Stroke Stroke is available at www.ahajournals.org/journal/str AHA/ASA GUIDELINE 2021 Guideline for the Prevention of Stroke in Patients With Stroke and Transient Ischemic Attack A Guideline From the American Heart Association/American Stroke Association Reviewed for evidence-based integrity and endorsed by the American Association of Neurological Surgeons and Congress of Neurological Surgeons. Endorsed by the Society of Vascular and Interventional Neurology The American Academy of Neurology affirms the value of this statement as an educational tool for neurologists. Dawn O. Kleindorfer, MD, FAHA, Chair; Amytis Towfighi, MD, FAHA, Vice Chair; Seemant Chaturvedi, MD, FAHA; Kevin M. Cockroft, MD, MSc, FAHA; Jose Gutierrez, MD, MPH; Debbie Lombardi-Hill, BS, FAHA; Hooman Kamel, MD; Walter N. Kernan, MD*; Steven J. Kittner, MD, MPH, FAHA; Enrique C. Leira, MD, MS, FAHA; Olive Lennon, PhD; James F. Meschia, MD, FAHA; Thanh N. Nguyen, MD, FAHA; Peter M. Pollak, MD; Pasquale Santangeli, MD, PhD; Anjail Z. Sharrief, MD, MPH, FAHA; Sidney C. Smith Jr, MD, FAHA; Tanya N. Turan, MD, MS, FAHA ; Linda S. Williams, MD, FAHA Key Words: AHA Scientific Statements ischemic attack, transient secondary prevention stroke TOP 10 TAKE-HOME MESSAGES FOR THE SECONDARY STROKE PREVENTION GUIDELINE 1. Specific recommendations for prevention strate- gies often depend on the ischemic stroke/tran- sient ischemic attack subtype. Therefore, new in this guideline is a section describing recommen- dations for the diagnostic workup after ischemic stroke, to define ischemic stroke etiology (when possible), and to identify targets for treatment in order to reduce the risk of recurrent ischemic stroke. Recommendations are now grouped by etiologic subtype. 2. Management of vascular risk factors remains extremely important in secondary stroke preven- tion, including (but not limited to) diabetes, smok- ing cessation, lipids, and especially hypertension. 