Inclusion Criteria- From 18 to 85 years of age.
- Evidence of proximal anterior circulation large vessel occlusion (TIMI /TICI 0-1) (Tables 2A & B). Target vessel occlusion may include the supra-clinoid segment of the ICA through the M1 segment of the MCA.
- Presented with symptoms consistent with acute ischemic stroke within 8 hours of symptom onset. Patients who presented within 3 hours must be ineligible or refractory to IV rtPA therapy.
- At time of enrollment, neurological deficit resulting in an NIH Stroke Scale (NIHSS) score of 10 or greater.
- Core infarct volume assessed by CTP, CTA or DWI scans within 60 minutes to arterial puncture.
- Signed informed consent.
Exclusion Criteria- History of stroke in the past 3 months.
- Vessel tortuosity too difficult to allow endovascular access.
- Pre-existing neurological or psychiatric disease that could confound the study results such as a pre-stroke mRS score of 1 or greater.
- Known severe allergy to contrast media.
- Uncontrolled hypertension (defined as systolic blood pressure > 185 mmHg or diastolic blood pressure > 110 mmHg).
- Noncontrast CT evidence of the following conditions before enrollment:
- Significant mass effect with midline shift;
- Evidence of intracranial hemorrhage.
- Angiographic evidence of an arterial stenosis proximal to the occlusion that could prevent thrombus removal.
- Angiographic evidence of preexisting arterial injury.
- Life expectancy less than 90 days.
- Participation in another clinical investigation that could confound the evaluation of the study.