between healthy dogs and dogs with impaired renal function are needed to validate this relationship.

Systemic reactive angioendotheliomatosis mimicking hypertrophic cardiomyopathy in a domestic shorthair cat

A two-year-old, 3.9-kg, male castrated, domestic shorthair cat presented to The Ohio State University Veterinary Medical Center for acute onset neurological signs. During hospitalization, he was diagnosed with an American College of Veterinary Internal Medicine (ACVIM) stage B1 hypertrophic cardiomyopathy phenotype on echocardiogram. His clinical signs acutely worsened, including seizure activity and panting, and he was euthanized. Necropsy revealed the histopathologic diagnosis of systemic reactive angioendotheliomatosis, which notably severely affected the myocardium. In this case report, we present the antemortem diagnostic results and postmortem necropsy results of this rare condition in cats. This case demonstrates that echocardiographic assessment of the heart in cats affected by systemic reactive angioendotheliomatosis may lead to the false diagnosis of hypertrophic cardiomyopathy and thus should be considered as a differential diagnosis in cats with symmetrical left ventricularl wall thickening on echocardiography.

Usefulness of noninvasive blood pressure measurement in captive Red Panda (Ailurus fulgens)

The red panda (Ailurus fulgens) can be found in zoos around the world, and various behavioral restraint procedures are used as part of their health care. Wild animals that are kept in zoos, including red pandas, are known to have a longer life span than those in the wild. Therefore, the health management of aging animals is considered especially important for zoos that maintain many precious wild animals. Blood pressure measurement is important for determining cardiovascular dynamics, however there are no reports of blood pressure measurements performed in red pandas without anesthesia. In this study, we measured blood pressure in four red pandas, over 4 years to establish a blood pressure measurement method using behavioral restraints. As a result, the blood pressure of red pandas was found to be similar to that of dogs and cats. In addition, in one case of red panda that evaluated high blood pressure during the measurement period, we added the antihypertensive drug and showed good effect for improvement of hypertension on long- term monitoring. Blood pressure values obtained using noninvasive methods were useful for red pandas. Moreover, these data were considered important for animal welfare.

Assessing functional properties of diet protein hydrolysate and oil from fish waste on canine immune parameters, cardiac biomarkers, and fecal microbiota

Locally produced fish hydrolysate and oil from the agrifood sector comprises a sustainable solution both to the problem of fish waste disposal and to the petfood sector with potential benefits for the animal's health. This study evaluated the effects of the dietary replacement of mainly imported shrimp hydrolysate (5%) and salmon oil (3%; control diet) with locally produced fish hydrolysate (5%) and oil (3.2%) obtained from fish waste (experimental diet) on systemic inflammation markers, adipokines levels, cardiac function and fecal microbiota of adult dogs. Samples and measurements were taken from a feeding trial conducted according to a crossover design with two diets (control and experimental diets), six adult Beagle dogs per diet and two periods of 6 weeks each. The experimental diet, with higher docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids contents, decreased plasmatic triglycerides and the activity of angiotensin converting enzyme, also tending to decrease total cholesterol. No effects of diet were observed on serum levels of the pro-inflammatory cytokines interleukin (IL)-1β, IL-8, and IL-12/IL-23 p40, and of the serum levels of the anti-inflammatory adipokine adiponectin. Blood pressure, heart rate and echocardiographic measurements were similar between diets with the only exception of left atrial to aorta diameter ratio that was higher in dogs fed the experimental diet, but without clinical relevance. Diet did not significantly affect fecal immunoglobulin A concentration. Regarding fecal microbiome, Megasphaera was the most abundant genus, followed by Bifidobacterium, Fusobacterium, and Prevotella, being the relative abundances of Fusobacterium and Ileibacterium genera positively affected by the experimental diet. Overall, results from the performed short term trial suggest that shrimp hydrolysate and salmon oil can be replaced by protein hydrolysate and oil from fish by-products without affecting systemic inflammatory markers, cardiac structure and function, but potentially benefiting bacterial genera associated with healthy microbiome. Considering the high DHA and EPA contents and the antioxidant properties of fish oil and hydrolysate, it would be worthwhile in the future to assess their long-term effects on inflammatory markers and their role in spontaneous canine cardiac diseases and to perform metabolomic and metagenomics analysis to elucidate the relevance of microbiota changes in the gut.

