Association between echocardiographic indexes and urinary Neutrophil Gelatinase-Associated Lipocalin (uNGAL) in dogs with myxomatous mitral valve disease.

Neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker of tubular damage, and its elevation has been described in human and canine cardiorenal syndrome. The aim was to evaluate the association between echocardiographic indexes and urine NGAL (uNGAL) and uNGAL normalized to urine creatinine (uNGALC) in dogs with MMVD. This is a multicentric prospective cross-sectional study. A total of 77 dogs with MMVD at different ACVIM stages were included. All dogs underwent echocardiography, serum chemistry, and urinalysis. Echocardiographic data analyzed were shortening fraction (SF), left ventricular diastolic (LVIDDn) and systolic (LVIDSn) diameters normalized for body weight, left atrium to aortic root ratio (LA/Ao), maximal (LAVMax) and minimal (LAVMin) left atrial volumes, LA stroke volume (LASV), early diastolic mitral peak velocity (EVmax), EVmax to tissue Doppler E' wave (E/E'), aortic (VTIAo) and mitralic (VTIMit) velocity time integrals and their ratio (VTIMit/VTIAo), and tricuspid regurgitation velocity (TRVmax). In the univariate analysis LASV, TRVmax, LAVMax, LVIDDn, and VTIMit/VTIAo were independent predictors of increased uNGAL and uNGALC; however, only LASV [(OR: 1.96, 95% CI: 1.16 to 3.31) P = 0.01 for NGAL, and (OR: 2.79, 95% CI: 1.50 to 5.17) P < 0.001 for NGALC] and TRVmax [(OR: 1.73, 95% CI: 1.20-2.51) P = 0.002 for NGAL, and (OR: 1.50, 95% CI: 10.07-2.10) P = 0.015 for NGALC] remained statistically significant in the multivariable analysis. Based on our results, LASV and TRVmax are associated with increased uNGAL and uNGALC. These parameters might detect dogs with MMVD at higher risk of developing kidney damage.

Effects of acute atrial fibrillation and cardioversion on left and right atrial pressures in a dog.

The occurrence of right-sided congestive heart failure (CHF) in dogs with left-sided heart disease is well-recognized, but its mechanisms are incompletely understood. A 12-year-old Maltese dog was admitted to the clinic for left atrial decompression to treat recurrent CHF due to severe myxomatous mitral valve disease (MMVD). Left atrial decompression was successful but atrial fibrillation (AF) occurred during the procedure. Electric cardioversion restored normal sinus rhythm (NSR) and the dog's recovery was uneventful. This sequence of events made it possible to study intracameral pressures individually in each atrium in a dog with naturally occurring MMVD during AF and again during NSR. Although pressures in both atria declined following cardioversion, the right atrial pressure declined to a greater degree. These findings indicated a disproportionate effect of AF on right atrial pressure. This difference was noteworthy given the long-standing clinical observation that dogs with MMVD have a higher prevalence of right-sided CHF when AF is present. Key clinical message: A dog with MMVD had a greater reduction in right atrial pressure than in left atrial pressure when its AF was cardioverted as part of a cardiac catheterization procedure. This observation proposed a mechanism for the well-known but unexplained observation that dogs with MMVD manifest right-sided CHF disproportionately more often when they have AF.

Effets de la fibrillation auriculaire aiguë et de la cardioversion sur les pressions auriculaires gauche et droite chez un chien. La présence d'une insuffisance cardiaque congestive du côté droit (ICC) chez les chiens atteints d'une cardiopathie du côté gauche est bien connue, mais ses mécanismes ne sont pas complètement compris. Un chien maltais de 12 ans a été admis à la clinique pour une décompression auriculaire gauche afin de traiter une ICC récurrente due à une grave maladie myxomateuse de la valvule mitrale (MMVD). La décompression auriculaire gauche a réussi, mais une fibrillation auriculaire (FA) s'est produite pendant la procédure. La cardioversion électrique a rétabli le rythme sinusal normal (NSR) et la récupération du chien s'est déroulée sans incident. Cette séquence d'événements a permis d'étudier les pressions individuellement dans chaque oreillette chez un chien atteint de MMVD d'origine naturelle pendant la FA et à nouveau pendant la NSR. Bien que les pressions dans les deux oreillettes aient diminué après la cardioversion, la pression de l'oreillette droite a diminué dans une plus grande mesure. Ces résultats ont indiqué un effet disproportionné de la FA sur la pression auriculaire droite. Cette différence était remarquable compte tenu de l'observation clinique de longue date selon laquelle les chiens atteints de MMVD ont une prévalence plus élevée d'ICC du côté droit en cas de FA.Message clinique clé :Un chien atteint de MMVD présentait une réduction plus importante de la pression auriculaire droite que de la pression auriculaire gauche lorsque sa FA était cardiovertie dans le cadre d'une procédure de cathétérisme cardiaque. Cette observation propose un mécanisme pour l'observation bien connue mais inexpliquée selon laquelle les chiens atteints de MMVD manifestent une ICC du côté droit de manière disproportionnée plus souvent lorsqu'ils souffrent de FA.(Traduit par Dr Serge Messier).

