BACKGROUND: This study aimed to evaluate the periprocedural and postprocedural outcomes of endovascular treatments for cerebral vasospasm after subarachnoid hemorrhage using data from the Japan Registry of Neuroendovascular Therapy 4 (JR-NET4) (2015-2019). METHODS: In this retrospective multicenter study, procedures of endovascular treatment for cerebral vasospasms registered in JR-NET4 were analyzed. The procedure outcomes and complications for percutaneous transluminal angioplasty (PTA) and intra-arterial administration of vasodilators (IA-vasodilator) were compared. The factors associated with imaging and symptom improvement were assessed. RESULTS: Analysis of 1549 procedures revealed that 83.5% of procedures were IA-vasodilator and 16.5% of procedures were PTA. Postprocedural imaging improvement was achieved in 97.0% of patients, and 50.1% of patients experienced symptomatic improvement. The overall complication rate was 1.6%. No significant differences were detected in overall complication rates between patients who underwent PTA and intra-arterial administration of vasodilators
however, hemorrhagic complications were significantly more frequent in patients who underwent PTA. Shorter intervals from symptom onset and the absence of periprocedural complications were associated with improved imaging and neurological outcomes. Local anesthesia and prior treatment with endovascular embolization for ruptured aneurysms were associated with enhanced neurological improvements. CONCLUSION: Endovascular treatment for cerebral vasospasm is safe and effective. Factors such as early intervention and treatment under local anesthesia may contribute to neurological improvements. However, caution is warranted for PTA due to the slightly higher incidence of hemorrhagic complications.