Cardiac troponin I: evaluation of a biomarker for the diagnosis of heart disease in the dog

The Effect of a Subsequent Dose of Dexmedetomidine or Other Sedatives following an Initial Dose of Dexmedetomidine on Electrolytes, Acid-Base Balance, Creatinine, Glucose, and Cardiac Troponin I in Cats: Part II

The administered dose of dexmedetomidine may occasionally fail to produce the anticipated sedative effects. Therefore, a subsequent dose or administration of another sedative may enhance sedation; however, patient safety may be affected. The safety of seven different drugs administered at the following time point after an insufficient dose of dexmedetomidine was evaluated in a crossover, blind, experimental study that included six healthy adult cats. All cats received an initial dose of dexmedetomidine and a subsequent dose of either dexmedetomidine (Group DD), NS 0.9% (DC), tramadol (DT), butorphanol (DBT), buprenorphine (DBP), ketamine (DK), or midazolam (DM). Animal safety was assessed using repeated blood gas analysis and measurement of electrolytes, glucose, cardiac troponin I, and creatinine to evaluate cardiac, respiratory, and renal function. The median values of creatinine, cardiac troponin I, pH, partial pressure of carbon dioxide, potassium, and sodium did not change significantly throughout the study. Heart rate was significantly decreased in all groups after administration of the drug combinations, except for in the DK group. Respiratory rate decreased significantly after administration of the initial dose of dexmedetomidine and in the DBP and DM groups. The partial pressure of oxygen, although normal, decreased significantly after the administration of dexmedetomidine, whereas the median concentration of glucose increased significantly following the administration of dexmedetomidine. The results of our study suggest that the drug combinations used did not alter the blood parameters above normal limits, while cardiac and renal function were not compromised. Therefore, a safe level of sedation was achieved. However, the administration of dexmedetomidine reduced the partial pressure of oxygen; thus, oxygen supplementation during sedation may be advantageous. Additionally, the increase in glucose concentration indicates that dexmedetomidine should not be used in cats with hyperglycaemia, whereas the decrease in haematocrit suggests that dexmedetomidine is not recommended in anaemic cats.

Investigation of the cardiac effects of exercise testing on apparently healthy Boxer dogs

BACKGROUND

Holter electrocardiographic monitoring is a cornerstone of diagnostic testing for arrhythmogenic cardiomyopathy (ACM) in Boxer dogs, but physical activity during monitoring is not controlled. In humans, exercise testing (ExT) can identify latent tachyarrhythmias associated with cardiomyopathy, and exercise increases serum cardiac troponin-I concentrations ([hs-cTnI]). These effects have not yet been investigated in Boxer dogs.

HYPOTHESIS/OBJECTIVES

Subjecting Boxer dogs to brief, moderate-intensity ExT can identify changes in Holter recordings and [hs-cTnI] compared to baseline results.

ANIMALS

Thirty overtly healthy, client-owned Boxer dogs.

METHODS

Prospective interventional study. Dogs underwent baseline diagnostic testing including 24-hour Holter monitoring and [hs-cTnI], followed by brief ExT (accompanied, brisk stair-climbing and -descending for <5 minutes).

RESULTS

Eleven dogs (37%) had >100 premature ventricular complexes (PVCs)/24 hours at baseline (3), ExT (3), or both (5). After ExT, these dogs had more PVCs/24 hours and greater increases in [hs-cTnI] compared to those with ≤100 PVCs/24 hours. Dogs with the striatin mutation had more PVCs/24 hours and a greater increase in [hs-cTnI] after ExT than did dogs without the striatin mutation.

CONCLUSIONS AND CLINICAL IMPORTANCE

Exercise testing may improve the binary classification of Boxer dogs with or without ACM by increasing the number of PVCs and [hs-cTnI] in affected dogs to a greater degree than in unaffected dogs. This effect also is associated with presence or absence of the striatin mutation. Exercise should be a controlled variable when screening Boxer dogs for ACM.

Long-term outcome and troponin I concentrations in Great Danes screened for dilated cardiomyopathy: an observational retrospective epidemiological study

INTRODUCTION

Dilated cardiomyopathy (DCM) is common in Great Danes (GDs) but screening for this condition can be challenging. We hypothesised that cardiac troponin-I (cTnI) concentration is elevated in GDs with DCM and/or ventricular arrhythmias (VAs), and is associated with reduced survival time in GDs.

ANIMALS

One hundred and twenty-four client-owned GDs assigned echocardiographically as normal (n = 53), equivocal (n = 37), preclinical DCM (n = 21), or clinical DCM (n = 13).

MATERIALS AND METHODS

A retrospective epidemiological study. Echocardiographic diagnosis, VAs, and contemporaneous cTnI concentrations were recorded. Diagnostic accuracy and cTnI cut-offs were determined with receiver operating characteristic analyses. Effects of the cTnI concentration and disease status on survival and cause of death were explored.

RESULTS

Median cTnI was greater in clinical DCM (0.6 ng/mL [25th-75th percentiles: 0.41-1.71 ng/mL]) and GDs with VAs (0.5 ng/mL [0.27-0.80 ng/mL], P<0.001). Elevated cTnI detected these dogs with good accuracy (area under the curve: 0.78-0.85; cut-offs 0.199-0.34 ng/mL). Thirty-eight GDs (30.6%) suffered a cardiac death (CD); GDs suffering CD (0.25 ng/mL [0.21-0.53 ng/mL]) and specifically sudden cardiac death (SCD) (0.51 ng/mL [0.23-0.72 ng/mL]) had higher cTnI than GDs dying of other causes (0.20 ng/mL [0.14-0.35 ng/mL]; P<0.001). Elevated cTnI (>0.199 ng/mL) was associated with shorter long-term survival (1.25 years) and increased risk of SCD. Great Danes with VAs had shorter survival times (0.97 years).

CONCLUSIONS

A cardiac troponin-I concentration is a useful adjunctive screening tool. Elevated cTnI is a negative prognostic indicator.

CHANGES IN SERUM CARDIAC TROPONIN I IN ASIAN ELEPHANTS (ELEPHAS MAXIMUS) WITH ELEPHANT ENDOTHELIOTROPIC HERPESVIRUS INFECTION

Elephant endotheliotropic herpesvirus (EEHV) is one of the most important causes of mortality in Asian elephants (Elephas maximus). The unusual tropism of EEHV for endothelial cells of capillaries can lead to catastrophic vascular dysfunction, hemorrhage, cardiac damage, and death. Cardiac troponin I (cTnI) is an intracellular protein of cardiomyocytes that is released into circulation in levels directly correlated to the severity of cardiomyocyte damage. The purpose of this study was to assess if cTnI could be used to distinguish when EEHV viremia leads to clinical disease versus subclinical infection. Thirty-seven individual Asian elephants contributed 53 blood samples that were evaluated for EEHV viremia using quantitative polymerase chain reaction and analyzed for cTnI using a high-sensitivity assay. Viremia was categorized as none (24/53), low (< 20,000 vge/ml, 12/53) and high (≥20,000 vge/ml, 17/53). Seven of the nonviremic samples had detectable cTnI. Nine low-viremia samples were positive for EEHV1 (1A and 1B combined) and lacked a detectable cTnI. Fourteen high-viremia samples were positive for EEHV1 and had detectable cTnI. There was statistical significance between having viremia and having a detectable cTnI value (P = 0.0001), and animals with EEHV1 viremia were more likely to have a positive cTnI value (P = 0.04). The presence of cTnI was associated with the presence of clinical signs, with higher values of cTnI in the presence of clinical signs versus subclinical viremia (P = 0.0001). In addition, four elephants contributed multiple samples from a single viremic event and results displayed a trend of elevation in troponin values with progression of EEHV viremia. The association of EEHV viremia with cTnI suggests these markers might be used in conjunction to help predict when EEHV viremia is likely to progress to EEHV-HD for an individual.

