Optimal Antithrombotic Therapy in Ischemic Stroke Patients with Non-Valvular Atrial Fibrillation and Atherothrombosis

Inclusion Criteria: 1. Patients with an acute ischemic stroke or TIA from 8 days and up to 360 days from the onset of symptoms 2. Age 20 or older 3. Patients with non-valvular atrial fibrillation (chronic or paroxysmal) who start or continue taking an oral anticoagulant 4. Patients who have one of the following atherothrombotic diseases 1. A past history of ischemic heart disease (myocardial infarction, angina pectoris, coronary artery bypass graft (CABG), percutaneous coronary intervention (PCI) 2. A past history of peripheral artery disease (symptomatic peripheral arterial occlusive disease, lower extremity bypass surgery/angioplasty/stenting) 3. Carotid artery stenosis (symptomatic or asymptomatic (=\>50% diameter), a history of carotid artery stenting (CAS) or carotid endarterectomy (CEA)) 4. Intracranial artery stenosis (=\>50% stenosis of the diameter of a major intracranial artery: intracranial internal carotid artery, anterior cerebral artery (ACA)-A1 and A2, middle cerebral artery (MCA)-M1 and M2, posterior cerebral artery (PCA)-P1 and P2, vertebral artery, and basilar artery; a history of intracranial stent placement or intracranial bypass surgery) 5. A past history of atherothrombotic brain infarction, lacunar infarction, or branch atheromatous disease 5. Patients without severe disability (modified Rankin Scale score =\<4) 6. Patients who can take oral medications 7. Patients who can receive follow-up survey 8. Provision of written informed consent either directly or by a suitable surrogate Exclusion Criteria: 1. History of myocardial infarction or acute coronary syndrome within the past 12 months 2. Patients who underwent PCI with drug-eluting stents within the past 12 months or PCI with bare-metal stents within the past 3 months 3. Patients who underwent carotid artery stent placement, intracranial stent placement, or lower extremity stent placement within the past 3 months 4. History of symptomatic intracranial hemorrhage or gastrointestinal bleeding within the past 6 months 5. Hemorrhagic diathesis or blood coagulation disorders 6. Platelet counts \<100,000 /mm3 at enrollment. 7. Severe anemia (hemoglobin \<7 g/dL) 8. Severe renal failure (creatinine clearance =\<15 mL/min) or undergoing chronic hemodialysis. 9. Severe liver dysfunction (Grade B or C of the Child-Pugh classification) 10. Patients with severe disability requires constant nursing care, bedridden (modified Rankin Scale score =5) 11. Pregnant or possibly pregnant women 12. Active cancer 13. Expectation of survival less than 2 years 14. Anticoagulant or antiplatelet is scheduled to be discontinued for more than 4 weeks during the follow-up period 15. Planned revascularization procedure during the follow-up period 16. Patients who are enrolled in other trials 17. Patients judged as inappropriate for this study by investigators