These conditions are thought to be rare causes of ischemic stroke in adults, but may be more important causes of ischemic stroke in children. (See "Ischemic stroke in children and young adults: Epidemiology, etiology, and risk factors", section on 'Hematologic'.) The 2021 American Heart Association/American Stroke Association (AHA/ASA) guidelines note that it is uncertain whether testing for these hematologic traits is beneficial in the context of secondary stroke prevention [14]. Suspicion for hypercoagulable states as the cause of stroke may be heightened in younger patients with cryptogenic stroke, a history or family history of unprovoked thrombosis, prior spontaneous abortion, or concomitant systemic signs and symptoms suggestive of hypercoagulability. The same guidelines note that for patients with ischemic stroke or TIA of unknown source (despite a thorough diagnostic evaluation) who are found to have an inherited thrombophilia, antiplatelet treatment is reasonable to reduce the risk of recurrent stroke or TIA [14]. The evaluation and management of these conditions is discussed in greater detail separately. (See "Antithrombin deficiency" and "Protein C deficiency" and "Protein S deficiency" and "Factor V Leiden and activated protein C resistance" and "Prothrombin G20210A" and "Overview of homocysteine" and "Cerebral venous thrombosis: Treatment and prognosis".) Cancer-related hypercoagulable state Patients with cancer may be at increased risk for stroke due to hypercoagulability and other potential mechanisms, including compression or invasion of blood vessels, marantic endocarditis, infections, paraneoplastic disorders, and complications of cancer therapies [28,29]. (See "Cancer-associated hypercoagulable state: Causes and mechanisms".) For patients with TIA or ischemic stroke attributed to cancer hypercoagulability, optimal treatment for secondary stroke prevention is unknown, and data are limited [29]. Empiric treatment with low molecular weight heparin is often used, but the clinical risk and benefit compared with antiplatelets remains uncertain [30]. In patients with venous thromboembolism (VTE) and cancer, anticoagulant therapy is the mainstay of treatment. Low molecular weight heparin or DOACs are preferred in patients without renal insufficiency, whereas warfarin is the preferred treatment in patients with renal insufficiency (eg, creatinine clearance <30 mL/minute). (See "Anticoagulation therapy for venous thromboembolism (lower extremity venous thrombosis and pulmonary embolism) in adult patients with malignancy".) The 2021 AHA/ASA guidelines note only that in the setting of atrial fibrillation and cancer, it is reasonable to consider anticoagulation with DOACs in preference to warfarin for stroke prevention [14]. https://www.uptodate.com/contents/overview-of-secondary-prevention-for-specific-causes-of-ischemic-stroke-and-transient-ischemic-attack/print 12/25 7/6/23, 12:09 PM Overview of secondary prevention for specific causes of ischemic stroke and transient ischemic attack - UpToDate CRYPTOGENIC STROKE Cryptogenic stroke is variably defined and generally designates the category of brain infarction that is not attributed to an established source of cardioembolism, large artery atherosclerosis, small artery disease, or other determined cause of stroke. However, the term cryptogenic stroke has been applied to patients with an incomplete diagnostic evaluation, a complete but unrevealing evaluation, or an evaluation that identifies multiple potential causes of stroke. (See "Cryptogenic stroke and embolic stroke of undetermined source (ESUS)", section on 'Classification'.) Embolic stroke of undetermined source (ESUS) is a subcategory of cryptogenic stroke defined as a nonlacunar brain infarct without proximal arterial stenosis or cardioembolic sources; ESUS requires a full standardized stroke evaluation to exclude other causes. While the less well- defined term of cryptogenic stroke has been reported to account for approximately 25 to 40 percent of ischemic strokes, the more specific term of ESUS consistently accounts for approximately 20 percent of ischemic strokes. (See "Cryptogenic stroke and embolic stroke of undetermined source (ESUS)", section on 'Embolic stroke of undetermined source'.) For secondary prevention, most patients with a cryptogenic ischemic stroke or TIA should be treated with blood pressure control, low-density lipoprotein cholesterol lowering therapy, and lifestyle modification. Initial antiplatelet therapy is advised while awaiting the results of long- term cardiac monitoring. For patients initially diagnosed with cryptogenic stroke who have atrial fibrillation of any duration detected on long-term monitoring, even if detected remotely from the incident stroke, anticoagulant therapy with warfarin or a direct oral anticoagulant is advised rather than antiplatelet therapy. (See "Cryptogenic stroke and embolic stroke of undetermined source (ESUS)", section on 'Secondary prevention'.) SOCIETY GUIDELINE LINKS Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Stroke in adults" and "Society guideline links: Fibromuscular dysplasia".) INFORMATION FOR PATIENTS UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." th th The Basics patient education pieces are written in plain language, at the 5 to 6 grade reading https://www.uptodate.com/contents/overview-of-secondary-prevention-for-specific-causes-of-ischemic-stroke-and-transient-ischemic-attack/print 13/25 7/6/23, 12:09 PM Overview of secondary prevention for specific causes of ischemic stroke and transient ischemic attack - UpToDate level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more th th sophisticated, and more detailed. These articles are written at the 10 to 12 grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon. Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.) Basics topics (see "Patient education: Stroke (The Basics)") Beyond the Basics topics (see "Patient education: Transient ischemic attack (Beyond the Basics)" and "Patient education: Stroke symptoms and diagnosis (Beyond the Basics)" and "Patient education: Ischemic stroke treatment (Beyond the Basics)") SUMMARY AND RECOMMENDATIONS Large artery disease Secondary prevention for ischemic stroke or transient ischemic attack (TIA) attributed to large artery disease may include the following measures: Symptomatic internal carotid stenosis In addition to medical management, revascularization is generally beneficial for patients with recently symptomatic internal carotid artery atherosclerotic stenosis with 50 to 99 percent luminal narrowing. In the setting of complete carotid occlusion, medical management is the only practical option. (See 'Symptomatic carotid stenosis' above.) Extracranial vertebral artery In most cases, ischemic stroke and TIA due to extracranial vertebral artery stenosis is managed by intensive medical treatment with multifactorial risk reduction. (See 'Extracranial vertebral artery stenosis' above.) Intracranial atherosclerosis Aggressive medical management is superior to stenting for patients with recently symptomatic high-grade intracranial large artery stenosis. (See 'Intracranial large artery atherosclerosis' above.) Arterial dissection Antithrombotic therapy with either antiplatelet or anticoagulant agents is used for the secondary prevention of ischemic stroke and TIA caused by cervical arterial dissection. (See 'Dissection' above.) https://www.uptodate.com/contents/overview-of-secondary-prevention-for-specific-causes-of-ischemic-stroke-and-transient-ischemic-attack/print 14/25 7/6/23, 12:09 PM Overview of secondary prevention for specific causes of ischemic stroke and transient ischemic attack - UpToDate Small artery disease Antiplatelet therapy and treatment of modifiable risk factors is the mainstay for secondary stroke prevention in patients with lacunar stroke or TIA due to small artery disease. (See 'Small artery disease' above.) Cardiogenic embolism Virtually all patients with atrial fibrillation who have a history of stroke or TIA should be treated with oral anticoagulation in the absence of contraindications. (See 'Atrial fibrillation' above.) Other cardiac sources of embolism for which anticoagulation is often indicated include: Left ventricular thrombus (see 'Left ventricular