Analytical validation, sample stability, and clinical evaluation of a new high-sensitivity cardiac troponin I immunoassay for use in dogs, with comparison to a previous ultrasensitive assay.

Cardiac troponin I (cTnI) is considered the gold standard biomarker for myocardial injury and shows a high degree of homology between humans and dogs. The ADVIA Centaur XP High-Sensitivity Troponin I (AC-cTnI-HS) assay has been validated for use in humans but not dogs. The study objectives were to analytically validate the AC-cTnI-HS assay in dogs, to assess correlation between the AC-cTnI-HS and a previous ADVIA Centaur TnI-Ultra (AC-cTnI-U) assay, to assess cTnI sample storage stability, and to clinically evaluate the AC-cTnI-HS assay in healthy dogs and dogs with cardiac disease. Canine serum samples were used for analytical validation. Intra- and inter-assay variability, dilutional parallelism, and spiking recovery were assessed. Samples from 196 client-owned dogs were evaluated (healthy dogs (n = 39) or dogs with congenital heart disease (n = 54), myxomatous mitral valve disease (n = 68), dilated cardiomyopathy (n = 15), or myocarditis (n = 20)). Inter- and intra-assay coefficient of variation (%CV) was between 2.8-41.4% and 3.8-30.2%, respectively, with pools with concentrations >20 pg/mL all having %CVs <10%. The observed to expected ratios for dilutional parallelism and spiking recovery experiments ranged between 92.3 and 266.7.0% and 84.3 and 108%, respectively. A strong correlation between the AC-cTnI-HS and AC-cTnI-U assays was observed (Spearman's ρ = 0.927), though a proportional bias existed, with AC-cTnI-HS assay concentrations being proportionally lower than AC-cTnI-U assay concentrations. Serum samples stored at -80°C had stable cTnI measurements for up to 2.7 years and after a single freeze-thaw cycle. Healthy dogs and dogs with congenital heart disease had significantly lower cTnI concentrations than dogs in the other three groups. The AC-cTnI-HS assay precisely, reproducibly, and accurately measures cTnI concentrations in dog serum with cTnI concentrations >20 pg/mL.

A masked, placebo-controlled, randomized clinical trial evaluating safety and the effect on cardiac function of low-dose rapamycin in 17 healthy client-owned dogs.

Introduction: Geroscience studies of low-dose rapamycin in laboratory species have identified numerous benefits, including reversing age-related cardiac dysfunction. Cardiovascular benefits have been observed in dogs with 10 weeks of treatment, raising questions about possible benefits and adverse effects of long-term use of low-dose rapamycin. The objectives of this study were to assess the impact of 6 months of low-dose rapamycin on echocardiographic indices of cardiac function in healthy dogs and to document the occurrence of adverse events. Methods: Seventeen client-owned dogs aged 6-10 years, weighing 18-36 kg, and without significant systemic disease were included in a prospective, randomized, placebo-controlled, masked clinical trial. Low-dose rapamycin (0.025 mg/kg) or placebo was administered three times per week for 6 months. Baseline, 6-month, and 12-month evaluation included physical examination, cardiology examination, and clinicopathology. Three-month evaluation included physical examination and clinicopathology. Owners completed online questionnaires every 2 weeks. Results: There were no statistically significant differences in echocardiographic parameters between rapamycin and placebo groups at 6 or 12 months. No clinically significant adverse events occurred. In 26.8% of the bi-weekly surveys owners whose dogs received rapamycin reported perceived positive changes in behavior or health, compared to 8.1% in the placebo group (p = 0.04). Discussion: While no clinically significant change in cardiac function was observed in dogs treated with low-dose rapamycin, the drug was well-tolerated with no significant adverse events.

Feasibility of a point-of-care ultrasound protocol for cardiorespiratory evaluation of horses in different clinical settings.

