Endovascular Therapy for Non-Acute Intracranial Atherosclerotic Occlusion: A Feasible Treatment Modality, but is it Beneficial?

Intracranial atherosclerotic stenosis (ICAS) is a common cause of cerebral infarction, and it is more prevalent in East Asia.Given the high rate of stroke recurrence associated with ICAS, endovascular treatment (EVT) such as balloon angioplasty and stenting has been explored as a therapeutic option.Although randomized controlled trials such as SAMMPRIS and CASSISS, which compared selfexpanding stents with medical management in patients with symptomatic ICAS, failed to demonstrate the efficacy of EVT due to the high risk of periprocedural stroke 1, 2) , a post-market surveillance study indicated that the periprocedural risk is low when the stent is used within its stipulated indications 3) .On the other hand, EVT has not been widely adopted for intracranial atherosclerotic occlusion (ICAO), except during the hyperacute phase (24 hours).For patients with non-acute ICAO (24 h), medical management, including fluid infusion, dual antiplatelet therapy, and statins, remains the firstline approach.In this issue of the Journal of Atherosclerosis and Thrombosis, Li et al. reported 264 patients with non-acute ICAO who underwent EVT.They primarily (51%) employed a combination of plain old balloon angioplasty and drug-coated balloon angioplasty, thereby achieving a successful recanalization rate of 87% 4) .Their report is of importance as previous reports were limited to case series and small observational cohorts (Table 1).Their findings add further evidence to the feasibility of EVT for the treatment of non-acute ICAO.According to these reports, successful recanalization can be achieved, regardless of the occluded vessel.However, it remains unclear whether EVT benefits patients with non-acute ICAO.Li et al. reported a periprocedural complication rate of 15.5% (which is not particularly high in comparison to prior studies) and a 6-month rate of recurrent stroke or death of 9.6% in the successful recanalization group.The combined rate of these outcomes was not substantially different from the 31.4% reported in the unsuccessful recanalization group.Moreover, these recurrence rates were higher than those reported in the medical treatment arms of the SAMMPRIS and CASSISS trials (12.2% and 7.2% at one year, respectively).It is important to note, however, that the patient populations differed.These trials focused on secondary prevention in patients with ICAS, while the CASSISS trial included a higher proportion of patients with transient ischemic attacks, which may have contributed to the lower event rates 1, 2) .To justify the periprocedural risk of EVT for nonacute ICAO, careful patient selection is essential.High-risk individuals can be identified based on predictors such as patient characteristics 5) , infarct distribution 6) , collateral circulation status, and the perfusion imaging findings.In conclusion, Li et al., along with previous studies from China, have demonstrated the feasibility of performing EVT for non-acute ICAO.A large prospective cohort study comparing patients with and without EVT is therefore needed to identify the subgroups that would benefit the most from this treatment.