Endovascular Treatment Strategies for Acute Intracranial Atherosclerotic Stenosis-Related Large Vessel Occlusion.

Mechanical thrombectomy (MT) is the recommended therapy based on Grade A evidence for acute ischemic stroke due to large vessel occlusion (LVO). However, acute intracranial atherosclerotic stenosis-related LVO (ICAS-LVO), which is prevalent in East Asian populations, including the Japanese, represents a distinct clinical entity characterized by progressive hemodynamic compromise, a high risk of reocclusion, and unique technical challenges during endovascular treatment (EVT) for this condition. Unlike typical embolic LVO, the efficacy of MT alone in ICAS-LVO has not been firmly established, and optimal treatment strategies remain controversial. This review presents a practical, stepwise EVT strategy for ICAS-LVO based on published reports and the authors' clinical experience. The proposed strategy consists of 4 key components: 1) comprehensive diagnosis; 2) early antithrombotic management; 3) stage- and lesion-specific EVT techniques; and 4) meticulous postprocedural management. Because preprocedural diagnosis of ICAS-LVO is often difficult, diagnosis should be established dynamically by integrating information on atherosclerotic risk factors, the clinical course, the presence or absence of characteristic imaging findings, and intraprocedural observations such as guidewire behavior, residual stenosis after recanalization, and early reocclusion. As the initial EVT approach, MT is recommended as the first-pass strategy, similar to embolic LVO, given its diagnostic and therapeutic utility, with prompt initiation of antiplatelet therapy when indicated. When immediate flow restoration is achieved after stent retriever (SR) deployment, the degree of stent expansion provides critical information regarding the presence and location of underlying ICAS. In such cases, prolonging the SR deployment, referred to as SR angioplasty, may be considered a vessel-sparing adjunctive technique to enhance the effects of circulating antiplatelet agents while achieving gentle vessel dilation. If recanalization cannot be achieved with MT alone, or if severe residual stenosis or early reocclusion is observed, timely escalation to percutaneous transluminal cerebral balloon angioplasty, with or without intracranial stent placement, should be considered. Postprocedural management focuses on continuation of antiplatelet therapy, careful blood pressure control, and close clinical and imaging surveillance to detect early reocclusion. Preparedness for urgent retreatment in cases of acute reocclusion, as well as elective angioplasty for residual stenosis, is essential. This strategy-oriented approach highlights the importance of adaptive decision-making throughout EVT and may help optimize outcomes in patients with ICAS-LVO.