Perioperative changes in plasma cardiac troponin I concentration during mitral valvuloplasty for severe mitral regurgitation in dogs.

Background: Mitral valvuloplasty (MVP) is a surgical procedure for treating severe mitral regurgitation in dogs. Although MVP is considered highly invasive, the extent of myocardial injury, postoperative complications, and recovery has not been evaluated. Aim: This study examined the degree of MVP invasiveness, the extent of myocardial damage, postoperative complications, cardiomyocyte recovery, and timing of hospital discharge. Methods: Cardiac troponin I (cTnI) was used to investigate the myocardial damage caused by cardiac arrest associated with a surgical approach to the myocardium in 13 patients with MVP and five controls with patent ductus arteriosus (PDA) who underwent similar anesthesia and thoracotomy. Results: The level of cTnI peaked 1 day after surgery and was significantly higher in the MVP group (median, 19.90 ng/ml) than in the control group (median, 1.50 ng/ml p < 0.001). At day 7, the cTnI level was significantly higher in the MVP group (1.9 ng/ml) than in the control group (0.1 ng/ml) (p < 0.001), and recovery to the preoperative level took 10 days in the MVP group but returned to the preoperative level at day 7 in the control group. Although the mean arterial pressure of cardiopulmonary bypass (CPB) at the time of use was 42.92 mmHg, the peak cTnI levels in the two patients who exhibited a temporary decrease of 20 mmHg or less (46.03 ng/ml) were significantly higher than in the other 11 patients (19.70 ng/ml) (p < 0.05). Preoperative cTnI levels were correlated with the severity of postoperative complications (P = 0.03, F = 0.71). Conclusion: The results showed that MVP caused temporary greater myocardial tissue damage than thoracotomy, but postoperative recovery was smoother. A high preoperative cTnI level requires relatively more careful postoperative management, and measuring the level of cTnI over time after surgery can provide information about the extent of myocardial damage and recovery from surgery and help determine the time of discharge.

Development of an artificial intelligence-based algorithm for predicting the severity of myxomatous mitral valve disease from thoracic radiographs by using two grading systems.

A heart-convolutional neural network (heart-CNN) was designed and tested for the automatic classification of chest radiographs in dogs affected by myxomatous mitral valve disease (MMVD) at different stages of disease severity. A retrospective and multicenter study was conducted. Lateral radiographs of dogs with concomitant X-ray and echocardiographic examination were selected from the internal databases of two institutions. Dogs were classified as healthy, B1, B2, C and D, based on American College of Veterinary Internal Medicine (ACVIM) guidelines, and as healthy, mild, moderate, severe and late stage, based on Mitral INsufficiency Echocardiographic (MINE) score. Heart-CNN performance was evaluated using confusion matrices, receiver operating characteristic curves, and t-SNE and UMAP analysis. The area under the curve (AUC) was 0.88, 0.88, 0.79, 0.89 and 0.84 for healthy and ACVIM stage B1, B2, C and D, respectively. According to the MINE score, the AUC was 0.90, 0.86, 0.71, 0.82 and 0.82 for healthy, mild, moderate, severe and late stage, respectively. The developed algorithm showed good accuracy in predicting MMVD stages based on both classification systems, proving a potentially useful tool in the early diagnosis of canine MMVD.

Prolonged survival with mitral valve plasty for acute mitral regurgitation due to mitral valve dysplasia and chordal rupture in a young small dog: A case report.

Background: We aimed to report the second case of mitral valve plasty (MVP) for acute mitral regurgitation (MR) due to mitral valve dysplasia in a young small dog. Case Description: A 5-month-old female Jack Russell, weighing 3.5 kg, presented with dyspnea and collapse upon excitation. Acute MR with pulmonary edema due to chordal rupture was diagnosed with a suspected congenital mitral valve anomaly. Despite treatment with high-dose drugs, heart failure symptoms and enlargement worsened. An artificial chordal replacement (ACR) was inserted using polytetrafluoroethylene sutures, and annuloplasty was performed. The dog was discharged on postoperative day 7. After 7 years, the dog underwent operations for complete anterior cruciate ligament tears with no cardiac signs. After 11.5 years, the dog showed no cardiac issues and died from a non-cardiac disease. Conclusion: The MVP method with ACR employed demonstrated better durability and promoted longer survival than that of previous dog mitral valve replacements.

Potential prognostic indicators in dogs with advanced heart failure secondary to myxomatous mitral valve disease.