BACKGROUND: A point-of-care ultrasound (POCUS) protocol for evaluation of the cardiac and respiratory systems in horses does not exist. OBJECTIVES: (a) Describe the windows of a POCUS protocol for cardiorespiratory assessment of horses (CRASH); (b) Estimate the number of acoustic windows that can be acquired by a sonographer-in-training; (c) Estimate the time required to complete the protocol for specific groups of horses; (d) Describe the sonographic abnormalities detected in horses presented with cardiovascular, respiratory, or systemic disease. ANIMALS: Twenty-seven healthy horses, 14 horses competing in athletic events, and 120 horses with clinical disease. METHOD: A pocket-sized ultrasound device was used to acquire 7 sonographic cardiorespiratory windows in various clinical scenarios. The duration of the examination was timed, and images were evaluated for diagnostic quality. Abnormalities in horses with clinical disease were determined by an expert sonographer. RESULTS: The CRASH protocol could be performed in healthy and diseased horses in hospital, barn, and competition settings between 5.5 ± 0.9 (athletic horses) and 6.9 ± 1.9 min (horses with clinical disease). Thoracic windows were obtained most consistently, followed by right parasternal long-axis echocardiographic windows. Frequently detected abnormalities were pleural fluid, lung consolidation, B-lines, and moderate-to-severe left-sided heart disease. CONCLUSIONS: The CRASH protocol was feasible using a pocket-sized ultrasound device in various groups of horses, could be completed rapidly in a variety of settings, and frequently identified sonographic abnormalities when evaluated by an expert sonographer. The diagnostic accuracy, observer agreement, and utility of the CRASH protocol merit further evaluation.

Whole blood and plasma taurine reference intervals in adult Cavalier King Charles Spaniels and correlations between taurine concentration, diet and mitral valve disease.

OBJECTIVE: To determine breed-specific reference intervals for whole blood (WB) and plasma taurine concentrations in adult, overtly healthy Cavalier King Charles Spaniels (CKCSs) and determine whether taurine concentrations differ across preclinical myxomatous mitral valve disease (MMVD) stages or between CKCSs eating diets that meet World Small Animal Veterinary Association (WSAVA) nutritional guidelines versus other diets. ANIMALS: 200 privately owned CKCSs. PROCEDURES: Clinically healthy adult CKCSs were recruited prospectively. Diet and supplement history was collected. Dogs were staged by echocardiography using MMVD consensus guidelines. Taurine concentrations were measured in deproteinized lithium heparin WB and plasma samples with the postcolumn ninhydrin derivatization method on a dedicated amino acid analyzer. RESULTS: There were 12 stage A (6%), 150 stage B1 (75%), and 38 stage B2 (19%) CKCSs. Seventy-eight dogs (39%) were reported by their owners to be eating diets meeting WSAVA nutritional guidelines; 116 (58%) were not. Taurine concentrations in plasma (P = .444) and WB (P = .073) were not significantly different across MMVD stages or between CKCSs eating diets meeting WSAVA nutritional guidelines versus other diets (P = .345 and P = .527, respectively). Reference intervals for WB taurine (152 to 373 µM) and plasma taurine (51 to 217 µM) concentrations in CKCSs were generated. CLINICAL RELEVANCE: In CKCSs, taurine concentrations do not differ significantly based on preclinical MMVD stage, nor do they differ significantly based on consumption of a diet that does or does not meet WSAVA nutritional guidelines.

Asymptomatic Canine Degenerative Valve Disease: Diagnosis and Current and Future Therapies.

Degenerative valve disease (DVD) is the leading cause of heart disease and heart failure in the dog. The first consensus statement published in 2009 by the American College of Veterinary Internal Medicine was updated in 2019 and provides guidelines for the diagnosis and treatment of DVD. These updated guidelines recommend treatment with pimobendan in stage B2 DVD characterized by sufficient left heart enlargement. Asymptomatic dogs with DVD that do not meet or exceed the definition of stage B2 are considered stage B1. No treatment is recommended in stage B1 DVD. This article discusses the relevant scientific background and practical application of the updated DVD guidelines related to stage B. In addition, management of common sequelae of DVD that can result in clinical signs unrelated to congestive heart failure will be reviewed. The impact of new evidence on current recommendations and a glimpse into novel diagnostic approaches and possible future therapies will also be addressed.

Analytical validation of a novel point-of-care immunoassay for canine N-terminal pro-brain natriuretic peptide analysis.

