Iron parameters analysis in dogs with myxomatous mitral valve disease.

BACKGROUND: Myxomatous mitral valve disease (MMVD) is the most common acquired cardiovascular disease in small breed dogs. In contrast to human patients with heart failure (HF), iron deficiency (ID) prevalence in dogs with MMVD is weakly known. The study aimed to assess the usability of ID markers in serum and reticulocyte parameters from whole blood of dogs with MMVD to evaluate early ID symptoms. RESULTS: Sixty-eight dogs (43 male and 25 female) were included in the study. MMVD dogs were assigned according to the 2019 ACVIM guidelines for groups B1 (n = 9), B2 (n = 10), C (n = 27) and D (n = 10). Groups were also combined into B1 and B2 as non-symptomatic HF and C with D as symptomatic HF. Healthy controls were 12 dogs. Serum iron concentration below the reference range in dogs with MMVD was 12.5%. Other ID indices, such as %SAT, UIBC, and TIBC were similar in the MMVD groups and healthy controls (p > 0.05 for all parameters). Statistical comparison between control group and 4 groups of different stages of MMVD showed that significant differences occur only in serum transferrin. The assessment of ferritin and soluble transferrin receptors using Western Blotting did not show differences between control (n = 7) and MMVD (n = 33) dogs. Study has shown positive correlation between ID parameters and echocardiographic indices such as LA/Ao and LVIDdN, and some biochemical parameters. A significant increase in reticulocytes percentage, assessed manually, was observed in the HF group of animals (p = 0.027) compared to the control group. CONCLUSIONS: Studies have shown that ID parameters in serum are not significantly different in dogs with MMVD compared to healthy dogs. However, there is a clear correlation between atrial size and normalised left ventricular size to body size and some biochemical parameters, including ID parameters and therefore the severity of MMVD.

Volumetric quantification identifies some left atrial dilations undetected by left atrium:aorta ratio measurements: A prospective echocardiographic study in 155 Cavalier King Charles Spaniels with and without degenerative mitral valve disease.

INTRODUCTION: Degenerative mitral valve disease (DMVD) is the most common canine heart disease with a high predisposition in Cavalier King Charles Spaniels (CKCSs). Mitral regurgitation related to DMVD can lead to left atrial (LA) dilation, which is associated with survival time. Left-atrial-to-aortic (LA:Ao) ratio assessed by two-dimensional echocardiography is commonly used to evaluate LA size. The objectives of this prospective observational study were therefore 1) to compare different echocardiographic methods (i.e., monoplane and biplane Simpson's methods of discs (SMOD) and area-length methods (ALM)) in evaluating LA volume (LAvol) in CKCSs, 2) to assess LA volumes according to DMVD severity and, 3) compare the ability of LAvol and LA:Ao ratio to identify LA enlargement in CKCSs with subclinical DMVD (i.e., American College of Veterinary Internal Medicine (ACVIM) stage B). MATERIALS AND METHODS: 155 CKCSs, either healthy or affected by DMVD, were recruited. Variability and concordance between volumetric methods were evaluated. Values were analyzed according to 2019 ACVIM stages. RESULTS: All Lin's concordance correlation coefficients regarding intra- and inter-observer variability were considered as very good to excellent. Monoplane methods and ALM produced higher values of LAvol than biplane methods and SMOD, respectively. The upper limit of normal end-systolic LAvol/body weight (LASvol/BW) was defined as 0.90 mL/kg. Left atrial volumes significantly increased with ACVIM stages. Additionally, 37% of stage B1 CKCSs demonstrated LA enlargement using LASvol/BW assessment, with significantly lower LASvol/BW values in dogs with regurgitation fraction ≤30% than in others (p<0.01). CONCLUSION: In CKCSs, LAvol methods are not interchangeable. In ACVIM stage B CKCSs, LAvol quantification is more effective to detect LA enlargement than LA linear measurements.

Utility of focused cardiac ultrasonography training in veterinary students to differentiate stages of subclinical myxomatous mitral valve disease in dogs.