The Preliminary Chronic Effects of Electromagnetic Radiation from Mobile Phones on Heart Rate Variability, Cardiac Function, Blood Profiles, and Semen Quality in Healthy Dogs

The present study aims to determine the effects of long-term exposure to electromagnetic radiation from mobile phones (MPs) on heart rate variability (HRV), cardiac function, blood profiles, body surface temperature, and semen quality in healthy dogs. Eight male dogs were exposed to MPs (1962–1966 MHz; specific absorption rate 0.96 W/kg) for 2 h/day, 5 days/week, for 10 weeks. Holter monitoring for HRV analysis was performed at baseline (BL) and every 2 weeks, until the end of the study. Electrocardiograms (ECG), blood pressure (BP), echocardiography, cardiac troponin I (cTnI), hematology and biochemistry profiles, body surface temperature, and semen quality were evaluated at BL, week 5, and week 10 during exposure. The results showed that most of the HRV parameters did not significantly differ among timepoints, except for the mean of an interval between continuous normal R waves in week 6 that was higher than that at BL (p = 0.022). The RR and QT intervals from ECG in week 5 were prolonged, compared to the BL values (p = 0.001 and p = 0.003, respectively), but those parameters were within the normal limits. The echocardiography, BP, cTnI concentrations, body surface temperature, and semen quality results were not different from BL values. In conclusion, this study found no evidence suggesting an adverse effect of cell phone exposure on HRV, cardiac function, blood profiles, body surface temperature, or semen quality in healthy dogs, when exposed for 10 weeks.

Evaluation of serum cardiac troponin-I concentrations for diagnosis of infective endocarditis in dogs

Background

Infective endocarditis (IE) in dogs is associated with severe disease and a high case fatality rate but often presents with nonspecific clinical signs.

Hypothesis/Objectives

Serum concentration of cardiac troponin‐I (cTnI) is elevated in dogs with IE and can differentiate dogs with IE from dogs with other diseases with similar clinical features. Concentration of serum cTnI is negatively correlated with survival time in dogs with IE.

Animals

Seventy‐two client‐owned dogs; 29 with IE, 27 with stage‐B myxomatous mitral valve disease (MMVD), and 16 with immune‐mediated disease (IMD).

Methods

Retrospective clinical cohort study. Concentration of serum cTnI was measured in all dogs at time of diagnosis. Clinical findings and echocardiographic interpretation were also recorded. Statistical analyses included Kruskal‐Wallis test, pairwise Mann‐Whitney U tests, receiver operator characteristic, and Cox proportional hazards.

Results

Serum concentration of cTnI was significantly higher in the IE group (0.69 ng/mL [0.03‐80.8]) than in the MMVD (0.05 ng/mL [0.02‐0.11], P < .001) and IMD groups (0.05 ng/mL [0.03‐0.57], P < .001). Increased cTnI was a moderately accurate predictor of IE (area under the curve 0.857 (95% confidence interval [CI] 0.745‐0.968, P < .001). A cTnI cutoff of 0.625 ng/mL had 100% specificity (95% CI 90%‐100%) and 52% sensitivity (95% CI 33%‐70%) in this study sample. There was no association between cTnI concentration and survival time in dogs with IE (hazard ratio 1.013, 95% CI 0.993‐1.034, P = .2).

Conclusions and Clinical Importance

Cardiac troponin‐I concentrations are higher in dogs with IE compared to dogs with preclinical MMVD or IMD. In dogs with a compatible clinical presentation, serum cTnI concentrations >0.625 ng/mL are supportive of IE.

Exploration of serum cardiac troponin I as a biomarker of cardiomyopathy in southern sea otters (Enhydra lutris nereis)

OBJECTIVE

To compare serum cardiac troponin I (cTnI) concentrations between sea otters with and without cardiomyopathy and describe 2 cases of cardiomyopathy with different etiologies.

ANIMALS

25 free-ranging southern sea otters (Enhydra lutris nereis) with (n = 14; cases) and without (11; controls) cardiomyopathy and 17 healthy managed southern sea otters from aquariums or rehabilitation centers (controls).

PROCEDURES

Serum cTnI concentration was measured in live sea otters. Histopathologic and gross necropsy findings were used to classify cardiomyopathy status in free-ranging otters; physical examination and echocardiography were used to assess health status of managed otters. Two otters received extensive medical evaluations under managed care, including diagnostic imaging, serial cTnI concentration measurement, and necropsy.

RESULTS

A significant difference in cTnI concentrations was observed between cases and both control groups, with median values of 0.279 ng/mL for cases and < 0.006 ng/mL for free-ranging and managed controls. A cutoff value of ≥ 0.037 ng/mL yielded respective sensitivity and specificity estimates for detection of cardiomyopathy of 64.3% and 90.9% for free-ranging cases versus free-ranging controls and 64.3% and 94.1% for free-ranging cases versus managed controls.

CONCLUSIONS AND CLINICAL RELEVANCE

Cardiomyopathy is a common cause of sea otter death that has been associated with domoic acid exposure and protozoal infection. Antemortem diagnostic tests are needed to identify cardiac damage. Results suggested that serum cTnI concentration has promise as a biomarker for detection of cardiomyopathy in sea otters. Serial cTnI concentration measurements and diagnostic imaging are recommended to improve heart disease diagnosis in managed care settings.

Cardiac diagnostic test results and outcomes in 44 dogs naturally infected with Trypanosoma cruzi

Background

The protozoal parasite Trypanosoma cruzi causes myocarditis in dogs.

Objectives

To describe the cardiac diagnostic test results and outcomes of dogs naturally infected with T. cruzi.

Animals

Forty‐four client‐owned dogs.

Methods

Medical records were retrospectively reviewed to identify dogs with an indirect fluorescent antibody test result for T. cruzi ≥1 : 80. Data collected included signalment, cardiac diagnostic test results (ECG, echocardiography, cardiac troponin I) and outcome. Outcomes were categorized as alive, dead (cardiac or noncardiac) or lost to follow up.

Results

ECG abnormalities were present in 41 dogs with ventricular arrhythmias (n = 28) and atrioventricular block (AVB) (n = 15) most commonly identified. Echocardiographic chamber enlargement was present in 28 dogs and most often included the right ventricle (RV) (n = 15) and left atrium (n = 12). Troponin was ≥2 times the reference range in 20/36 (56%) dogs. In univariate analysis using nonparametric Kaplan‐Meier, ventricular arrhythmias with a modified Lown score ≥2 (P = .02), presence of AVB (P = .04), and RV enlargement (P = .006) were associated with decreased survival times. Right ventricular enlargement (HR 3.6; 95% confidence interval [CI] 1.4‐9.3; P = .007) and higher body weight at presentation (HR 1.0; 95% CI 1.0‐1.1; P = .04) were associated with decreased time to death in the final explanatory multivariable model.

Conclusions and Clinical Importance

Cardiac abnormalities were common and variable, and RV enlargement was associated with shorter survival time. A diagnostic evaluation that includes screening for arrhythmias, echocardiography, and cTnI can provide useful information related to the characterization of heart disease in dogs seropositive for T. cruzi.

Accuracy of history, physical examination, cardiac biomarkers, and biochemical variables in identifying dogs with stage B2 degenerative mitral valve disease

Background

Treatment is indicated in dogs with preclinical degenerative mitral valve disease (DMVD) and cardiomegaly (stage B2). This is best diagnosed using echocardiography; however, relying upon this limits access to accurate diagnosis.

Objectives

To evaluate whether cardiac biomarker concentrations can be used alongside other clinical data to identify stage B2 dogs.

Animals

Client‐owned dogs (n = 1887) with preclinical DMVD prospectively sampled in Germany, the United Kingdom, and the United States.

Methods

Dogs that met inclusion criteria and were not receiving pimobendan (n = 1245) were used for model development. Explanatory (multivariable logistic regression) and predictive models were developed using clinical observations, biochemistry, and cardiac biomarker concentrations, with echocardiographically confirmed stage B2 disease as the outcome. Receiver operating characteristic curves assessed the ability to identify stage B2 dogs.

