Effect of pimobendan on physical fitness, lactate and echocardiographic parameters in dogs with preclinical mitral valve disease without cardiomegaly

Evaluation of bioequivalence of pimobendan oral solution and pimobendan oral capsules in healthy Beagle dogs

INTRODUCTION/OBJECTIVES

This study aimed to determine the pharmacokinetics and bioequivalence of pimobendan administered as the originator reference product Vetmedin® pimobendan 5-mg capsules and a newly developed liquid formulation Vetmedin® pimobendan 1.5-mg/mL oral solution.

ANIMALS

Pharmacokinetic profiles were investigated in 12 male and 12 female adult Beagle dogs.

MATERIALS AND METHODS

The study was a randomized, four-period, two-sequence, full-replicate crossover design with maximum concentration (Cmax) and area under the plasma concentration-time curve to last sampling time (AUC0→last) used as pivotal bioequivalence parameters. For each treatment period, all animals were treated with a single dose of 5 mg/animal pimobendan, resulting in a dose of 0.33 mg/kg to 0.56 mg/kg. For each administration period, one predose and 15 postdose blood samples were taken over a period of 12 h. Plasma samples were analyzed for concentrations of pimobendan and the active metabolite O-desmethyl pimobendan.

RESULTS

Both formulations were well tolerated. Bioequivalence of the test product pimobendan 1.5-mg/mL oral solution with the reference product pimobendan 5-mg capsules was demonstrated for both the parent compound pimobendan and the metabolite O-desmethyl pimobendan since the 90% confidence intervals of the ratios of Cmax and AUC0→last were entirely contained within the range of 0.8-1.25.

STUDY LIMITATIONS

The study was performed according to international guidelines with healthy dogs specifically bred for experimental purposes. Comparable data for client-own dogs are not available.

CONCLUSION

The new Vetmedin® pimobendan 1.5-mg/mL oral solution is a bioequivalent pharmaceutical preparation that is expected to improve dosing accuracy and compliance, especially in toy breed and small dogs.

Pimobendan oral solution is bioequivalent to pimobendan chewable tablets in beagle dogs

BACKGROUND

Myxomatous mitral valve disease (MMVD) is frequently diagnosed in small breed dogs. Pimobendan oral solution has been developed to improve dosing accuracy in small and toy breed dogs.

HYPOTHESIS/OBJECTIVES

Demonstrate bioequivalence of pimobendan oral solution with pimobendan chewable tablets using a pharmacokinetic and a pharmacodynamic study in healthy purpose bred dogs.

ANIMALS

In the pharmacokinetic study, 24 beagle dogs were dosed in a 4-period crossover design. In the pharmacodynamic study, 4 mongrel and 2 beagle dogs implanted with telemetry probes were included in a 2-way crossover design.

METHODS

Both studies were designed as prospective, randomized crossover trials. Dogs were given single doses of 5 mg/dog of either formulation followed by serial blood sampling for determination of pimobendan and O-desmethyl-pimobendan (ODMP; main metabolite). Because of high variability in the pharmacokinetics, the reference scaled average bioequivalence (RSABE) method was applied. For the pharmacodynamic study, animals were dosed with 0.25 mg/kg of either formulation. Baseline corrected left ventricular maximal pressure (LVdP/dtmax) and heart rate were recorded continuously and compared with a predefined bioequivalence threshold.

RESULTS

Pimobendan was verified as a high variability drug. Based on the RSABE method, both formulations were bioequivalent. Pharmacodynamic results supported bioequivalence.

CONCLUSIONS AND CLINICAL IMPORTANCE

The novel oral solution of pimobendan was found to be bioequivalent, both applying the Food and Drug Administration (FDA) supported RSABE method and based on pharmacodynamic data. Thus, the novel liquid formulation can be used to facilitate accurate dosing of small and toy breed dogs.

