Left ventricular eccentricity index to assess precapillary pulmonary hypertension in dogs.

INTRODUCTION: Interventricular septal flattening, frequently present in pulmonary hypertension (PH) can be quantified by the left ventricular eccentricity index (EI) measured at end-diastole (EId), end-systole (EIs) and at maximal septal flattening (EIm). In humans, EI correlates with invasive pulmonary arterial pressure. The aim of this study was to evaluate if EI correlates with parameters of right heart remodeling (RHR) and if EI is a quantitative marker of PH in dogs. MATERIALS AND METHODS: Left ventricular eccentricity indices were retrospectively measured in four groups (no, mild, moderate and severe PH) with interpretable tricuspid and/or pulmonary regurgitation. RESULTS: Ninety-seven dogs were included, with no (n = 29), mild (n = 13), moderate (n = 25) and severe (n = 30) PH. The intra- and inter-observer variability for EI measurements ranged from 2 % to 11 %. All EI were significantly elevated in severe compared to no, mild and moderate PH (P < 0.0005). In the moderate group, EIs and EIm were higher compared to the no PH group (P < 0.01). Tricuspid and pulmonary regurgitation pressure gradients and RHR parameters correlated with EId, EIs and EIm in all groups. Optimal cut-off values discriminating moderate and severe PH from no and mild PH were 1.24 (Sensitivity (Se) 60 %; Specificity (Sp) 90 %) for EId, 1.34 (Se 67 %; Sp 95 %) for EIs and 1.37 (Se 76 %; Sp 83 %) for EIm. CONCLUSIONS: Left ventricular eccentricity indices are reproducible echocardiographic variables increasing with severity of PH. Dogs with moderate and severe PH can be discriminated from dogs with no or mild PH using EIs and EIm.

Caudal vena cava point-of-care ultrasound in dogs with degenerative mitral valve disease without clinically important right heart disease.

OBJECTIVES: Caudal vena cava (CVC) diameter and collapsibility index (CVCD and CVCCI) have been used to assess intravascular volume status (IVS). Maladaptations with progressive degenerative mitral valve disease (DMVD) lead to hypervolemia. We hypothesised that stages of DMVD will affect ultrasonographic CVC variables in dogs without clinically important right heart disease. ANIMALS, MATERIALS AND METHODS: This retrospective study included 79 dogs with DMVD presented to the cardiology department between January 2017 and 2019. Subxiphoid views were used to obtain CVC cineloops. By visual inspection, CVC was subjectively scored as flat, normal or fat. Maximal and minimal CVCD were measured and indexed to aortic diameter (CVCD-max/Ao and CVCD-min/Ao); CVCCI was calculated as (CVCD-max-CVCD-min)/CVCD-max. Fisher's exact and Kruskal-Wallis tests were used to compare CVC variables. RESULTS: Subjective assessment was associated with American College of Veterinary Internal Medicine (ACVIM) stages (P < 0.001). The proportion of fat CVC was greater in stages C and D. In stage D, CVCD-max/Ao was larger compared with stages B1, B2 and C (P = 0.002, P = 0.002 and P = 0.035, respectively). In stages C and D, CVCD-min/Ao was larger compared with B1 (P = 0.016 and P = 0.001) and B2 (P = 0.002 and P < 0.001. In stages C and D, CVCCI was less than stage B1 (P = 0.016 and P = 0.044) and B2 (P = 0.001 and P = 0.010). CONCLUSIONS: In dogs with DMVD without clinically important right heart disease, CVC variables differ across ACVIM stage. Subjective and objective CVC variables may be used to predict hypervolemia.

Effect of thyroxine supplementation on glomerular filtration rate in hypothyroid dogs.