BACKGROUND: N-terminal pro-brain natriuretic peptide (NT-proBNP) is a widely used point-of-care (POC) cardiac biomarker in human medicine. Canine NT-proBNP is used less in veterinary medicine, possibly due to the lack of a POC canine NT-proBNP assay resulting in temporal delay, increased degradation in transport, and high reported variability in the available assay. A new quantitative POC analyzer allows fast, onsite measurement of NT-proBNP, minimizing preanalytical error and reducing variability. OBJECTIVE: We aimed to analytically validate an NT-proBNP assay (Vcheck) according to American Society of Veterinary Clinical Pathology (ASVCP) and Clinical Laboratory Improvement Amendments (CLIA) specifications. METHODS: Archived and prospective plasma and serum samples were collected from male and female, client-owned dogs of various breeds with cardiac abnormalities (n = 81) and a healthy control population (n = 225). Precision, accuracy, analytical sensitivity, and specificity, and other statistical analyses were performed. RESULTS: Imprecision was considered acceptable with a coefficient of variation ranging from 9% at 4000 pmol/L to 20% at 600 pmol/L. The lower limit of quantitation was 650 pmol/L based on repetitive measures evaluation. Comparison of the Vcheck assay with the Cardiopet NT-proBNP assay revealed an excellent correlation with minimal bias when preanalytical factors were controlled. Significant degradation of NT-proBNP occurred when current methods were used at refrigerated and room temperatures, which could change diagnostic and prognostic decision-making. Age-partitioned reference intervals have high reference values of 750 pmol/L and 1280 pmol/L for juvenile and adult dogs, respectively. CONCLUSIONS: The Vcheck NT-ProBNP assay provides analytically acceptable results. Onsite testing can minimize variability related to preanalytical error and provide clinically useful contemporaneous results. Samples should be centrifuged immediately and analyzed within 2 hours of collection.

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.

Intracardiac heartworms in dogs: Clinical and echocardiographic characteristics in 72 cases (2010-2019).

BACKGROUND: Heartworms, a cause of pulmonary hypertension (PH) in dogs, can migrate from the pulmonary arteries into the heart resulting in life-threatening caval syndrome (CS). OBJECTIVES: To describe clinical and echocardiographic characteristics in dogs with intracardiac heartworms including estimated heartworm burden and frequency of PH and pigmenturia. ANIMALS: Seventy-two client-owned dogs with heartworms. METHODS: Retrospective study. Data collected from an electronic medical records search for dogs with intracardiac heartworms included clinicopathologic, echocardiographic, and procedural findings. Dogs with heartworms isolated to the pulmonary arteries were excluded. RESULTS: Estimated intracardiac heartworm burden was low in 14 of 72 (19%) and high in 58 of 72 (81%) dogs. The majority were small breed (54/72; 75%; 29/72; 40% Chihuahuas) and had a high likelihood of PH (67/72; 93%). Pigmenturia was the second most common clinical finding (31/72; 43%) after lethargy (32/72; 44%). Anemia (37/55; 36%), pigmenturia (30/58; 52%), and bilirubinuria (28/36; 78%) were significantly more common in dogs with a high worm burden (P < .05). Based on the presence of anemia, pigmenturia, and clinical signs, 18 of 72 dogs (25%) were considered to have CS. CONCLUSIONS AND CLINICAL IMPORTANCE: Although the majority of dogs with intracardiac heartworms had a high worm burden and high likelihood of PH, only 25% had clinical evidence of CS. Echocardiography is a useful tool to identify intracardiac heartworms, detect likelihood of PH, and could be useful for staging heartworm positive small breed dogs for intracardiac heartworm migration.

Temporal changes in clinical and radiographic variables in dogs with preclinical myxomatous mitral valve disease: The EPIC study.

BACKGROUND: The Evaluation of pimobendan in dogs with cardiomegaly caused by preclinical myxomatous mitral valve disease (EPIC) study monitored dogs with myxomatous mitral valve disease (MMVD) as they developed congestive heart failure (CHF). OBJECTIVES: To describe the changes in clinical and radiographic variables occurring as dogs with MMVD and cardiomegaly develop CHF, compared to similar dogs that do not develop CHF. ANIMALS: One hundred and thirty-five, and 73 dogs that did or did not develop CHF, respectively. MATERIALS AND METHODS: The following variables were evaluated in 2 groups of dogs (dogs that did or did not develop CHF): Heart rate (HR), clinic respiratory rate (RR), home-measured resting respiratory rate (RRR), rectal temperature (RT), body weight (BW), and vertebral heart sum (VHS). Absolute value and rate of change of each variable were calculated for each day a dog was in study. Daily means were calculated and plotted against time. The onset of CHF or last visit before leaving the study were set as reference time points. RESULTS: The most extreme values and rate of change occurred in variables immediately before onset of CHF. Vertebral heart sum increased earliest. Heart rate, RR, and RRR also increased. Rectal temperature and BW decreased. Increases in RR and RRR were most extreme and occurred immediately before CHF. CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs with MMVD and cardiomegaly experience increases in HR, RR, RRR, and VHS, and decreases in BW and RT as they develop CHF. The variables with highest absolute change and rate of change were RR and RRR. These findings reinforce the value of RR and RRR as indicators of impending or incipient CHF.