BACKGROUND: Differentiation of the subclinical phases of myxomatous mitral valve disease (MMVD) in dogs relies heavily on echocardiography. Focused cardiac ultrasonography (FCU) is a point-of-care technique that can assess heart size. HYPOTHESIS/OBJECTIVES: Veterinary students trained in FCU can differentiate dogs with subclinical MMVD based on left ventricular (LV) and left atrial (LA) dimensions. ANIMALS: Forty-eight dogs with subclinical MMVD. METHODS: Veterinary students were trained to measure LV dimension and LA-to-aortic root dimension ratio (LA : Ao) using FCU. Dogs were categorized into 2 cohorts based on whether or not the LV normalized internal diastolic dimension was ≥1.7 and LA : Ao was ≥1.6. Agreement between FCU and echocardiographic studies performed by cardiologists was evaluated. RESULTS: One-hundred and forty-six FCU examinations were performed by 58 veterinary students on 48 dogs. Overall agreement between students and cardiologists was moderate (Fleiss' kappa, 0.54; 95% confidence interval [CI], 0.39-0.69; P < .001). Percentage accuracy in observations with heart dimensions less than the cutoffs (86/89, 97%) was significantly higher than in observations in with larger hearts (31/57, 54%; P < .001). Agreement increased from moderate to good as heart sizes became more extreme. Degree of confidence by students in performing FCU was significantly higher at the end vs start of the study. CONCLUSIONS AND CLINICAL IMPORTANCE: Categorization of dogs with subclinical MMVD by veterinary students using FCU was associated with moderate to good agreement with echocardiography. Focused cardiac ultrasonography is a point-of-care method that can help assess clinical stage in dogs with subclinical MMVD.

MITRAL REGURGITATION IN SADDLE-BILLED STORKS (EPHIPPIORHYNCHUS SENEGALENSIS) IN HUMAN CARE: DIAGNOSIS, ECHOCARDIOGRAPHIC MEASUREMENTS, AND MANAGEMENT.

The asymptomatic and slow progressive nature of cardiopathies represents a risk to the welfare of avian species in human care. Diagnosis and treatment of cardiac disease in birds pose a challenge due to unique anatomic and physiologic characteristics. Comprehensive cardiac assessments with diagnostic tools such as echocardiography, color-Doppler, the biomarker cardiac troponin I (cTn1), and cholesterol serum concentrations have been utilized in different bird species with varying success. Saddle-billed storks (Ephippiorhynchus senegalensis) have been maintained in human care for over 80 yrs and several institutions have noted heart murmurs and cardiomegaly. Despite these findings, peer-reviewed literature describing cardiopathies is lacking for this species. This case series documents the identification of mitral valve regurgitation in saddle-billed storks in a breeding center. Transcoelomic echocardiography using a ventromedial approach with a two-chambered view and color Doppler was utilized. Echocardiographic measurements were taken and compared 1 yr later in most of the birds. There was left atrial enlargement and worsened mitral regurgitation in one geriatric patient, and no progression of the disease in two young birds. Serum samples showed that cTn1 had different concentrations depending on the severity of the disease, whereas cholesterol was within reference range for all birds. Treatment with digoxin and pimobendan was recommended in one bird, serum concentrations of digoxin were tested in a 6-mon span, results were within therapeutic range, and there were no overt adverse effects. There was a suspected genetic component in this population, as four of the five birds with confirmed mitral regurgitation were related.

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.

Improved owner quality of life following surgical repair of canine myxomatous mitral valve disease.

OBJECTIVE: To determine quality-of-life changes in owners of dogs undergoing mitral valve repair for myxomatous mitral valve disease, up to 12 months postoperatively. SAMPLE: Owners of 26 dogs undergoing mitral valve repair at a single UK veterinary referral hospital. METHODS: Dogs underwent mitral valve repair under cardiopulmonary bypass as previously described. Owner quality of life was assessed by self-completion of a previously validated questionnaire preoperatively and at 1, 3, 6, and 12 months postoperatively. RESULTS: There was a statistically significant improvement in quality-of-life scores from preoperatively up to 3 months postoperatively and a statistically significant improvement in individual question scores up to 6 months postoperatively. CLINICAL RELEVANCE: Results suggested that owner quality of life is significantly improved following surgical repair of their pet's myxomatous mitral valve disease, and this improvement continues beyond the immediate postoperative period. These results may be useful when counseling owners of surgical candidates and is another useful outcome measure.

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.

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.

Mitral Valve Repair-The Development and Rise of Options in the Veterinary World.