BACKGROUND: Glomerular filtration rate (GFR) is decreased in humans with hypothyroidism, but information about kidney function in dogs with hypothyroidism is lacking. HYPOTHESIS: Hypothyroidism influences GFR in dogs. The objective of this study was to assess GFR in hypothyroid dogs before implementation of thyroxine supplementation and after re-establishing euthyroidism. ANIMALS: Fourteen hypothyroid dogs without abnormalities on renal ultrasound examination or urinalysis. METHODS: Blood pressure and GFR (measured by exogenous creatinine clearance) were measured before treatment (T0, n=14) and at 1 month (T1, n=14) and at 6 months (T6, n=11) after beginning levothyroxine supplementation therapy (20 microg/kg/d, PO). The response to therapy was monitored at T1 by measuring serum total thyroxine and thyroid stimulating hormone concentrations. If needed, levothyroxine dosage was adjusted and reassessed after 1 month. Statistical analysis was performed using a general linear model. Results are expressed as mean+/-standard deviation. RESULTS: At T0, the average age of dogs in the study group was 6.3+/-1.4 years. Their average body weight decreased from 35+/-18 kg at T0 to 27+/-14 kg at T6 (P<.05). All dogs remained normotensive throughout the study. GFR increased significantly with levothyroxine supplementation; the corresponding results were 1.6+/-0.4 mL/min/kg at T0, 2.1+/-0.4 at T1, and 2.0+/-0.4 at T6 (P<.01). CONCLUSION: GFR was <2 mL/min/kg in untreated hypothyroid dogs. Re-establishment of a euthyroid state increased GFR significantly.

Clinical evaluation of a novel liquid formulation of L-thyroxine for once daily treatment of dogs with hypothyroidism.

BACKGROUND: A liquid solution of levothyroxine (L-T4) is available for treatment of canine hypothyroidism. HYPOTHESIS: Once daily oral administration of a liquid L-T4 solution is effective and safe for controlling hypothyroidism in dogs. ANIMALS: Thirty-five dogs with naturally occurring hypothyroidism. METHODS: Dogs received L-T4 solution PO once daily at a starting dosage of 20 microg/kg body weight (BW). The dose was adjusted every 4 weeks, based on clinical signs and peak serum total T4 (tT4) concentrations. Target peak serum tT4 and thyroid stimulating hormone (TSH) concentrations, 4-6 hours posttreatment, were 35-95 nmol/L and < 0.68 ng/mL, respectively. Dogs were followed for up to 22 weeks after establishment of the maintenance dose. RESULTS: Clinical signs of hypothyroidism improved or resolved in 91% of dogs after 4 weeks of L-T4 treatment at 20 microg/kg once daily. The maintenance dose was established in 76, 94, and 100% of dogs after 4, 8, and 12 weeks of treatment, respectively. This was 20 microg L-T4/kg BW for 79% of the dogs, 30 microg/kg BW for 15%, and 10-15 microg/kg BW in the remaining 6%, once daily. Thereafter, median peak tT4 and TSH concentrations were 51 nmol/L and 0.18 ng/mL, respectively, and remained stable during the 22-week follow-up; clinical signs did not recur. CONCLUSIONS AND CLINICAL IMPORTANCE: All of the hypothyroid dogs had rapid clinical and hormonal responses to supplementation with the PO-administered L-T4 solution. The starting dosage of 20 microg L-T4/kg BW once daily was suitable for 79% of dogs.

CSF omeprazole concentration and albumin quotient following high dose intravenous omeprazole in dogs.

Clinical signs of syringomyelia and hydrocephalus occur secondary to cerebrospinal fluid (CSF) accumulation within the central nervous system. Omeprazole is recommended to treat these conditions despite little evidence of its capacity to decrease CSF production in the dog. Studies into new treatments are hampered by difficulties in measuring CSF production. The albumin quotient (QAlb), the ratio between CSF and serum albumin concentrations, may reflect CSF production and any decrease in CSF production should be associated with an increase in QAlb. The primary objective of this study was to determine CSF omeprazole concentration after administration of a high intravenous dose of omeprazole and to evaluate its impact on QAlb in the dog. The second aim was to validate QAlb as a surrogate marker of CSF production. Eighteen dogs were included in this prospective crossover placebo-controlled study. Each dog received omeprazole (10 mg/kg), acetazolamide (50 mg/kg) combined with furosemide (1 mg/kg) and saline. Blood and CSF samples were obtained on day 0 and then every 7 days, one hour after drug administration. Omeprazole concentrations (2.0 ±â€¯0.4 µmol/L) reached in CSF after high dose omeprazole were lower than the concentrations previously described as decreasing CSF production in dogs. There was no significant increase in QAlb following administration of acetazolamide/furosemide, prohibiting validation of QAlb as a surrogate marker for CSF production. Several dogs presented transient mild side effects after injection of acetazolamide/furosemide. High dose omeprazole was well tolerated in all dogs.

