Objectives - Primary: To test the hypothesis that apixaban is superior to aspirin for the prevention of recurrent stroke in patients with cryptogenic ischemic stroke and atrial cardiopathy. - Secondary: To test the hypothesis that the relative efficacy of apixaban over aspirin increases with the severity of atrial cardiopathy.



Eligible Ages
Over 45 Years
Eligible Genders
Accepts Healthy Volunteers

Inclusion Criteria

  • Age ≥ 45 years. - Clinical diagnosis of ischemic stroke + brain imaging to rule out hemorrhagic stroke. - Modified Rankin Scale (MRS) score ≤ 4. - Ability to be randomized within 3 to 180 days after stroke onset. - ESUS, defined as all of the following: - Stroke detected by CT or MRI that is not lacunar. Lacunar is defined as a subcortical (this includes pons and midbrain) infarct in the distribution of the small, penetrating cerebral arteries whose largest dimension is ≤1.5 cm on CT or ≤2.0 cm on MRI diffusion images/<1.5 cm on T2 weighted MR images. The following are not considered lacunes: multiple simultaneous small deep infarcts, lateral medullary infarcts, and cerebellar infarcts. Patients with a clinical lacunar stroke syndrome and no infarct on imaging are excluded. - Absence of extracranial or intracranial atherosclerosis causing ≥50 percent luminal stenosis of the artery supplying the area of ischemia. Patients must undergo vascular imaging of the extracranial and intracranial vessels using either catheter angiography, CT angiogram (CTA), MR angiogram (MRA), or ultrasound, as considered appropriate by the treating physician and local principal investigator. - No major-risk cardioembolic source of embolism, including intracardiac thrombus, mechanical prosthetic cardiac valve, atrial myxoma or other cardiac tumors, moderate or severe mitral stenosis, myocardial infarction within the last 4 weeks, left ventricular ejection fraction <30 percent, valvular vegetations, or infective endocarditis). Patent foramen ovale is not an exclusion. All patients must undergo electrocardiogram, transthoracic or transesophageal echocardiography (TTE or TEE) and at least 24 hours of cardiac rhythm monitoring (Holter monitor or telemetry or equivalent). Additional cardiac imaging, such as cardiac MRI, or cardiac CT will be performed at the discretion of the local treating physician and principal investigator. Additional cardiac rhythm monitoring, such as monitored cardiac outpatient telemetry (MCOT) or an implanted cardiac monitor, will be at the discretion of the treating physician and local principal investigator. - No other specific cause of stroke identified, such as arteritis, dissection, migraine, vasospasm, drug abuse, or hypercoagulability. Special testing, such as toxicological screens, serological testing for syphilis, and tests for hypercoagulability, will be performed at the discretion of the treating physician and local principal investigator.

Exclusion Criteria

  • History of atrial fibrillation (AF), AF on 12-lead ECG, or any AF of any duration during heart-rhythm monitoring prior to randomization. - Clear indication for treatment-dose anticoagulant therapy, such as venous thromboembolism or a mechanical heart valve. - Need for antiplatelet agent, such as aspirin or clopidogrel - History of spontaneous intracranial hemorrhage. - Chronic kidney disease with serum creatinine ≥2.5 mg/dL.For Canadian sites only, estimated creatinine clearance (eCrCl) <15 mL/min is also an exclusion criterion. - Active hepatitis or hepatic insufficiency with Child-Pugh score B or C. - Clinically significant bleeding diathesis. - Unresolved anemia (hemoglobin <9 g/dL) or thrombocytopenia (<100 x 10E9/L). - Clinically significant gastrointestinal bleeding within the past year (e.g., not due to external hemorrhoids). - At risk for pregnancy: premenopausal or postmenopausal woman within 12 months of last menses without a negative pregnancy test or not committing to adequate birth control, which includes an oral contraceptive, two methods of barrier birth control such as condom with or without spermicidal lubricant + diaphragm, or abstinence. - Known allergy or intolerance to aspirin or apixaban. - Concomitant participation in another clinical trial involving a drug or acute stroke intervention. - Considered by the investigator to have a condition that precludes follow-up or safe participation in the trial. - Inability of either participant or surrogate to provide written, informed consent for trial participation.

Study Design

Phase 3
Study Type
Intervention Model
Parallel Assignment
Intervention Model Description
Active treatment will be either apixaban 5 mg or aspirin 81 mg. An adjusted dose of apixaban 2.5 mg will be used for subjects with at least two of the following: age greater than or equal to 80 years, body weight less than or equal to 60 kg, or known serum creatinine greater than or equal to 1.5 mg/dL. There will be six possible study tablets: apixaban 5 mg (regular dose), apixaban 2.5 mg (adjusted dose), apixaban 5 mg placebo, apixaban 2.5 mg placebo, aspirin 81 mg, and aspirin placebo. All subjects will be randomized to receive active treatment with either active apixaban or active aspirin. Study treatments will be supplied in a double-dummy fashion as apixaban 5 mg (2.5 mg for the adjusted dose) or matching placebo, and aspirin 81 mg or matching placebo.
Primary Purpose
Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Masking Description
Eligible patients will be allocated in a 1:1 ratio to apixaban or aspirin using the minimal sufficient balance randomization method to prevent serious treatment imbalances by study site.

Arm Groups

ArmDescriptionAssigned Intervention
Active agent: Apixaban
Patients with a recent embolic stroke of undetermined source (ESUS) and evidence of atrial cardiopathy will receive Apixaban
  • Drug: Apixaban
    5 mg by mouth twice daily (2.5 mg for subjects meeting standard criteria for an adjusted dose).
    Other names:
    • Eliquis
Active Comparator
Active control: Aspirin
Patients with a recent embolic stroke of undetermined source (ESUS) and evidence of atrial cardiopathy will receive Aspirin
  • Drug: Aspirin
    Aspirin 81 mg by mouth once daily.
    Other names:
    • Aspirin Tablet

More Details

Columbia University

Study Contact

Detailed Description

ARCADIA is a multicenter, biomarker-driven, randomized, double-blind, active-control, phase 3 clinical trial of apixaban versus aspirin in patients who have evidence of atrial cardiopathy and a recent stroke of unknown cause. Eleven hundred subjects will be recruited over 2.5 years at up to 200 sites in and out of the NINDS StrokeNet consortium. Subjects will be followed for a minimum of 1.5 years and a maximum of 7 years for the primary efficacy outcome of recurrent stroke and the primary safety outcomes of symptomatic intracranial hemorrhage and major hemorrhage other than intracranial hemorrhage.


Study information shown on this site is derived from ClinicalTrials.gov (a public registry operated by the National Institutes of Health). The listing of studies provided is not certain to be all studies for which you might be eligible. Furthermore, study eligibility requirements can be difficult to understand and may change over time, so it is wise to speak with your medical care provider and individual research study teams when making decisions related to participation.