Relationship between syringomyelia and myxomatous mitral valve disease in Cavalier King Charles spaniels.

BACKGROUND: Syringomyelia (SM) and myxomatous mitral valve disease (MMVD) are highly prevalent in Cavalier King Charles spaniels (CKCS). Cardiac status in CKCS with and without SM is currently unknown. OBJECTIVES: To investigate the association between SM and MMVD severity in CKCS and CKCS with SM with and without clinical signs of SM. ANIMALS: Fifty-five CKCS: 40 with SM (22 symptomatic and 18 asymptomatic) and 15 without SM. METHODS: A combined retrospective and prospective study. MRI and echocardiography were used to diagnose SM and MMVD, respectively. The association between SM and MMVD severity (left ventricle internal diameter in diastole normalized to bodyweight [LVIDDN] and left atrium to aortic ratio [LA/Ao]) were tested using multivariable linear regression analysis adjusting for sex and age. RESULTS: Overall, no significant difference in LVIDDN and LA/Ao was found between CKCS with or without SM. However, CKCS with symptomatic SM had significantly smaller LVIDDN (1.45 [1.30-1.50]) (median [IQR]) and LA/Ao (1.20 [1.10-1.28]) compared to CKCS with asymptomatic SM (1.60 [1.50-1.90] and 1.40 [1.20-1.75]) as well as CKCS without SM (0.24 [0.03-0.45] and 0.30 [0.05-0.56]) (all P values <.03). CONCLUSIONS AND CLINICAL IMPORTANCE: An association between MMVD and SM was not confirmed in this cohort of CKCS, indicating that MMVD and SM do not co-segregate. However, CKCS with symptomatic SM had smaller left ventricle and atrial size compared to CKCS with asymptomatic SM and CKCS without SM.

Efficacy of a mitral regurgitation severity index to predict long-term outcome in dogs with myxomatous mitral valve disease.

BACKGROUND: Predicting progression of myxomatous mitral valve disease (MMVD) in dogs can be challenging. HYPOTHESIS/OBJECTIVES: The mitral regurgitation severity index (MRSI) will predict time to congestive heart failure (CHF) and all-cause death in dogs with MMVD. ANIMALS: Eight hundred sixty-nine client-owned dogs. METHODS: Retrospective study pooling data from 4 previous samples including dogs with MMVD stage B2 or C. MRSI was calculated as: (heart rate [HR]/120) × left atrium-to-aorta ratio (LA:Ao) × (age in years/10) × 100. Alternative MRSI formulas substituting radiographic measures of left atrial size were also calculated. Cox proportional hazard modeling and time-dependent receiver-operator characteristic curves quantified prognostic performance. RESULTS: For Stage B2 pooled samples, MRSI > 156 was predictive of time to CHF (median 407 vs 1404 days; area under the curve [AUC] 0.68; hazard ratio 3.02 [95% CI 1.9-4.9]; P < .001). MRSI > 173 was predictive of all-cause death (median survival 868 vs 1843 days; AUC 0.64; hazard ratio 4.26 [95% CI 2.4-7.5]; P < .001). MRSI showed superior predictive value compared to the individual variables of HR, LA:Ao, and age. Variations of the MRSI equation substituting radiographic vertebral left atrial size for LA:Ao were also significantly predictive of outcome in stage B2. MRSI was not consistently predictive of outcome in Stage C. CONCLUSIONS AND CLINICAL IMPORTANCE: MRSI was predictive of outcome (onset of CHF and all-cause death) in MMVD Stage B2, demonstrating utility as a useful prognostic tool. Echocardiographic LA:Ao can be effectively replaced by radiographically determined LA size in the MRSI formula.

