Treatment of acute ischemic stroke due to occlusion of a large vessel by mechanical thrombectomy in patients with unknown onset or not meeting the criteria for CT eligibility (ASPECTS <6) based on MRI criteria (DWIFLAIR mismatch)

Prior treatment

• Significant disability prior to the current event defined as > 2 points on the modified Rankin Scale (mRS) and/or significant cognitive impairment prior to the current event (documented in the patient's medical records).
• Previous or chronic disease of the central nervous system that significantly impairs the functional state and/or has a poor prognosis (brain tumors, aneurysms, arteriovenous malformations, open brain surgery with dura mater/dural incision).
• Very high blood pressure, i.e. systolic blood pressure>185 mm Hg or diastolic blood pressure >110 mm Hg immediately before the intervention. NOTE: If pharmacological intervention (e.g., bolus administration of labetalol or urapidil, or in the absence of a satisfactory continuous infusion response via an infusion pump) has produced a satisfactory response (blood pressure <185/110 mmHg) prior to randomization and / or initiation of treatment and in the opinion of the physician, adequate blood pressure control can be maintained throughout the course of treatment, the patient will be enrolled in the study.

Other illness

• Intracranial bleeding in neuroimaging (CT or MRI of the brain).
• Clinical suspicion of subarachnoid bleeding (even if the CT or MRI result is normal).
• Clinical suspicion of cerebral venous sinus thrombosis.
• Known heart failure (if medical history available) with EF <25%; in the absence of information without the need for testing at the randomization stage.
• Severe liver disease, including liver failure, cirrhosis, or portal hypertension.

Lab values

• Severe renal failure (eGFR <30 ml / min / 1.73 m2).
• Platelet count <100,000/mm3.
• Glucose concentration <50 mg/dl (2.8 mmol/l) or >400 mg/dl (22.2 mmol/l) immediately before the intervention.

Other

• Neuroimaging pathologies other than ischemia-related pathologies that may be responsible for acute symptoms.
• Significant pathologies detected accidentally in neuroimaging (e.g. tumor, giant aneurysm, massive brain atrophy).
• Infective endocarditis or pericarditis.
• Pregnancy or breast-feeding.
• Life expectancy <3 months, participation in another clinical trial at the time of randomization or planned enrollment in another clinical trial within less than 30 days from randomization, provided that there is pathophysiological or formal-administrative interference in the protocols of these studies.
• Acute pancreatitis.
• Suspected systemic vasculitis or primary central nervous system vasculitis.
• MRI contraindications or inability to identify contraindications.

• Obtaining informed consent to participate in the trial prior to randomization. NOTE: Patients whose severe neurological deficit makes it impossible to sign the consent form may give their verbal consent to participate in the study. This consent should be additionally confirmed by the signature of an independent witness who is not a family member of the patient and does not participate in the study. Patients with aphasia and / or other speech disorders may be enrolled in the study if, in the opinion of the recruiting neurologist or neurologist in training, they are able to understand the study concept.
• Adult patients with acute ischemic stroke due to the occlusion of a large intracranial or extracranial vessel (angio-CT or angio-MR) in a place that allows mechanical recanalization using a stent-retriever.
• Current DWI-FLAIR mismatch. In the WAKE-IN study, a DWI-FLAIR mismatch is defined as: No hyperintense change in the FLAIR sequence corresponding to acute ischemia in DWI or the ratio of the volume of restriction of diffusion in the DWI sequence (hyperintensive lesion) to the corresponding hyperintense lesion volume in the FLAIR sequence 1.5 or higher. Note: The presence of other changes in the FLAIR sequence, such as "chronic" white matter lesions, do not exclude from participation in the study.
• The neurological deficit was assessed at 5-18 points on the NIHSS scale.
• Age>18 years of age.
• Arm A: 1.Unknown time of onset (not more than 24 hours from when the patient was symptom-free), or the time from onset to estimated arterial puncture between 6 and 24 hours.
• Arm A: 2. Failure to meet the DAWN and DEFUSE-3 eligibility criteria.
• Arm B: 1.From 0 to 5 points on the ASPECTS scale.
• Arm B: 2. Time from the first symptoms of acute stroke to arterial puncture not exceeding 6 hours.