Results

Age, appetite, serum alanine aminotransferase activity, body condition, serum creatinine concentration, murmur intensity, and plasma N‐terminal propeptide of B‐type natriuretic peptide (NT‐proBNP) concentration were independently associated with the likelihood of being stage B2. The discriminatory ability of this explanatory model (area under curve [AUC], 0.84; 95% confidence interval [CI], 0.82‐0.87) was superior to NT‐proBNP (AUC, 0.77; 95% CI, 0.74‐0.80) or the vertebral heart score alone (AUC, 0.76; 95% CI, 0.69‐0.83). A predictive logistic regression model could identify the probability of being stage B2 (AUC test set, 0.86; 95% CI, 0.81‐0.91).

Conclusion and Clinical Importance

Our findings indicate accessible measurements could be used to screen dogs with preclinical DMVD. Encouraging at‐risk dogs to seek further evaluation could result in a greater proportion of cases being appropriately managed.

Canine Traditional Laboratory Tests and Cardiac Biomarkers

In small animals, cardiac disease evaluation through laboratory tests can be a challenge. This review will present both historical and updated perspectives on the clinical pathology of cardiac diseases in dogs and demonstrate that laboratory tests are useful tools for the management of patients with cardiac diseases.

Serum proteome profiling in canine chronic valve disease using a TMT-based quantitative proteomics approach

Chronic valve disease (CVD) is the most common clinically significant heart disease of dogs, affecting 20 to 40% of dogs. The aim of this study was to evaluate the serum protein profile of healthy and CVD affected dogs, by means of an isobaric tandem mass tag (TMT) label-based high-resolution quantitative proteomic approach. Additionally, conventional cardiac biomarkers were measured in the serum, functional bioinformatics analysis was employed for elucidating molecular mechanisms and pathways associated with CVD, and validation of proteomic results was performed by immunoassays and Western blotting. Of 290 identified and quantified proteins, 15 proteins showed significantly different abundances (p < .05), including antithrombin-III, alpha-2-antiplasmin, tetranectin, apolipoprotein M, adiponectin, inter-alpha-trypsin inhibitor heavy chain H1, gelsolin and apolipoprotein B-100. The identified proteins with differently abundances are involved in a number of pathways, such as complement and coagulation cascades, haemostasis, regulation of actin cytoskeleton, lipid metabolism and transport. We found comparative similarities with human disease in terms of identified proteins and GO pathways, which confirmed similar pathophysiology of this disease, but also differences, mainly in lipid metabolism. SIGNIFICANCE: There have been few investigations of canine serum proteome despite the potential for biomarker discovery and comparative disease analysis. Establishing serum proteomic signatures in healthy dogs and dogs with CVD will benefit for understanding the aetiology of disease in dogs, identify putative biomarkers and provide models of comparative human disease. Circulating biomarkers are important for understanding of the mechanisms of cardiovascular disease and high incidence of CVD in dogs prioritizes the search for novel biomarkers.

Diagnostic methods for the canine idiopathic dilated cardiomyopathy: A narrative evidence-based rapid review

Idiopathic dilated cardiomyopathy (DCM) is an important etiology of mortality and morbidity in dogs and its diagnosis relies on systolic dysfunction, chambers dilation, electrical instability and congestion. During the last decades veterinary cardiologists have been joining efforts to obtain diagnostic resources to correctly identify canine DCM in the preclinical stage. Unfortunately, most diagnostic resources have been used with the support of research with weak evidence, without high quality methodologies such as systematic reviews or meta-analysis. Therefore, the support of evidence-based medicine is tailored by empiricism and diagnostic criteria lose'out the ability to properly classify dogs suffering DCM. The presentation of the evidence in medicine is established by multiple sources and the most reliable source has been the presentation of evidence-based medicine from systematic reviews and meta-analysis. Rapid reviews can be interpreted as a pragmatic approach to systematic reviews and although a rapid review follows most of the critical steps of a systematic review to provide timely evidence, some components of a systematic review process are either simplified or omitted. The objective of this narrative evidence-based rapid review is twofold. First: To recognize and to stratify the level of evidence offered by rigorous selected papers about the diagnosis of DCM. Second: To classify the degree of clinical recommendation of the diagnostic resources available.

Serial measurements of cardiac troponin I in heart failure secondary to canine mitral valve disease

Serial measurements of cardiac troponin I (cTnI) levels are considered to be better predictors of cardiac death than single-time-point analyses in human medicine. We hypothesised that cTnI levels could reflect the severity of myxomatous mitral valve disease (MMVD), and that serial changes in the cTnI level had a prognostic value in dogs with congestive heart failure (CHF) secondary to MMVD. Seventy-six dogs were initially enrolled and classified by the American College of Veterinary Internal Medicine (ACVIM) staging system. The single-timepoint cTnI concentration in these dogs significantly increased with the ACVIM stage. Twenty-seven dogs with CHF subsequently underwent serial measurement of cTnI levels, and the results showed that those who demonstrated a decrease in cTnI levels from the first to the third visit exhibited a higher risk of cardiac death than did those without such changes (P=0.012). We suspect that the downward trend in cTnI levels may be affected by medical treatment for CHF. In conclusion, although cTnI levels could reflect the severity of MMVD to a certain extent, the serial changes may be affected by medical treatment. Therefore, caution should be exercised when cTnI is used for assessment of the prognosis of CHF secondary to MMVD in dogs.

Analytical quality assessment and method comparison of two immunoassays for the measurement of serum cardiac Troponin I in dogs and cats

BACKGROUND

Cardiac troponin I (cTnI) is a sensitive and specific biomarker for myocardial injury. Validation of point-of-care (POC) analyzers for cTnI measurement is valuable to the critical care setting, in which rapid results can facilitate prompt diagnoses. An immunoassay for detecting cTnI is available for the POC AIA-360 analyzer (Tosoh Bioscience), but this has not been validated using canine and feline serum.

OBJECTIVES

The objectives were (a) to determine precision, accuracy, and linearity of cTnI measurement using the AIA-360 immunoassay in pooled canine and feline samples, and (b) to compare results for individual canine and feline samples with those obtained using a reference chemiluminescence method (Immulite 1000, Siemens).

METHODS

Intra- and inter-assay repeatability was determined using pooled canine and feline samples, and the coefficient of variation (CV) was calculated for each. Pooled samples were also serially diluted to assess linearity. A modified spike and recovery analysis was performed by mixing pooled samples with different concentrations. Bland-Altman and Deming regression analyses were used to determine bias for individual samples, and the total observed error (TE_obs ) was calculated.

RESULTS

Coefficient of variation values were well within the required maximum of 20%. Linearity was demonstrated over the range of samples tested, and the recovery study showed minimal proportional inaccuracies. Although the correlation between the analyzers was excellent, there was a large mean bias due to relative proportional bias. Total observed error consequently exceeded the total allowable error (TE_A ).

CONCLUSION

Although, in most respects, the analyzer demonstrated adequate performance, pronounced bias contributed to the large TE_obs , indicating a requirement for analyzer-specific reference intervals.

Risk factors and select cardiac characteristics in dogs naturally infected with Trypanosoma cruzi presenting to a teaching hospital in Texas

Background

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, causes sudden death and chronic heart disease with no currently approved treatment.

Objective

To report epidemiologic and select cardiac characteristics associated with T. cruzi infection in dogs presenting to a teaching hospital in Texas.

Animals

Three hundred seventy‐five client‐owned dogs.

Methods

A retrospective search of medical records identified dogs tested for T. cruzi antibodies or with histologic T. cruzi parasites. Data retrieved included signalment, location of residence, reported reason for testing, cardiac troponin I (cTnI) concentration, and ECG abnormalities.