Both open surgical repair and a hybrid-interventional option are now available for mitral valve repair (MVR) at select veterinary centers worldwide, making the need for awareness of options and the intricacies around case selection of increasing importance. This article will overview both options currently available and their current stages of progress.

Pimobendan prevents cardiac dysfunction, mitigates cardiac mitochondrial dysfunction, and preserves myocyte ultrastructure in a rat model of mitral regurgitation.

BACKGROUND: Pimobendan has been proven to delay the onset of congestive heart failure (CHF) in dogs with mitral regurgitation (MR); however, molecular underlying mechanisms have not been fully elucidated. This study aimed to investigate (1) the effects of pimobendan on cardiac function, cardiac mitochondrial quality and morphology, and cardiac ultrastructure in a rat model of chronic MR and (2) the direct effect of pimobendan on intracellular reactive oxygen species (ROS) production in cardiac cells. MR was surgically induced in 20 Sprague-Dawley rats, and sham procedures were performed on 10 rats. Eight weeks post-surgery, the MR rats were randomly divided into two groups: the MR group and the MR + pimobendan group. Pimobendan (0.15 mg/kg) was administered twice a day via oral gavage for 4 weeks, whereas the sham and MR groups received equivalent volumes of drinking water. Echocardiography was performed at baseline (8 weeks post-surgery) and at the end of the study (4 weeks after treatment). At the end of the study protocol, all rats were euthanized, and their hearts were immediately collected, weighed, and used for transmission electron microscopy and mitochondrial quality assessments. To evaluate the role of pimobendan on intracellular ROS production, preventive or scavenging properties were tested with H2O2-induced ROS generation in rat cardiac myoblasts (H9c2). RESULTS: Pimobendan preserved cardiac functions and structure in MR rats. In addition, pimobendan significantly improved mitochondrial quality by attenuating ROS production and depolarization (P < 0.05). The cardiac ultrastructure and mitochondrial morphology were significantly preserved in the MR + pimobendan group. In addition, pimobendan appeared to play as a ROS scavenger, but not as a ROS preventer, in H2O2-induced ROS production in H9c2 cells. CONCLUSIONS: Pimobendan demonstrated cardioprotective effects on cardiac function and ultrastructure by preserving mitochondrial quality and acted as an ROS scavenger in a rat model of MR.

Effect of a specially formulated diet on progression of heart enlargement in dogs with subclinical degenerative mitral valve disease.

BACKGROUND: Previous studies in dogs with degenerative mitral valve disease (DMVD) have identified altered myocardial energy metabolism and oxidation, which might contribute to cardiac hypertrophy. Diets rich in medium chain fatty acids and antioxidants are a potential means of treatment. A previous clinical study found significantly smaller left atrial diameter (LAD) and left atrium-to-aorta diameter ratio (LA : Ao) in dogs with subclinical DMVD fed a specially formulated diet vs control diet for 6 months. HYPOTHESIS/OBJECTIVES: A specially formulated diet will slow or arrest left heart enlargement in dogs with subclinical DMVD over 365 days. ANIMALS: One hundred twenty-seven dogs with unmedicated subclinical DMVD; 101 dogs in the per protocol cohort. METHODS: Randomized double-blinded controlled multicenter clinical trial. RESULTS: The study's primary composite outcome measure was the sum of percentage change in LAD and left ventricular internal dimension at end-diastole (LVIDd) at day 365. In the per protocol cohort, the outcome measure increased by 8.0% (95% confidence interval [CI], 2.9%-13.1%) in dogs receiving the test diet vs 8.8% (95% CI, 5.1%-12.5%) in dogs receiving control diet (P = .79). Neither component of the primary outcome measure was significantly different between groups (LAD, P = .65; LVIDd, P = .92). No difference was found in mitral valve E wave velocity (P = .36) or the proportion of dogs withdrawn from the study because of worsening DMVD and heart enlargement (P = .41). CONCLUSIONS AND CLINICAL IMPORTANCE: Feeding a specially formulated diet for 365 days was not associated with a significantly different rate of change of left heart size in dogs with subclinical DMVD as compared to control.

Differences in Left Ventricular Enlargement Secondary to Chronic Volume Loading Between English Springer Spaniels and Two Similar Sporting Breeds.

