Genetics of canine subvalvular aortic stenosis (SAS)

Cardiac biomarkers N-terminal fragment of the prohormone B-type natriuretic peptide and cardiac troponin I for characterization of the cardiac disease phenotype of the English Bull Terrier

The N-terminal fragment of prohormone B-type natriuretic peptide (NT-proBNP) and cardiac troponin I (cTnI) contribute information regarding cardiac load and function and myocardial injury, respectively, to the clinical work-up of dogs with heart disease. The English bull terrier (BT) has a predisposition to a complex cardiac phenotype. This prospective case-control study aimed to further characterize this phenotype through cardiac biomarker evaluation. Fifteen healthy BT (group 1) and 50 BT with various heart disease presentations (groups 2-4) were included. The main presentations were MVD (45 dogs) and MS (13 dogs). 16/50 dogs had echocardiographic evidence of cardiac remodeling: 7 with either increased left atrial (LA) or left ventricular (LV) volumes (group 3) and 9 with increased LA and LV volumes (group 4). Cardiac biomarkers were not significantly different between dogs with disease subtypes MVD or MS versus dogs with other disease presentations. When evaluated in relation to remodeling, median NT-proBNP and cTnI in group 4 (1004 pmol/L, 0.09 ng/mL) were significantly higher than in group 1 (257 pmol/L, 0.02 ng/mL), group 2 (300 pmol/L, 0.026 ng/mL) and group 3 (250 pmol/L, 0.02 ng/mL). There was significant discriminatory ability for both biomarkers between group 4 and groups 1, 2 or 3. Furthermore, cTnI significantly differentiated dogs with any degree of remodeling (groups 3 + 4) from those without (groups 1 + 2). The cardiac disease phenotype of the BT is not associated with a unique cardiac biomarker profile. Rather, biomarker levels are similar to those reported in other breeds with valvular heart disease.

Congenital pulmonic and aortic stenosis in Newfoundland dogs: Results of a 14-year French cardiovascular screening program (921 dogs)

INTRODUCTION

Aortic stenosis (AS) and pulmonic stenosis (PS) are two of the most common canine congenital heart diseases (CHD), with a high relative risk for Newfoundland dogs to develop inherited subvalvular AS. For this reason, a cardiovascular screening program has been set up by the French Newfoundland kennel club in order to manage mattings and reduce AS prevalence.

MATERIALS AND METHODS

The records of untreated and non-anesthetized adult Newfoundland dogs screened between 2010 and 2023 were retrospectively reviewed. All dogs underwent physical examination and standard transthoracic echocardiography with concomitant ECG tracing. All examinations were reviewed by one single board-certified specialist in cardiology.

RESULTS

A total of 921 dogs were screened during the study period (female:male sex ratio = 1.94, median age [IQR] = 1.9 years [1.6-2.7], body weight = 55.0 kg [50-60]). For most dogs (90.6% for AS and 91% PS), a single examination was required to obtain a definitive cardiac status, although most operators (122/133 = 91.7%) were non-specialist general practitioners. Out of the 921 screened dogs, 913/921 (99.1%) and 919/921 (99.8%) were respectively free of AS and PS, with no AS and PS detection during the last 3 years of the program. The inbreeding coefficient, which was assessed from the pedigree analysis of all screened dogs except one, was not significantly different between dogs with either AS (0.59%; P = 0.86) or PS (0.39%; P = 0.72) and those without any arterial stenosis (0.39%).

CONCLUSION

This 14-year cardiovascular screening program has experienced a strong involvement of veterinarians, breeders, and owners throughout France. Unlike reports from other European and North American countries, this program suggests the low and decreasing prevalence of both AS and PS in the Newfoundland breed in France.

Genetic variants for Alzheimer's disease and comorbid conditions

BACKGROUND

Alzheimer's disease and related dementias (ADRD) frequently co-occur with comorbidities such as diabetes and cardiovascular diseases in elderly populations.

OBJECTIVE

Utilize a life-course approach to identify genetic variants that are associated with the co-occurrence of ADRD and another comorbid condition.

