Journal of Veterinary Cardiology最新文献

Introduction/objectives: Mitral regurgitation (MR) is often caused by myxomatous mitral valve disease which affects many small-breed dogs, including Chihuahua dogs. The aim of the study was to assess the prevalence of MR and tricuspid regurgitation (TR), valvular thickening, and prolapse in a group of apparently healthy Chihuahua dogs.

Animals, materials and methods: Ninety-seven privately owned Chihuahua dogs, recruited via the Swedish Chihuahua Club, were included in the study. A prospective observational study was conducted where clinical examinations, electrocardiograms, and echocardiographic and Doppler examinations were performed in all dogs.

Results: Mitral regurgitation was found in 37 (38%) dogs and was considered mild in 31 dogs, moderate in four dogs, and severe in two dogs. A systolic murmur over the mitral valve area was heard in 21 (22%) dogs. Mitral valve thickening was observed in 36 (37%) and mitral valve prolapse in 12 (12%) dogs. Tricuspid valve regurgitation was present in 14 (14%) of all dogs and in 30% of dogs with MR. Dogs with MR were significantly older (median: 7.6 years) than dogs without MR (median: 3 years); P < 0.0001.

Study limitations: Whether or not the presence of MR reflects early stages of myxomatous mitral valve disease cannot be ascertained without the use of histological examination of the mitral valves.

Conclusions: Mitral regurgitation was common in this group of apparently healthy Chihuahua dogs, and at the age of 6.4 years, there is a 50% chance that a dog has developed MR. In the age group 9-10 years, MR was found in 80% of the dogs.

Introduction/objectives: The aim of the study was to characterize the activated macrophage (ionized calcium-binding adaptor molecule-1-positive [Iba1⁺]) population in myxomatous mitral valve disease (MMVD)-affected valve leaflets and associated papillary muscle (PM), as well as fibrosis within the PM associated with MMVD.

Animals, materials and methods: Mitral valve leaflets and posteromedial PM were collected from a total of 25 dogs consisting of three groups: normal group (normal valves; n = 6), mild group (mildly affected valves; n = 5), and severe group (severely affected valves; n = 14). Histological sections of mitral valves were assessed by immunohistochemistry for ionized calcium-binding adaptor molecule-1, and PM sections were similarly assessed for ionized calcium-binding adaptor molecule-1 and with Sirius red for fibrosis.

Results: Significant increases in Iba1⁺ macrophages were noted in mitral valve leaflets from the severe group compared with the mild group (P=0.020) and the normal group (P=0.001). No significant difference in Iba1⁺ macrophages within the PM was noted between groups (P=0.662). Significant increases in the area of fibrosis were seen within the PM in the severe group compared with the normal and mild groups (P=0.001 and P=0.023, respectively).

Study limitations: The sample size is small, and the dogs in the normal and MMVD-affected groups are not age-matched. Furthermore, many dogs from the tissue donation program lack complete health status information.

Conclusions: Inflammation may play an important role in canine MMVD. Further investigation is needed to determine if myxomatous changes in the valves or increased fibrosis in the associated PM are initiated by inflammation.

Mitral regurgitation is the most prevalent valvular heart disease in dogs and humans, leading to symptoms of heart failure, reduction in the quality of life, recurrent hospitalizations, and increased mortality. Mitral transcatheter edge-to-edge repair (M-TEER) is an established intervention for severe mitral regurgitation in human patients and has recently emerged as a promising intervention in dogs. The prospect of a minimally invasive intervention for dogs is a breakthrough development and simultaneously raises important questions of procedural timing, documenting benefit vs. risk, and outcomes compared to surgical repair or medical therapy alone. The evolution of M-TEER in humans has been documented through early feasibility studies, randomized clinical trials comparing M-TEER to medical therapy or surgical repair, and national and international registries. This review focuses on M-TEER technologies, patient selection, procedural performance, and outcomes in humans and dogs. A major goal of this review is to draw upon the extensive human experience as potentially useful in guiding the rollout in dogs and to review the many lessons learned in the human experience that may be relevant to M-TEER in dogs.