Results

Trypanosoma cruzi‐infected dogs (N = 63, 16.8%) were significantly younger than negative dogs (N = 312) (mean, 5.9 ± 3.8 versus 7.4 ± 4.0 years; P = .007) with no difference by sex or breed. Ninety‐one breeds were tested; the highest percent infected were non‐sporting (10/35; 29%) and toy breed (10/42; 24%) groups. The odds of infection were 13 times greater among dogs with an infected housemate or littermate (95% confidence interval [CI], 3.94‐50.45; P < .001). Infected dogs were more likely to have ventricular arrhythmias (odds ratio [OR], 2.19; 95% CI, 1.15‐4.33, P = .02), combinations of ECG abnormalities (OR, 2.91; 95% CI, 1.37‐5.99; P = .004), and cTnI >0.129 ng/mL (ADVIA; OR, 10.71; 95% CI, 1.60‐212.21; P = .035).

Conclusions and Clinical Importance

Dogs infected with T. cruzi were identified in Texas in many breed groups including breeds affected by well‐described heart diseases that mimic Chagas disease suggesting a need for increased awareness, including knowledge of when to consider testing.

Evaluation of a high-sensitivity cardiac troponin I assay compared to a first-generation cardiac troponin I assay in Doberman Pinschers with and without dilated cardiomyopathy

BACKGROUND

Echocardiography and 24-hour ECG are the gold standard tests to diagnose dilated cardiomyopathy (DCM) in Doberman Pinschers (DP), but myocardial damage might be detected earlier using a high-sensitivity cardiac troponin I (hs-cTnI) assay.

OBJECTIVE

To evaluate and compare an hs-cTnI assay (Advia Centaur TnI-Ultra assay) with a conventional cTnI assay in DP with different stages of DCM and in healthy DP.

ANIMALS

Three hundred forty-five examinations from 162 DP with and 179 DP without DCM.

METHODS

Prospective longitudinal study. Dogs were allocated into 6 groups based on echocardiographic and 24-hour ECG criteria: (1) healthy group (179 dogs), (2) last-normal group (29 dogs), which included dogs that were considered to be healthy at the time of their examination but were assigned to the last-normal group retrospectively when DCM was diagnosed at their next examination within 1.5 years, (3) only arrhythmias (45 dogs, 119 examinations), (4) only echocardiographic changes (24 dogs, 61 examinations), (5) echocardiographic changes with ventricular premature complexes (41 dogs, 100 examinations), and (6) decompensated (23 dogs, 36 examinations). Hs-cTnI and conventional cTnI concentration measurements were performed and compared.

RESULTS

A cutoff value of hs-cTnI concentration >0.113 ng/mL had a sensitivity of 81.2% and a specificity of 73.2% to identify the presence of DCM. The conventional cTnI assay showed a similar test performance, but the hs-cTnI assay identified more dogs (21/29 dogs, 72%) in the last-normal group compared to the conventional cTnI test (18/29 dogs, 62%).

CONCLUSIONS AND CLINICAL IMPORTANCE

The hs-cTnI is an additional test with good potential to identify early DCM.

Intense exercise and endurance-training program influence serum kinetics of muscle and cardiac biomarkers in dogs

Few data exist on the physiological consequences of an incremental exercise test (IET) and training in dogs. Here we evaluated the effect of an endurance-training program (ETP) on the kinetics of the serum biomarkers: creatine kinase (CK), aspartate aminotransferase (AST), myoglobin, cardiac troponin I (cTnI), and creatine kinase isoenzyme MB (CK-MB). Eighteen Beagle dogs were assigned to three groups: sedentary (S), untrained (U), and trained (T). The dogs from the groups T and U underwent IET, and their lactate threshold (LT) was determined. The LT and velocity corresponding to the LT (VLT) was determined by visual inspection. The VLT was utilized to determine the training intensity level. Thus, the dogs from group T underwent an eight-week aerobic conditioning program with the intensity training set to 70-80% of the VLT. Next, dogs from the groups T and U have submitted to IET again. The group S did not undergo IETs or training. The maximal velocity (Vmax) at which the dog achieves in the IET and heart rate were determined. For biomarkers, venous blood samples were collected before the experimental procedure (baseline) and before and 1, 6, 12, 24, 48, and 72 h after the IETs. VLT and Vmax increased in group T (P < .05), indicating an improvement in dogs' aerobic and anaerobic fitness. CK and AST rose (P < .05), peaking 6 h after both IETs and returning to baseline levels after 12-24 h. Levels of cTnI and myoglobin were unaltered. CK-MB peaked 1 h after the IETs and returned to baseline levels after 12 h (P < .05). We concluded that ETP improved the aerobic capacity of the dogs without any skeletal or cardiac muscle injury.

Value of cardiac biomarker measurement in the differential diagnosis of infiltrative cardiomyopathy patients with preserved left ventricular systolic function

Background

This study aimed to explore the value of cardiac biomarker [serum high sensitive troponin T (hs-TNT) and N-terminal pro-brain natriuretic peptide (NT-proBNP)] measurement in the differential diagnosis of infiltrative cardiomyopathy patients [Friedreich's ataxia (FA), Fabry disease (FD) and light-chain (AL) cardiac amyloidosis (CA)] with preserved left ventricular (LV) systolic function.

Methods

Between 2012 and 2014, all consecutive patients presenting at our center with infiltrative cardiomyopathy and concomitant symmetrical LV hypertrophy as well as preserved LV systolic function were included in this study. Serum hs-TNT and NT-proBNP, morphologic and functional features derived from echocardiography and cardiac magnetic resonance imaging (cMRI) examinations were compared among these patients.

Results

A total of 57 patients (FA 20, FD 23 and CA 14) were included. Hs-TNT and NT-proBNP levels were significantly higher in the CA group [median: hs-TNT 98 pg/mL, NT-proBNP 4,110 pg/mL] than in the FA group [hs-TNT 14 pg/mL, NT-proBNP 40 pg/mL] and FD group [hs-TNT 18 pg/mL, NT-proBNP 131 pg/mL, both P<0.001]. There was a negative correlation between NT-proBNP and estimated glomerular filtration rate (eGFR) in CA patients (r=-0.72, P=0.012). Both hs-TNT >60 pg/mL (sensitivity 0.79, specificity 0.93) and NT-proBNP >1,000 pg/mL (sensitivity 0.91, specificity 0.93) excellently differentiated CA from FA and FD.

Conclusions

Increased hs-TNT and NT-proBNP levels are suggestive of CA diagnosis among patients with infiltrative cardiomyopathy and preserved LV ejection fraction.

Evaluation of serum neutrophil gelatinase-associated lipocalin as a novel biomarker of cardiorenal syndrome in dogs

Worsening renal function and azotemia in patients with heart failure (HF) are strongly associated with disease severity and poor prognosis. Increasing interest in this correlation led to the description and classification of cardiorenal syndrome (CRS). We evaluated the role of neutrophil gelatinase-associated lipocalin (NGAL) in the early detection of CRS in dogs with HF. Ten healthy dogs and 31 dogs admitted with HF were included in our study. NGAL and troponin-I were measured on samples collected on the day of admission; creatinine was measured on admission and again on day 7. The CRS group was defined as subsequently developing renal azotemia. Of 31 dogs with HF, 20 were included in the HF group, and 11 were included in the CRS group. The admission NGAL concentrations of the CRS group were significantly higher than those of other groups ( p < 0.001). The severity of HF evaluation based on the modified New York Heart Association classification showed significant correlation with NGAL ( p < 0.001) and troponin-I ( p = 0.009) concentration. However, only serum NGAL concentration at admission was significantly associated with the development of CRS in dogs with HF ( p = 0.021). The admission serum NGAL ≥ 16.0 ng/mL (optimal cutoff value) had a sensitivity of 90.9% and specificity of 90.0% in predicting the development of CRS.