INTRODUCTION: English springer spaniels have larger, rounder ventricles than most other breeds. How this geometry impacts responses to volume overload remains unknown. We compared left ventricular size between English springer spaniels and two similarly sized sporting breeds (Border collies and Labrador retrievers) in naturally occurring chronic left ventricular volume loading conditions (mitral regurgitation and patent ductus arteriosus [PDA]) to examine whether differences in remodelling responses exist between these breeds. ANIMALS, MATERIALS AND METHODS: We searched records for cases of mitral regurgitation and PDA in three breeds. We recorded age, sex, presence of congestive heart failure (CHF), body weight and specific echocardiographic variables. We compared normalised measures of left ventricular size between breeds. Cases with CHF were further examined as a separate group. RESULTS: One-hundred-and-ninety-one dogs were included: 110 with degenerative mitral valve disease, 42 with mitral dysplasia and 39 with PDA. One third of all cases had CHF. All measures of left ventricular size were larger in English springer spaniels in mitral regurgitation cases (P<0.001), whereas PDA cases did not differ. English springer spaniels with PDA resulting in CHF had larger systolic dimensions and volumes than similarly affected non-English Springer Spaniel dogs (P=0.003). CONCLUSIONS: English springer spaniels have greater left ventricular dimensions when exposed to chronic mitral regurgitation, compared with Border collies and Labrador retrievers, but not when exposed to volume overload from a PDA. English springer spaniels differ in their left ventricular morphology from two other sporting breeds, supporting previous studies that they have a unique cardiac morphotype.

Resolution of congestive heart failure and reverse remodeling in two Chihuahuas with flail mitral valve leaflets.

Development of a flail mitral valve (MV) leaflet secondary to ruptured chordae tendineae in the setting of myxomatous mitral valve disease is a known complication of the disease that often results in severe mitral regurgitation. Two cases are presented in which a flail anterior MV leaflet caused severe mitral regurgitation and led to the development of congestive heart failure in male castrated Chihuahuas. Over variable periods of time, repeat cardiac evaluation disclosed reverse left-sided cardiac remodeling and lessened mitral regurgitation that allowed for withdrawal of furosemide in both dogs. While rare, improvement in mitral regurgitation severity may occur without surgical intervention, allowing for reverse left-sided cardiac remodeling and discontinuation of furosemide.

Prevalence of mitral valve regurgitation in 102 asymptomatic Chinese Crested dogs.

INTRODUCTION: Mitral regurgitation (MR) is one of the main features of myxomatous mitral valve disease (MMVD), which is the most common heart disease in dogs. Myxomatous mitral valve disease affects many small breed dogs, and some breeds such as Cavalier King Charles Spaniels, Dachshunds, Yorkshire terriers, and Miniature Schnauzers have been studied more in detail. Breed-specific information regarding MMVD is valuable for providing appropriate advice on management and breeding. Data, based on insurance statistics in Sweden, show that Chinese Crested dogs (CCD) are twice as likely to visit the veterinarian for a heart-related problem than other breeds. ANIMALS: One-hundred two privately owned, healthy CCD were recruited via the Swedish CCD club. MATERIALS AND METHODS: This was a prospective observational study, in which clinical examinations, blood pressure measurements, and echocardiographic and Doppler examinations were performed in all dogs. Pulsed wave tissue Doppler imaging was performed in 87 dogs. RESULTS: Mitral regurgitation was present in 39 (38%) dogs, whereas a systolic murmur was present in 35 (34%) dogs. Mitral valve prolapse was present in 32 (31%) dogs. Tricuspid regurgitation was found in 29 (28%) dogs. Dogs in the MR group were older (median 9.5 years), and males were overrepresented compared with the non-MR group. Differences were also found between groups regarding left atrial size and transmitral E wave velocity. CONCLUSIONS: The prevalence of MR in CCD is similar to reports in other small breeds. Whether the MR detected in these dogs is a sign of MMVD is unknown.

Selected hematological, biochemical, and echocardiographic variables as predictors of survival in canine patients with myxomatous mitral valve disease and congestive heart failure.