Effect of clinical signs, endocrinopathies, timing of surgery, hyperlipidemia, and hyperbilirubinemia on outcome in dogs with gallbladder mucocele.

Gallbladder mucocele (GBM) is a common extra-hepatic biliary syndrome in dogs with death rates ranging from 7 to 45%. Therefore, the aim of this study was to identify the association of survival with variables that could be utilized to improve clinical decisions. A total of 1194 dogs with a gross and histopathological diagnosis of GBM were included from 41 veterinary referral hospitals in this retrospective study. Dogs with GBM that demonstrated abnormal clinical signs had significantly greater odds of death than subclinical dogs in a univariable analysis (OR, 4.2; 95% CI, 2.14-8.23; P<0.001). The multivariable model indicated that categorical variables including owner recognition of jaundice (OR, 2.12; 95% CI, 1.19-3.77; P=0.011), concurrent hyperadrenocorticism (OR 1.94; 95% CI, 1.08-3.47; P=0.026), and Pomeranian breed (OR, 2.46; 95% CI 1.10-5.50; P=0.029) were associated with increased odds of death, and vomiting was associated with decreased odds of death (OR, 0.48; 95% CI, 0.30-0.72; P=0.001). Continuous variables in the multivariable model, total serum/plasma bilirubin concentration (OR, 1.03; 95% CI, 1.01-1.04; P<0.001) and age (OR, 1.17; 95% CI, 1.08-1.26; P<0.001), were associated with increased odds of death. The clinical utility of total serum/plasma bilirubin concentration as a biomarker to predict death was poor with a sensitivity of 0.61 (95% CI, 0.54-0.69) and a specificity of 0.63 (95% CI, 0.59-0.66). This study identified several prognostic variables in dogs with GBM including total serum/plasma bilirubin concentration, age, clinical signs, concurrent hyperadrenocorticism, and the Pomeranian breed. The presence of hypothyroidism or diabetes mellitus did not impact outcome in this study.

Investigation of physiologic leukopenia in Belgian Tervuren dogs.

BACKGROUND: Physiologic leukopenia in Tervuren dogs was reported in North America with a higher frequency in aged Tervurens. If not recognized, physiologic leukopenia can provoke unnecessary clinical investigations. HYPOTHESIS: The primary objective was to compare Tervurens and control dogs in Belgium with respect to the numbers of dogs with physiologic leukopenia. The secondary objectives were to compare Tervurens with control dogs and age classes within Tervurens and controls for parameters related to physiologic leukopenia. ANIMALS: Tervurens (n = 94) and control dogs (n = 48, maximum of 5 dogs per breed and 5 mixed breed dogs) were entered into the study. Dogs were 1-11 years old and healthy on routine physical examination. Dogs had no history of disease or drug administration in the previous 2 months. METHODS: Hematologic analyses were performed by an automated device within 30 hours of sampling. Blood smears were evaluated for cellular morphologic anomalies. RESULTS: Only 1 of the 94 Tervuren dogs had physiologic leukopenia (1.06%; 95% confidence interval, 0.05-5.22). Furthermore, the white blood cell (WBC) count in Tervuren dogs (median, 10.00 x 109/L; range, 5.90-20.80) was not significantly different (P = .55) from that of control dogs (median, 9.75 x 109/L; range, 5.20-20.90). The WBC count decreased significantly (P < .001) with age in Tervuren dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: Physiologic leukopenia is uncommon in the Belgian Tervuren dog. Differences with earlier data published in North America might be due to genetic or environmental differences.