Cardiopulmonary and inflammatory biomarkers in heartworm disease

In heartworm disease, several biomarkers of cardiopulmonary injury and inflammatory activity have been studied during the recent years. D-dimer is a fibrin degradation product present after a clot is degraded, which has been reported to provide support for the diagnosis of pulmonary thromboembolism in heartworm disease. Furthermore, concentrations increment with increased disease severity and during the adulticide treatment. This increase in concentration has proved to be valuable. Cardiac biomarkers troponin I, myoglobin and NT-proBNP demonstrated presence of myocardial injury and heart failure, especially in chronic infections, which in some cases, slightly improve after the adulticide treatment. An acute phase response in dogs with Dirofilaria immitis, characterized by variations of acute phase proteins (APP), has been reported, indicating inflammatory processes that could contribute to disease progression. Among them, C-reactive protein (CRP) increases according to the severity of the disease; and a strong correlation between pulmonary hypertension and CRP has been observed. In cats, little work has been done to ascertain the utility of these biomarkers in feline heartworm; the only published study in D. immitis–seropositive cats reported significantly higher concentrations in positive APP serum amyloid A, haptoglobin and ceruloplasmin.

Follow-up of troponin I concentration in dogs with atrioventricular block and dual-chamber pacing in a case-matched study

BACKGROUND

Increased cardiac troponin I (cTnI) concentration has been reported in dogs with atrioventricular (AV) block before and shortly following pacemaker implantation. The role of AV dyssynchrony, age, or concurrent cardiac disease on cTnI concentration remains unknown.

OBJECTIVES

To investigate change in cTnI concentration following dual-chamber pacemaker implantation on short- and long-term follow-up and to compare cTnI values to a case-matched control group.

ANIMALS

Thirty-eight client-owned dogs with permanent AV block and 38 matched control dogs.

METHODS

Retrospective review of medical records. Pacemaker group consisted of dogs with AV block and dual-chamber pacing. Control group matched the study population in age and cardiac disease. cTnI was compared between pacemaker and control group on short- and long-term follow-up. Different lead types and influence of arrhythmia on cTnI were tested.

RESULTS

cTnI was high at presentation (median 0.66 ng/ml; range 0.03-18.6) and showed a significant reduction over time after pacemaker implantation (p < 0.0001). Median cTnI values were significantly different between pacemaker and control group on short-term (p = 0.0004; 0.11 ng/ml, range 0.03-1.36 versus 0.06 ng/ml, range 0.03-0.46), but not on long-term follow-up (p = 0.0547; 0.14 ng/ml, range 0.03-0.73 versus 0.07 ng/ml, range 0.03-0.46). Lead type and severity of arrhythmia did not show a significant correlation to cTnI concentration.

CONCLUSIONS

On long-term follow-up, cTnI remained mildly elevated in some of the pacemaker dogs but was not significantly different to the matched control group.

Comparison of myocardial damage among dogs at different stages of clinical leishmaniasis and dogs with idiopathic chronic kidney disease

Canine leishmaniasis (CanL) is a systemic disease caused by the protozoan parasite Leishmania infantum. Myocarditis in CanL has been described previously in CanL by histopathological analysis of post-mortem specimens and by evaluation of cardiac troponin I (cTnI) levels. However, the degree of myocardial damage at different stages of CanL and the role that concurrent azotaemia plays in this myocardial injury are unknown. The aim of this study was to prospectively evaluate and compare the presence of myocardial injury in dogs at different stages of clinical CanL and in dogs with severe idiopathic chronic kidney disease (CKD) by measuring cTnI. Forty-eight dogs were included in the study, divided into four groups: (1) group A (10 healthy dogs); (2) group B (17 dogs with CanL without renal azotaemia, classified as mild to severe in the LeishVet scheme); (3) group C (11 dogs with CanL and renal azotaemia, classified as very severe in the LeishVet scheme); and (4) group D (10 dogs with idiopathic CKD). Dogs in group C had significantly higher cTnI than dogs in groups B and D, although cTnI was also elevated in these groups. Dogs in group A had normal cTnI values. Dogs in groups D and C had similar renal IRIS classification scorers. Severe lymphoplasmocytic myocarditis and a positive real time PCR of L. infantum DNA were observed in all dogs in group C. Dogs with very severe CanL exhibit more myocardial injury than dogs with milder CanL or dogs with idiopathic CKD.

Cloning and Sequencing of Equine Cardiac Troponin I and Confirmation of Its Usefulness as a Target Analyte for Commercial Troponin I Analyzers

The analysis of cardiac troponin I (cTnI) in the diagnosis of myocardial injury in domestic animals is gaining popularity. In this study, equine cTnI was sequenced and compared with previously characterized cTnI from other species. A 6-amino-acid N-terminal deletion unique to the horse was identified. This deletion was outside the epitope region of cTnI recognized by most commercial immunoassays and did not affect the ability of a commercial analyzer system to detect recombinant equine cTnI. No function could be ascribed to the deleted portion. These data support the use of commercial analyzers in measuring equine cTnI.

Cardiac Troponins in Dogs and Cats

Cardiac troponins are sensitive and specific markers of myocardial injury. The troponin concentration can be thought of as a quantitative measure of the degree of injury sustained by the heart, however, it provides no information on the cause of injury or the mechanism of troponin release. Conventionally, the cardiac troponins have been used for diagnosis of acute myocardial infarction in humans and have become the gold standard biomarkers for this indication. They have become increasingly recognized as an objective measure of cardiomyocyte status in both cardiac and noncardiac disease, supplying additional information to that provided by echocardiography and ECG. Injury to cardiomyocytes can occur through a variety of mechanisms with subsequent release of troponins. Independent of the underlying disease or the mechanism of troponin release, the presence of myocardial injury is associated with an increased risk of death. As increasingly sensitive assays are introduced, the frequent occurrence of myocardial injury is becoming apparent, and our understanding of its causes and importance is constantly evolving. Presently troponins are valuable for detecting a subgroup of patients with higher risk of death. Future research is needed to clarify whether troponins can serve as monitoring tools guiding treatment, whether administering more aggressive treatment to patients with evidence of myocardial injury is beneficial, and whether normalizing of troponin concentrations in patients presenting with evidence of myocardial injury is associated with reduced risk of death.

Long-term Intrinsic Rhythm Evaluation in Dogs with Atrioventricular Block

Background

Atrioventricular block (AVB) is a conduction abnormality along the atrioventricular node that, depending on etiology, may lead to different outcomes.

Objectives

To evaluate variations of intrinsic rhythm (IR) in dogs that underwent pacemaker implantation (PMI).

Animals

Medical records of 92 dogs affected by 3rd degree atrioventricular block (3AVB), advanced 2nd degree AVB (2AVB), paroxysmal 3AVB, 2:1 2AVB, or 3AVB with atrial fibrillation (AF) were retrospectively reviewed.

Method

The patient IR was documented with telemetry on the day of 1 – (95% CI, 1–2), 33 – (95% CI, 28–35), 105 – (95%CI, 98–156), and 275 days (95%CI, 221–380) after PMI. According to AVB grade at different examinations, AVB was defined as progressed, regressed, or unchanged.

Results

In 48 dogs, 3AVB remained unchanged, whereas in 7 it regressed. Eight cases of 2AVB progressed, 3 regressed and 2 remained unchanged. Eight cases of paroxysmal 3AVB progressed and 3 remained unchanged. Four dogs affected by 2:1 2AVB progressed, 2 regressed, and 1 remained unchanged. All cases with 3AVB with AF remained unchanged. Regression occurred within 30 days after PMI, whereas progression was documented at any time. Variations in IR were associated with type of AVB (P < .03) and time of follow‐up (P < .0001).

Conclusions and clinical importance

The degree of AVB assessed at the time of PMI should not be considered definitive because more than one‐third of the cases in this study either progressed or regressed. Additional studies would be necessary to elucidate possible causes for transient AVB in dogs.

