Randomization of Endovascular Treatment in Acute Ischemic Stroke in the Extended Time Window

Inclusion Criteria:

1. Acute ischemic stroke where patient is ineligible for IV thrombolytic treatment or thetreatment is contraindicated (e.g., subject presents beyond recommended time fromsymptom onset), or where patient has received IV thrombolytic therapy without clinicalimprovement.
2. No significant pre-stroke functional disability (mRS ≤2)
3. Baseline NIHSS score obtained prior to randomization must be equal or higher than 8points (assessed within one hour prior to qualifying imaging)
4. Age ≥18 years (no upper age limit)
5. Occlusion (TICI 0-1) of the intracranial ICA (distal ICA or T occlusions) and/orMCA-M1 segment suitable for endovascular treatment, as evidenced by CTA, MRA orangiogram, with or without concomitant cervical carotid occlusion or stenosis.
6. The presence of Age-Adjusted modified Clinical ASPECTS Mismatch (mCAM) defined asASPECTS 5-10 and one of the following criteria:
7. NIHSS ≥ 8 and >50% involvement in 0-1 Cortical (e.g. M1-6) ASPECTS areas (anyage);
8. NIHSS ≥ 8 and >50% involvement in 0-2 Cortical (e.g. M1-6) ASPECTS areas (and age < 80 years old);
9. NIHSS ≥ 15 and >50% involvement in 0-3 Cortical (e.g. M1-6) ASPECTS areas (andage < 80 years old).
10. Patient treatable within 6-24 hours of symptom onset. Symptoms onset is defined aspoint in time the patient was last seen well (at baseline). Treatment start is definedas arterial puncture.
11. Informed consent obtained from patient or acceptable patient surrogate

Exclusion Criteria:

-Clinical criteria

1. Known hemorrhagic diathesis, coagulation factor deficiency, or oral anticoagulanttherapy with INR > 3.0
2. Baseline platelet count < 30.000/µL
3. Baseline blood glucose of < 50mg/dL
4. Severe, sustained hypertension (SBP > 185 mm Hg or DBP > 110 mm Hg) NOTE: If the bloodpressure can be successfully reduced and maintained at the acceptable level using AHAguidelines recommended medication (including iv antihypertensive drips), the patientcan be enrolled.
5. Patients in coma defined as totally unresponsive; responding only with reflexes orbeing areflexic (Intubated patients for transfer could be randomized only in case anNIHSS is obtained by a neurologist prior transportation).
6. Seizures at stroke onset which would preclude obtaining a baseline NIHSS
7. Serious, advanced, or terminal illness with anticipated life expectancy of less thanone year.
8. History of life-threatening allergy (more than rash) to contrast medium
9. Subjects who has received IV t-PA treatment beyond 4.5 hours from the beginning of thesymptoms
10. Woman of childbearing potential who is known to be pregnant or who has a positivepregnancy test on admission.
11. Subject participating in a study involving an investigational drug or device thatwould impact this study.
12. Cerebral vasculitis
13. Patients with a pre-existing neurological or psychiatric disease that would confoundthe neurological or functional evaluations, mRS score at baseline must be ≤2. Thisexcludes patients who are severely demented, require constant assistance in a nursinghome type setting or who live at home but are not fully independent in activities ofdaily living (toileting, dressing, eating, cooking and preparing meals, etc.)
14. Unlikely to be available for 90-day follow-up (e.g. no fixed home address, visitorfrom overseas).

• Neuroimaging criteria

15. Hypodensity on CT or restricted diffusion on MRI amounting to an ASPECTS score of <5.
16. Complete involvement of more than 3 cortical ASPECTS areas (e.g. M1, M2, M3, M4, M5,or M6).
17. Complete absence of leptomeningeal collaterals on CT angiography (e.g. Malignant CTApattern or score 0).
18. CT or MR evidence of hemorrhage (the presence of GRE microbleeds is allowed).
19. Significant mass effect with midline shift.
20. Evidence of ipsilateral carotid occlusion, high grade stenosis or arterial dissectionin the extracranial or petrous segment of the internal carotid artery that cannot betreated or will prevent access to the intracranial clot or excessive tortuosity ofcervical vessels precluding device delivery/deployment
21. Subjects with occlusions in multiple vascular territories (e.g., bilateral anteriorcirculation, or anterior/posterior circulation)
22. Evidence of intracranial tumor (except small meningioma).