StrokeNet Thrombectomy Endovascular Platform

Inclusion criteria

• Suspected diagnosis acute ischemic stroke
• Likely causative intracranial large or medium vessel occlusion STEP PLATFORM

Exclusion criteria

• Proven contraindication to endovascular thrombectomy
• Prisoners/incarcerated DOMAIN-SPECIFIC ELIGIBILITY CRITERIA: Each domain may have additional eligibility criteria. STEP EVT INDICATION EXPANSION DOMAIN INCLUSION CRITERIA: 1\. Age 18 years or older 2. Pre-stroke modified Rankin Scale score 0-2 3. Presentation to enrolling hospital within 24 hours of last known well/stroke onset 4. Able to initiate arterial puncture within 2 hours from qualifying CTA/MRA or CTP/MRP imaging \*CT/MR and qualifying CTA/MRA or CTP/MRP should be repeated if more than 120 minutes have elapsed since the imaging and randomization has not been performed. The exception is for LVO Mild deficit/Low NIHSS 0-5 for which imaging would only need to be repeated if there has been significant improvement in the NIHSS prior to randomization. 5\. Has one of the following presentations:
• LVO patients with mild deficits/low NIHSS (must have both):
• Mild presenting neurologic deficits - NIHSS 0-5 (Must have some focal neurological deficit attributable to the target occlusion if NIHSS 0)
• Complete occlusion of the intracranial Internal Carotid Artery (ICA) or M1 Middle Cerebral Artery (MCA)
• Medium/Distal Vessel Occlusion:
• Visualized complete occlusion or perfusion deficit (Tmax \> 4s) supportive of a cortical branch occlusion in one of the following vessels: i) Non-dominant/Co-dominant M2 (defined as serving \< 50% of entire overall MCA territory) ii) M3
• If symptom onset is \> 6h, the core must be less than 50% of the territory supplied by the occluded vessel as evident by either: i) Hypodensity and loss of grey-white border on NCCT or ii)ADC \<620 mm2/s on diffusion MRI or rCBF\<30% on CTP
• NIHSS \> =8 STEP EVT INDICATION EXPANSION DOMAIN EXCLUSION CRITERIA:
• Presumed septic embolus; suspicion of bacterial endocarditis
• Seizure at stroke onset or between onset and enrollment
• Known anaphylactic reaction to contrast material that precludes endovascular reperfusion therapy
• Intracranial occlusion suspected to be chronic, based on history and/or imaging
• Intracranial dissection, based on history and/or imaging
• Cerebral vasculitis, based on history and/or imaging
• Known pregnancy
• Known pre-existing medical, neurological or psychiatric disease that would confound the neurological or functional evaluations
• Known serious, advanced, or terminal illness or life expectancy less than 6 months in the investigator judgment
• Known or high suspicion for underlying intracranial atherosclerotic disease (ICAD)
• Laboratory a. Known platelet count \<100,000/uL
• CT ASPECT score \<6 (MRI ASPECT score \<7)
• Unfavorable vascular anatomy that limits access to the occluded artery precluding endovascular reperfusion therapy.
• Acute occlusions in multiple vascular territories (e.g., bilateral anterior circulation, or anterior/posterior circulation)
• Tandem occlusions
• Significant mass effect with midline shift (\>5mm)
• Evidence of intra-cranial tumor (except small meningioma defined as (1) \<=3 cm, (2) asymptomatic) as confirmed on CT/MRI)
• Evidence of acute intracranial hemorrhage