CREATINAFOSFOQUINASE-ISOENZIMA MB MASSA (CK-MB MASSA) E TROPONINA I (cTnI) EM CÃES (<italic>Canis familiaris</italic>)

<title>Resumo</title><p>Os marcadores cardíacos, sobretudo a CK-MB massa e a cTnI, tem demonstrado um papel essencial seja em cardiologia clínica ou cirúrgica veterinária e humana, permitindo um diagnóstico mais preciso e acurado nas lesões miocárdicas. O objetivo deste trabalho foi mensurar os marcadores cardíacos em tela na Medicina Veterinária, aprimorar sua utilização e obter informações sobre estes métodos laboratoriais não invasivos que permitem o monitoramento da integridade da célula miocárdica. A quantificação dos parâmetros foi feita do soro de cães saudáveis atendidos na rotina do setor de Clínica Médica de Pequenos Animais do Hospital Veterinário da Universidade Estadual do Norte Fluminense Darcy Ribeiro. O kit de ensaio imunométrico por quimioluminescência turbo (IMMULITE Turbo, Siemens®) humano mostrou-se eficaz na avaliação na espécie canina, tanto para CK-MB massa quanto cTnI. Além disso, os valores encontrados para CK-MB massa e cTnI contribuirão significativamente para a rotina clínica ou para os trabalhos experimentais em cães.</p>

Correlation of serum cardiac troponin I and acute phase protein concentrations with clinical staging in dogs with degenerative mitral valve disease

BACKGROUND

Cardiac troponin I (cTnI) correlates with severity of myocardial injury. Nonspecific inflammation in congestive heart failure (CHF) could be assessed by C-reactive protein (CRP), haptoglobin (Hp), and ceruloplasmin (Cp) measurements.

OBJECTIVES

The aim of the study was to determine whether serum cTnI, CRP, Hp, and Cp concentrations differ among various stages of mitral valve disease (MVD) in dogs.

MATERIALS AND METHODS

Dogs with MVD were allocated to 3 groups (I - asymptomatic; II - mild to moderate CHF; III advanced CHF) according to the scheme of the International Small Animal Cardiac Healthy Council (ISACHC). Concentrations of cTnI, CRP, Cp, and Hp were measured in all dogs upon admission, and cTnI and CRP were measured bimonthly during a 4-month follow-up period.

RESULTS

In total 46 dogs with MVD were enrolled for the cross-sectional part (21 Group I, 11 Group II, 14 Group III), and 35 dogs were included in the longitudinal study. Initial mean Cp concentrations were similar among all groups. There was a statistically significant difference in Hp and CRP concentrations between group I (n = 21, P = .019) and III (n = 14, P < .001). There was a statistically significant decrease in CRP (P = .033) and cTnI (P = .009) concentrations over the longitudinal study (all groups). CRP concentrations were significantly higher in group I than III (P = .004). During the 6-month monitoring period of 35 dogs, there was a statistically significant positive correlation between cTnI and CRP (P < .001).

CONCLUSION

Differences in CRP concentrations between clinical stages of MVD suggest a clinically and therapeutically relevant inflammatory component.

Acute undifferentiated leukaemia in a dog

BACKGROUND

Acute undifferentiated leukaemia (AUL) is considered a separate entity in the context of acute leukaemias. AUL is extremely rare in both humans and dogs, has a rapid clinical course and does not respond to treatment. It is characterised by the presence of blast cells within the bone marrow and/or peripheral blood at levels ≥ 20% and even up to 100% of all nucleated cells. Blast cells are unable to be differentiated on morphological, cytochemical and phenotypic criteria into myeloid or lymphoid lineages because of their immaturity and/or atypia.

CASE REPORT

An 8-year-old German Shepherd dog was referred for depression, asthenia, mild anaemia, thrombocytopenia and marked leucocytosis. Abdominal ultrasound showed hepatomegaly, splenomegaly, bilateral nephromegaly and enlargement of mesenteric lymph nodes. Echocardiography revealed biventricular hypertrophy with abnormal tissue density of the myocardium. Blood and bone marrow smears were composed of 95% unclassifiable and/or atypical blast cells and signs of dysplasia of the erythroid and thrombocytic/megakaryocytic lineages were present. Blast cells were negative for all cytochemical stains used and flow cytometry of peripheral blood revealed 85% of total leucocytes consisting of small-to-medium-sized cells, negative for all lymphoid and myeloid markers except CD45 and CD34. After necropsy, cytology and histology revealed that blast cells had diffusely infiltrated all tissues examined. Both erythroid and megakaryocytic extramedullary haemopoiesis was also detected in the spleen, lymph nodes and liver. All immunohistochemical stains used were negative.

CONCLUSION

On the basis of all the results, a diagnosis of acute leukaemia involving a very primitive haematopoietic precursor was made.

Serum cardiac troponin I concentrations decrease following treatment of primary immune-mediated haemolytic anaemia

OBJECTIVES

The measurement of serum cardiac troponin I concentrations in dogs with a range of non-primary cardiac illnesses suggests that cardiac myocyte damage is commonplace. Dogs with primary immune-mediated haemolytic anaemia have increased serum cardiac troponin I concentrations at the time of diagnosis. However, it is unclear whether biochemical evidence of cardiac myocyte damage improves following successful treatment of anaemia.

METHODS

A haematology profile was performed and serum cardiac troponin I concentrations were measured in 19 dogs with primary immune-mediated haemolytic anaemia before and after treatment.

RESULTS

The haematocrit increased significantly (P = 0 · 0001) following treatment of primary IMHA (median pre: 0 · 13 L/L, median post: 0 · 33 L/L). The serum cardiac troponin I concentrations decreased significantly (P < 0 · 05) after treatment (median pre: 0 · 26 ng/mL, median post: 0 · 16 ng/mL).

CLINICAL SIGNIFICANCE

Serum cardiac troponin I concentration decreases following successful treatment of primary immune-mediated haemolytic anaemia. The clinical and prognostic significance of serum cardiac troponin I concentrations before and after treatment in dogs with primary immune-mediated haemolytic anaemia merits further investigation.

Comparison of computed tomography pulmonary angiography and point-of-care tests for pulmonary thromboembolism diagnosis in dogs

OBJECTIVES

To evaluate the feasibility of CT pulmonary angiography for identification of naturally occurring pulmonary thromboembolism in dogs using predefined diagnostic criteria and to assess the ability of echocardiography, cardiac troponins, D-dimers and kaolin-activated thromboelastography to predict the presence of pulmonary thromboembolism in dogs.

METHODS

Twelve dogs with immune-mediated haemolytic anaemia and evidence of respiratory distress were prospectively evaluated. Dogs were sedated immediately before CT pulmonary angiography using intravenous butorphanol. Spiral CT pulmonary angiography was performed with a 16 detector-row CT scanner using a pressure injector to infuse contrast media through peripheral intravenous catheters. Pulmonary thromboembolism was diagnosed using predefined criteria. Contemporaneous tests included echocardiography, arterial blood gas analysis, kaolin-activated thromboelastography, D-dimers and cardiac troponins.

RESULTS

Based on predefined criteria, four dogs were classified as pulmonary thromboembolism positive, three dogs were suspected to have pulmonary thromboembolism and the remaining five dogs had negative scans. The four dogs identified with pulmonary thromboembolism all had discrete filling defects in main or lobar pulmonary arteries. None of the contemporaneous tests was discriminant for pulmonary thromboembolism diagnosis, although the small sample size was limiting.

CLINICAL SIGNIFICANCE

CT pulmonary angiography can be successfully performed in dogs under sedation, even in at-risk patients with respiratory distress and can both confirm and rule out pulmonary thromboembolism in dogs.