The standards of reporting trials in pets (PetSORT): Explanation and elaboration

Well-designed randomized controlled trials (RCTs) provide the best evidence of the primary research designs for evaluating the effectiveness of interventions. However, if RCTs are incompletely reported, the methodological rigor with which they were conducted cannot be reliably evaluated and it may not be possible to replicate the intervention. Missing information also may limit the reader's ability to evaluate the external validity of a trial. Reporting guidelines are available for clinical trials in human healthcare (CONSORT), livestock populations (REFLECT), and preclinical experimental research involving animals (ARRIVE 2.0). The PetSORT guidelines complement these existing guidelines, providing recommendations for reporting controlled trials in pet dogs and cats. The rationale and scientific background are explained for each of the 25 items in the PetSORT reporting recommendations checklist, with examples from well-reported trials.

Hemodynamic effect of pimobendan following intramuscular and intravenous administration in healthy dogs: A pilot study

Background

Pimobendan is widely used for the treatment of dogs with heart failure via the oral route. A new injectable form of pimobendan is now available and its potential usefulness via intravenous route has been recently demonstrated in dogs. However, the cardiovascular effects of intramuscular (IM) administration of injectable pimobendan have not been investigated yet.

Hypothesis

IM administration of pimobendan may have the same hemodynamic effect as the IV route.

Methods

Six healthy Beagle dogs underwent a placebo-controlled double-blind crossover study. The early cardiovascular effects after a single dose of IM and IV injections of pimobendan (0.2 ml/kg; Pimo IM and Pimo IV, respectively) were compared to the same volume of IM placebo (Saline IM) in anesthetized dogs. Clinical [heart rate (HR) and blood pressure (BP)] and echocardiographic hemodynamic parameters [left ventricular (LV) inflow waveforms of diastolic early wave (eV), atrial systolic wave (aV), diastolic early mitral ring velocity (e′), peak velocity (pV), stroke volume (SV), cardiac output (CO), and systemic vascular resistance (SVR)] were monitored with 15 min intervals for 120 min.

Results

Diastolic BP decreased significantly at 30 min in Pimo IM compared to Saline IM. Mean eV and CO values significantly increased from 75 min, e′ from 60 min, pV from 75 min, and SV from 15 to 120 min, whereas SVR significantly decreased at 30–60 min in Pimo IM compared to those of Saline IM (P < 0.05). Compared with the Pimo IV, eV and pV were significantly lower at 30–60 min (P < 0.05) while SV was significantly higher at 90–105 min in Pimo IM (P < 0.05). Other hemodynamic parameters (BP, HR, SVR, CO, e′, and E/e′) did not significantly change between Pimo IM and IV.

Conclusions

The hemodynamic effect of pimobendan following IM and IV injection was described. Our results suggested that IM administration of pimobendan is equally comparable and possibly interchangeable with IV administration. This warrant further studies to investigate the clinical effectiveness of IM pimobendan in treating dogs with congestive heart failure or in heart failure cases unable to receive IV or oral administration.

Evaluation of a Treadmill-Based Submaximal Fitness Test in Pugs, and Collecting Breed-Specific Information on Brachycephalic Obstructive Airway Syndrome

Simple Summary

In the present study, a submaximal fitness test on a treadmill was evaluated to assess its feasibility under standardised conditions. Moreover, its effectiveness in identifying pugs with clinical signs of brachycephalic obstructive airway syndrome was examined. It was apparent that respiratory symptoms can be exposed during the fitness test, and intensified with an increased duration of exercise. This method of testing improves the clinical evaluation of the dogs and helps identify restrictions due to brachycephalic obstructive airway syndrome. Since most of the dogs could be familiarised with the treadmill, it may be a feasible option for performing fitness tests in brachycephalic dogs. Major benefits, therefore, are that each dog can be closely monitored during the entire process, and that the examination can be conducted under standardised conditions.