Mitral valve transcriptome analysis in thirty-four age-matched Cavalier King Charles Spaniels with or without congestive heart failure caused by myxomatous mitral valve disease.

We here report the results of a mitral valve transcriptome study designed to identify genes and molecular pathways involved in development of congestive heart failure (CHF) following myxomatous mitral valve disease (MMVD) in dogs. The study is focused on a cohort of elderly age-matched dogs (n = 34, age ~ 10 years) from a single breed-Cavalier King Charles Spaniels (CKCS)-with a high incidence of MMVD. The cohort comprises 19 dogs (10♀, 9♂) without MMVD-associated CHF, and 15 dogs (6♀, 9♂) with CHF caused by MMVD; i.e., we compare gene expression in breed and age-matched groups of dogs, which only differ with respect to CHF status. We identify 56 genes, which are differentially expressed between the two groups. In this list of genes, we confirm an enrichment of genes related to the TNFß-signaling pathway, extracellular matrix organization, vascular development, and endothelium damage, which also have been identified in previous studies. However, the genes with the greatest difference in expression between the two groups are CNTN3 and MYH1. Both genes encode proteins, which are predicted to have an effect on the contractile activity of myocardial cells, which in turn may have an effect on valvular performance and hemodynamics across the mitral valve. This may result in shear forces with impact on MMVD progression.

Clinical relevance of serum ionized magnesium concentration in dogs with myxomatous mitral valve disease.

BACKGROUND: Hypomagnesemia is associated with a poor prognosis in humans with congestive heart failure (CHF), but studies in veterinary medicine are limited. HYPOTHESIS: Serum ionized magnesium concentration [iMg2+ ] would decrease as CHF progresses compared with the initial diagnostic levels and that lower [iMg2+ ] would be negatively associated with prognosis in dogs with CHF. ANIMALS: A total of 181 client-owned dogs with myxomatous mitral valve disease (MMVD) were included. They were classified into the preclinical stage (NO-CHF, n = 108), stage C (n = 42), and stage D (n = 31) based on the American College of Veterinary Internal Medicine MMVD classification. METHODS: This is a retrospective study from 2 referral centers. The [iMg2+ ] was compared among the NO-CHF, stage C, and stage D groups. Kaplan-Meier curves and the log-rank test were used to compare the incidence of death between groups. Multivariable Cox regression analysis was used to estimate the association of hypomagnesemia with the death. RESULTS: In the stage D group, the [iMg2+ ] was lower than that in the NO-CHF (P < .0001) and stage C groups (P < .003). In the Kaplan-Meier survival analysis, the 1-year cumulative survival rate in hypomagnesemic dogs was 53% compared with 91.5% in normomagnesemic dogs (log-rank test, P < .0001). In the multivariable Cox analysis, lower concentration of [K+ ] and [iMg2+ ], along with higher Evel , were associated with negative prognoses. Specifically, hypomagnesemia was associated with an approximately 4-fold increased risk of death (hazard ratio = 4.015; 95% confidence interval, 1.537-10.488; P = .005). CONCLUSIONS AND CLINICAL IMPORTANCE: Assessing the [iMg2+ ] might serve as a potential marker for estimating the severity and prognosis indirectly in dogs with MMVD. Combining [iMg2+ ] measurement with other diagnostic methods, such as echocardiography, could improve the prognostic evaluation of MMVD in dogs.

Determination of radiographic vertebral heart score and vertebral left atrial size cutoffs based on echocardiographic left atrial size in dogs with myxomatous mitral valve disease.