thrombus' above) Cardiomyopathy (see 'Cardiomyopathy' above) Prosthetic heart valves (see 'Valvular disease' above) Moderate to severe mitral stenosis, even in the absence of atrial fibrillation (see 'Valvular disease' above) Congenital heart disease (see 'Congenital heart disease' above) Patent foramen ovale (PFO) device closure is more effective than medical therapy alone for select patients with a PFO-associated stroke. Evaluation and treatment are discussed in detail separately. (See "Stroke associated with patent foramen ovale (PFO): Evaluation".) Aortic atherosclerosis The optimal treatment for the prevention of ischemic stroke and TIA attributed to aortic arch atherosclerosis is not clear. Medical management with antiplatelet and low-density lipoprotein cholesterol lowering therapy is reasonable. (See 'Aortic atherosclerosis' above.) Sickle cell disease Stroke is a frequent complication of sickle cell disease, and the risk of recurrent stroke is high. Stroke risk can be reduced with chronic transfusion therapy. (See 'Sickle cell disease' above and "Prevention of stroke (initial or recurrent) in sickle cell disease".) Hypercoagulable states Anticoagulation with warfarin is the gold standard for patients with antiphospholipid syndrome and arterial thromboembolism; some experts add low- dose aspirin for selected patients with arterial events who also have additional risk factors for atherosclerotic vascular disease. With TIA or ischemic stroke attributed to cancer hypercoagulability, the optimal treatment for secondary stroke prevention is unknown. Inherited thrombophilias are thought to be rare causes of ischemic stroke in adults. For patients with ischemic stroke or TIA of unknown source (despite a thorough diagnostic https://www.uptodate.com/contents/overview-of-secondary-prevention-for-specific-causes-of-ischemic-stroke-and-transient-ischemic-attack/print 15/25 7/6/23, 12:09 PM Overview of secondary prevention for specific causes of ischemic stroke and transient ischemic attack - UpToDate evaluation) who are found to have an inherited thrombophilia, antiplatelet treatment is reasonable. (See 'Hypercoagulable states' above.) ACKNOWLEDGMENTS The UpToDate editorial staff acknowledges J Philip Kistler, MD, Hakan Ay, MD, and Karen L Furie, MD, MPH, who contributed to an earlier version of this topic review. Use of UpToDate is subject to the Terms of Use. REFERENCES 1. Klijn CJ, Kappelle LJ, Tulleken CA, van Gijn J. Symptomatic carotid artery occlusion. A reappraisal of hemodynamic factors. Stroke 1997; 28:2084. 2. Klijn CJ, Kappelle LJ, Algra A, van Gijn J. Outcome in patients with symptomatic occlusion of the internal carotid artery or intracranial arterial lesions: a meta-analysis of the role of baseline characteristics and type of antithrombotic treatment. Cerebrovasc Dis 2001; 12:228. 3. Khazaal O, Neale N, Acton EK, et al. Early neurologic deterioration with symptomatic isolated internal carotid artery occlusion: a cohort study, systematic review, and meta- analysis. Stroke Vasc Interv Neurol 2022; 2. 4. Myrcha P, Gloviczki P. A systematic review of endovascular treatment for chronic total occlusion of the internal carotid artery. Ann Transl Med 2021; 9:1203. 5. Jovin TG, Gupta R, Uchino K, et al. Emergent stenting of extracranial internal carotid artery occlusion in acute stroke has a high revascularization rate. Stroke 2005; 36:2426. 6. Barnett HJ. Delayed cerebral ischemic episodes distal to occlusion of major cerebral arteries. Neurology 1978; 28:769. 7. Barnett HJ, Peerless SJ, Kaufmann JC. "Stump" on internal carotid artery a source for further cerebral embolic ischemia. Stroke 1978; 9:448. 8. EC/IC Bypass Study Group. Failure of extracranial-intracranial arterial bypass to reduce the risk of ischemic stroke. Results of an international randomized trial. N Engl J Med 1985; 313:1191. 