Abstract

Despite efforts of veterinarians and breeders, brachycephalic obstructive airway syndrome (BOAS) is still a common problem in pugs, underlining the need for objective tests to identify and prevent breeding with affected dogs. In the current study, a submaximal, treadmill-based fitness test was evaluated as a tool to identify signs of airway obstruction not recognisable under rest conditions. In addition to this, different body conformation and measurements were assessed regarding their association with BOAS. A total of 62 pugs and 10 mesocephalic dogs trotted with an individual comfort speed on a treadmill for 15 min. Before and during the examination, dogs were examined for signs of respiratory distress, and a functional BOAS grading was applied. The influence of body conformation on BOAS grading was tested in a univariable and multivariable logistic regression model. During exercise, more respiratory noises were observed, and existing respiratory noises became more apparent in comparison to when at rest. In the multivariable logistic regression model, no factor had a statistically significant influence on BOAS classification. Submaximal fitness testing helped to identify signs of respiratory distress not apparent under resting conditions, and could be a valuable addition for identifying dogs with BOAS. Performing testing on a treadmill facilitates continuous observation of the patients, and enables standardisation of the test regarding the test environment, as well as provides an uninterrupted, steady workload.

Assessment of Right Ventricular Function, Blood Lactate Levels, and Serum Peptidomics Profiles Associated With Mitral Valve Disease in Dogs

Background

Degenerative mitral valve disease is a common heart problem in dogs. The aims are to evaluate the relationships between right and left ventricular function, and blood lactate concentrations, assess prognostic contribution, and investigate whether serum peptidomics profile could reveal markers or determine the stage in dogs with valve degeneration.

Materials and Methods

Ninety-three dogs were evaluated in this study. Thirty-nine dogs' serum was collected and analyzed using matrix-assisted laser desorption/ionization-time of flight mass spectrometry. The Kaplan–Meier curve was used to predict the outcomes of mitral valve disease. Follow-up was obtained by a questionnaire or telephone to determine a survival time.

Results

The BUN/creatinine ratio, vertebral heart score, and left atrium/aorta ratio were the independent predictors of cardiac mortality. Right ventricular systolic dysfunction was found in 50% of dogs with mitral valve disease. Dogs with right ventricular dysfunction had a significantly higher incidence of lower fractional shortening and larger right ventricular dimensions. The occurrence of right-sided dysfunction is proportionate to age and the degree of left ventricular dysfunction. High blood lactate concentrations were investigated in dogs with mitral valve disease stage C compared with stage B. The peptides such as mitogen-activated protein kinase, kallikrein, and tenascin-C appeared in the heart disease progression group.

Conclusion

Right-hearted function assessment, blood lactate levels, and peptidomics analysis may help early detection and prognosis of this disease in dogs. Peptidomics profiles from this study demonstrate the possibility for prognosis indicators of heart valve degeneration.

The effect of treatment with pimobendan in dogs with preclinical mitral valve disease - a placebo-controlled double-blinded crossover study

Background

Pimobendan is a widely used medication for the treatment of dogs with congestive heart failure (CHF) and preclinical degenerative mitral valve disease (DMVD) with cardiomegaly. The benefit of a treatment in dogs with preclinical DMVD but without cardiomegaly has not yet been elucidated. Some positive effects concerning life quality and a decrease in cardiac biomarkers could be verified. This study aimed to further investigate these results using a placebo-controlled double-blinded crossover design. Out of a total of 15 dogs, eight were allocated to sequence-group AB, in which dogs received pimobendan (A) during the first treatment period and placebo (B) during the second period. Accordingly, sequence-group BA was treated first with placebo followed by pimobendan. Each treatment period lasted six months and included a baseline investigation and follow-ups after 90 and 180 days. The investigations included a questionnaire completed by the owners, echocardiographic examination, and measurements of NT-proBNP, cTnI and lactate before and after a standardised submaximal exercise test.

Results

NT-proBNP values decreased significantly during the treatment period with pimobendan, and the post-exercise increase was attenuated at day 180. No significant treatment effects could be verified for cTnI and lactate, neither pre- nor post-exercise. Left ventricular size decreased under treatment, whereas no significant changes in left atrial size were detected. The owners described their dogs under treatment with pimobendan as being more active at day 90 (11/15) and day 180 (12/15). Those animals treated with placebo were described as being more active at day 90 (2/15) and day 180 (5/15).

Conclusions

Pimobendan had reducing effects on the concentrations of pre- and post-exercise cardiac biomarkers and the size of the left ventricle in dogs with DMVD ACVIM B1. Exercise testing in addition to an assessment of cardiac biomarkers might improve the decision when to initiate pimobendan treatment in dogs with DMVD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-03014-5.