Progression of myxomatous mitral valve disease (MMVD) in dogs is a common cause of left atrial enlargement. Recently, a classification of left atrial (LA) size based on echocardiographic measurement has been proposed. This study aims to determine the radiographic LA size by reporting the cutoff values of VHS and VLAS for different groups of echocardiographic-measured LA size in dogs with MMVD. This retrospective analytical cross-sectional study included dogs diagnosed with MMVD grouped based on the echocardiographic LA size into normal (LA/Ao < 1.6), mild (1.6-1.89), moderate (1.9-2.2), and severe enlargement (>2.2) and were compared with ACVIM classification. VHS and VLAS were measured on the right lateral radiograph for each dog and cutoff values were calculated. One hundred and three dogs with MMVD were included in the study. A very strong positive correlation was observed between LA/Ao ratio and VHS (rs , 0.823, P < .01) or VLAS (rs , 0.834, P < .01). For VHS, a cutoff of 10.7 v, 11 v, and 11.5 v were established for echocardiographic LA thresholds of 1.6, 1.9, and 2.2 with a sensitivity of 79%, 92%, and 90% and a specificity of 97%, 90.7%, and 78.1%, respectively. For VLAS, a cutoff of 2.5 v, 2.7 v, and 2.9 v were established for echocardiographic LA cutoffs of 1.6, 1.9, and 2.2 with a sensitivity of 73%, 80%, and 83.3% and a specificity of 94%, 92%, and 86.3%, respectively. The results of this study may facilitate clinical decisions based on radiographic examination in dogs with myxomatous mitral valve disease.

Current use of real-time three-dimensional transthoracic echocardiography in animals.

This review includes 36 studies of transthoracic real-time three-dimensional echocardiography (RT3DE) in animals. Most of these studies concern cardiac chamber quantification of the left atrium and left ventricle, in dogs. Comparisons of RT3DE and different two-dimensional echocardiographic (2DE) methods have been reported in dogs with myxomatous mitral valve disease (MMVD), dilated cardiomyopathy, and in healthy control dogs. Comparisons of RT3DE and standard reference methods have been reported in healthy control dogs. In dogs with MMVD, volumetric RT3DE measurements of left atrium do not appear to provide superior prognostic value compared with 2DE methods using Simpson's method of discs in dogs with MMVD. The major advantages of RT3DE compared to 2DE include improvements in visualization of the complex morphology of the mitral valve, the estimation of mitral valve regurgitation, and improved visualization of complex congenital cardiac abnormalities.

Clinical presentation, echocardiographic findings, treatment strategies, and prognosis of dogs with myxomatous mitral valve disease presented with pericardial effusion due to suspected left atrial tear: a retrospective case-control study.

INTRODUCTION/OBJECTIVES: Left atrial tear (LAT) is a life-threatening complication in dogs with myxomatous mitral valve disease (MMVD). The study objective was to describe clinical presentation, echocardiographic findings, treatment strategies, and survival in dogs with LAT compared to a control group of dogs with a similar stage of MMVD but no LAT. ANIMALS AND MATERIALS AND METHODS: Two-center retrospective case-controlled study including 15 dogs with and 15 dogs without LAT was conducted. Clinical and echocardiographic data were reviewed, and survival information were collected. RESULTS: Nine dogs in each group were in stage C of MMVD, while the remaining were in stage B2. No differences between groups were found regarding age, body weight, sex, kidney values, and echocardiography-derived cardiac dimensions. Most reported clinical signs associated with LAT included weakness, respiratory signs, and syncope. Treatment varied and was mainly focused on the management of congestive heart failure. Three dogs with LAT received a pericardiocentesis. All 15 dogs with LAT had died of cardiac causes, five dogs during the first seven days after admission. The median survival time for all 15 dogs with LAT was 52 days compared to 336 days in the control group (P=0.103). When excluding five dogs with LAT that died during the first seven days, the median survival increased to 407 days, not different compared to the control group (P=0.549). CONCLUSIONS: Dogs with MMVD and LAT have a high short-term mortality; however, when surviving the acute phase, the long-term prognosis may not differ from dogs with a similarly advanced degree of MMVD but without LAT.

Untargeted metabolomic profiling of dogs with myxomatous mitral valve disease and congestive heart failure shows metabolic differences associated with the presence of cardiac cachexia.