Improved corneal clarity following lamellar keratectomy for corneal lipidosis in a canine with ocular manifestations of hypothyroidism

OBJECTIVE

To report the corneal clarity outcome following lamellar keratectomy of arcus lipoides corneae secondary to canine hypothyroidism and report a unique retinal manifestation of systemic disease.

ANIMAL STUDIED

Four-year-old spayed female Sheepdog-Poodle canine.

PROCEDURE

Lamellar keratectomy OD.

RESULTS

Bilateral severe arcus lipoides corneae was noted in the initial presentation. Bilateral, symmetric, and multifocal bullous retinal detachments were observed at subsequent visits. Biochemical testing revealed hyperlipidemia presumed to be associated with primary acquired thyroiditis. Corneal clarity and visual behaviors were significantly improved following unilateral lamellar keratectomy with no evidence of recurrence within the year following surgery. Bilateral retinal detachments and hyperlipidemia resolved months after initiation of thyroxine supplementation. Corneal lipidosis in the untreated eye remained static.

CONCLUSIONS

Lamellar keratectomy is a viable surgical option for the treatment of arcus lipoides corneae. Hypothyroidism should be considered a differential diagnosis for spontaneous, bilateral, multifocal, and serous retinal detachments.

Persistent left cranial vena cava in a dog

A 10-year-old golden retriever was presented for the evaluation of exercise intolerance. Physical examination and laboratory tests showed no abnormalities except for mild anaemia. Standard transthoracic echocardiography revealed dilated coronary sinus, raising suspicion of a persistent left cranial vena cava, and the persistency of this anomaly was confirmed by agitated-saline study. Right ventricular echocardiographic parameters did not change significantly, while conventional parameters and global longitudinal strain analysis revealed left ventricular systolic dysfunction. Moreover, post-systolic shortening and early systolic lengthening were detected by two-dimensional speckle tracking echocardiography. This report shows that post-systolic shortening and early systolic lengthening may be useful diagnostic markers indicating regional left ventricular systolic dysfunction. Further studies are needed to elucidate whether persistent left cranial vena cava contributes to left ventricular systolic dysfunction or is an accidental benign finding in dogs.

Assessing the use of blood microRNA expression patterns for predictive diagnosis of myxomatous mitral valve disease in dogs

Background

Myxomatous mitral valve disease (MMVD) is a common, acquired, and progressive canine heart disease. The presence of heart murmur and current cardiac biomarkers are useful in MMVD cases but are not sufficiently discriminatory for staging an individual patient.

Objectives

This study aimed to conduct a preliminary assessment of canine serum and plasma expression profiles of 15 selected miRNA markers for accurate discrimination between MMVD patients and healthy controls. Additionally, we aim to evaluate the effectiveness of this method in differentiating between pre-clinical (stage B1/B2) and clinical (stage C/D) MMVD patients.

Animals

Client-owned dogs (n = 123) were recruited for the study. Following sample exclusions (n = 26), healthy controls (n = 50) and MMVD cases (n = 47) were analyzed.

Methods

A multicenter, cross-sectional, prospective investigation was conducted. MicroRNA expression profiles were compared among dogs, and these profiles were used as input for predictive modeling. This approach aimed to distinguish between healthy controls and MMVD patients, as well as to achieve a more fine-grained differentiation between pre-clinical and clinical MMVD patients.

Results

Performance metrics revealed a compelling ability of the method to differentiate healthy controls from dogs with MMVD (sensitivity 0.85; specificity 0.82; and accuracy 0.83). For the discrimination between the pre-clinical (n = 29) and clinical (n = 18) MMVD cases, the results were promising (sensitivity 0.61; specificity 0.79; and accuracy 0.73).

Conclusion and clinical importance

The use of miRNA expression profiles in combination with customized probabilistic predictive modeling shows good scope to devise a reliable diagnostic tool to distinguish healthy controls from MMVD cases (stages B1 to D). Investigation into the ability to discriminate between the pre-clinical and clinical MMVD cases using the same method yielded promising early results, which could be further enhanced with data from an increased study population.

