Feline arterial thromboembolism: an update Stephanie A. Smith, DVM, MS a, * , Anthony H. Tobias, BVSc, PhD b a Department of Biochemistry, College of Medicine, 506 South Mathews, MC-714, University of Illinois, Urbana, IL 61801, USA b Department of Small Animal Clinical Sciences, University of Minnesota, 1365, Gortner Avenue, St. Paul, MN 55108, USA Arterial thromboembolism (ATE) has been recognized in cats for almost three quarters of a century. A case report published in 1930 described the typical clinical and necropsy findings in a cat presented for posterior paralysis with a distal aortic thromboembolus [1]. A series of nine cases of ATE in cats was published 25 years later [2]. By the 1960s, ATE was well recognized, with a prevalence rate of 1 in 142 new feline admissions to the Teaching Hospital, University of Pennsylvania [3]. The prevalence of ATE does not seem to have changed much in the last four decades. From 1992 to 2001, ATE was diagnosed in 1 in 175 new feline admissions to the University of Minnesota Veterinary Medical Center (UMVMC) [4]. The last seven decades have brought marked improvement in the veterinary clinician’s ability to recognize ATE in cats and some improve- ment in supportive measures for the acute episode but little improvement in the prevention of ATE. Although options for anticoagulation therapy have expanded to include a variety of new drugs, optimal thromboprophylaxis for cats at risk for ATE has yet to be determined. Pathophysiology Thrombosis is the formation of a blood clot within the heart or blood vessels. It is generally accepted that prior to development of ATE in cats, the thrombus forms within the left side of the heart. Eventually, the thrombus dislodges and is carried through the systemic vasculature until it becomes lodged due to the diameter of the thrombus exceeding the diameter of the * Corresponding author. E-mail address: sasmith6@uiuc.edu (S.A. Smith). 0195-5616/04/$ - see front matter Ó 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.cvsm.2004.05.006 Vet Clin Small Anim 34 (2004) 1245–1271