METHODS

Research data from African American participants of the Indianapolis-Ibadan Dementia Project (IIDP) linked with electronic medical record (EMR) data and genome-wide association study (GWAS) data were utilized. The age of onset for ADRD was obtained from longitudinal follow-up of the IIDP study. Age of onset for comorbid conditions was obtained from EMR. The analysis included 1177 African Americans, among whom 174 were diagnosed with ADRD. A semi-parametric marginal bivariate survival model was used to examine the influence of single nucleotide polymorphisms (SNPs) on dual time-to-event outcomes while adjusting for sex, years of education, and the first principal component of GWAS data.

RESULTS

Targeted analysis of 20 SNPs that were reported to be associated with ADRD revealed that six were significantly associated with dual-disease outcomes, specifically congestive heart failure and cancer. In addition, eight novel SNPs were identified for associations with both ADRD and a comorbid condition.

CONCLUSIONS

Using a bivariate survival model approach, we identified genetic variants associated not only with ADRD, but also with comorbid conditions. Our utilization of dual-disease models represents a novel analytic strategy for uncovering shared genetic variants for multiple disease phenotypes.

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.

Subvalvular Aortic Stenosis: Learning From Human and Canine Clinical Research

Subvalvular aortic stenosis (SAS) is the most common congenital heart disease (CHD) in dogs and is also prevalent in human children. A fibrous ridge below the aortic valve narrows the left ventricular outflow tract (LVOT) and increases blood flow velocity, leading to devastating side effects in diseased patients. Due to the similarities in presentation, anatomy, pathophysiology, cardiac development, genomics, and environment between humans and dogs, canine SAS patients represent a critical translational model of human SAS. Potential adverse outcomes of SAS include arrhythmias, left-sided congestive heart failure, endocarditis, exercise intolerance, syncope, and sudden cardiac death. The greatest divergence between canine and human SAS clinical research has been the standard of care regarding treatment of these outcomes, with pharmacological intervention dominating best practices in veterinary medicine and surgical intervention comprising the standard practice for human SAS patients. Regardless of the species, the field has yet to identify a treatment option to prevent disease progression or permanently remove the fibrous ridge, but historical leaps in SAS research support a continued translational approach as the most promising method for achieving this goal.

Cardiac Disease and Screening in Breeding Dogs

Acquired and congenital heart diseases are relatively common in dogs, particularly in certain breeds. Modes of inheritance and genetic causes have been established for several cardiac diseases within various breeds. Breed screening is used to try and reduce the prevalence of certain canine cardiac diseases. Although breed screening seems to help reduce the prevalence of canine heart disease, the outcomes of specific breeding programs are variable and depend on multiple factors.

Infective endocarditis in dogs in the UK: 77 cases (2009-2019)

OBJECTIVES

To determine the causative organisms, clinical features and outcome of canine infective endocarditis in the UK.

MATERIALS AND METHODS

Medical records of three veterinary referral hospitals were searched for dogs with infective endocarditis between December 2009 and December 2019. Signalment, clinical signs, causative organism, valve affected, treatment and survival data were recorded.

RESULTS

Seventy-seven cases with possible or definite infective endocarditis (according to the modified Duke criteria) were included. The majority were large breed (40/77 - 51.9%). There were 47 of 77 (61%) male dogs and the mean age was 7.3 ±3 years. A causative organism was identified in 26 of 77 (33.8%) cases. The most common organisms were Escherichia coli (7/27 - 25.9%), Pasteurella spp. (5/27 - 18.5%), Staphylococcus spp. (4/27 - 14.8%) and Corynebacterium spp. (4/27 - 14.8%). Bartonella spp. were not detected in any patients. The mitral valve was most commonly affected (48/77 - 62.3%). Clinical features were non-specific, with lethargy being the most common clinical sign observed (53/77 - 68.8%). Fifty-three dogs (68.8%) survived to discharge. The median survival time post discharge was 425 days (2 to 3650 days). The development of congestive heart failure was associated with a poorer outcome. Cardiac troponin concentration, antithrombotic use and the development of thromboembolism or arrhythmias were not significantly associated with outcome.

CLINICAL SIGNIFICANCE

Some dogs with infective endocarditis that survive to discharge can have a long lifespan. The inability to detect an underlying organism is common and Bartonella spp. may be a less prevalent cause of canine infective endocarditis in the UK than in the USA.