BACKGROUND: Advanced heart failure (AHF) secondary to myxomatous mitral valve disease (MMVD) in dogs has unclear predictive variables and survival time. METHODS: This retrospective study included 38 dogs with AHF and 38 with stable congestive heart failure (CHF), both due to MMVD. Predictive variables for AHF were analysed, and survival times were calculated using logistic regression and the Kaplan-Meier method. RESULTS: Left atrium to aortic root ratio, normalised left ventricular dimension at the end-diastole and end-systole, isovolumic relaxation time (IVRT) and early transmitral inflow velocity to IVRT ratio were associated with AHF progression. The median survival times were significantly longer in the stable group than in the AHF group. After AHF diagnosis, the median survival times for all-cause and cardiogenic mortality were 194 and 354 days, respectively. LIMITATIONS: This was a single-centre retrospective observational study. The study population was small, with breed bias (overrepresentation of Maltese dogs). Additionally, the treatment plans depended on clinical experience. CONCLUSIONS: AHF in dogs with CHF secondary to MMVD is linked to left heart chamber enlargement and increased left ventricular dimensions, significantly reducing survival time to around six months post-diagnosis. Early recognition and appropriate management may improve outcomes, highlighting the importance of advanced treatment strategies.

The impact of intravenous medetomidine and vatinoxan on echocardiographic evaluation of dogs with stage B1 mitral valve disease.

INTRODUCTION/OBJECTIVE: The purpose of this study was to investigate the echocardiographic effects of intravenous medetomidine and vatinoxan in dogs with stage B1 mitral valve disease. We hypothesised medetomidine-vatinoxan would reduce the need for manual restraint during echocardiography without producing detrimental cardiovascular effects or echocardiographic changes. ANIMALS: Twelve client-owned dogs with stage B1 mitral valve disease. METHODS: A transthoracic echocardiographic examination was performed before and after sedation with intravenous medetomidine (10 µg/kg) and vatinoxan (200 µg/kg). Vital parameters were also recorded, and the level of sedation was assessed subjectively. The data were analysed with Student's t-tests with an alpha level of <0.05. RESULTS: End-systolic volume and left ventricular systolic diameter increased (from 0.89 ± 0.19 mL/kg to 1.13 ± 0.29 mL/kg and 0.96 ± 0.12 cm to 1.10 ± 0.10 cm, respectively) and ejection fraction (from 66.33 ± 4.0% to 56.23 ± 9.54%) and fractional shortening (from 36.13 ± 5.42% to 27.24 ± 5.6%) decreased significantly after sedation. End diastolic volume, left ventricular diastolic diameter, and left atrial size remained statistically unchanged, while aortic (from 1.34 ± 0.2 m/s to 0.99 ± 0.14 m/s) and pulmonic (from 0.94 ± 0.16 m/s to 0.66 ± 0.15 m/s) velocities decreased significantly. No dogs had a mean arterial pressure below 65 mmHg. Sedation enabled echocardiographic examination without manual restraint. No adverse effects were observed with the dose studied. CONCLUSIONS: Echocardiographic parameters were not completely comparable with the baseline values, which should be taken into consideration when evaluating dogs sedated with intravenous medetomidine-vatinoxan.

Platelet hyperresponsiveness and increased platelet-neutrophil aggregates in dogs with myxomatous mitral valve disease and pulmonary hypertension.

BACKGROUND: Pulmonary hypertension (PH) in dogs with myxomatous mitral valve disease (MMVD) is caused by increased pulmonary venous pressure. Thrombosis, vascular remodeling, and vasoconstriction mediated by platelets could exacerbate PH. HYPOTHESIS: Dogs with PH will exhibit a hypercoagulable state, characterized by increased platelet activation, platelet-leukocyte, and platelet-neutrophil aggregate formation. ANIMALS: Eleven dogs (≥3.5 kg) diagnosed with MMVD and PH and 10 dogs with MMVD lacking PH. METHODS: Prospective cohort ex vivo study. All dogs underwent echocardiographic examination, CBC, 3-view thoracic radiographs, and heartworm antigen testing. Severity of PH and MMVD were assessed by echocardiography. Viscoelastic monitoring of coagulation was assessed using thromboelastography (TEG). Platelet activation and platelet-leukocyte/platelet-neutrophil interactions were assessed using flow cytometry. Plasma serotonin concentrations were measured by ELISA. RESULTS: Unstimulated platelets from dogs with MMVD and PH expressed more surface P-selectin than MMVD controls (P = .03). Platelets from dogs with MMVD and PH had persistent activation in response to agonists. The number of platelet-leukocyte aggregates was higher in dogs with MMVD and PH compared with MMVD controls (P = .01). Ex vivo stimulation of whole blood resulted in higher numbers of platelet-neutrophil aggregates in dogs with MMVD and PH (P = .01). Assessment of hypercoagulability based on TEG or plasma serotonin concentrations did not differ between groups. CONCLUSION AND CLINICAL IMPORTANCE: Platelet hyperresponsiveness and increased platelet-neutrophil interaction occur in dogs with MMVD and PH, suggesting that platelets play a role of in the pathogenesis of PH. Clinical benefits of antiplatelet drugs in dogs with MMVD and PH require further investigation.