9. Powers WJ, Clarke WR, Grubb RL Jr, et al. Extracranial-intracranial bypass surgery for stroke prevention in hemodynamic cerebral ischemia: the Carotid Occlusion Surgery Study randomized trial. JAMA 2011; 306:1983. https://www.uptodate.com/contents/overview-of-secondary-prevention-for-specific-causes-of-ischemic-stroke-and-transient-ischemic-attack/print 16/25 7/6/23, 12:09 PM Overview of secondary prevention for specific causes of ischemic stroke and transient ischemic attack - UpToDate 10. Rainer WG, Cramer GG, Newby JP, Clarke JP. Fibromuscular hyperplasia of the carotid artery causing positional cerebral ischemia. Ann Surg 1968; 167:444. 11. Choi PM, Singh D, Trivedi A, et al. Carotid Webs and Recurrent Ischemic Strokes in the Era of CT Angiography. AJNR Am J Neuroradiol 2015; 36:2134. 12. Boesen ME, Eswaradass PV, Singh D, et al. MR imaging of carotid webs. Neuroradiology 2017; 59:361. 13. Mac Grory B, Emmer BJ, Roosendaal SD, et al. Carotid web: an occult mechanism of embolic stroke. J Neurol Neurosurg Psychiatry 2020; 91:1283. 14. Kleindorfer DO, Towfighi A, Chaturvedi S, et al. 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. Stroke 2021; 52:e364. 15. Coward LJ, McCabe DJ, Ederle J, et al. Long-term outcome after angioplasty and stenting for symptomatic vertebral artery stenosis compared with medical treatment in the Carotid And Vertebral Artery Transluminal Angioplasty Study (CAVATAS): a randomized trial. Stroke 2007; 38:1526. 16. Jenkins JS, Patel SN, White CJ, et al. Endovascular stenting for vertebral artery stenosis. J Am Coll Cardiol 2010; 55:538. 17. Stayman AN, Nogueira RG, Gupta R. A systematic review of stenting and angioplasty of symptomatic extracranial vertebral artery stenosis. Stroke 2011; 42:2212. 18. Markus HS, Harshfield EL, Compter A, et al. Stenting for symptomatic vertebral artery stenosis: a preplanned pooled individual patient data analysis. Lancet Neurol 2019; 18:666. 19. Xu R, Zhang X, Liu S, et al. Percutaneous transluminal angioplasty and stenting for vertebral artery stenosis. Cochrane Database Syst Rev 2022; 5:CD013692. 20. Chimowitz MI, Lynn MJ, Derdeyn CP, et al. Stenting versus aggressive medical therapy for intracranial arterial stenosis. N Engl J Med 2011; 365:993. 21. Gornik HL, Persu A, Adlam D, et al. First International Consensus on the diagnosis and management of fibromuscular dysplasia. Vasc Med 2019; 24:164. 22. Arboix A, Alio J. Acute cardioembolic cerebral infarction: answers to clinical questions. Curr Cardiol Rev 2012; 8:54. 23. Ay H, Furie KL, Singhal A, et al. An evidence-based causative classification system for acute ischemic stroke. Ann Neurol 2005; 58:688. 24. Homma S, Di Tullio MR, Sciacca RR, et al. Effect of aspirin and warfarin therapy in stroke patients with valvular strands. Stroke 2004; 35:1436. https://www.uptodate.com/contents/overview-of-secondary-prevention-for-specific-causes-of-ischemic-stroke-and-transient-ischemic-attack/print 17/25 7/6/23, 12:09 PM Overview of secondary prevention for specific causes of ischemic stroke and transient ischemic attack - UpToDate 25. January CT, Wann LS, Calkins H, et al. 2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society in Collaboration With the Society of Thoracic Surgeons. Circulation 2019; 140:e125. 26. Whitlock RP, Sun JC, Fremes SE, et al. Antithrombotic and thrombolytic therapy for valvular disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest 2012; 141:e576S. 27. Amarenco P, Davis S, Jones EF, et al. Clopidogrel plus aspirin versus warfarin in patients with stroke and aortic arch plaques. Stroke 2014; 45:1248. 28. Salazar-Camelo RA, Moreno-Vargas EA, Cardona AF, Bayona-Ortiz HF. Ischemic stroke: A paradoxical manifestation of cancer. Crit Rev Oncol Hematol 2021; 157:103181. 29. Dearborn JL, Urrutia VC, Zeiler SR. Stroke and Cancer- A Complicated Relationship. J Neurol Transl Neurosci 2014; 2:1039. 