Early Endovascular Treatment in Isolated Internal Carotid Artery Occlusion

Prior treatment

• Chronic internal carotid artery occlusion, defined as known carotid artery occlusion (imaging examination) ≥30 days before randomization or highly suspected chronic internal carotid artery occlusion based on medical history and CT/MRI.
• Patients have contraindications to the use of heparin and antiplatelet drugs.

Other illness

• Severe comorbid condition with life expectancy less than 6 months at baseline.
• Other suspected cerebrovascular diseases (vasculitis, untreated cerebrovascular malformation, intracranial aneurysm, etc.) based on history and CTA/MRA.
• Known life-threatening allergic reactions to contrast media or intravascular products.
• Evidence of intracranial hemorrhage on CT/MRI.
• Pre-existing neurological or psychiatric disease that would confound the neurological or functional evaluations.
• Seizures at stroke onset if they make the diagnosis of stroke doubtful and preclude obtaining an accurate baseline NIHSS assessment.

Other

• The patient underwent carotid endarterectomy within 1 month.
• Women who are pregnant or planning to become pregnant at the time of the study and who are known to be pregnant or breastfeeding at the time of admission.
• Tandem occlusion, which was defined as internal carotid artery occlusion combined with large intracranial vessel occlusion (T or L shape of internal carotid artery, M1 or M2 segment of middle cerebral artery, A1 or A2 segment of anterior cerebral artery, P1 or P2 segment of posterior cerebral artery).
• No known vascular access.
• Suspected aortic dissection based on medical history, clinical evaluation or/and imaging.
• Patient unable to come or unavailable for follow-up.

• Age ≥18.
• Clinical signs consistent with an acute ischemic stroke and randomization no later than 23 hours after the time last known to be well.
• CTP, CTA or enhanced MRA within 1 hour before randomization showed that the offending vessel was isolated internal carotid artery occlusion, namely occlusion of C1-C6 segments (according to Bouthillier's segmentation) at any location. There was no ipsilateral intracranial branch occlusion (T or L shape of internal carotid artery, M1 or M2 segment of middle cerebral artery, A1 or A2 segment of anterior cerebral artery, P1 or P2 segment of posterior cerebral artery).
• Neurological deficit with a NIHSS of \>5, or ≤5 points with disabling symptoms (complete hemianopsia, severe aphasia, neglect, any limb weakness that cannot sustain resistance to gravity, and functional loss that is considered by doctors and patients to be potentially disabling by clinical evaluation).
• Mismatch: target Mismatch Profile on CT perfusion or MRI (ischemic core volume is \< 70 ml, mismatch ratio is ≥1.8 and mismatch volume is ≥15 ml); clinical-imaging mismatch defined as an ASPECTS score of more than 5, was present if perfusion data were not available or imaging quality was poor enough to be interpreted.
• mRS Score before stroke ≤2.
• Patient/Legally Authorized Representative has signed the Informed Consent form.