OBJECTIVE: To determine the effects of cardiac cachexia on the metabolomic profile in dogs with myxomatous mitral valve disease (MMVD). ANIMALS: 3 groups of dogs with MMVD enrolled between November 30, 2018, and April 7, 2022: (1) Dogs with congestive heart failure (CHF) and cachexia (CHF-cachexia group; n = 10); (2) dogs with CHF that had no cachexia (CHF-no cachexia group; n = 10); and (3) dogs with asymptomatic disease (American College of Veterinary Internal Medicine [ACVIM] Stage B2) with no cachexia (B2 group; n = 10). METHODS: Metabolomic profiles were analyzed from serum samples using ultra-high-performance liquid chromatography-tandem mass spectroscopy. Dogs in the 3 groups were compared, with statistical significance defined as P < .05 with a low false discovery rate (q < .10) and nominal statistical significance defined as P < .05 but q > .10. RESULTS: Numerous metabolites were significantly (n = 201) or nominally significantly (n = 345) different between groups. For example, when comparing the CHF-cachexia vs CHF-no cachexia groups, lipids were the predominant metabolite differences, including many medium- and long-chain dicarboxylates and dicarboxylate acylcarnitines. For comparisons of the CHF-cachexia vs B2 groups and the CHF-no cachexia vs B2 groups, amino acids, nucleotides, and cofactors/vitamins were the predominant metabolite differences. CLINICAL RELEVANCE: Some significant metabolite differences were identified between dogs with and without cardiac cachexia.

Differentially expressed platelet activation-related genes in dogs with stage B2 myxomatous mitral valve disease.

BACKGROUND: Peripheral blood carries a reservoir of mRNAs that regulate cardiac structure and function potential. Although it is well recognized that the typical symptoms of Myxomatous Mitral Valve Disease (MMVD) stage B2 are long-standing hemodynamic disorder and cardiac structure remodeling caused by mitral regurgitation, the transcriptomic alterations in blood from such dogs are not understood. RESULTS: In the present study, comparative high-throughput transcriptomic profiling of blood was performed from normal control (NC) and naturally-occurring MMVD stage B2 (MMVD) dogs. Using Weighted Gene Co-expression Network Analyses (WGCNA), Gene Ontology (GO), and Kyoto Encyclopedia of Gene and Genomes (KEGG), we identified that the turquoise module was the most highly correlated with echocardiographic features and found 64 differentially expressed genes (DEGs) that were significantly enriched in platelet activation related pathways. Therefore, from the turquoise module, we selected five DEGs (MDM2, ROCK1, RIPK1, SNAP23, and ARHGAP35) that, according to real-time qPCR, exhibited significant enrichment in platelet activation related pathways for validation. The results showed that the blood transcriptional abundance of MDM2, ROCK1, RIPK1, and SNAP23 differed significantly (P < 0.01) between NC and MMVD dogs. On the other hand, Correlation Analysis revealed that MDM2, ROCK1, RIPK1, and SNAP23 genes negatively regulated the heart structure parameters, and followed the same trend as observed in WGCNA. CONCLUSION: We screened four platelet activation related genes, MDM2, ROCK1, RIPK1, and SNAP23, which may be considered as the candidate biomarkers for the diagnosis of MMVD stage B2. These findings provided new insights into MMVD pathogenesis.

Use of physical examination, electrocardiography, radiography, and biomarkers to predict echocardiographic stage B2 myxomatous mitral valve disease in preclinical Cavalier King Charles Spaniels.

INTRODUCTION: Cavalier King Charles Spaniels (CKCS) are predisposed to developing myxomatous mitral valve disease (MMVD). Dogs with stage B2 MMVD benefit from medication. OBJECTIVES: To develop (1) breed-specific cut-offs for individual screening tests and (2) predictive models utilizing physical examination (PE), ECG, radiograph, and blood-based biomarker variables in combination for identification of echocardiographic stage B2 MMVD in preclinical CKCS. ANIMALS: Adult, preclinical CKCS not receiving cardiac medications (N = 226). MATERIALS AND METHODS: Prospective, cross-sectional study. Enrolled CKCS underwent PE, ECG, radiography, Doppler blood pressure measurement, echocardiography, and biomarker testing. Dogs were grouped by MMVD stage using echocardiography only. The discriminatory ability of individual tests to identify stage B2 was assessed, and prediction models were developed using variables derived from four 'tests' (PE, ECG, radiography, and biomarkers). RESULTS: N-terminal pro-B-type natriuretic peptide (NT-proBNP) and radiographic vertebral heart size (VHS) had the best discriminatory ability of individual diagnostic tests to differentiate stage A/B1 CKCS from stage B2, with an area under the curve (AUC) of 0.855 and 0.843, respectively. An NT-proBNP ≥1138 pmol/L or a VHS ≥11.5 had high specificity for predicting stage B2 (90.1% and 90.6%, respectively). Prediction models incorporating variables from multiple tests had better discriminatory ability than single tests. The four-test prediction model had an AUC of 0.971. Three and two-test models had AUCs ranging between 0.925-0.959 and 0.895-0.949, respectively. CONCLUSIONS: Both NT-proBNP and VHS have good utility for predicting echocardiographic stage B2 MMVD in CKCS as individual tests. Prediction models incorporating multiple test variables have superior discriminatory ability.

