Endovascular Treatment for Symptomatic Non-acute Carotid Occlusion

Symptomatic non-acute carotid artery occlusion may lead to recurrent ischemic events, chronic cerebral hypoperfusion, and cognitive decline. Best medical treatment is the standard foundation of care, but selected patients with persistent hypoperfusion may remain at risk. Endovascular recanalization may improve cerebral perfusion, but procedure-related distal embolization and new ischemic lesions remain important safety concerns.

Eligible patients will have symptomatic non-acute carotid artery occlusion, ipsilateral cerebral hypoperfusion, and baseline cognitive impairment defined by an education-adjusted Montreal Cognitive Assessment score of 25 or lower. Participants will be randomized in a 1:1:1 ratio to best medical treatment alone, endovascular recanalization without proximal protection plus best medical treatment, or endovascular recanalization with proximal balloon protection plus best medical treatment.

In the proximal protection group, a balloon guide catheter will be used to achieve proximal flow arrest or flow control during key procedural steps. In the unprotected endovascular group, recanalization will be performed without routine proximal balloon flow control. The primary safety outcome is the number of new ischemic lesions on diffusion-weighted magnetic resonance imaging within 24 to 72 hours. The primary efficacy outcome is the change in Montreal Cognitive Assessment score from baseline to 6 months.

Inclusion criteria

• The age ranged from 18 to 80 years
• Unilateral carotid artery occlusion confirmed by CTA or DSA (excluding anterior and middle cerebral artery occlusion)
• Complete 3T-MRI within 1-3 days before operation
• The time of carotid artery occlusion was more than 24h (confirmed by imaging or according to the patient's condition), and not more than 3 months
• Ischemic stroke or TIA related to occluded vessels existed in the past 3 months, and the last ischemic event was > 2 weeks; and there was cognitive impairment, MoCA score ≤ 25 after education correction
• Imaging confirmed that there was hypoperfusion in the ipsilateral cerebral hemisphere of carotid artery occlusion, which met at least any of the following requirements:

①Head CT perfusion imaging showed low perfusion in the lesion vascular area (CBF decreased by 30% compared with contralateral perfusion)

②ASITN/SIR collateral circulation score based on DSA < 3 points

③Cerebral infarction with hemodynamic abnormalities confirmed by head MRI (such as watershed infarction)

• Sign the informed consent form

Exclusion criteria

• There was severe neurological dysfunction (mRS ≥ 4) before enrollment
• The ipsilateral common carotid artery was occluded, or the ipsilateral middle cerebral artery was severely stenosed or occluded
• Non atherosclerotic occlusion (such as vasculitis, moyamoya disease, etc.)
• Patients with massive cerebral infarction (infarction volume based on MRI-DWI/ADC is more than 70ml)
• Untreated intracranial aneurysms, intracranial tumors (except meningiomas) or any intracranial vascular malformations
• Evidence of cardiogenic embolism
• Allergic to heparin, aspirin, clopidogrel, statins, metals, anesthetics, contrast agents, or unable to tolerate general anesthesia surgery
• Any history of intracranial hemorrhage within 30 days (including cerebral parenchyma, ventricle, subarachnoid hemorrhage, subdural or epidural)
• History of primary cerebral parenchymal hemorrhage
• There are contraindications to antiplatelet drugs
• There are coagulation disorders and systemic bleeding
• Thrombocytopenia (<100 × 10⁹/L)
• Uncontrolled severe hypertension (systolic blood pressure>180mmHg or diastolic blood pressure>110mmHg)
• Severe coronary heart disease, severe liver injury (AST or ALT more than 3 times the normal value), liver cirrhosis and severe renal insufficiency (creatinine>177 μmol/L) were observed
• Major surgical operations within 30 days or in the next 90 days
• It is known that patients with dementia, cognitive impairment caused by other reasons or mental diseases cannot complete the assessment of neurological and cognitive functions
• There are cerebral infarction that clearly involves the key brain areas of cognition, or there are neurological deficits that affect the accuracy of cognitive function assessment, such as severe aphasia, neglect, and audiovisual impairment. According to the judgment of the researchers, the decline of cognitive function is mainly caused by irreversible brain tissue injury
• The expected survival time of patients with other diseases was less than 2 years
• Pregnancy or lactation
• Patients have been included in other studies, which is in conflict with this study