Endovascular treatment of symptomatic vasospasm and delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage – a systematic review and meta-analysis

Endovascular rescue therapy, including intra-arterial spasmolysis and balloon angioplasty, is widely used for symptomatic vasospasm and delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH), but its impact on functional recovery is unclear. We systematically reviewed evidence on patient-centered outcomes, including effects by follow-up time, intervention type, and clinical severity. PubMed, EMBASE, and Web of Science were searched (2000–2024; updated July 2025). Prospective and retrospective studies of adults with aSAH receiving endovascular treatment for symptomatic vasospasm/DCI were included. Data extraction followed a PICO framework, and quality was assessed using the Newcastle–Ottawa Scale. Due to inconsistent reporting of angiographic resolution and DCI-related infarction, quantitative synthesis focused on dichotomized favorable functional outcome. Single-arm proportions were pooled using random-effects generalized linear mixed models with prespecified subgroup analyses. Thirty-nine studies (1,627 patients) were included; 38 contributed to pooled analysis. The proportion of favorable functional outcome was 0.55 (95% CI 0.50–0.61), with substantial heterogeneity (I² ≈ 71%). Subgroup analyses by follow-up duration, intervention modality, and baseline severity showed no significant differences. The two randomized trials reported conflicting results and had limited follow-up. Safety reporting varied but was generally acceptable for pharmacologic spasmolysis; some series suggested higher complication rates with mechanical interventions. Approximately half of patients treated with endovascular rescue for symptomatic vasospasm/DCI achieve a favorable functional outcome. However, marked heterogeneity and predominantly observational evidence limit conclusions regarding effectiveness. Standardized, adequately powered randomized trials are needed to clarify the role of endovascular rescue after aSAH.