To compare the safety and efficacy of carotid revascularization performed within 48 hours versus after 14 days in patients with symptomatic carotid stenosis accompanied with MRI-confirmed acute infarction (high signal on diffusion-weighted imaging accompanied by low apparent diffusion coefficient signal) in the responsible vascular territory.

Carotid artery stenosis is an important cause of stroke, and about 20-30% of ischemic stroke can be attributed to carotid artery stenosis. In the past 20 years, the prevalence of carotid artery stenosis in my country has increased by 70.07%, which has imposed a heavy burden on the national economy and society. At present, for symptomatic carotid artery stenosis, carotid artery revascularization, mainly carotid endarterectomy (CEA) and carotid artery stenting (CAS), combined with optimal drug therapy (antiplatelet + lipid-lowering), has become the mainstream treatment. In 2004, Rothwell et al. conducted a meta-analysis of individual case data from the European Carotid Surgery Trial (ECST) and the North American Symptomatic Carotid Endarterectomy Trial (NASCET). The results showed that when the waiting time between the onset of symptoms and the receipt of revascularization was prolonged, the effect of carotid artery revascularization in preventing future strokes would be significantly weakened. The latest guidelines issued by the European Stroke Organisation (ESO) recommend that 50-99% of patients with symptomatic carotid stenosis undergo acute CEA, preferably within 14 days after the ischemic event. Based on these clinical research evidence, an increasing number of patients have undergone acute CEA over the past two decades. For example, a study in the United States confirmed that the median waiting time from the occurrence of an ischemic event to receiving CEA decreased from 22 days in 2009 to 12 days in 2014, and the proportion of patients treated within the 14-day interval increased from 37% to 58%. Similarly, data from Germany from 2003 to 2014 showed that the interval from the ischemic event to receiving CEA decreased from 28 days to 8 days. Despite this, in China, the proportion of patients who received carotid revascularization within 14 days is still relatively low due to concerns about increased perioperative complications of acute revascularization.

Previously, the investigators retrospectively analyzed 1172 patients with symptomatic carotid stenosis, and used diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) sequences to identify whether there was acute new infarction before surgery. Further analysis found that for patients with symptomatic carotid stenosis combined with acute new infarction, regardless of the type of revascularization (CEA or CAS), the risk of postoperative serious adverse events was significantly increased. Therefore, for patients with preoperative new infarction on MRI, the investigators urgently need more effective treatment strategies to reduce the incidence of postoperative adverse events and improve the long-term prognosis of patients. The discussion of the timing of surgery is an important part of the treatment strategy. However, there is no large-scale clinical study report on whether preoperative new infarction on MRI has an auxiliary effect on the optimal timing of surgery for symptomatic carotid artery stenosis. Therefore, the investigators plan to initiate a multicenter, prospective, randomized, open-label, blinded RCT trial to explore whether preoperative new infarction on MRI can serve as a new marker for the safety and effectiveness of revascularization surgery in patients with symptomatic carotid artery stenosis.

Inclusion Criteria:

• Age ≥18 years;
• Diagnosed with symptomatic carotid stenosis, defined as the occurrence of sudden-onset neurological symptoms within the territory of the responsible artery within 180 days before randomization (e.g., contralateral hemiparesis, slurred speech/difficulty in expression, ipsilateral monocular vision loss, etc.);
• Stenosis located in the extracranial segment of the internal carotid artery (with or without involvement of the adjacent common carotid artery);
• Degree of stenosis in the responsible carotid artery confirmed to be ≥50% and ≤99% by CTA/MRA/DSA, based on NASCET criteria;
• Brain MRI within 72 hours before randomization indicating an acute infarction in the responsible vascular territory, characterized by high signal on DWI and low signal on ADC;
• Modified Rankin Scale (mRS) score <3;
• Written informed consent obtained from the patient or their legal representative.

Exclusion Criteria:

• Progressive neurological deterioration within 72 hours before randomization, defined as an increase in mRS score by ≥2 points or NIHSS score by ≥4 points;
• Brain MRI within 72 hours before randomization indicating a large infarction (infarct size > 1/2 of the middle cerebral artery territory);
• MRI evidence of hemorrhagic cerebrovascular diseases (e.g., brain tumor, brain abscess, vascular malformations) or other non-ischemic cerebrovascular diseases (e.g., multiple sclerosis);
• Non-atherosclerotic carotid stenosis (e.g., carotid artery dissection, carotid web, floating thrombus, fibromuscular dysplasia, Takayasu arteritis, etc.);
• Need for simultaneous surgical intervention for tandem lesions in the ipsilateral carotid artery or other vascular surgeries;
• History of cerebrovascular surgery within 6 months before randomization;
• Coexisting cerebrovascular stenosis requiring revascularization within 3 months after randomization;
• History of spontaneous intracranial hemorrhage within 12 months before randomization;
• Clear indication for anticoagulation therapy (suspected cardiac embolic source such as atrial fibrillation, known mechanical heart valve, or suspected infective endocarditis);
• Laboratory abnormalities, including white blood cell count < 2×10⁹/L, hematocrit < 30%, platelet count < 100×10⁹/L, INR > 1.5, or heparin-induced thrombocytopenia;
• Inability to use antiplatelet therapy due to specific reasons, such as active gastrointestinal ulcers, gastrointestinal bleeding within the past 3 months, known severe allergy, severe renal insufficiency (creatinine >1.5 times the normal upper limit), hepatic dysfunction (ALT or AST >2 times the normal upper limit), or severe heart failure (NYHA Class III-IV);
• Presence of other severe diseases that may affect adherence to the study protocol, such as severe infection, advanced chronic obstructive pulmonary disease (COPD), active malignant tumors, dementia, psychiatric disorders, or uncontrolled severe hypertension;
• Pregnant or breastfeeding women who are not in menopause;
• Participation in another investigational device or drug trial that may interfere with this study;
• Any other medical condition or history that, in the investigator's judgment, may affect the efficacy or safety assessment of the study.