Prevalence, risk factors and survival in dogs with myxomatous valve degeneration

ABSTRACT The objective of this study was to describe the prevalence, survival time, and risk factors of myxomatous mitral valve disease (MMVD) in dogs by a retrospective observational cohort study design of a Brazilian veterinary center, admitted from 2012 to 2018 (2.585 days). Considering the 105 dog files confirmed as MMVD, the prevalence of the disease was higher in small-breed dogs with ages from 10 to 19 years (30.3%). The survival time of the dogs at B1 stage (1.854 ± 145 days) was higher than the B2 (1.508+209) and C/D (930 ± 209). Higher risks of death (hazard ratio) were detected in the presence of syncope (2.5), pulmonary crackling (2.0), dyspnea (1.9), and higher values of vertebral heart scale (1.7), radiographic left atrium dimension (1.8), the ACVIM staging (1.7), and the duration of QRS complex (1.05). The results achieved demonstrated higher prevalence of MMVD in old small-breed dogs, associated with longer survival time in the B1 stage of the disease, and higher risk of death related to the presence of clinical signs, such as dyspnea, syncope, and pulmonary crackling, beyond some radiographic, echocardiographic, and electrocardiographic variables of heart or atrial enlargement.摘要 本研究旨在通过一项针对巴西某兽医中心2012至2018年（共计2585天）收治病例的回顾性观察队列研究，描述犬黏液瘤性二尖瓣疾病（myxomatous mitral valve disease, MMVD）的患病率、存活时间及危险因素。本研究纳入105份确诊为MMVD的犬只病历，结果显示，10至19岁的小型犬中该病的患病率更高，达30.3%。B1期患犬的存活时间（1854±145天）高于B2期（1508±209天）与C/D期（930±209天）。研究发现，存在晕厥（风险比2.5）、肺部啰音（2.0）、呼吸困难（1.9），以及脊柱心评分（1.7）、影像学左心房内径（1.8）、美国兽医内科学会（ACVIM）分期（1.7）、QRS波时限（1.05）偏高的个体，其死亡风险更高。本研究结果表明，老年小型犬中MMVD的患病率更高，且B1期患犬的存活时间更长；除心脏或心房扩大的影像学、超声心动图及心电图相关指标外，呼吸困难、晕厥、肺部啰音等临床症状也与更高的死亡风险相关。