Axillary temperature measurement: a less stressful alternative for hospitalised cats?

Rectal temperature measurement (RTM) can promote stress and defensive behaviour in hospitalised cats. The aim of this study was to assess if axillary temperature measurement (ATM) could be a reliable and less stressful alternative for these animals. In this prospective study, paired rectal and axillary temperatures were measured in 42 cats, either by a veterinarian or a student. To assess the impact of these procedures on the cat's stress state, their heart rate was checked and a cat stress score (CSS) was defined and graded from 1 (relaxed) to 5 (terrified). A moderate correlation was found between RTM and ATM (r=0.52; P<0.0001). RTM was on average 0.9 °C (1.6 °F) higher than ATM (P<0.0001), although a wide variation was found in the difference between these two measurements (-2.1 °C to 3.6 °C (-3.8 °F to 6.5 °F)). ATM failed to identify hypothermia in 25 per cent of the cases and hyperthermia in 19 per cent of the cases but may be considered less stressful than RTM. Indeed, RTM induced a mildly greater increase in heart rate (+6 bpm; P=0.01) and in CSS (+0.2; P=0.001) than ATM. The results were not affected by operator type. In conclusion, RTM should remain the standard method to obtain accurate temperatures in cats.

Evaluation of the effect of oral omeprazole on canine cerebrospinal fluid production: A pilot study.

Administration of omeprazole by ventriculo-cisternal perfusion or intravenously has been shown to decrease cerebrospinal fluid (CSF) production in dogs and rabbits. Oral omeprazole has consequently been recommended to reduce CSF production in dogs with conditions in which clinical signs may be attributable to an accumulation of CSF in the central nervous system (e.g. hydrocephalus, syringomyelia). The albumin quotient (QAlb), the ratio between CSF and serum albumin concentration, has been proposed as a reliable means to evaluate CSF production; decreasing CSF production should cause an increase in QAlb. The aims of this study were to assess the effect of oral administration of omeprazole on QAlb in dogs and to compare two methods to assess CSF albumin concentration. Fifteen healthy Beagle dogs received omeprazole (1.2 mg/kg/day) orally for 14 days; CSF and blood were obtained before and after treatment. CSF albumin concentrations were evaluated by nephelometry and high-resolution protein electrophoresis. Regardless of the method used for measuring albumin, QAlb did not change significantly following oral omeprazole administration, suggesting that CSF production in healthy dogs may not be affected by chronic oral therapy with omeprazole.

Species comparison of oral bioavailability, first-pass metabolism and pharmacokinetics of acetaminophen.

Species differences in oral bioavailability, first-pass metabolism and pharmacokinetics of biopharmaceutics classification system (BCS) class I compound acetaminophen were studied. The absolute bioavailability was 42.2%, 39.0%, 44.5%, 75.5% and 91.0% in chickens, turkeys, dogs, pigs and horses, respectively. After hydrolysis of metabolites by beta-glucuronidase/sulfatase, apparent bioavailability increased significantly in all species (turkeys: 72.4%, dogs: 100.5%, pigs: 102.2%), except horses (91.6%). Mean metabolic ratios of [acetaminophen glucuronide]/[acetaminophen] between 0 and 1h were significantly higher after oral dosing in turkeys, dogs and pigs, revealing the role of first-pass metabolism in incomplete bioavailability. Evidence of species differences in acetaminophen metabolism is provided by differences in plasma clearance, which was inversely proportional to bioavailability. In conclusion, differences in BA appeared to originate predominantly from differences in first-pass metabolism, demonstrating that the BCS high permeability classification of acetaminophen is consistent across the mammalian species studied. In turkeys, however, incomplete absorption additionally seemed to contribute to the low BA.