Secondary Prevention of Small Subcortical Strokes Trial (SPS3)

INCLUSION: Small subcortical ischemic stroke or subcortical TIA. Inclusion criteria are based on TOAST criteria supplemented by required MRI data. All of the following criteria must be met: One of the lacunar stroke clinical syndromes (adapted from Fisher) lasting > 24 hrs within the past 6 months Absence of signs or symptoms of cortical dysfunction such as aphasia, apraxia, agnosia, agraphia, homonymous visual field defect, etc. No ipsilateral cervical carotid stenosis (≥50%) by a reliable imaging modality done in an approved laboratory since the qualifying small subcortical stroke (S3), if hemispheric. No major-risk cardioembolic sources requiring anticoagulation or other specific therapy. Minor-risk cardioembolic sources will be permitted if anticoagulation is not prescribed by the patient's primary care physician. Subcortical TIA with corresponding lesion on DWI. MRI evidence of S3: a. Presence of an S3 (1.5 and 2 cm in diameter corresponding to the qualifying event on DWI; when TIA, ADC image must confirm lesion or T2/FLAIR (hyperintense lesions) (required for all brainstem events) OR multiple S3s on FLAIR/TI(<1.5 cm in diameter) (hypointense lesions) b. Absence of cortical stroke and large subcortical stroke (recent or remote). EXCLUSION: To be eligible for entry into the study, the patient must not meet any of the criteria listed below: Disabling stroke (Modified Rankin Scale less than or equal to 4) Previous intracranial hemorrhage (excluding traumatic) or hemorrhagic stroke Age under 30 years High risk of bleeding (e.g. recurrent GI or GU bleeding, active peptic ulcer disease, etc) Anticipated requirement for long-term use of anticoagulants (e.g. recurrent DVT) or other antiplatelets Prior cortical stroke (diagnosed either clinically or by neuroimaging), or prior cortical or retinal TIA Prior ipsilateral carotid endarterectomy Impaired renal function: GFR <40 Intolerance or contraindications to aspirin or clopidogrel (including thrombocytopenia, prolonged INR) A score < 24 (adjusted for age and education) on the Folstein Mini Mental Status Examination Medical contraindication to MRI Pregnancy or women of child-bearing potential who are not following an effective method of contraception Geographic or social factors making study participation impractical Unable or unwilling to provide informed consent Unlikely to be compliant with therapy/unwilling to return for frequent clinic visits Patients concurrently participating in another study with an investigational drug or device Other likely specific cause of stroke (e.g. dissection, vasculitis, prothrombotic diathesis, drug abuse)