CLINICAL GUIDELINES American Society of Hematology 2018 guidelines for management of venous thromboembolism: optimal management of anticoagulation therapy Daniel M. Witt,1 Nathan P. Clark,3 Mark A. Crowther,11 John J. Riva,2,14 and Department of Pharmacotherapy, College of Pharmacy, University of Utah, Salt Lake City, UT; 2 Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada; 3 Clinical Pharmacy Anticoagulation and Anemia Service, Kaiser Permanente Colorado, Aurora, CO; 4 School of Medicine, Hofstra Northwell, Hempstead, NY; 5 Division of Clinical Pharmacology and Toxicology, Department of Medicine, McMaster University, Hamilton, ON, Canada; 6 Unit for Health Promotion Research, Department of Public Health, University of Southern Denmark, Esbjerg, Denmark; 7 Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, GA; 8 Aurora Medical Center Summit, Summit, WI; 9 Cambridge, ON, Canada; 10 Department of Medicine and Surgery, Insubria University, Varese, Italy; 11 Department of Medicine, McMaster University, Hamilton, ON, Canada; 12 Department of Medicine, University of Toronto, Toronto, ON, Canada; Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL; and 14 Department of Family Medicine, McMaster University, Hamilton, ON, Canada Background: Clinicians confront numerous practical issues in optimizing the use of anticoagulants to treat venous thromboembolism (VTE). Objective: These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians and other health care professionals in their decisions about the use of anticoagulants in the management of VTE. These guidelines assume the choice of anticoagulant has already been made. Methods: ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. 