The prevalence of pulmonary hypertension in Cavalier King Charles spaniels compared with other breeds with myxomatous mitral valve disease.

Abstract

INTRODUCTION: Pulmonary hypertension (PH) is a common consequence of myxomatous mitral valve disease (MMVD). Cavalier King Charles spaniels (CKCS) are frequently affected with MMVD&#xa0;and appear to have different disease progression compared to other dogs. This study aimed to determine if CKCS are more likely to develop PH as a result of MMVD than dogs of other breeds. A secondary aim was to explore whether breed or PH impacted survival. ANIMALS: A total of 187 dogs diagnosed with MMVD, 94 CKCS and 93 non-CKCS, were included in this study. METHODS: This is a retrospective review of dogs with MMVD. Data were analyzed for presence of PH, congestive heart failure (CHF) and echocardiographic variables including the ratio between mitral E wave velocity (E vel) and isovolumic relaxation time (E/IVRT) and were compared between CKCS/non-CKCS and dogs with/without PH. Survival analysis was also performed. RESULTS: American College of Veterinary Internal Medicine (ACVIM) stage (p&#xa0;<&#xa0;0.001), CKCS (p&#xa0;=&#xa0;0.005), left atrium-to-aortic ratio (LA/Ao) (p&#xa0;<&#xa0;0.001), E vel (p&#xa0;<&#xa0;0.001) and log(E/IVRT) (p&#xa0;<&#xa0;0.001) were significant at the univariate level for PH development. At the multivariate level, only ACVIM stage remained significant (p&#xa0;=&#xa0;0.044), suggesting that worsening MMVD was the predominant determinant of PH development in this study. Pulmonary hypertension was associated with greater likelihood of CHF (p&#xa0;<&#xa0;0.001) and death (both cardiac [p&#xa0;<&#xa0;0.001] and all-cause mortality [p&#xa0;=&#xa0;0.011]). Cavalier King Charles spaniels were more likely to experience cardiac death than non-CKCS (p&#xa0;=&#xa0;0.004). CONCLUSIONS: In this study, development of PH was associated with worse MMVD, according to ACVIM stage.