INTRODUCTION/OBJECTIVES: We investigated the association of breed, age, weight, duration of therapy, and selected blood and echocardiographic variables with the survival of dogs with congestive heart failure (CHF) due to myxomatous mitral valve disease. We also sought to identify differences in selected echocardiographic and routine blood variables between dogs with stable and unstable CHF and between hospitalized and non-hospitalized patients. ANIMALS, MATERIALS AND METHODS: This retrospective study included dogs with a complete cardiovascular workup. Blood analysis and the initial and final echocardiographic results were included. Covariates were analyzed using Cox proportional hazards models. RESULTS: One hundred sixty-five dogs with myxomatous mitral valve disease were evaluated in this study: 96 stable patients and 69 unstable CHF patients. In total, 107 dogs (64.8%) died, and 58 (35.2%) were censored. The median survival time of the dogs that died was 11.5 months (range 11 days to 4.3 years). Unstable CHF patients had significantly higher neutrophils and lower potassium concentrations than stable CHF patients, and hospitalized patients had higher white blood cell, neutrophil, and monocyte counts and urea and creatinine concentrations than non-hospitalized patients. Variables negatively associated with survival were older age, unstable CHF, duration of therapy, white blood cell count, urea concentration, and left atrium to aorta ratio. Chihuahuas had a lower risk of death. CONCLUSIONS: Selected blood and echocardiographic variables distinguish dogs with stable and unstable CHF and predict survival.

Caudal pulmonary artery to vein ratio on radiography can predict pulmonary hypertension in dogs with mitral regurgitation.

Pulmonary hypertension (PH) is an important predictor of poor outcomes in dogs with mitral regurgitation (MR). The feasibility of radiography to predict PH in dogs with MR is unknown. This retrospective, observational, and analytic study aimed to identify a radiographic parameter to predict PH in dogs with MR. A total of 302 dogs diagnosed with MR on echocardiography were enrolled. Medical record and radiographic findings such as the size of the main pulmonary artery, left atrium, left ventricle, and right chamber, and cranial and caudal pulmonary arteries and veins were evaluated according to the presence of PH. The diameters of the cranial and caudal pulmonary vessels were compared to the fourth rib and the ninth rib, respectively, and the ratio of the pulmonary artery to the corresponding vein (CdPA/CdPV) was calculated. Pulmonary hypertension was diagnosed in 77 dogs (25.5%) and the prevalence of PH increased with MR grade. The CdPA/CdPV was significantly higher (P < 0.001) in the presence of PH. Multivariate analysis showed that the CdPA/CdPV was the only independent radiographic parameter that had a significant association with PH in dogs with MR (P = 0.028). The cut-off value of the CdPA/CdPV = 1.10 showed 90.6% specificity and 31.1% sensitivity for detecting PH in dogs with MR. In dogs with MR, PH can be predicted with high specificity when the caudal pulmonary artery is 1.1 times larger than the corresponding vein on radiographs.

Prospective pilot study on the predictive significance of plasma miR-30b-5p through the study of echocardiographic modifications in Cavalier King Charles Spaniels affected by different stages of myxomatous mitral valve disease: The PRIME study.

Specific microRNAs expressions may accurately characterize different stages of canine myxomatous mitral valve disease. This preliminary pilot study aimed to (1) describe the clinical and echocardiographic parameters of Cavalier King Charles Spaniels affected by myxomatous mitral valve disease at different American College of Veterinary Internal Medicine (ACVIM) stages (B1, B2 and C) and healthy control group (ACVIM A), comparing the parameters collected during the first examination (T0) and the end of the follow-up (T1); (2) assess the association between the values of echocardiographic parameters at T1 and the expression profile of miR-30b-5p at T0. Thirty-five Cavalier King Charles Spaniels (median age 4.29 years and median weight 9 Kg) in different ACVIM stages were included (7 A, 19 B1, 6 B2 and 3 C). Inverse probability weighting analysis was performed to estimate the association of the exposure variable (miR-30b-5p) with the outcome variables (clinical and echocardiographic variables). Time was included as variable. The results pointed out that high levels of plasma miR-30b-5p corresponded to lower values of left ventricular end-diastolic diameter normalized for body weight, end-diastolic and end-systolic volumes indexed for body weight, and left atrium-to aortic root ratio. Hence, higher miR-30b-5p expressions were associated with milder forms of mitral valve disease in our study population. In contrast, the results obtained for the intensity of heart murmur, the mitral regurgitation severity, and the Mitral INsufficiency Echocardiographic score) were not statistically significant. A relationship between high abundance of miR-30b-5p and myxomatous mitral valve disease that appear echocardiographically more stable over time has been demonstrated. In conclusion, Cavalier King Charles Spaniels affected by myxomatous mitral valve disease that at the first cardiologic evaluation showed an upregulation of miR-30b-5p are expected to experience lesser variations on their echocardiographic examination between T0 and T1.

