Please select the eligibility criteria that correspond to the clinical trial below.
Title: A Phase 3, Active (Warfarin) Controlled, Randomized, Double-Blind, Parallel Arm Study to Evaluate Efficacy and Safety of Apixaban in Preventing Stroke and Systemic Embolism in Subjects With Nonvalvular Atrial Fibrillation
Brief Summary: The trial seeks to determine if apixaban, an investigational anticoagulant (blood-thinner) is as effective as standard therapy (warfarin) in preventing stroke and systemic embolism in subjects with atrial fibrillation and risk factors for stroke.


Options:
A: Inclusion Criteria:

* Males and females ≥ 18 yrs with atrial fibrillation (AF) and one or more of the following risk factors for stroke:
* Age ≥ 75, previous stroke
* transient ischemic attack (TIA) or Systemic Embolism (SE)
* Symptomatic congestive heart failure or left ventricular dysfunction with left ventricular ejection fraction (LVEF) ≤ 40%
* Diabetes mellitus or hypertension requiring pharmacological treatment
B: Inclusion Criteria:

* Recent ESUS (between 7 days and 6 months), defined as:
* Recent ischemic stroke (including transient ischemic attack with positive neuroimaging) visualized by brain imaging that is not lacunar, and
* Absence of cervical carotid atherosclerotic stenosis\> 50% or occlusion, and
* No atrial fibrillation after ≥ 24-hour cardiac rhythm monitoring, and
* No intra-cardiac thrombus on either transesophageal or transthoracic echocardiography, and
* No other specific cause of stroke (for example, arteritis, dissection, migraine/vasospasm, drug abuse)

Exclusion Criteria:

* Severely disabling stroke (modified Rankin score ≥4)
* Indication for chronic anticoagulation or antiplatelet therapy
* Estimated glomerular filtration rate (eGFR) \< 30 mL/min/1.73 m\^2
C: Inclusion Criteria:

* 21 years of age or older; male or female.
* Able to provide written informed consent.
* History of documented AF within the prior 12 months
* A moderate to high risk of stroke, as defined by CHADS2 index score of at least 2

Exclusion Criteria:

* Transient atrial fibrillation secondary to other reversible disorders
* Subjects with moderate or severe mitral stenosis, unresected atrial myxoma, or a mechanical heart valve
* Subjects with any contraindication for anticoagulant agents;
* Subjects with conditions associated with high risk of bleeding or have known or suspected hereditary or acquired bleeding disorders
* Females of childbearing potential including the following:

  * Females with a history of tubal-ligation
  * Females less than 2 years post-menopausal
D: Inclusion Criteria:

1. Male or female patients
2. Must be \>18 years of age
3. Must have TIA or ischemic stroke (NIHSS score \<9 - see section 2.7 for further clarification)
4. Symptom onset is \< 72 hours prior to enrollment or Study therapy must initiated within 48 hours of symptom onset (in case where onset time cannot be established, it will be considered to be the time when the patient was lst know to be well
5. Informed consent must be obtained from either the patient or substitute decision maker (according to local REB policy) prior to any study related procedures being performed
6. All patients will have a MRI including DWI prior to randomization
7. DWI lesion volume must be \<25ml
8. Patients without DWI lesions, but a clinical history considered consistent with TIA, determined by the attending physician, can be included

Exclusion Criteria:

1. Patients with stroke mimics - such as seizures, migraine etc
2. Patients with contraindications to MRI including metallic implants
3. Patients with any past sensitivity to gadolinium contrast media will be eligible, but will not undergo PWI or contrast enhanced MRA (both optional sequences)
4. Patients with renal failure defined as Glomerular Filtration Rate (GFR) \< 30 ml/min
5. Patients deemed, as attending stroke physician, to have any ongoing bleeding risks or unsuitable for dabigatran therapy
6. Patients with MRI demonstrated additional pathology including arteriovenous malformations, intracranial aneurysms, tumors or abscess, which potentially increase the rise of bleed. Individuals with small incidental leasions, at low risk of bleed such as meningiomas may be included at the discretion of the investigator.
7. Patients with an acute DWI lesion volume of \>25 ml (DWI volume to be estimated using the ABC/2 technique 110)\*\*
8. Age \<18 years
9. Pregnant or breast feeding women.
10. Severe dysphagia necessitating naso-gastric (NG) feeding (dabigatran can not be delivered via NG tube)
11. Planned thrombolysis or endovascular intervention for the index event
12. Thrombolysis for ischemic stroke within the preceding 7 days
13. Planned carotid endarterectomy/carotid artery stent within 30 days Note: Carotid Investigations will be completed prior to enrolment. Patients with symptomatic stenoses and a planned carotid procedure will be excluded.
14. Any history of spontaneous intracranial bleeding
15. Clear indication for anticoagulation, including atrial fibrillation, mechanical cardiac valves, deep venous thrombosis, pulmonary embolism or known hypercoagulable state
16. Co-morbid illness with expected life expectancy of \<90 days

Answer: A