Change of Vertebral Left Atrial Size in Dogs With Preclinical Myxomatous Mitral Valve Disease Prior to the Onset of Congestive Heart Failure

It has been proposed that vertebral left atrial size (VLAS) on thoracic radiographs can be used to assess the left atrial enlargement in dogs with myxomatous mitral valve disease (MMVD). However, it remains unclear whether VLAS can be used to distinguish dogs between pre-clinical MMVD that are at a greater risk of developing congestive heart failure (CHF) from those at a lower risk. We investigated this possibility. Forty-one dogs with MMVD were retrospectively classified into one of two groups, a group that developed CHF (group CHF, n = 17) or remained CHF-free (group no-CHF, n = 24). The value of vertebral heart scale (VHS) and VLAS at three time-points, change in VHS and VLAS at a specific time interval (ΔVHS, ΔVLAS) and rate of change in the values per month (ΔVHS/month, ΔVLAS/month) were compared. At the first visit, there were no significant differences in VLAS between the groups. At the median of 105 (interquartile ranges 83–155) days prior to the onset of CHF (group CHF) or the last visit (group no-CHF), VLAS was significantly higher in group CHF (mean, 2.9; standard deviation ± 0.4) than in group no-CHF (2.6 ± 0.3) (p = 0.028). ΔVLAS/month (area under the curve, 0.91; p