Survival in cats with primary and secondary cardiomyopathies

OBJECTIVES: Feline cardiomyopathies (CMs) represent a heterogeneous group of myocardial diseases. The most common CM is hypertrophic cardiomyopathy (HCM), followed by restrictive cardiomyopathy (RCM). Studies comparing survival and outcome for different types of CM are scant. Furthermore, little is known about the cardiovascular consequences of systemic diseases on survival. The aim of this retrospective study was to compare survival and prognostic factors in cats affected by HCM, RCM or secondary CM referred to our institution over a 10 year period. METHODS: The study included 94 cats with complete case records and echocardiographic examination. Fifty cats presented HCM, 14 RCM and 30 secondary CM. RESULTS: A statistically significant difference in survival time was identified for cats with HCM (median survival time of 865 days), RCM (273 days) and secondary CM (<50% cardiac death rate). In the overall population and in the primary CM group (HCM + RCM), risk factors in the multivariate analysis, regardless of the CM considered, were the presence of clinical signs, an increased left atrial to aortic root (LA/Ao) ratio and a hypercoagulable state. CONCLUSIONS AND RELEVANCE: Primary CMs in cats share some common features (ie, LA dimension and hypercoagulable state) linked to feline cardiovascular physiology, which influence survival greatly in end-stage CM. The presence of clinical signs has to be regarded as a marker of disease severity, regardless of the underlying CM. Secondary CMs are more benign conditions, but if the primary disease is not properly managed, the prognosis might also be poor in this group of patients.