The effect of obesity and subsequent weight reduction on cardiac structure and function in dogs.

BACKGROUND: In people, the cardiovascular effects of obesity include systemic hypertension, cardiac remodelling and both systolic and diastolic dysfunction, whilst weight reduction can reverse myocardial remodelling and reduce risk of subsequent cardiovascular disease. To date, variable results are reported in studies of the effect of obesity and controlled weight reduction on cardiovascular morphology and function in dogs. This prospective study aimed to assess cardiac function, heart rate variability, cardiac biomarkers and body composition before and after weight reduction in pet dogs with obesity. Twenty-four client-owned dogs referred for weight management due to obesity were recruited. To assess the cardiac effects of obesity, body composition analysis (by dual energy X-ray absorptiometry, DEXA) and cardiovascular assessment (echocardiography, Doppler blood pressure, electrocardiography, cardiac biomarkers) were performed prior to weight management. Twelve dogs completed the study and reached target weight, receiving a further cardiovascular assessment and DEXA. A Wilcoxon-signed rank test was used to compare each variable pre- and post- weight reduction. RESULTS: Median (interquartile range) duration of weight loss was 224 days (124-245 days), percentage weight loss was 23% (18-31%) of starting weight. Median change in body fat mass was -50% (-44% to -55%; P = 0.004), whilst median change in lean mass was -7% (+ 1% to -18%, P = 0.083). Before weight reduction, diastolic dysfunction (evidence of impaired relaxation in all dogs), increased left ventricular wall thickness and mildly elevated systolic blood pressure (14/24 ≥ 160 mmHg, median 165 mmHg (140-183)) were common features in dogs with obesity. However, systolic left ventricular wall dimensions were the only variables that changed after weight reduction, with a decrease in both the systolic interventricular septum (P = 0.029) and systolic left ventricular free wall (P = 0.017). There was no evidence of decreased heart rate variability in dogs with obesity (P = 0.367), and no change in cardiac biomarker concentrations with weight reduction (N-terminal proBNP, P = 0.262; cardiac troponin I P = 0.657). CONCLUSIONS: Canine obesity results in diastolic dysfunction and left ventricular hypertrophy, the latter of which improves with significant weight and fat mass reduction. Further studies are required to clarify the clinical consequences of these findings.

Analysis of canine cardiovascular therapeutic agent prescriptions using electronic health records in primary care veterinary practices in the United Kingdom.

INTRODUCTION/OBJECTIVES: Canine cardiovascular (CV) diseases are often managed in primary care settings. The objectives were to describe CV therapeutic agent (CVTA) prescribing patterns in primary care practices in the United Kingdom (UK) and to evaluate recorded clinical signs, diagnostic tests and justifications for use of torasemide, a recently marketed and authorised loop-diuretic in the UK. ANIMALS, MATERIALS AND METHODS: Electronic health records (EHRs) describing 3,579,420 consultations (1,043,042 unique dogs) were collated (1 April 2014 and 31 December 2018) by the Small Animal Veterinary Surveillance Network from 270 veterinary practices. Consultations prescribing at least one CVTA were identified. Annual variation in individual CVTA prescriptions was analysed using mixed-effects binomial regression models. Free-text clinical narratives were manually read to determine the first-prescribing event for torasemide. RESULTS: Twenty-nine thousand and seven consultations (0.81% of all consultations, 95% confidence interval [CI], 0.76-0.86) prescribed CVTA in 14,148 (1.36%) dogs. Furosemide (52.8% of CV-prescribing consultations, 95% CI 50.7-54.9) and pimobendan (51.9%, 95% CI 50.1-53.7) were most prescribed. Longitudinal analysis (2014-2018) showed a significant negative temporal trend for angiotensin-converting enzyme inhibitors (p < 0.001), and furosemide (p = 0.003) and a positive temporal trend for pimobendan (p = 0.020) and torasemide (p < 0.001). First prescriptions of torasemide were identified in 16.5% of torasemide-prescribing consultations. Where justification for prescription of torasemide was identified (32.5%), furosemide resistance was the most common (92.0%). CONCLUSIONS: EHRs can be used to temporally monitor prescribing habits, including responses to market authorisations. Despite authorisation in the UK for torasemide use as a first-line diuretic, it was most commonly prescribed after furosemide resistance.

Low plasma taurine levels in English cocker spaniels diagnosed with dilated cardiomyopathy.

OBJECTIVES: The aims of this study were to evaluate taurine levels in English cocker spaniels with dilated cardiomyopathy and assess their survival time and natural progression of their disease. MATERIALS AND METHODS: Retrospective comparison of English cocker spaniels with dilated cardiomyopathy phenotype with and without taurine deficiency at the cardiology department of a UK academic referral centre between 2008 and 2018. RESULTS: Taurine plasma concentration was available in 16 English cocker spaniels with dilated cardiomyopathy phenotype; 13 of 16 had congestive heart failure and three of 16 did not. Taurine concentration was low (<50 µmol/L) in 13 of 16 and normal in three of 16. Deficient dogs received taurine supplementation in addition to conventional cardiac medications. Eight dogs were still alive at the end of this study and eight were dead. MST for all dogs included in the study was 2800 days. Left ventricular systolic function improved and left ventricular dimensions reduced in English cocker spaniels with taurine deficiency following taurine supplementation and conventional cardiac therapy, although similar results were observed in English cocker spaniels with normal taurine concentration on cardiac therapy alone. CLINICAL SIGNIFICANCE: Based on laboratory reference intervals, low taurine concentrations were common in English cocker spaniels with dilated cardiomyopathy, showing a possible association between dilated cardiomyopathy in English cocker spaniels and taurine deficiency; supplementation with taurine was not curative.

Immunohistochemical differentiation of reactive from malignant mesothelium as a diagnostic aid in canine pericardial disease.

OBJECTIVES: To develop a provisional immunohistochemistry panel for distinguishing reactive pericardium, atypical mesothelial proliferation and mesothelioma in dogs. MATERIALS AND METHODS: Archived pericardial biopsies were subject to haematoxylin and eosin staining, immunohistochemistry for cytokeratin, vimentin, insulin-like growth factor II mRNA-binding protein 3, glucose transporter 1 and desmin. Samples were scored for intensity and number of cells stained. RESULTS: Ten biopsies of reactive mesothelium, 17 of atypical mesothelial proliferation, 26 of mesothelioma and five of normal pericardium were identified on the basis of haematoxylin and eosin staining. Cytokeratin and vimentin were expressed in all biopsies, confirming mesothelial origin. Normal pericardial samples had the lowest scores for insulin-like growth factor II mRNA-binding protein 3, glucose transporter 1 and desmin. Mesothelioma and atypical proliferative samples were similar to each other, with higher scores for insulin-like growth factor II mRNA-binding protein 3 and glucose transporter 1 than the reactive samples. Desmin staining was variable. Insulin-like growth factor II mRNA-binding protein 3 was the best to distinguish between disease groups. CLINICAL SIGNIFICANCE: An immunohistochemistry panel of cytokeratin, vimentin, insulin-like growth factor II mRNA-binding protein 3 and glucose transporter 1 could provide superior information compared with haematoxylin and eosin staining alone in the diagnosis of cases of mesothelial proliferation in canine pericardium, but further validation is warranted.