Canine mitral valve size as measured by computed tomography.

OBJECTIVE: To measure the mitral annulus in dogs. Our hypothesis was that mitral measurement would be possible and consistent among observers using CT. SAMPLE: Thoracic CT scans of dogs without known heart disease. PROCEDURES: Five trained investigators measured 4 aspects of the mitral valve and the fourth thoracic vertebrae (T4) length using multiplanar reformatting tools. Ten randomly chosen animals were measured by all investigators to determine interobserver reliability. RESULTS: There were 233 CT scans eligible for inclusion. Dogs weighed 2 to 96 kg (mean, 28.1 kg), with a variety of breeds represented. Golden Retrievers (n = 28) and Labrador Retrievers (n = 37) were overrepresented. The intraclass correlations were all greater than 0.9, showing excellent agreement between observers. The means and SDs of each measurement were as follows: trigone-to-trigone distance, 17.2 ± 4.7 mm; the remaining circumference, 79.0 ± 17.5 mm; commissure-to-commissure distance, 30.8 ± 6.5 mm; septal leaflet-to-lateral leaflet distance, 26.3 ± 6.0 mm; T4 length, 16.9 ± 3.1 mm; and the total circumference normalized by T4, 5.7 ± 0.7 mm. CLINICAL RELEVANCE: This study provides information that may help in the development of future treatment for mitral valve dysfunction and subsequent annular enlargement.

The leaflet-annulus index in canine myxomatous mitral valve disease.

Myxomatous mitral valve disease (MMVD) is the most common chronic heart valve disease, leading to the eccentric hypertrophy. Recently, the leaflet-annulus index (LAI), which focuses on the mitral valve apparatus, has been considered a prognostic factor for human mitral regurgitation (MR); however, it has not been reported in veterinary medicine. In the present study, we retrospectively evaluated the LAI in dogs with MMVD. Eight-three dogs with MMVD diagnosed using echocardiography were included in this study. The anteroposterior length, anterior and posterior cusp coaptation lengths, LAI, left ventricular end-diastolic internal diameter normalized to body weight (LVIDDN), and left atrium to aorta ratio (LA/Ao) were measured. A significant correlation between the LAI, LVIDDN, and LA/Ao of MR grading, and left ventricle dilation was observed. In conclusion, LAI could help determine annular widening, suggesting the decision of an appropriate for SVR in clinical settings.

The outcome of surgical mitral valve repair with loop-in-loop technique in dogs with different stage myxomatous mitral valve disease.

OBJECTIVES: Surgical mitral valve repair is a possible option for dogs with myxomatous mitral valve disease. However, information on surgical results and postoperative echocardiography is limited. This study aimed to verify the stage-specific surgical results of mitral valve repair and postoperative echocardiographic changes for two years following surgery. ANIMALS: Adult dogs (n = 55) treated with surgical mitral valve repair using the loop-in-loop technique were included in this study. Medical records were retrospectively reviewed. RESULTS: Ninety percent of cases (50/55) survived to discharge, which survival was significantly decreased in myxomatous mitral valve disease advanced-stage dogs, Stage B2 (n = 14): 100%, Stage C (n = 27): 96.2%, and Stage D (n = 14): 71.4%. Significant reductions of overall heart size (vertebral heart score: preoperative 11.4 vs. post one month 10.2, P < 0.001), left atrium (left atrium to aortic root ratio: preoperative 2.3 vs. post one month 1.5, P < 0.001) and left ventricle (left ventricular end-diastolic diameter [normalized for bodyweight]: preoperative 2.2 vs. post one month 1.5, P < 0.001) were documented one month after surgery, showing successful management of mitral regurgitation. All medications for mitral valve disease were discontinued three months after surgery. The recurrence of mitral regurgitation was not evident during the two-year follow-up period. CONCLUSIONS: Surgical mitral valve repair with the loop-in-loop technique is associated with significant decreases in indices of cardiac size at one-month post-repair. Disease stage influences operative survival after surgical mitral valve repair.