Isayama Noriko, Uchimura Yusuke, Sasaki Kenta, Maeda Erika, Takahashi Toshihisa, Watanabe Megumi
Department of Cardiology, Ueno no Mori Animal Hospital, Tokyo, Japan.
Front Vet Sci. 2022 Jun 23;9:918457. doi: 10.3389/fvets.2022.918457. eCollection 2022.
Myxomatous mitral valve disease (MMVD) is one of the most common heart diseases in dogs, and there is a dearth of reports that have investigated reference values for left ventricular end-diastolic internal diameter corrected for body weight (LVIDDN) exclusively in toy breeds.
Eighty-six client-owned healthy dogs weighing <5 kg, including Toy Poodles, Chihuahuas, Yorkshire Terriers, Papillon, and other small breeds or small mixed breeds (mixed breed, Pomeranian, dachshund, Shih Tzu, and Maltese). In this retrospective single-center study, data were collected from dogs attending clinic for annual checkup between April 2014 and March 2021.
Experienced echocardiographers performed transthoracic echocardiography, with reference ranges established using healthy dogs. Measurements of body weight (BW), heart rate, and several echocardiographic variables were obtained. The association between BW and echocardiographic parameters was assessed by linear regression analyses. M-mode measurements were obtained and normalized using equations developed from the regression analyses.
The LVIDDN value for 95% of dogs weighing <5 kg was achieved by dividing the M-mode measurement by BW raised to the power 0.332. The upper limit of the prediction interval for breeds weighing <5 kg was much lower than the value currently applied.
We propose a reference LVIDDN value of ≥1.6 for the diagnosis of stage B2 MMVD in toy breed dogs. The results of our study will guide clinicians in deciding when to start treatment for MMVD in small breed dogs.
黏液瘤样二尖瓣疾病（MMVD）是犬类最常见的心脏病之一，然而专门针对玩具犬种体重校正左心室舒张末期内径（LVIDDN）参考值的研究报告却很匮乏。
86只体重小于5千克的客户自养健康犬，包括玩具贵宾犬、吉娃娃犬、约克夏梗犬、蝴蝶犬以及其他小型犬种或小型混种犬（混种犬、博美犬、腊肠犬、西施犬和马尔济斯犬）。在这项回顾性单中心研究中，收集了2014年4月至2021年3月期间到诊所进行年度体检的犬只的数据。
经验丰富的超声心动图检查人员进行经胸超声心动图检查，参考范围依据健康犬只确定。获取了体重（BW）、心率以及多个超声心动图变量的测量值。通过线性回归分析评估BW与超声心动图参数之间的关联。采用回归分析得出的公式进行M型测量并进行标准化。
对于体重小于5千克的犬只，95%的LVIDDN值通过将M型测量值除以BW的0.332次幂获得。体重小于5千克犬种预测区间的上限远低于目前应用的值。
我们提出对于玩具犬种诊断B2期MMVD的参考LVIDDN值≥1.6。我们的研究结果将指导临床医生决定何时开始对小型犬种的MMVD进行治疗。