Cardiac troponin I in healthy newborn goat kids and in goat kids with cardiac nutritional muscular dystrophy

This study was designed to establish serum cardiac troponin I (cTnI) concentrations in healthy newborn goat kids and in those with cardiac nutritional muscular dystrophy (NMD). Thirty-five single full-term newborn goat kids (20 males and 15 females; age: 6.1 ± 3.5 h; weight 3.4 ± 0.68 kg), together with their respective mothers (Group 1; G1) were enrolled consecutively. Thirty-one goat kids (age: 9.5 ± 4.3 days) with NMD, together with 20 control goat kids (age: 7.8 ± 4.3 days) were also included in this study (Group 2; G2). Blood samples were collected from G1 within 12 h of birth and from G2 on admission. Serum samples were collected and analysed for cTnI. In G1, the mean serum concentration of cTnI in goat kids was 0.290 ± 0.37 ng/mL, with no statistically significant difference between male and female kids (P = 0.61). The mean cTnI concentration in the does was 0.017 ± 0.04, ng/mL. Serum values of cTnI in the goat kids and in their respective mothers differed significantly (P = 0.0001). In G2, the mean cTnI concentration was 0.02 ± 0.05 ng/mL in the control and 11.18 ± 20.07 ng/mL in the diseased goat kids, with a statistically significant difference between diseased and control goat kids (P = 0.017). Serum concentrations of cTnI are higher in goat kids than in their respective mothers. In conclusion, the cTnI assay appears to be a sensitive and specific marker for myocardial injury in goat kids.

Evaluation of a high-sensitivity assay for measurement of canine and feline serum cardiac troponin I

BACKGROUND

Cardiac troponins are established as the gold standard biomarkers for acute cardiac injury. As even small elevations of cardiac troponins have prognostic relevance in people, it is important to investigate the performance of sensitive assays for use in veterinary medicine.

OBJECTIVES

The aim of this study was to evaluate analytical and overlap performance of a high-sensitivity cardiac troponin I (cTnI) assay, the ADVIA Centaur CP TnI-Ultra assay, in dogs and cats.

METHODS

Serum samples from dogs and cats with cardiac disease or arrhythmias, along with samples of purified canine free cTnI and complexed cTnI, T, and C (cTnI-T-C) were used in the assay validation study. Intra- and inter-assay variation, linearity under dilution, spike-and-recovery analysis, and detection limit were investigated to assess analytical performance. Overlap performance was evaluated based on the ability of the assay to discriminate between healthy animals and animals with cardiac disease or arrhythmias.

RESULTS

Intra-assay variation of cTnI in canine and feline serum ranged from 3.9 to 6.4% and from 4.0 to 4.8%, respectively. Inter-assay variation ranged from 2.7 to 4.7% and from 4.0 to 7.8%, respectively. The assay demonstrated acceptable linearity under dilution within a clinically relevant range of cTnI concentrations. Spike-and-recovery analysis showed excessive recovery in the range 150.7%-242.0% for free cTnI and 121.1-196.3% for complexed cTnI-T-C, partly due to a matrix effect. Overlap performance was acceptable as animals with cardiac disease or arrhythmias (n = 45 dogs, n = 53 cats) had significantly higher cTnI concentrations than healthy controls (P < .0001).

CONCLUSIONS

The results confirm the ADVIA Centaur CP TnI-Ultra assay as a valuable tool for assessing cTnI and thus myocardial injury in dogs and cats.

Qualification of cardiac troponins for nonclinical use: a regulatory perspective

The US Food and Drug Administration (FDA) Biomarker Qualification Review Team presents its perspective on the recent qualification of cardiac troponins for use in nonclinical safety assessment studies. The goal of this manuscript is to provide greater transparency into the qualification process and factors that were considered in reaching a regulatory decision. This manuscript includes an overview of the data that were submitted and a discussion of the strengths and shortcomings of these data supporting the qualification decision. The cardiac troponin submission is the first literature-based biomarker application to be reviewed by the FDA and insights gained from this experience may aid future submissions and help streamline the characterization and qualification of future biomarkers.

Cardiac biomarker changes in camels (Camelus dromedarius) secondary to road transportation

OBJECTIVES

Little is known about cardiac biomarkers in camels despite their extensive use as draft animals. This study was designed to establish reference ranges for the cardiac biomarkers cardiac troponin I (cTnI) and creatine kinase myocardial b fraction (CK-MB) in healthy camels and to investigate their changes in response to road transportation.

ANIMALS

Twenty-five healthy camels transported for a 5 h round-trip journey.

METHODS

None of the camels had evidence of cardiac abnormalities on cardiac auscultation, echocardiography or electrocardiography. Three blood samples were obtained from each camel: 24 h before transportation (T0), within 2 h after unloading (T1) and 24 h after transportation (T2).

RESULTS

The mean cTnI concentration in the camels was 0.032 ± 0.023 ng/mL. All the camels had resting cTnI concentrations of <0.08 ng/mL. At T1, the cTnI concentration was significantly higher (P < 0.001) in all 25 camels compared to values at T0. The CK-MB concentration in the camels was 0.19 ± 0.05 ng/mL. All the camels had resting CK-MB concentrations of <0.33 ng/mL. At T1, the CK-MB concentration was higher in 3/25 camels compared to values at both T0 and T2. Concerning the hematobiochemical variables, significant increases were detected at T1 in total white blood cells, total protein, globulin, magnesium and phosphorus. Cardiac troponin I, CK-MB and all the hematobiochemical parameters had returned to their pre-transport values at T2.

CONCLUSIONS

5 h road transportation might have transient adverse effects on the cardiac muscle of healthy camels.

The cardiac biomarkers troponin I and CK-MB in nonpregnant and pregnant goats, goats with normal birth, goats with prolonged birth, and goats with pregnancy toxemia

This study was designed to establish the reference range for the cardiac biomarkers cardiac troponin I (cTnI) and creatine kinase myocardial band (CK-MB) in nonpregnant and pregnant goats, goats with normal birth, goats with prolonged birth associated with dystocia, and goats with pregnancy toxemia. Fifty-seven does, categorized into three groups (G1 to G3), were used. These groups were comprised of 20 healthy does (G1), 19 does with prolonged birth (G2), and 18 does with pregnancy toxemia (G3). Six blood samples (T0 to T5) were collected from G1. The first blood sample (T0) was taken before insemination, the second (T1) at the first trimester, the third (T2) at the second trimester, the fourth (T3) at the last trimester, the fifth (T4) within 12 h of parturition, and the sixth blood sample (T5) was taken 10 days after parturition. A sample of blood was obtained from G2 and G3 upon admission to the hospital. At T0 to T3, no cTnI was detected in any of the 20 does in G1. At parturition (T4), seven of the 20 goats (35%) exhibited slightly elevated cTnI concentrations (range, 0.01 to 0.04 ng/mL). Ten days after parturition (T5), cTnI was not detected in any of the 20 goats. In 10 of the 19 goats (53%) with prolonged birth (G2), the cTnI was significantly elevated to a mean value of 0.094 ± 0.155 ng/mL, with a maximum value of 0.61 ng/mL. In 16 of the 18 goats (89%) with pregnancy toxemia (G3), the cTnI was significantly elevated to a value of 0.852 ± 1.472 ng/mL, with a maximum value of 5.219 ng/mL. Comparing the values of CK-MB in G1 (T0 to T5), G2 and G3 revealed nonsignificant differences. Only a slight elevation in the CK-MB levels in goats with prolonged birth (G2) was noted. We concluded that in healthy does, the cardiac biomarker cTnI is not elevated during normal pregnancy. The serum cTnI concentration may be elevated in a number of goats at normal vaginal or cesarean delivery. Finally, cTnI is significantly elevated in does with pregnancy toxemia and could be used as a prognostic indicator in such cases. The cardiac biomarker CK-MB is not a good indicator of parturition stress in does. Serum cTnI is elevated in goats with pregnancy toxemia, indicating some degree of cardiac dysfunction.

Detection and comparison of microRNA expression in the serum of Doberman Pinschers with dilated cardiomyopathy and healthy controls

Background

Dilated cardiomyopathy (DCM) is the most common heart disease in Doberman Pinschers. MicroRNAs (miRNAs) are short non-coding RNAs playing important roles in gene regulation. Different miRNA expression patterns have been described for DCM in humans and might represent potential diagnostic markers. There are no studies investigating miRNA expression profiles in canine DCM. The aims of this study were to screen the miRNA expression profile of canine serum using miRNA microarray and to compare expression patterns of a group of Doberman Pinschers with DCM and healthy controls.

