VWF and Left atrial enlargement: Given the propensity of cats with advanced subclinical HCM and left atrial enlargement to experience arterial thromboembolism (ATE), and the established/expected clinical benefits of clopidogrel and other antithrombotic agents in these cats, the observed dose-dependent decrease in VWF protein after rapamycin treatment supports that rapamycin may be protective of not only maladaptive hypertrophy, but of at least one of the disease’s outcomes as well (i.e., ATEs) [56,57,58,59].