Radiographic lung congestion scores in dogs with acute congestive heart failure caused by myxomatous mitral valve disease.

BACKGROUND: In humans, lung congestion scores are predictive of recurrence of acute congestive heart failure (CHF) and are superior to cardiac biomarkers in predicting survival. OBJECTIVES: The primary aim of this retrospective study was to determine if a modified lung congestion score (LCS) in dogs diagnosed with acute CHF because of myxomatous mitral valve disease was associated with time until recurrence or death. ANIMALS: Complete medical records were available for a total of 94 dogs between 2010 and 2019, but only 35 dogs fulfilled the criteria for inclusion. METHODS: This retrospective study used descriptive statistics to describe the cumulative and corrected LCS. Correlations were used to examine the association of the corrected LCS and time until recurrence or death, selected echocardiographic variables, and timing of furosemide administration. RESULTS: The mean LCS was 8.4 (SD 3.3) and corrected LCS was 0.48 (SD 0.19). The pattern was predominantly symmetric (40% of dogs) and focal (caudal) but more commonly right-sided when asymmetric (40% vs 20%). The median number of days after initial diagnosis of acute CHF to readmission and death was 150 days (range 4-572), and 266 days (range 5-965), respectively. No significant association between the dog's corrected LCS and number of days until readmission (r = .173, P = .42) nor survival (r = .109, P = .56) was found. There was a negative significant correlation (r = -.71, P < .001) between the time interval of furosemide administration and corrected LCS.

Isometric myography is a feasible method to identify and quantify endothelial dysfunction in dogs with myxomatous mitral valve disease.

OBJECTIVE: To assess the feasibility of isometric myography in pet dogs with myxomatous mitral valve disease (MMVD) to determine its use in quantifying endothelial dysfunction. ANIMALS: 9 dogs euthanized for medical reasons. METHODS: Femoral, renal, and mesenteric arteries were collected postmortem and stored in physiological saline solution at 4 °C for myography. Mitral valves were scored for myxomatous degeneration (grades 1 to 4). Sections of arteries were mounted in wells, immersed in physiological saline solution perfused with 95% O2 and 5% CO2 at 37 °C, and stretched to an internal circumference (IC) that generated the maximal difference between active and passive wall tension (IC1). Normalization factors were calculated by dividing the IC1 by the IC at which the passive wall tension was 100 mm Hg (IC100). Vasoconstriction to phenylephrine and vasodilation to acetylcholine (endothelial dependent) and sodium nitroprusside (endothelial independent) were assessed by cumulative dose-response curves. RESULTS: Median MMVD grade was 3. Mean values of normalization factors were 1.00 ± 0.14 (renal, n = 15), 1.00 ± 0.10 (femoral, 8), and 1.05 ± 0.12 (mesenteric, 6). Responses to phenylephrine were similar between dogs (P = .14). Reduced responses to acetylcholine compared with sodium nitroprusside were identified in 15 arteries, suggesting endothelial dysfunction. CLINICAL RELEVANCE: Isometric myography of arteries from pet dogs is feasible and can identify loss of endothelial-dependent relaxation in dogs with MMVD postmortem. Its use in further research can lead to a better understanding of the pathophysiology mechanisms of this disease.

No impact of polymorphism in the phosphodiesterase 5A gene in Cavalier King Charles Spaniels on pimobendan-induced inhibition of platelet aggregation response.