30. Navi BB, Iadecola C. Ischemic stroke in cancer patients: A review of an underappreciated pathology. Ann Neurol 2018; 83:873. Topic 1119 Version 29.0 https://www.uptodate.com/contents/overview-of-secondary-prevention-for-specific-causes-of-ischemic-stroke-and-transient-ischemic-attack/print 18/25 7/6/23, 12:09 PM Overview of secondary prevention for specific causes of ischemic stroke and transient ischemic attack - UpToDate GRAPHICS Antithrombotic therapy according to cause of transient ischemic attack (TIA) This algorithm is intended to provide basic guidance regarding the use of antithrombotic therapy based on mechanism for patients with a TIA. For further details, including suggested dosing regimens of antithrombot agents, refer to the relevant UpToDate topic reviews. ICA: internal carotid artery; CEA: carotid endarterectomy; CAS: carotid artery stenting; DAPT: dual antiplatelet 2 therapy (eg, aspirin and clopidogrel, or aspirin and ticagrelor); ABCD : age, blood pressure, clinical features, duration of symptoms, and diabetes; BP: blood pressure; SBP: systolic blood pressure; DBP: diastolic blood pressure. Indications for long-term oral anticoagulation include atrial fibrillation, ventricular thrombus, mechanical h valve, and treatment of venous thromboembolism. Some experts prefer DAPT based upon observational evidence. Long-term single-agent antiplatelet therapy using aspirin, clopidogrel, or aspirin-extended-release dipyrida https://www.uptodate.com/contents/overview-of-secondary-prevention-for-specific-causes-of-ischemic-stroke-and-transient-ischemic-attack/print 19/25 7/6/23, 12:09 PM Overview of secondary prevention for specific causes of ischemic stroke and transient ischemic attack - UpToDate Graphic 131695 Version 3.0 https://www.uptodate.com/contents/overview-of-secondary-prevention-for-specific-causes-of-ischemic-stroke-and-transient-ischemic-attack/print 20/25 7/6/23, 12:09 PM Overview of secondary prevention for specific causes of ischemic stroke and transient ischemic attack - UpToDate Antithrombotic therapy according to cause of acute ischemic stroke This algorithm is intended to provide basic guidance regarding the immediate use of antithrombotic therapy with an acute ischemic stroke. For further details, including scoring of the NIHSS and suggested dosing regim antithrombotic agents, refer to the relevant UpToDate topic reviews. https://www.uptodate.com/contents/overview-of-secondary-prevention-for-specific-causes-of-ischemic-stroke-and-transient-ischemic-attack/print 21/25 7/6/23, 12:09 PM Overview of secondary prevention for specific causes of ischemic stroke and transient ischemic attack - UpToDate HTN: hypertension; SBP: systolic blood pressure; DBP: diastolic blood pressure; ICA: internal carotid artery; C endarterectomy; OA: oral anticoagulation; CAS: carotid artery stenting; DAPT: dual antiplatelet therapy (eg, a clopidogrel, or aspirin and ticagrelor); NIHSS: National Institutes of Health Stroke Scale; CT: computed tomog magnetic resonance imaging. Brain and neurovascular imaging, cardiac evaluation, and (for select patients) other laboratory tests. Indications for long-term oral anticoagulation include atrial fibrillation, ventricular thrombus, mechanical h treatment of venous thromboembolism. "Large" infarcts are defined as those that involve more than one-third of the middle cerebral artery territor one-half of the posterior cerebral artery territory based upon neuroimaging with CT or MRI. Though less relia infarct size can also be defined clinically (eg, NIHSS score >15). Long-term aspirin therapy is alternative (though less effective) if OA contraindicated or refused. Direct oral anticoagulant agents have a more rapid anticoagulant effect than warfarin, a factor that may inf choice of agent and timing of OA initiation. Some experts prefer DAPT, based upon observational evidence. Long-term single-agent antiplatelet therapy for secondary stroke prevention with aspirin, clopidogrel, or as release dipyridamole. Graphic 131701 Version 2.0 https://www.uptodate.com/contents/overview-of-secondary-prevention-for-specific-causes-of-ischemic-stroke-and-transient-ischemic-attack/print 22/25 7/6/23, 12:09 PM Overview of secondary prevention for specific causes of ischemic stroke and transient ischemic attack - UpToDate Cardioaortic sources of cerebral embolism Sources with high primary risk for Sources with low or uncertain primary ischemic stroke risk for ischemic stroke Atrial fibrillation Cardiac sources of embolism: Paroxysmal atrial fibrillation Mitral annular calcification Left atrial thrombus Patent foramen ovale Left ventricular thrombus Atrial septal aneurysm Sick sinus syndrome Atrial septal aneurysm