The Current Status of Endovascular Treatment for Extracranial Vertebral Artery Stenosis in Japan: A Subanalysis of the Japanese Registry of Neuroendovascular Therapy 4

Endovascular treatment (EVT) is a potential therapeutic option for extracranial vertebral artery (VA) stenosis; however, its efficacy or optimal procedures remain unknown. This study aimed to investigate the recent status of EVT for extracranial VA stenosis in Japan using a nationwide registry. We conducted a post hoc analysis of the Japanese Registry of Neuroendovascular Therapy 4 that enrolled patients who underwent EVT at 166 hospitals in Japan from 2015 to 2019. The outcomes of this study were as follows: procedural success indicating that the planned procedure was completed, modified Rankin Scale (mRS) score at 30 days, and procedure-related complications evaluated according to the procedure during EVT (percutaneous transluminal angioplasty vs. stenting and with or without the use of embolic protection devices [EPDs]). Of 308 eligible patients, 301 (95%) were treated for atherosclerotic stenosis, predominantly by stenting (74%). EPDs were used in 43%, primarily with the distal balloon (63%). The proportion of procedural success was 98%. Functional independence (mRS of 0-2) at 30 days was achieved in 80% of the total cohort, and there were no differences between patients treated with or without stenting or EPDs (74% vs. 82%, p = 0.12, and 80% vs. 80%, p = 0.93). Procedural complications occurred in 28 (9.1%) patients similarly in each group, with distal embolism and vessel dissection being common. In conclusion, EVT is a reasonable option for extracranial VA stenosis as a daily clinical practice. This study emphasizes the potential of EVT in managing extracranial VA stenosis and the need for further research to refine treatment strategies.