Results

Eight Doberman Pinschers were examined by echocardiography and 24-hour-ECG and classified as healthy (n = 4) or suffering from DCM (n = 4). Total RNA was extracted from serum and hybridized on a custom-designed 8x60k miRNA microarray (Agilent) containing probes for 1368 individual miRNAs. Although total RNA concentrations were very low in serum samples, 404 different miRNAs were detectable with sufficient signal intensity on miRNA microarray. 22 miRNAs were differentially expressed in the two groups (p < 0.05 and fold change (FC) > 1.5), but did not reach statistical significance after multiple testing correction (false discovery rate adjusted p > 0.05). Five miRNAs were selected for further analysis using quantitative Real-Time RT-PCR (qPCR) assays. No significant differences were found using specific miRNA qPCR assays (p > 0.05).

Conclusions

Numerous miRNAs can be detected in canine serum. Between healthy and DCM dogs, miRNA expression changes could be detected, but the results did not reach statistical significance most probably due to the small group size. miRNAs are potential new circulating biomarkers in veterinary medicine and should be investigated in larger patient groups and additional canine diseases.

Evaluation of C-reactive protein, haptoglobin and cardiac troponin 1 levels in brachycephalic dogs with upper airway obstructive syndrome

Background

Brachycephalic dogs have unique upper respiratory anatomy with abnormal breathing patterns similar to those in humans with obstructive sleep apnea syndrome (OSAS). The objective of this study was to evaluate the correlation between anatomical components, clinical signs and several biomarkers, used to determine systemic inflammation and myocardial damage (C-reactive protein, CRP; Haptoglobin, Hp; cardiac troponin I, cTnI), in dogs with brachycephalic upper airway obstructive syndrome (BAOS).

Results

Fifty brachycephalic dogs were included in the study and the following information was studied: signalment, clinical signs, thoracic radiographs, blood work, ECG, components of BAOS, and CRP, Hp and cTnI levels. A high proportion of dogs with BAOS (88%) had gastrointestinal signs. The prevalence of anatomic components of BAOS was: elongated soft palate (100%), stenotic nares (96%), everted laryngeal saccules (32%) and tracheal hypoplasia (29.1%). Increased serum levels of biomarkers were found in a variable proportion of dogs: 14% (7/50) had values of CRP > 20 mg/L, 22.9% (11/48) had values of Hp > 3 g/L and 47.8% (22/46) had levels of cTnI > 0.05 ng/dl. Dogs with everted laryngeal saccules had more severe respiratory signs (p<0.02) and higher values of CRP (p<0.044). No other statistical association between biomarkers levels and severity of clinical signs was found.

Conclusions

According to the low percentage of patients with elevated levels of CRP and Hp, BAOS does not seem to cause an evident systemic inflammatory status. Some degree of myocardial damage may occur in dogs with BAOS that can be detected by cTnI concentration.

Cardiac troponin I in calves with congenital heart disease

BACKGROUND

The association between plasma cardiac troponin I (cTnI) and the magnitude of cardiac enlargement in calves with congenital heart disease (CHD) are not well defined.

OBJECTIVE

To investigate the relationship between plasma cTnI concentrations and cardiac size in healthy calves and calves with CHD.

ANIMALS

A total of 19 healthy calves (control) and 12 Holstein calves with CHD (patent ductus arteriosus, ventricular septal defect, tetralogy of Fallot or double outlet right ventricle).

METHODS

Case control study. All animals underwent a comprehensive transthoracic echocardiographic study to document cardiac health or presence of CHD. The vertebral heart score (VHS) was determined in each animal using right lateral survey radiographic images. Blood samples were collected via jugular venipuncture and plasma cTnI concentration and creatine kinase (CK) activity were determined by a 3rd generation immunoassay and an automatic biochemical analyzer, respectively. Groups were compared using Mann-Whitney U-test and receiver-operating characteristics (ROC) curve analysis.

RESULTS

Calves with CHD had significantly larger VHS values and higher plasma cTnI concentrations (P < .001) compared to control. Creatine kinase activity was not different between the control and CHD groups of calves. Diagnostic cutoffs of VHS and plasma cTnI for discrimination of groups were 8.9 vertebrae and 0.035 ng/mL, respectively. The cTnI concentration in plasma was significantly correlated with VHS (r (2) =0.512, P < .001).

CONCLUSION AND CLINICAL RELEVANCE

Our results suggest that determination of plasma cTnI concentrations in calves with clinical signs compatible with CHD might prove useful as a guide to quantify cardiac remodeling associated with increased cardiac size.

Dosagem sérica de troponina I em cães com desnível do segmento ST utilizando quimioluminescência

Com o intuito de verificar algum dano nas células do miocárdio, utilizaram-se 38 cães, 20 com traçado eletrocardiográfico normal, grupo 1, e 18 com desníveis do segmento ST, grupo 2, em registro na derivação II, velocidade de 50mm/s e sensibilidade N (1mV=1cm). No grupo 1, a dosagem sérica da troponina I (cTnI) destinou-se à obtenção dos valores referenciais (ng/mL) que seriam confrontados com os obtidos no grupo 2. A média e o desvio-padrão foram, respectivamente, 0,16ng/mL e 0,11ng/mL e 0,20ng/mL e 0,11ng/mL, nos grupos 1 e 2. A cTnI não apresentou evidências de associação com idade, massa corpórea, creatinafosfoquinase total e potássio nos dois grupos. Não houve diferenças significativas nos valores de cTnI entre os grupos. Conclui-se que é possível a utilização do kit de ensaio imunométrico quimioluminescente humano para a espécie canina e que a hipóxia-isquemia, revelada pelo desnível do segmento ST não acarreta dano miocárdico ou este é mínimo e indetectável.

Incidence of elevation of cardiac troponin I prior to and following routine general anaesthesia in dogs

OBJECTIVE

To estimate the incidence of raised cTnI after general anaesthesia in dogs and to explore major risk factors influencing this.

STUDY DESIGN

Prospective clinical study. Animals A total of 107 (ASA physical status 1-2) dogs, 63% male and 37% female, median age 5 years (range 0.3-13.4), median weight 24.4 kg (range 4.2-66.5 kg) undergoing anaesthesia for clinical purposes.

METHODS

Venous blood samples were taken within 24 hours prior to induction and 24 hours after the termination of anaesthesia. Serum concentrations of cardiac troponin I were measured using a chemiluminescent enzyme immunometric assay with a lower level of detection of 0.20 ng mL(-1) (below this level <0.20 ng mL(-1)). Continuous data were assessed graphically for normality and paired and unpaired data compared with the Wilcoxon signed ranks and Mann-Whitney U-tests respectively. Categorical data were compared with the Chi squared or Fisher's exact test as appropriate (p < 0.05).

RESULTS

Of the 107 dogs recruited, 100 had pre- and post-anaesthetic cTnI measured. The median pre-anaesthesia cTnI was '<0.20' ng mL(-1) (range '<0.20'-0.43 ng mL(-1)) and the median increase from pre-anaesthesia level was 0.00 ng mL(-1) (range -0.12 to 0.61 ng mL(-1)). Fourteen dogs had increased cTnI after anaesthesia relative to pre-anaesthesia (14%, 95% CI 7.2-20.8%, range of increase 0.03-0.61 ng mL(-1)). Six animals had cTnI levels that decreased (range 0.02-0.12 ng mL(-1)). Older dogs were more likely to have increased cTnI prior to anaesthesia (OR = 5.32, 95% CI 1.35-21.0, p = 0.007) and dogs 8 years and over were 3.6 times as likely to have an increased cTnI after anaesthesia (95% CI 1.1-12.4, p = 0.028).

CONCLUSION AND CLINICAL RELEVANCE

Increased cTnI after anaesthesia relative to pre-anaesthesia levels was observed in a number of apparently healthy dogs undergoing routine anaesthesia.