and patent foramen ovale Atrial flutter Left ventricular aneurysm without thrombus Recent myocardial infarction (within one month prior to stroke) Left atrial spontaneous echo contrast ("smoke") Mitral stenosis or rheumatic valve disease Congestive heart failure with ejection fraction <30% Mechanical heart valves Bioprosthetic heart valves Chronic myocardial infarction together with low Apical akinesia ejection fraction (<28%) Dilated cardiomyopathy (prior established diagnosis or left ventricular dilatation with an ejection fraction of <40% or fractional shortening of <25%) Wall motion abnormalities (hypokinesia, akinesia, dyskinesia) other than apical akinesia Nonbacterial thrombotic endocarditis Hypertrophic cardiomyopathy Infective endocarditis Left ventricular hypertrophy Papillary fibroelastoma Left ventricular hypertrabeculation/non- compaction Left atrial myxoma Recent aortic valve replacement or coronary artery bypass graft surgery Presence of left ventricular assist device Paroxysmal supraventricular tachycardia Aortic sources of embolism: Complex atheroma in the ascending aorta or proximal arch (protruding with >4 mm thickness, or mobile debris, or plaque ulceration) The high- and low-risk cardioaortic sources in this table are separated using an arbitrary 2% annual https://www.uptodate.com/contents/overview-of-secondary-prevention-for-specific-causes-of-ischemic-stroke-and-transient-ischemic-attack/print 23/25 7/6/23, 12:09 PM Overview of secondary prevention for specific causes of ischemic stroke and transient ischemic attack - UpToDate or one-time primary stroke risk threshold. Data from: 1. Ay H, Benner T, Arsava EM, et al. A computerized algorithm for etiologic classi cation of ischemic stroke: the Causative Classi cation of Stroke System. Stroke 2007; 38:2979. 2. Ay H, Furie KL, Singhal A, et al. An evidence-based causative classi cation system for acute ischemic stroke. Ann Neurol 2005; 58:688. 3. Arsava EM, Ballabio E, Benner T, et al. The Causative Classi cation of Stroke system: an international reliability and optimization study. Neurology 2010; 75:1277. 4. Kamel H, Elkind MS, Bhave PD, et al. Paroxysmal supraventricular tachycardia and the risk of ischemic stroke. Stroke 2013; 44:1550. 5. Kirklin JK, Pagani FD, Kormos RL, et al. Eighth annual INTERMACS report: Special focus on framing the impact of adverse events. J Heart Lung Transplant 2017; 36:1080. Reproduced and modi ed with permission from: Ay H, Furie KL, Singhal A, et al. An evidence-based causative classi cation system for acute ischemic stroke. Ann Neurol 2005; 58:688. Copyright 2005 American Neurological Association. Graphic 60843 Version 11.0 https://www.uptodate.com/contents/overview-of-secondary-prevention-for-specific-causes-of-ischemic-stroke-and-transient-ischemic-attack/print 24/25 7/6/23, 12:09 PM Overview of secondary prevention for specific causes of ischemic stroke and transient ischemic attack - UpToDate Contributor Disclosures Natalia S Rost, MD, MPH No relevant financial relationship(s) with ineligible companies to disclose. Shadi Yaghi, MD, FAHA No relevant financial relationship(s) with ineligible companies to disclose. Scott E Kasner, MD Grant/Research/Clinical Trial Support: Bayer [Stroke]; Bristol Meyers Squibb [Stroke]; Medtronic [Stroke]; WL Gore and Associates [Stroke]. Consultant/Advisory Boards: Abbvie [Stroke]; AstraZeneca [Stroke]; BMS [Stroke]; Diamedica [Stroke]; Medtronic [Stroke]. All of the relevant financial relationships listed have been mitigated. John F Dashe, MD, PhD No relevant financial relationship(s) with ineligible companies to disclose. Contributor disclosures are reviewed for conflicts of interest by the editorial group. When found, these are addressed by vetting through a multi-level review process, and through requirements for references to be provided to support the content. Appropriately referenced content is required of all authors and must conform to UpToDate standards of evidence. Conflict of interest policy https://www.uptodate.com/contents/overview-of-secondary-prevention-for-specific-causes-of-ischemic-stroke-and-transient-ischemic-attack/print 25/25