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.

Retrospective evaluation of the utility of shock index to determine the presence of congestive heart failure in dogs with myxomatous mitral valve disease (2019-2021): 98 cases.

OBJECTIVES: To calculate the shock index (SI) in dogs with myxomatous mitral valve disease (MMVD) and to evaluate its use to predict the presence of congestive heart failure (CHF). DESIGN: Retrospective study. SETTING: Small animal university veterinary teaching hospital. ANIMALS: Ninety-eight dogs with MMVD and 20 healthy dogs as part of a control group. INTERVENTIONS: Heart rate (HR) and systolic blood pressure (SBP) were recorded, and SI was calculated by dividing HR by SBP for each dog. MEASUREMENTS AND MAIN RESULTS: The mean (SD) HR, SBP, and SI were 123/min (32.6), 147 mm Hg (21.5), and 0.86 (0.3), respectively, for dogs with MMVD and 98/min (20.9), 145 mm Hg (18.7), and 0.68 (0.13), respectively, for control dogs. Dogs with MMVD had a significantly higher HR compared with control dogs (P < 0.01), and an elevation in HR was seen as the severity of MMVD increased. Dogs in stage B2 and C/D MMVD had a significantly higher SI value compared with control dogs (P = 0.04 and P < 0.01, respectively). SI was significantly higher in dogs in stage C/D MMVD compared with dogs in stage B2 MMVD (P < 0.01). Ten of 98 (10%) dogs had an arrhythmia. HR, SBP, and SI were not significantly different between dogs with and without arrhythmias (P = 0.13, P = 0.57, and P = 0.07, respectively), but significantly more dogs with CHF had an arrhythmia (P = 0.01). SI (area under the curve [AUC]: 0.98) and HR (AUC: 0.95) were excellent indicators for the presence of CHF. An optimal SI cutoff value ≥1.1 had 92% sensitivity and 95% specificity for predicting the presence of CHF, and an optimal HR cutoff value of ≥157/min had 92% sensitivity and 93% specificity for the prediction of CHF. CONCLUSIONS: When there are compatible clinical signs, SI values ≥1.1 may suggest the presence of CHF in dogs with MMVD.

Echocardiographic findings in apparently healthy Czechoslovakian wolfdogs.

INTRODUCTION: To echocardiographically evaluate a large number of apparently healthy Czechoslovakian wolfdogs (CWDs) to identify possible subclinical cardiac abnormalities and to generate reference intervals. ANIMALS: One-hundred and seventeen apparently healthy client-owned CWDs. MATERIALS AND METHODS: Standard two-dimensional, M-mode, and Doppler echocardiographic measurements were obtained on non-sedated, manually restrained standing dogs. Animals with no relevant echocardiographic abnormalities were used to generate reference intervals. Echocardiographic variables were compared between males and females and between dogs with and without mitral regurgitation (MR). RESULTS AND DISCUSSION: Among the 117 CWDs, 103 dogs were used to generate reference intervals. The 14 dogs with abnormalities had more than trivial MR (12 dogs), subaortic stenosis (one dog), and equivocal subaortic stenosis (one dog). The 44 males were heavier than 59 females (P<0.001) and had a larger maximum left atrial dimension (P=0.015), left ventricular internal dimension at end-diastole (P<0.001) and systole (P<0.001), and thicker interventricular septum thickness at end-diastole (P=0.016). A positive linear correlation was identified between bodyweight and aortic root and left atrial diameters and left ventricular dimensions and between age and aortic root and left atrial diameter and peak late transmitral flow velocity. A negative linear correlation was identified between age and peak early transmitral flow velocity and the ratio between peak early and late transmitral flow velocities. No differences in echocardiographic-derived cardiac dimensions were detected between healthy dogs and dogs with more than trivial MR. CONCLUSIONS: In this population of CWDs, subclinical cardiac abnormalities were uncommon, and they were mainly classified as MR.

Blood cardioplegia reduces intraoperative ventricular fibrillation and transfusion requirements compared to crystalloid cardioplegia in canine mitral valve repair.