BACKGROUND: A variant in the canine phosphodiesterase (PDE) 5A gene (PDE5A:E90K) is associated with decreased concentrations of circulating cyclic guanosine monophosphate (cGMP) and response to PDE5 inhibitor treatment. Pimobendan is a PDE inhibitor recommended for medical treatment of certain stages of myxomatous mitral valve disease (MMVD) in dogs. HYPOTHESIS: PDE5A:E90K polymorphism attenuates the inhibitory effect of pimobendan on in vitro platelet aggregation and increases basal platelet aggregation in Cavalier King Charles Spaniels (CKCS). Selected clinical variables (MMVD severity, sex, age, hematocrit, platelet count in platelet-rich plasma [PRP], and echocardiographic left ventricular fractional shortening [LV FS]) will not show an association with results. ANIMALS: Fifty-two privately owned CKCS with no or preclinical MMVD. METHODS: Using blood samples, we prospectively assessed PDE5A genotype using Sanger sequencing and adenosine diphosphate-induced platelet aggregation response (area under the curve [AUC], maximal aggregation [MaxA], and velocity [Vel]) with and without pimobendan using light transmission aggregometry. Dogs also underwent echocardiography. RESULTS: Pimobendan inhibited platelet function as measured by AUC, MaxA, and Vel at a concentration of 10 µM (P < .0001) and Vel at 0.03 µM (P < .001). PDE5A:E90K polymorphism did not influence the inhibitory effect of pimobendan or basal platelet aggregation response. CONCLUSIONS AND CLINICAL IMPORTANCE: The PDE5A:E90K polymorphism did not influence in vitro basal platelet aggregation response or the inhibitory effect of pimobendan on platelet aggregation in CKCS. Dogs with the PDE5A:E90K polymorphism did not appear to have altered platelet function or response to pimobendan treatment.

Pharmacokinetics of pimobendan after oral administration to dogs with myxomatous mitral valve disease.

BACKGROUND: Pimobendan is an important therapy for dogs with myxomatous mitral valve disease (MMVD). The pharmacokinetics are reported in healthy dogs but not in dogs with heart disease. HYPOTHESIS/OBJECTIVES: To determine if dog characteristics such as age, breed, body condition score, ACVIM stage of heart disease or biochemical laboratory value alter the pharmacokinetics of orally administered pimobendan and its metabolite in a cohort of dogs with naturally occurring MMVD. ANIMALS: Fifty-seven client-owned dogs with MMVD ACVIM Stage B2, C, or D and administered pimobendan to steady state blood concentrations. METHODS: Prospective, observational study. Samples were collected using a sparse-sampling protocol at specific intervals after administration of pimobendan. Plasma pimobendan and the active metabolite (O-desmethyl-pimobendan, ODMP) concentrations were determined via high-pressure liquid chromatography and fluorescence detection. Data was analyzed via a population pharmacokinetic approach and nonlinear mixed effects modeling (NLME). Numerous covariates were examined in the NLME model. RESULTS: The absorption and elimination half-lives (t1/2 ) were approximately 1.4 and 1 hour for pimobendan and 1.4 and 1.3 hours for ODMP, respectively. Pharmacokinetic parameters were highly variable, especially the values for pimobendan absorption and elimination rate, and absorption rate of ODMP with coefficients of variation of 147.84%, 64.51% and 64.49%, respectively. No covariate evaluated was a significant source of variability. CONCLUSIONS AND CLINICAL IMPORTANCE: The pharmacokinetic parameters were highly variable among this group of dogs with MMVD. The variability was not associated with the dog's age, body weight or condition score, stage of heart disease, dose, serum creatinine, or alkaline phosphatase.

Postmortem Evaluation of Cardiac Valvular Disease in Bald Eagles (Haliaeetus leucocephalus) and a Golden Eagle (Aquila chrysaetos).

Limited data are available regarding cardiac diseases in birds of prey despite their prevalence in these avian species. Literature regarding valvular lesions in birds of prey is scarce and includes single reports of left atrioventricular valvular endocarditis in an adult, free-ranging, male bald eagle (Haliaeetus leucocephalus) and aortic valvular endocarditis in an adult, free-ranging, female red-tailed hawk (Buteo jamaicensis). The purpose of this study was to evaluate the prevalence, signalment, gross necropsy findings, and histologic lesions of valvular lesions in eagles. In this retrospective study, necropsy reports for 24 free-ranging and captive eagles were evaluated over a 15-year period (July 3, 2006-February 28, 2021). Six (25%; 95% confidence interval: 8.9-58.9) birds, 5 bald eagles and 1 golden eagle (Aquila chrysaetos), met the inclusion criteria. Five (83.3%) of the 6 birds had valvular degeneration, 2 (33.3%) had endocarditis, and Staphylococcus aureus was cultured from 1 (16.7%) of the endocarditis cases. The 6 eagles with valvular lesions were all captive adults. Four of the birds were female (66.7%), and the aortic and left atrioventricular valves were equally affected. Acute or chronic cerebral infarcts were present in all 6 birds. Valvular cardiac disease should be considered as a differential diagnosis in eagles exhibiting respiratory distress, neurologic signs, syncope, or in cases of sudden death.