Long-term incidence and risk of noncardiovascular and all-cause mortality in apparently healthy cats and cats with preclinical hypertrophic cardiomyopathy.

BACKGROUND: Epidemiologic knowledge regarding noncardiovascular and all-cause mortality in apparently healthy cats (AH) and cats with preclinical hypertrophic cardiomyopathy (pHCM) is limited, hindering development of evidence-based healthcare guidelines. OBJECTIVES: To characterize/compare incidence rates, risk, and survival associated with noncardiovascular and all-cause mortality in AH and pHCM cats. ANIMALS: A total of 1730 client-owned cats (722 AH, 1008 pHCM) from 21 countries. METHODS: Retrospective, multicenter, longitudinal, cohort study. Long-term health data were extracted by medical record review and owner/referring veterinarian interviews. RESULTS: Noncardiovascular death occurred in 534 (30.9%) of 1730 cats observed up to 15.2 years. Proportion of noncardiovascular death did not differ significantly between cats that at study enrollment were AH or had pHCM (P = .48). Cancer, chronic kidney disease, and conditions characterized by chronic weight-loss-vomiting-diarrhea-anorexia were the most frequently recorded noncardiovascular causes of death. Incidence rates/risk of noncardiac death increased with age in AH and pHCM. All-cause death proportions were greater in pHCM than AH (65% versus 40%, respectively; P < .001) because of higher cardiovascular mortality in pHCM cats. Comparing AH with pHCM, median survival (study entry to noncardiovascular death) did not differ (AH, 9.8 years; pHCM, 8.6 years; P = .10), but all-cause survival was significantly shorter in pHCM (P = .0001). CONCLUSIONS AND CLINICAL IMPORTANCE: All-cause mortality was significantly greater in pHCM cats due to disease burden contributed by increased cardiovascular death superimposed upon noncardiovascular death.

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.

Anatomy, baseline characteristics, and procedural outcome of patent ductus arteriosus in German Shepherd dogs.

BACKGROUND: German Shepherd dogs (GSD) are predisposed to developing patent ductus arteriosus (PDA) and are reportedly prone to type III (tubular) PDA anatomy. Dogs with type III anatomy are not considered favorable candidates for device-based intervention. OBJECTIVE: To describe the PDA anatomy, baseline characteristics, and procedural outcome of GSD with PDA. ANIMALS: Twenty-eight client-owned GSD. METHODS: Retrospective review of medical records of 28 GSD diagnosed with PDA that underwent surgical ligation or transcatheter device closure between 2007 and 2017. RESULTS: German Shepherd dogs with PDA often presented with clinical signs (50%), concurrent congenital heart disease (35.7%), and arrhythmias (29%). Dogs were typically mature at presentation (median age, 12.1 months) and evenly distributed by sex (57% female). The PDA anatomy was classified in 24 of 28 GSD, with type II anatomy being most common (21/24). Three dogs had unusual anatomy (type IV in 1, type V in 2). Median minimal ductal diameter (MDD) in this population was larger than previously reported in a mixed population and ranged between 4.4 and 4.9 mm depending upon imaging modality. Successful closure was achieved using an Amplatz canine duct occluder (ACDO) in 22 dogs or by surgical ligation in 6 dogs. No cases of type III anatomy were confirmed. CONCLUSIONS AND CLINICAL IMPORTANCE: The majority of GSD in this population had type II PDA anatomy that was amenable to ACDO deployment. Predisposition for large MDD and occasional, unusual PDA anatomy suggests that transesophageal echocardiography may be beneficial for optimal procedural planning in this breed.

International collaborative study to assess cardiovascular risk and evaluate long-term health in cats with preclinical hypertrophic cardiomyopathy and apparently healthy cats: The REVEAL Study.