OBJECTIVE: Cardioplegic solutions are indispensable for open-heart surgeries, including mitral valve repair (MVR), a potentially curative treatment for myxomatous mitral valve disease in dogs. However, procedural methodologies are not fully established, and complications are yet to be comprehensively understood. Cardioplegic solutions contain various substances to protect the myocardium under temporal cardiac arrest. Nevertheless, ventricular fibrillation (VF) occurs as a common complication after releasing the crossclamp. Based on these backgrounds, the search for optimal cardioplegic solutions in dogs undergoing MVR is an urgent issue. This study aims to evaluate the occurrence of VF in dogs treated with blood cardioplegia (BCP) versus crystalloid cardioplegia (CCP) during MVR. ANIMALS: A total of 251 client-owned dogs who underwent MVR from November 2015 to November 2017 were included. METHODS: We retrospectively assessed the relationship between VF and type of cardioplegia (CCP or BCP) based on surgical records, including VF incidence, transfusion use, crossclamp time, and echocardiographic measurements. RESULTS: Logistic regression analysis showed that the CCP group was associated with the occurrence of VF (OR, 2.378; CI, 1.133-4.992; P = .022). In addition, the CCP group was associated with transfusion use (OR, 2.586; CI, 1.232-5.428, P = .022). There was no difference between the groups for the pre- and postoperative echocardiographic measurements. CLINICAL RELEVANCE: The BCP group had a lower incidence of VF and less transfusion use than the CCP group. This finding indicates that BCP may be a superior cardioplegic technique for MVR in dogs.

Pulmonary-vein-to-pulmonary-artery ratio can be utilized to evaluate myxomatous mitral valve disease progression in dogs.

OBJECTIVE: To evaluate the diagnostic value of pulmonary-vein-to-pulmonary-artery ratio (PV:PA) in dogs with myxomatous mitral valve degeneration (MMVD), classified according to the American College of Veterinary Internal Medicine (ACVIM) consensus guidelines. ANIMALS: 80 client-owned dogs with either MMVD (n = 65) or no cardiovascular disease (control group; n = 15) between August 5, 2020, and July 19, 2023. METHODS: This is a retrospective study. Dogs with MMVD were classified according to ACVIM consensus guidelines. Echocardiograms, thoracic radiographs, and other measurements needed in this study were reviewed in all dogs. Spearman correlation was used to determine the correlation between the PV:PA and the following variables: vertebral heart size, vertebral left atrial size, left-atrium-to-aorta ratio, normalized left ventricular internal diameter, and peak transmitral early diastolic velocity. Receiver operating characteristic (ROC) curve analysis was used to evaluate the value of PV:PA in distinguishing between stages B1 and B2 and stages B2 and C. RESULTS: All conventional indices showed correlations with PV:PA. The area under the ROC curve (AUC) for stages B1 and B2 was 0.83, and the cutoff value for differentiating stage B2 was 1.52. The AUC for stages B2 and C was 0.81, and the cutoff value for differentiating stage C was 2.09. CLINICAL RELEVANCE: PV:PA was significantly different between control and the stage B1 group, stage B1 and B2 group, and stage B2 and C group. PV:PA can be an index that can be used in evaluating MMVD dogs.

Myxomatous mitral valve disease and associated pulmonary hypertension might increase serum angiopoietin-2 in dogs.

OBJECTIVE: To evaluate the relationships between the severity of myxomatous mitral valve disease (MMVD) and pulmonary hypertension (PH) and serum angiopoietin (Ang)-1 and Ang-2 concentrations in dogs with MMVD. ANIMALS: 74 dogs (control, n = 12; MMVD, n = 62) were included. METHODS: Serum Ang-1 and Ang-2 concentrations were estimated using the canine-specific ELISA kit. The concentrations were compared between dogs with MMVD and healthy dogs, and they were analyzed according to the severity of MMVD and PH. RESULTS: The median serum Ang-1 concentration did not differ among the study groups. The median serum Ang-2 concentration was higher in dogs with stage B2 MMVD (P = .041) and acute congestive heart failure (P = .002) than in control dogs. In addition, the median serum Ang-2 concentration was higher in MMVD dogs with PH than in those without PH (P = .031). Serum Ang-2 concentration was correlated with vertebral heart score (rs = 0.36, P = .004) and vertebral left atrial score (r = 0.50, P < .001) in dogs with MMVD, and correlated with vertebral heart score (r = 0.63, P = .01), maximum E wave amplitude of the diastolic transmitral flow (rs = 0.61, P = .018), ejection fraction (rs = -0.77, P < .001) and fractional shortening (rs = -0.56, P = .032) in dogs with acute congestive heart failure. CLINICAL RELEVANCE: Circulating Ang-2 levels increase in dogs with the severity of MMVD and the presence of PH.

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.

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.

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.

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.