Thromboembolic Therapies in Dogs and Cats: An Evidence-Based Approach Kari V. Lunsford, DVM * , Andrew J. Mackin, MVS, DVSc Department of Clinical Sciences, College of Veterinary Medicine, Mail Stop 9825, Spring Street, Mississippi State University, Mississippi State, MS 39762–6100, USA EVIDENCE-BASED MEDICINE The goal of evidence-based medicine is to use the best evidence from clinical re- search in combination with clinical expertise and patient and client factors in guid- ing the care of individual patients. Detailed guidelines for the evaluation of research evidence and clinical recommendations related to therapy of thrombo- embolic disease in human patients have been reviewed [1,2]. These guidelines call for data originating from large, well-designed, randomized controlled clinical tri- als evaluating therapies in clearly defined patient populations with naturally oc- curring diseases without comorbidity [3]. This approach cannot be practically applied to the veterinary literature, however, because the criteria would eliminate most of the available veterinary literature from the ‘‘best evidence’’ pool and few, if any, strong treatment recommendations could be made. In veterinary medi- cine, we are therefore forced to make use of less ideal ‘‘evidence,’’ such as extrap- olation from experimental studies in dogs and cats without naturally occurring diseases and from clinical trials in other species (particularly human clinical tri- als), as well as limited information gained from veterinary clinical experience, small clinical trials, case studies, and anecdotal reports. In this article, although specific treatment recommendations have been made for each of the common thromboembolic conditions seen in dogs and cats, these recommendations are made with the important caveat that, to date, such suggested therapeutic approaches are based on limited evidence. THROMBOEMBOLIC THERAPIES Medical treatment aimed at thromboembolic diseases consists of dissolving ex- isting thrombi (thrombolytic drugs) or preventing new thrombus formation, primarily by means of the use of antiplatelet drugs, heparin products, and vitamin K antagonists. Each of these specific drug classes is briefly reviewed *Corresponding author. E-mail address: lunsford@cvm.msstate.edu (K.V. Lunsford). 0195-5616/07/$ – see front matter ª 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.cvsm.2007.01.010 vetsmall.theclinics.com Vet Clin Small Anim 37 (2007) 579–609 VETERINARY CLINICS SMALL ANIMAL PRACTICE