Inclusion Criteria1. Age 18 and older (i.e., candidates must have had their 18th birthday)
2. NIHSS ≥8 at the time of neuroimaging
3. Presenting or persistent symptoms within 6 hours of when groin puncture can be obtained
4. Neuroimaging demonstrates large vessel proximal occlusion (distal ICA through MCA bifurcation)
5. The operator feels that the stroke can be appropriately treated with traditional endovascular approaches (the ADAPT approach or conventional first-line stent retriever approach)
6. Pre-event Modified Rankin Scale score 0-1
7. Non-contrast CT/CTA for trial eligibility performed or repeated at treating ADAPT stroke center.
8. Consenting requirements met according to local IRB
Exclusion Criteria1. Patient is more than 6-hours from symptom onset
2. Rapidly improving neurologic examination
3. Absence of large vessel occlusion on non-invasive imaging
4. Presence of an existing or pre-existing large territory infarction
5. Known or suspected pre-existing (chronic) large vessel occlusion in the symptomatic territory
6. Absent femoral pulses
7. Excessive vascular access tortuosity that will likely result in unstable access platform.
8. Pregnancy; if a woman is of child-bearing potential a urine or serum beta HCG test is positive.
9. Severe contrast allergy or absolute contraindication to iodinated contrast.
10. Clinical history, past imaging or clinical judgment suggests that the intracranial occlusion is chronic.
11. Patient has a severe or fatal comorbidities that will likely prevent improvement or follow-up or that will render the procedure unlikely to benefit the patient.
Head CT or MRI Scan Exclusion Criteria
- Presence of blood on imaging (subarachnoid hemorrhage (SAH)), intracerebral hemorrhage (ICH), etc.)
- High density lesion consistent with hemorrhage of any degree
- Significant mass effect with midline shift
- Core infarct lesion volume >50 cc.
- Large (more than 1/3 of the middle cerebral artery) regions of clear hypodensity on the baseline CT scan or ASPECTS of < 7; Sulcal effacement and/or loss of grey-white differentiation alone are not contraindications for treatment.