BACKGROUND: Hypertrophic cardiomyopathy is the most prevalent heart disorder in cats and principal cause of cardiovascular morbidity and mortality. Yet, the impact of preclinical disease is unresolved. HYPOTHESIS/OBJECTIVES: Observational study to characterize cardiovascular morbidity and survival in cats with preclinical nonobstructive (HCM) and obstructive (HOCM) hypertrophic cardiomyopathy and in apparently healthy cats (AH). ANIMALS: One thousand seven hundred and thirty client-owned cats (430 preclinical HCM; 578 preclinical HOCM; 722 AH). METHODS: Retrospective multicenter, longitudinal, cohort study. Cats from 21 countries were followed through medical record review and owner or referring veterinarian interviews. Data were analyzed to compare long-term outcomes, incidence, and risk for congestive heart failure (CHF), arterial thromboembolism (ATE), and cardiovascular death. RESULTS: During the study period, CHF, ATE, or both occurred in 30.5% and cardiovascular death in 27.9% of 1008 HCM/HOCM cats. Risk assessed at 1, 5, and 10 years after study entry was 7.0%/3.5%, 19.9%/9.7%, and 23.9%/11.3% for CHF/ATE, and 6.7%, 22.8%, and 28.3% for cardiovascular death, respectively. There were no statistically significant differences between HOCM compared with HCM for cardiovascular morbidity or mortality, time from diagnosis to development of morbidity, or cardiovascular survival. Cats that developed cardiovascular morbidity had short survival (mean ± standard deviation, 1.3 ± 1.7 years). Overall, prolonged longevity was recorded in a minority of preclinical HCM/HOCM cats with 10% reaching 9-15 years. CONCLUSIONS AND CLINICAL IMPORTANCE: Preclinical HCM/HOCM is a global health problem of cats that carries substantial risk for CHF, ATE, and cardiovascular death. This finding underscores the need to identify therapies and monitoring strategies that decrease morbidity and mortality.

Comparative, multidimensional imaging of patent ductus arteriosus and a proposed update to the morphology classification system for dogs.

BACKGROUND: Accurately assessing the morphology and shape of the patent ductus arteriosus (PDA) and obtaining measurements are important to avoid procedural complications. OBJECTIVES: To characterize and compare PDA morphology, shape, and dimensions with angiography and echocardiography. ANIMALS: 25 client-owned dogs with echocardiographically confirmed PDA. METHODS: Prospective case series. Imaging consisted of single plane angiography, transthoracic echocardiography from the right (TTE-R) and left (TTE-L), and two-dimensional, biplane, and three-dimensional transesophageal echocardiography (TEE-2D and TEE-3D). Measurements included angiographic minimal ductal diameter (MDD), echocardiographic pulmonary ostium in a single dimension (TTE-R, TTE-L, and TEE-2D) and in perpendicular dimensions (TEE-3D) with similar measurements of the ampulla 3 mm above the MDD or pulmonary ostium. The morphology and shape of the PDA were characterized. RESULTS: Catheter-based occlusion (N = 20) and surgical ligation (N = 5) were performed without complication. Angiographic morphology was classified as type II (N = 19), type III (N = 1), and other (N = 1). Angiographic MDD and TEE-2D pulmonary ostium measurements were significantly (P = .008) but weakly correlated (r = .56); similar relationships were found for ampulla diameter measurements (P < .0001; r = .75). In general, TEE-2D did not correlate with other imaging modalities measurements. Based on TEE-3D measurements, the majority of pulmonary ostium (17/24; 71%) and ampulla (19/24; 79%) were oval. CONCLUSIONS AND CLINICAL IMPORTANCE: Measurements using different imaging modalities are not interchangeable. TEE-3D provided an en face view of the PDA that cannot be replicated with other echocardiographic techniques and demonstrated an oval shape in the majority of dogs. We propose an update to the current classification system to include additional PDA morphologies.

An experimental canine patent ductus arteriosus occlusion device based on shape memory polymer foam in a nitinol cage.

Patent ductus arteriosus (PDA) is a congenital cardiovascular defect in which a fetal connection between the aorta and pulmonary artery does not spontaneously close shortly after birth. If left uncorrected serious complications and even death can occur. Surgical ligation is the traditional treatment method; however, it is an invasive procedure, that motivates development of a minimally invasive option. Shape memory polymer (SMP) foams are unique materials that hold promise in the field of minimally invasive occlusion devices. In this work, a prototype nitinol foam cage (NFC) incorporating SMP foams has been designed and evaluated in multiple mechanical and in vitro verification tests. The NFC demonstrated acceptable fatigue resistance in a preliminary strut integrity test, withstanding one million cycles without complete strut fracture. Radial force analysis of both thick- and thin-walled prototype variations generated less vessel distension and wall tension in a vessel mimic compared to a commercial device. The NFCs exhibited negligible in vitro migration, comparable to that of a commercial device, using simplified, ideal models of PDA. Deployment characteristics of the prototypes were evaluated and compared to that of a commercial device when delivered into physiological models of PDA. During mock deployments, a veterinary cardiologist noted that, while deliverable, the thin-walled NFC prototype exhibited poor deployment characteristics, however the thick-walled NFC had deployment characteristics comparable to that of a commercial device. The promising results of this study warrant further investigation of the NFC device for canine PDA closure.

