Carotid Implants for Stroke Prevention in Atrial Fibrillation

Inclusion Criteria: 1. Documented history of clinical AF 2. History of ischemic (i.e. non-hemorrhagic) stroke including symptoms of stroke resolving within 24 hours with positive neuro-imaging, meeting one of the following criteria: Group 1: Patient was on OAC at time of index stroke, with index stroke occurring \< 6 week from enrollment Group 2: Patient was not on OAC at time of stroke, with index stroke occurring \< 6 weeks from enrollment Group 3: Patient was on OAC at time of index stroke, with index stroke occurring 6 to 52 weeks from enrollment 3. Planned use of a Vitamin K antagonist (VKA) or a direct oral anticoagulant (DOAC) for the duration of the trial 4. Patient able to tolerate single antiplatelet therapy in addition to oral anticoagulation for 6 months, in the opinion of the investigator 5. Bilateral ultrasound or angiogram demonstrating all of the following: 1. Inner common carotid artery diameter range: ≥5.3 mm and ≤8.8 mm 2. Accessibility: up to 40 mm from skin to common carotid artery center 3. Implantation segment free of any atherosclerotic disease 4. Absence of carotid dissection or pre-existing stent(s) in common carotid artery 5. Absence of ≥50% stenosis of the internal carotid arteries as seen on ultrasound or angiography (CTA, MRA or DSA) i. For ultrasound, calculate the percentage of carotid stenosis using the Society of Radiologists in Ultrasound Consensus Criteria for Carotid Stenosis, where ≥50% stenosis is defined by internal carotid artery peak systolic velocity of ≥125 cm/sec, internal/common carotid peak systolic velocity ratio of 2 or more and end diastolic velocity of ≥40 cm/sec, or evidence of near occlusion. ii. For angiography, calculate the percentage of carotid stenosis using the North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria (\[D - N\]/D x 100, where N is the luminal diameter at the site of maximal narrowing and D is the diameter of normal distal internal carotid artery beyond the bulb where the artery walls are parallel. 6. Provision of informed consent Exclusion Criteria: 1. Contraindication to oral anticoagulation (e.g. history of intracranial hemorrhage, known hereditary or acquired coagulation disorders, or recurrent major bleeding) 2. Contraindication to additional single antiplatelet therapy for 6 months from randomization 3. Previously documented 50% or greater stenosis, or high-risk plaque in the opinion of the investigator, of the common carotid, internal carotid, subclavian, vertebral, or intracranial arteries that has not been treated with a revascularization procedure (i.e. stent or angioplasty) 4. Visualized active (acute/subacute) cervical or intracranial arterial thrombus (i.e. free-floating) on computed tomography (CT), magnetic resonance (MR), or digital subtraction (DS) angiography that is at risk of causing additional stroke/brain injury 5. Previously documented aneurysm of the internal carotid artery or its branches (i.e. ophthalmic, posterior communicating, anterior choroidal, anterior cerebral and middle cerebral arteries) that is 6 mm or greater in diameter. 6. Prior surgery or radiation of the neck at the implantation segment 7. Pre-existing percutaneous left atrial appendage occlusion device that was implanted after most recent ischemic stroke 8. Planned left atrial appendage occlusion procedure 9. Female who is pregnant or non-postmenopausal female who is not willing to use an effective method of birth control during duration of the trial 10. Overt systemic infection 11. Known sensitivity to nickel or titanium metals, or their alloys 12. Active participation in another investigational drug or device treatment trial 13. Any other condition that in the opinion of the investigator may adversely affect the safety of the patient or would limit the patient's ability to complete the trial