Proteomics reveals plasma protein SERPINH1 as a potential diagnostic biomarkers for myxomatous mitral valve disease stage B2.

BACKGROUND: Although it is well known that myxomatous mitral valve disease stage B2 (MMVD stage B2) is predominantly characterized by ECM remodeling of the mitral valve, ECM-related proteomics alterations in plasma from dogs with this disease have yet to be elucidated. OBJECTIVE: To determine whether the differentially expressed protein (DEP) associated with ECM are potential biomarkers of MMVD stage B2. METHODS: Tandem mass tag (TMT) quantitative proteomics analysis was performed to determine the DEPs in plasma samples from a discovery cohort (5 dogs with MMVD stage B2 and 3 healthy controls, poodle). Candidate proteins were identified using DEPs and ECM-related protein network analysis and confirmed by enzyme-linked immunosorbent assay (ELISA) and western blotting in a validation cohort (52 dogs with MMVD stage B2 and 56 healthy controls, multi-breed). The diagnostic potential of a candidate biomarker DEP was evaluated using receiver operating characteristic (ROC) curve analysis. RESULTS: A total of 90 DEPs were identified between healthy and MMVD stage B2 dogs, and of these 90 DEPs, 16 were ECM-related proteins. One ECM-related DEP, serpin family H member 1 (SERPINH1), was significantly overabundance at the protein level in MMVD stage B2 dog plasma, and SERPINH1 expression had an area under the ROC curve (AUC) value of 0.885 (95% CI = 0.814-0.956, P < 0.0001) that allowed discrimination of MMVD stage B2 dogs from healthy dogs. CONCLUSION: Plasma SERPINH1 has good predictive and diagnostic value at dog with MMVD stage B2, suggesting that SERPINH1 may be used as a biomarker for early prediction and diagnosis of stage B2 of MMVD. SIGNIFICANCE: MMVD is the most acquired cardiac disease in dogs. MMVD stage B2, is when the heart valve structure begins to change significantly but there are no clinical symptoms; it is a critical time during which to slow progression of the disease, so timely diagnosis is extremely important. This study suggests that plasma SERPINH1 levels might differentiate MMVD progression in dogs during the early stage. It is also the first study to consider SERPINH1 as a diagnostic biomarker in dogs with stage B2 MMVD. Another advantage is that dogs in the validation cohort were recruited from six breeds to reduce the impacts of breed factors and partly reflect the universality of SERPINH1 for diagnosing MMVD stage B2.

Analysis of Poincaré plot derived from 5-min electrocardiography in dogs with myxomatous mitral valve disease.

BACKGROUND: Evaluation of heart rate variability (HRV) is used for risk assessment in a variety of cardiac diseases including myxomatous mitral valve degeneration (MMVD). OBJECTIVES: To compare the geometric analysis of HRV using visual patterns of Poincaré plot among different classes of MMVD in dogs and to analyse the differences in beat-to-beat variability using tachograms and sequential Poincaré plots among different shapes. ANIMALS AND METHODS: Healthy and MMVD dogs were retrospectively reviewed. Five-minute ECG data was used to create Poincaré plots and shapes were compared among groups. Furthermore, a sub-analysis of 50 consecutive R-R intervals was performed. Pearson Chi-square with adjusted standardized residuals was used to compare the categorical data between groups. RESULTS: Fifteen healthy dogs and 157 dogs with MMVD were included in the study. Normal and B1 groups showed a predominance of triangular shape (73% and 60% respectively; p < 0.05). In B2 group the predominant shape was comet (40%; p < 0.05) while comet and torpedo were predominant in Ca group (41% and 36% respectively; p < 0.05). Visual geometric analysis revealed a lower dispersion of the cloud clustering towards the left lower corner of the plot with MMVD progression. Diamond and triangle revealed a lower mean heart rate compared to comet and torpedo shapes (p < 0.01). Interclass correlation between 3 observers was 0.906 (95% CI of 0.8 - 0.96). CONCLUSIONS: Poincaré plot shape changes with MMVD progression suggesting that geometrical analysis of HRV in dogs with cardiac conditions could be a useful tool in the risk assessment and further studies are warranted.