Ischemic stroke, i.e. irreversible damage of a part of the patient's brain, is caused by the formation of blood clot in the major vessel which gives blood supply to a certain part of the brain. At early time, within the first 4,5 hours, the conventional treatment is to try to dissolve this blood clot with a medication ("thrombolytic drug") which is administered to the blood through the needle in the vein. If the clot still remains there, additional treatment is possible - going directly to the clot via artery and taking it out with a special device. Patients may be included even if they are not treated with intravenous thrombolysis because of contraindication or other reasons. The purpose of the present study is to evaluate the benefit and safety efficacy of thrombectomy and standard stroke care in clinical routine treatment of acute occlusive stroke compared to standard stroke care only.

Inclusion criteria:

• Patients with acute stroke after exclusion of intracranial haemorrhage on CT/MRI scan.
• Confirmed diagnosis on CTA of persisting occlusion of the terminal Internal Carotid Artery (Car-T), proximal Middle Cerebral Artery (MCA, M1), proximal part of the insular segment of MCA (M2), proximal part of the anterior cerebral artery (A1), Basilar Artery (BA) or proximal part of the posterior cerebral artery (P1), consistent with the clinical symptoms. For inclusion in the study, CTA must not be performed later than 15 minutes after IVT start if given. For patients not treated with IVT, CTA should preferably be performed within 15 minutes of completion of the non-contrast CT but must be performed within 6 hours after stroke onset.
• Eligible patients for IVT are treated according to clinical guidelines (Attachment 1), and IVT, if given, initiated within 4.5 h.
• Initiation of thrombectomy is recommended within 6 hours after stroke onset but must be performed within to 8 hours if thrombectomy would still be of benefit for the patient as judged by the investigator.
• Baseline NIHSS Score at initiation of IVT is recommended between 7 and 25 for anterior circulation stroke and ≥7 without upper limit for posterior circulation stroke (baseline NIHSS score should be assessed by an NIHSS-certified physician), but patients may also be included beyond these scores if thrombectomy would still be of benefit for the patient as judged by the investigator.
• Age ≥18years.
• Anticipated life expectancy of at least 6 months.
• Patient or legal representative is competent to make a decision and has provided informed consent with regard to participation in the study, retrieval and storage of data and follow up procedures.
• Initiation of endovascular procedure (DSA/TBY, defined as start with groin puncture) within 2 hours from the start of IVT, or after CTA if IVT is not given (for TBY arm patients).

Exclusion criteria:

• Known significant pre-stroke disability (mRS ≥2).
• Extended early ischemic changes for basilar artery occlusion, according to the judgment of treating physician based on routine clinical practice of the hospital; if technical possibility exists, early irreversible ischemic changes may be confirmed by pc-ASPECTS score < 8 on CTASI (2) or extensive DWI lesion on pre-treatment MRI.
• Known pregnancy.
• Participation in any other investigational drug or device study, currently or in the previous 30 days.