Endovascular Therapy for Intracranial Atherosclerotic Stenosis: Evidence and Controversies

Intracranial atherosclerotic stenosis (ICAS) is a major cause of ischemic stroke worldwide, and is particularly prevalent in Asian populations. Patients with symptomatic severe ICAS remain at a high risk of recurrent stroke despite medical management (MM) alone, which has driven interest in elective endovascular revascularization. This review summarizes the history, evidence, and current controversies surrounding endovascular therapy for symptomatic ICAS, with emphasis on the periods before and after the pivotal randomized controlled trials, the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) trial and the Vitesse Intracranial Stent Study for Ischemic Stroke Therapy (VISSIT) trial. In the pre-SAMMPRIS/VISSIT era, percutaneous transluminal angioplasty (PTA) or PTA and stenting (PTAS) using coronary or dedicated intracranial stents demonstrated technical feasibility and seemingly acceptable short-term outcomes in observational studies. However, SAMMPRIS and VISSIT subsequently showed that PTAS was inferior to MM alone, largely because of high periprocedural stroke or death rates and the frequent occurrence of in-stent restenosis, establishing MM as the standard first-line treatment. Later observational studies suggested that outcomes may improve with stricter patient selection, avoidance of acute-phase intervention, adherence to on-label indications for the Wingspan system (Stryker Neurovascular, Fremont, CA, USA), and exclusion of high-risk lesion types, such as perforator-associated disease. Recent trials have renewed interest in elective endovascular revascularization. In particular, the Balloon Angioplasty for Symptomatic Intracranial Artery Stenosis (BASIS) trial demonstrated the superiority of submaximal balloon angioplasty plus MM over MM alone, suggesting that the procedure may reduce procedural risk while preserving long-term benefits. In parallel, drug-eluting stents and drug-coated balloons have shown promise in reducing restenosis and late ischemic events, while technical innovations-such as first-balloon-then-stent approaches, novel exchange guidewires, and tailored lesion-specific device and procedural selection-may further improve safety. Although current evidence does not support PTAS as a first-line therapy for symptomatic ICAS, evolving strategies suggest that selective patients may benefit from elective endovascular revascularization. Further large-scale, well-designed studies are needed to determine the optimal candidates, timing, devices, and techniques for this treatment.