Plasma N-terminal pro-B-type natriuretic peptide and urinary aldosterone-to-creatinine ratio in healthy Chihuahuas

BACKGROUND

Chihuahua represents an increasingly widespread breed predisposed to cardiac disease. N-terminal pro-B-type natriuretic peptide (NT-proBNP) might be a useful point-of-care biomarker for dogs suspected of having heart disease, but breed differences have been reported. The urinary aldosterone-to-creatinine ratio (UAldo: C) appears to be a good indicator of renin-angiotensin-aldosterone system activity in dogs, but Chihuahuas showed significantly higher UAldo: C than other breeds. The objective of this study was to assess preliminary breed-specific reference intervals for NT-proBNP and UAldo: C in healthy Chihuahuas and evaluate sex differences in these parameters.

RESULTS

Forty-three healthy Chihuahuas dogs were enrolled. The median NT-proBNP was 347 (125-515) pmol/L, and the median UAldo: C was 2.59 (1.57-4.61) µg/g. The NT-proBNP reference interval was 125 (90% CI 125-125) - 2121.4 (90% CI 941.6-2248) pmol/L. 91% of the Chihuahuas were below the nonbreed-specific cut-off (900 pmol/L). The UAldo: C reference interval was 0.6 (90% CI 0.5-0.9) - 16.8 (90% CI 10.9-27.4) µg/g. No significant sex differences in NT-proBNP or UAldo: C were found.

CONCLUSIONS

The median value, interindividual coefficient of variation and reference interval of NT-proBNP were in line with those reported for other small breeds. In contrast to previous studies, no sex differences in NT-proBNP were detected. As previously suggested, Chihuahuas seem to be characterized by higher values of UAldo: C than other breeds.

Glycyrrhizin intake higher than the current international guidelines has no detectable hypermineralocorticoid-like effect in dogs

Glycyrrhizin-enriched extracts from licorice root are associated with numerous health benefits and are widely used in phytotherapy. There is evidence that ingesting glycyrrhizin beyond threshold concentrations can impact the metabolism of cortisol, inhibiting its conversion to an inactive form, cortisone, via 11-hydroxysteroid dehydrogenase. A consequence can be a form of hypermineralocorticoidism, with elevated potassium excretion and associated hypertension, as demonstrated in rats and humans. Here, 3 orally dosed concentrations of glycyrrhizin (0.2, 0.4 and 0.6 mg/kg bodyweight/day) were assessed over 28 days in dogs. As the current guidelines reflect a lack of reliable data in this species, our aim was to provide relevant information for doses above the current guidelines. The specific purpose of this study was to demonstrate that an intake of licorice with a known therapeutic benefit to dogs does not cause hypermineralocorticoidism in this species. No changes in blood pressure, nor electrolyte excretion were observed in the dogs given these three glycyrrhizin concentrations.

Temporoorbital pulse rate can be obtained in ball pythons (Python regius) of any size and age and agrees with heart rate

BACKGROUND

Currently, a standardised technique to obtain pulse rate in reptiles is lacking. We evaluated the feasibility of obtaining a temporoorbital pulse rate in ball pythons of various ages and sizes and whether it agreed with the heart rate.

METHODS

Heart rate and pulse rate were recorded in 40 ball pythons (Python regius) weighing between 0.05 and 2.2 kg using a standard veterinary ultrasonic Doppler flow detector. The temporoorbital pulse rate was obtained on the dorsal aspect of the head at the level of the temporoorbital artery. Each measurement was performed in a randomised fashion by two operators, who were blinded to each other's results.

RESULTS

Pulse rate and heart rate were successfully obtained for all snakes. The median heart rate was 60 beats per minute (bpm) (range 48‒88 bpm), and the median pulse rate was 60 bpm (range 48‒88 bpm). The mean difference between the pulse rate and heart rate was 1.2 beats (95% limits of agreement: ‒10.6 to 13.0). When pulse rate and heart rate were measured at the same time, they were synchronous.

LIMITATIONS

Only healthy snakes were included.

CONCLUSIONS

Temporoorbital pulse rates can be easily obtained in ball pythons of any size. This novel method to assess peripheral pulse allows for a more complete cardiovascular evaluation in this species.

Non-invasive blood pressure measurement in conscious rabbits: A comparison of Doppler ultrasonic and oscillometric devices

BACKGROUND

This study aimed to compare Doppler (the most commonly used technique for non-invasive indirect blood pressure [NIBP] measurement in rabbits) and oscillometric devices for NIBP measurements in conscious rabbits.

