Endovascular therapy for intracranial atherosclerotic stenosis: A narrative review of evolving global evidence

Abstract: Intracranial atherosclerotic stenosis (ICAS) is one of the leading causes of ischemic stroke and is encountered particularly often in Asian populations. Although intensive medical therapy is the foundation of treatment, the risk of recurrent stroke remains substantial. This review summarizes the four-decade development of endovascular therapy for ICAS. Early attempts were obstructed by high periprocedural complication rates, and the treatment strategies became more selective and evidence-driven after the Stenting versus Aggressive Medical Therapy for Intracranial Arterial Stenosis trial. However, subsequent international studies suggested that changes in device selection, operator experience, perioperative management, and above all, patient selection began to alter the risk-benefit profile of intervention. In this evolving evidence base, studies from China have made important contributions alongside work from other regions. Trials such as CASSISS and BASIS have demonstrated that periprocedural risk can be effectively controlled through rigorous patient selection and standardized perioperative management, and refined endovascular techniques. The CASSISS trial established the safety boundary for delayed and carefully selected stenting, whereas the BASIS trial suggested that a stent-free strategy using plain balloon angioplasty plus intensive medical therapy significantly reduced the 1-year composite primary endpoint. These findings redefined the role of endovascular therapy as a feasible, precisely targeted option for a narrowly defined high-risk population. Future advances are expected to build upon these foundations, focusing on novel devices and advanced imaging modalities (e.g., high-resolution magnetic resonance vessel wall imaging, fractional flow reserve) to better refine lesion assessment, functional ischemia, and individualized risk stratification.