POSITIVE Stroke Clinical Trial

Primary Endpoint: The primary objective is to show that AIS patients, ineligible for or refractory to treatment with IV-tPA, with appropriate image selection, treated with mechanical thrombectomy within 6-12 hours of symptom onset have less stroke related disability and improved good functional outcomes as compared to those treated with best MT with respect to endpoint defined as: • 90-day global disability assessed via the modified Rankin score (mRS), analyzed using raw mRS scores. Statistical details can be found in section 7.2. Secondary Endpoints: * 90-day global disability in the 6-12 hr cohort assessed via the overall distribution of mRS * Proportion of patients with good functional recovery for the 6-12 hr cohort as defined by mRS 0-2 at 90 days * Mortality at 30 and 90 days * Intracranial hemorrhage with neurological deterioration (NIHSS worsening \>4) within 24 hours of randomization * Procedure related serious adverse events (SAE's) * Arterial revascularization measured by TICI 2b or 3 following device use