Solitaire™ With the Intention For Thrombectomy as PRIMary Endovascular Treatment (SWIFT PRIME) Trial (SWIFT PRIME)

Inclusion Criteria:

1. Age 18 - 80
2. Clinical signs consistent with acute ischemic stroke
3. Prestroke Modified Rankin Score ≤ 1
4. NIHSS ≥ 8 and < 30 at the time of randomization
5. Initiation of IV t-PA within 4.5 hours of onset of stroke symptoms (onset time is defined as the last time when the patient was witnessed to be at baseline), with investigator verification that the subject has received / is receiving the correct IV t-PA dose for the estimated weight prior to randomization.
6. Thrombolysis in Cerebral Infarction (TICI) 0-1 flow in the intracranial internal carotid artery, M1 segment of the MCA, or carotid terminus confirmed by CT or MR angiography that is accessible to the Solitaire™ FR Device.
7. Subject is able to be treated within 6 hours of onset of stroke symptoms and within 1.5 hours (90 minutes) from CTA or MRA to groin puncture.
8. Subject is willing to conduct protocol-required follow-up visits.
9. An appropriate signed and dated Informed Consent Form (as allowed according to country regulations and approved by ethics committee and/or IRB) has been obtained
10. Subject is affiliated with a social security system (if required by individual country regulations).
11. Subject meets national regulatory criteria for clinical trial participation.

Exclusion Criteria:

1. Subject who is contraindicated to IV t-PA as per local national guidelines.
2. Female who is pregnant or lactating or has a positive pregnancy test at time of admission.
3. As applicable by French law, subject who is a protected individual such as an incompetent adult or incarcerated person.
4. Rapid neurological improvement prior to study randomization suggesting resolution of signs/symptoms of stroke.
5. Known serious sensitivity to radiographic contrast agents.
6. Known sensitivity to Nickel, Titanium metals or their alloys.
7. Current participation in another investigational drug or device treatment study.
8. Known hereditary or acquired hemorrhagic diathesis, coagulation factor deficiency. (A subject without history or suspicion of coagulopathy does not require INR or prothrombin time lab results to be available prior to enrollment.)
9. Renal Failure as defined by a serum creatinine > 2.0 mg/dl (or 176.8 μmol/l) or Glomerular Filtration Rate [GFR] < 30Warfarin therapy with INR greater than 1.7.
10. Subject who requires hemodialysis or peritoneal dialysis, or who have a contraindication to an angiogram for whatever reason
11. Life expectancy of less than 90 days.
12. Clinical presentation suggests a subarachnoid hemorrhage, even if initial CT or MRI scan is normal.
13. Suspicion of aortic dissection.
14. Subject with a co-morbid disease or condition that would confound the neurological and functional evaluations or compromise survival or ability to complete follow-up assessments.
15. Subject currently uses or has a recent history of illicit drug(s) or abuses alcohol (defined as regular or daily consumption of more than 4 alcoholic drinks per day).
16. Known history of arterial tortuosity, pre-existing stent, and/or other arterial disease which would prevent the device from reaching the target vessel and/or preclude safe recovery of the device.

Imaging Exclusion Criteria:

1. Computed tomography (CT) or Magnetic Resonance Imaging (MRI) evidence of hemorrhage on presentation.
2. CT or MRI evidence of mass effect or intra-cranial tumor (except small meningioma).
3. CT or MRI evidence of cerebral vasculitis.
4. CT showing hypodensity or MRI showing hyperintensity involving greater than 1/3 of the middle cerebral artery (MCA) territory (or in other territories, >100 cc of tissue) on presentation.
5. Baseline non-contrast CT or DWI MRI evidence of a moderate/large core defined as extensive early ischemic changes of Alberta Stroke Program Early CT score (ASPECTS) < 6.
6. CT or MRI evidence of a basilar artery (BA) occlusion or posterior cerebral artery (PCA) occlusion.
7. CTA or MRA evidence of carotid dissection or complete cervical carotid occlusion requiring stenting at the time of the index procedure (i.e., mechanical thrombectomy)
8. Imaging evidence that suggests, in the opinion of the investigator, the subject is not appropriate for mechanical thrombectomy intervention (e.g., inability to navigate to target lesion, moderate/large infarct with poor collateral circulation, etc).