METHODS

Blood pressure (BP) measurements were obtained for 49 conscious rabbits using the Doppler and oscillometric devices. Each measurement was repeated in triplicate. Three rabbits were excluded from the study because it was not possible to obtain BP measurements using the oscillometric device. The American College of Veterinary Internal Medicine (ACVIM) guidelines were followed to compare the results obtained with the two devices.

RESULTS

A total of 164 systolic BP measurements were obtained with the Doppler device and 182 were obtained with the oscillometric technique. The mean of the three values obtained for each animal with each device was used for statistical analysis. The analysis demonstrated a poor level of agreement between the measurements obtained with the two devices.

LIMITATIONS

Oscillometric devices rely on built-in software algorithms to perform calculations and produce their measurements. However, the oscillometric devices currently available only have the software for dogs and cats installed. Therefore, these conclusions should be revised when a device with software specifically for rabbits is commercialised.

CONCLUSIONS

This study indicates that oscillometric devices should not be used as a substitute for the Doppler technique when measuring BP in rabbits.

Efficacy of oral AB070597 for the management of chronic kidney disease in cats: a prospective, randomised, controlled parallel-group study

OBJECTIVES

It has been reported that AB070597, which contains amino acids and peptides, may prevent the progression of chronic kidney disease (CKD) in cats. The aim of this study was to evaluate the effect of AB070597 on CKD in International Renal Interest Society (IRIS) stage 2 or 3 cats compared with a placebo.

METHODS

A prospective, randomised, controlled parallel-group study was conducted on 35 cats with CKD. The cats were randomly allocated to receive 300 mg of AB070597 or placebo for 180 days, and cats were re-examined every 30 days. Changes in the results were compared from baseline to endpoint in each group, and the efficacy of AB070597 in cats with CKD was assessed.

RESULTS

A total of 35 cats met the inclusion criteria, of which 20 received AB070597 and 15 received a placebo. Blood urea nitrogen (BUN), creatinine (Cre) and phosphorus levels increased significantly in the placebo group at 180 days compared with those at baseline, 30 days and 60 days, whereas these values were not significantly changed in the AB070597 group during the study period. The IRIS stage was also stable in cats with AB070597 from the baseline to the end of the study, whereas the IRIS stage progressed from stage 2 to stage 3 in 26% of cats with placebo. Body weight did not change significantly in either group.

CONCLUSIONS AND RELEVANCE

The administration of AB070597 in cats with CKD may be effective in preventing CKD progression.

Agreement of Doppler Ultrasound and Visual Sphygmomanometer Needle Oscillation with Invasive Blood Pressure in Anaesthetised Dogs

Visual sphygmomanometer needle oscillation (SNO) can occur before audible return of pulsatile flow (ARPF) when measuring blood pressure by Doppler ultrasound. The aim was to assess the agreement of SNO and ARPF with invasive blood pressure (iABP) in a clinical population of anaesthetised dogs. A total of 35 dogs undergoing surgery in dorsal recumbency necessitating arterial cannulation were included. Paired measurements of iABP and SNO, and iABP and ARPF, were collected. The agreement of non-invasive blood pressure (NIBP) and iABP measurements was analysed with concordance correlation coefficients (CCCs) and Bland-Altman plots. The proportions of SNO and ARPF measurements between 10 and 20 mmHg of iABP were compared. Both SNO and ARPF demonstrated greater agreement with invasive systolic (iSAP) than invasive mean (iMAP) pressures, and SNO demonstrated greater agreement with iSAP than ARPF measurements. The mean differences (95% limits of agreement) for SNO and APRF were -9.7 mmHg (-51.3-31.9) and -13.1 mmHg (-62.2-35.9), respectively. The CCC (95% CI) for SNO was 0.5 (0.36-0.64) and ARPF was 0.4 (0.26-0.54). A significantly greater proportion of SNO measurements were within 20 mmHg of iSAP compared to ARPF. Both NIBP techniques performed more poorly than veterinary consensus recommendations for device validation. Caution should be used clinically when interpreting values obtained by Doppler ultrasound in anaesthetised dogs.

