Chinese guidelines for diagnosis and treatment of intracranial atherosclerotic stenosis

Intracranial atherosclerotic stenosis (ICAS) is an important cause of ischemic stroke and transient ischemic attack (TIA), which is also associated with increased risks of cognitive impairment and dementia. The prevalence of both asymptomatic and symptomatic ICAS (asICAS and sICAS) is significantly higher in Asian populations than in Western populations. In recent years, substantial new evidence has emerged regarding the epidemiology, diagnosis, assessment, prognosis, and treatment of asICAS and sICAS. The China ICAS Research Group has developed this guideline based on published research and relevant domestic and international guidelines or expert consensus, to further clarify the definition, epidemiology, and prognosis of ICAS and the profiles of high-risk ICAS patients and provide evidence-based recommendations on screening, diagnosis, assessment, and treatment strategies of asICAS and sICAS. For imaging exams, noninvasive and contrast-independent modalities are generally suitable for screening and assessment of ICAS in stroke-free individuals with multiple risk factors as well as for routine exams of stroke patients, while contrast-dependent or invasive imaging methods may be employed for further assessment or guiding treatment decision-making in sICAS patients. In addition, vessel wall imaging is valuable for distinguishing the etiology of intracranial stenosis, particularly in young stroke patients. Multiple imaging modalities or methods are available for the assessment of cerebral perfusion, hemodynamics, and collateral circulation that may meet different needs. Regarding interventions, lifestyle modifications (healthy diet, safe exercise, smoking cessation) are recommended for both asICAS and sICAS patients. For stroke-free individuals with asICAS, controlling vascular risk factor is the primary strategy, while routine aspirin or endovascular treatment for primary stroke prevention is not recommended. For sICAS patients, the cornerstone is intensive medical management, including short-term dual antiplatelet therapy in high-risk patients (such as those with severe luminal stenosis, minor stroke, or high-risk TIA) followed by lifelong monotherapy, aggressive lipid control (targeting low-density lipoprotein cholesterol < 1.8 mmol/L), blood pressure control (<140/90 mmHg), and glycemic control (targeting HbA1c < 7.0%), with structured follow-up to enhance treatment adherence. Endovascular treatment is not recommended for sICAS with mild to moderate luminal stenosis (<70%) but may be considered for carefully selected patients with severe (70-99%), medically refractory sICAS, particularly those with hypoperfusion, with a preference to delay the intervention for more than 21 days after stroke to enhance safety.