Asymptomatic Canine Degenerative Valve Disease: Current and Future Therapies.

Degenerative valve disease (DVD) is the leading cause of heart disease and congestive heart failure (CHF) in the dog. The first published consensus statement provided guidelines for the diagnosis and treatment of DVD. Although treatment was not recommended in stage B1 DVD, consensus was not reached regarding evidence-based recommendations for treatment of stage B2 DVD. This article addresses the impact of new evidence on historical recommendations for stage B DVD and gives the reader a glimpse into possible future therapies. Management of common sequelae of DVD that can result in clinical signs that are not attributable to CHF is also discussed.

Biologic variability of cardiac troponin I in healthy dogs and dogs with different stages of myxomatous mitral valve disease using standard and high-sensitivity immunoassays.

BACKGROUND: Biologic variability (BV) is one aspect of interpreting changes in biomarker concentrations known to be clinically important in people with cardiac disease, but it has not been adequately addressed in dogs so far. OBJECTIVES: The purpose of the study was to determine BV of cardiac troponin I (cTnI) in healthy dogs and dogs with 3 stages of myxomatous mitral valve disease (MMVD). METHODS: Healthy dogs and dogs with 3 stages of MMVD were prospectively assigned to groups based on comprehensive clinical evaluation using current guidelines. Concentrations of cTnI were measured hourly, daily, and weekly using standard and high-sensitivity immunoassays. Within- (CVI ) and between-subject (CVG ) coefficients of variability, percent reference change value (RCV), and index of individuality (IoI) were calculated. RESULTS: All 10 healthy dogs and 76/112 (68%) of samples from 28 MMVD dogs had cTnI concentrations below the limit of detection (LOD) using a standard sensitivity immunoassay. Only 49/160 (31%) of healthy dog samples and no MMVD samples had cTnI below the high-sensitivity immunoassay LOD. Data analysis for the high-sensitivity immunoassay revealed CVI of 48.1%, CVG of 60.1%, RCV of 134.0%, and IoI of 0.804 in healthy dogs. In MMVD dogs, CVI was 39.6%, CVG was 80.7%, RCV was 110%, and IoI was 0.494. Of all MMVD dogs, those with Stage B2 had the lowest RCV of 91%. CONCLUSIONS: Biologic variability affects cTnI concentrations in healthy dogs and dogs with MMVD. Consideration of BV may be clinically relevant when monitoring individual changes in cTnI values, using high-sensitivity immunoassays.

Biologic variability of N-terminal pro-brain natriuretic peptide in healthy dogs and dogs with myxomatous mitral valve disease.

INTRODUCTION: To determine the biologic variability of N-terminal pro-brain natriuretic peptide (NTproBNP) in healthy dogs and dogs with various stages of myxomatous mitral valve disease (MMVD). ANIMALS: Thirty-eight privately owned dogs: 28 with MMVD and 10 healthy controls. MATERIALS AND METHODS: Prospective clinical study with comprehensive evaluation used to group dogs as healthy or into three stages of MMVD based on current guidelines. NTproBNP was measured hourly, daily, and weekly. For each group, analytical (CVA), within-subject (CVI), and between-subject (CVG) coefficients of variability were calculated in addition to percent critical change value (CCV) and index of individuality (IoI). RESULTS: For healthy dogs, calculated NTproBNP values were: CVA = 4.2%; CVI = 25.2%; CVG = 49.3%; IoI = 0.52, and CCV = 70.8%. For dogs with MMVD, calculated NTproBNP values were: CVA = 6.2%; CVI = 20.0%; CVG = 61.3%; IoI = 0.34, and CCV = 58.2%. CONCLUSIONS: Biologic variability affects NTproBNP concentrations in healthy dogs and dogs with MMVD. Monitoring serial individual changes in NTproBNP may be clinically relevant in addition to using population-based reference ranges to determine changes in disease status.

Pharmacotherapy of feline cardiomyopathy: Chronic management of heart failure.

The natural progression of cardiomyopathy in cats can lead to congestive heart failure. This review enumerates commonly and uncommonly used medications that can be used for the long-term treatment of cats that have positively responded to initial management of acute heart failure. The advantages, drawbacks, and authors' preferred approach are presented for each medication.