Large Artery Occlusion Treated in Extended Time With Mechanical Thrombectomy Trial

Prior treatment

• Considered unlikely to benefit from trial (e.g. advanced dementia, major pre-stroke disability (prior modified Rankins scale (mRS) ≥2), high likelihood of early death), as judged by the responsible treating clinician
• Known allergy to iodine, heparin, anaesthesia, or other definite contraindication to receiving endovascular treatment (EVT) procedure

Other illness

• Major co-morbid disease that could interfere with outcome assessments and follow-up (e.g. cancer, severe heart failure, kidney failure)
• Seizures at stroke onset or before randomization and baseline NIHSS scores cannot be accurately determined
• Severe, sustained hypertension that can not be controlled by medication (systolic BP \>220 mmHg or diastolic BP \>120 mmHg)
• EVT attempted after stroke onset
• Any other condition that, in the opinion of the investigator will pose a significant hazard to the subject if participating in the trial.
  • Neuroimaging Exclusion Criteria
• Intracranial hemorrhage (ICH), including parenchymal hemorrhage, ventricular hemorrhage, subarachnoid hemorrhage, and subdural/exsanguination
• Evidence of intracranial malignant tumor
• Any other condition that may affect EVT procedure, like the tortuous vascular path the device is difficult to reach the target position or difficult to recover

Lab values

• Baseline blood glucose of \<50 mg/dL (2.78 mmol/L) or \>400 mg/dL (22.20 mmol/L)
• Baseline platelet count \< 50,000/uL
• Known hereditary or acquired hemorrhagic diathesis, coagulation factor deficiency; recent oral anticoagulant therapy with International normalized ratio (INR) \>3

Other

• Clinical Exclusion Criteria
• Pregnancy
• Unable to undergo a CTP
• Presumed septic embolus, suspicion of bacterial endocarditis
• Unlikely to participate in follow-up assessments
• Currently participating in another trial that may affect outcomes.
• Significant mass effect with midline shift
• Aortic dissection
• Intracranial stent implanted in the same vascular territory
• Occlusions in multiple vascular territories confirmed on Computerized tomography angiography (CTA)/ Magnetic resonance imaging angiography (MRA) (e.g. bilateral MCA occlusions, or an MCA and a basilar artery occlusion)

• Age ≥18 years
• Present 24-72 hours of stroke onset or last seen well
• Clinical diagnosis of AIS due to anterior circulation LVO (from internal carotid artery (ICA) extracranial segment to middle cerebral artery (MCA) M1 and M2 segment) on brain imaging
• National Institute of Health stroke scale (NIHSS) ≥6 at randomisation
• Viable cerebral tissue on computerized tomography perfusion (CTP) assessed: infarct core volume \<50 mL, mismatch ratio ≥1.8, and mismatch volume ≥15 mL
• Written informed consent (by patient or proxy, according to local requirements)