Prevalence of Hypertrophic Cardiomyopathy and ALMS1 Variant in Sphynx Cats in New Zealand

Recently, hypertrophic cardiomyopathy (HCM) in Sphynx cats has been associated with a variant in the gene encoding Alström syndrome protein 1 (ALMS1). The primary aims of this study were to describe the prevalence of HCM in Sphynx cats in New Zealand, and to assess the association between HCM and the ALMS1 variant in this population. In this prospective study, 55 apparently healthy Sphynx cats from registered Sphynx breeders and pet owners in New Zealand were screened by a cardiologist. A total of 42 of these cats had a repeat cardiac examination after median 1.8 years (range: 1.6-2.2). The frequency of the ALMS1 variant was 70.9% (11 homozygous and 28 heterozygous). At the median age of 5.8 years (range: 2.4-13.1), the prevalence of HCM was 40% (20 out of 55 cats). Three cats with HCM died during the study with congestive heart failure. All three cats had focal but extensive myocardial ischemia or infarction at necropsy. The ALMS1 variant was not associated with the HCM diagnosis. In summary, HCM was common in the studied cohort, suggesting Sphynx cats are predisposed to this disease. While the ALMS1 variant was also frequently detected, it was not associated with HCM in this population.

Preclinical modeling of metabolic syndrome to study the pleiotropic effects of novel antidiabetic therapy independent of obesity

Cardiovascular-kidney-metabolic health reflects the interactions between metabolic risk factors, chronic kidney disease, and the cardiovascular system. A growing body of literature suggests that metabolic syndrome (MetS) in individuals of normal weight is associated with a high prevalence of cardiovascular diseases and an increased mortality. The aim of this study was to establish a non-invasive preclinical model of MetS in support of future research focusing on the effects of novel antidiabetic therapies beyond glucose reduction, independent of obesity. Eighteen healthy adult Beagle dogs were fed an isocaloric Western diet (WD) for ten weeks. Biospecimens were collected at baseline (BAS1) and after ten weeks of WD feeding (BAS2) for measurement of blood pressure (BP), serum chemistry, lipoprotein profiling, blood glucose, glucagon, insulin secretion, NT-proBNP, angiotensins, oxidative stress biomarkers, serum, urine, and fecal metabolomics. Differences between BAS1 and BAS2 were analyzed using non-parametric Wilcoxon signed-rank testing. The isocaloric WD model induced significant variations in several markers of MetS, including elevated BP, increased glucose concentrations, and reduced HDL-cholesterol. It also caused an increase in circulating NT-proBNP levels, a decrease in serum bicarbonate, and significant changes in general metabolism, lipids, and biogenic amines. Short-term, isocaloric feeding with a WD in dogs replicated key biological features of MetS while also causing low-grade metabolic acidosis and elevating natriuretic peptides. These findings support the use of the WD canine model for studying the metabolic effects of new antidiabetic therapies independent of obesity.

Effects of Telmisartan on Intraocular Pressure, Blood Pressure, and Ocular Perfusion Pressure in Normal and Glaucomatous Cats

Purpose

To determine the effect of telmisartan on intraocular pressure (IOP), blood pressure (BP), and ocular perfusion pressure (OPP) in normal and glaucomatous cats.

Methods

A four-week study was conducted in six normal adult cats, followed by a longer six-month study performed in 37 cats with spontaneous glaucoma and 11 age-matched normal cats. Telmisartan (1 mg/kg/day) or placebo-vehicle were administered orally once daily. IOP was measured by rebound tonometry. BP readings were obtained by oscillometric method. OPP was calculated as mean arterial pressure (MAP) - IOP. IOP and BP were obtained three times a week for the first study and weekly for the second study.

Results

Baseline IOP was significantly higher, and OPP was significantly lower in glaucomatous cats than in normal cats (P < 0.0001). These differences between glaucomatous and normal cats persisted throughout the study, regardless of treatment (P < 0.001). No significant differences in IOP, BP, or OPP were detected between any study phases in the first, normal feline cohort or between telmisartan- and placebo-treated glaucomatous cats at any timepoint in the second study.

Conclusions

Oral telmisartan was well tolerated and did not have a detrimental effect on BP or OPP in cats but did not lower IOP or improve OPP in cats with glaucoma.

Translational Relevance

While showing telmisartan could not be used as a sole therapy for IOP lowering, our data affirmed a lack of detrimental effects of telmisartan on BP and OPP in a translationally-relevant, spontaneous, large animal glaucoma model.