Stereotactic Radiosurgery With Versus Without Neoadjuvant Endovascular Embolization for Brain Arteriovenous Malformations With Associated Intracranial Aneurysms.

Background And Objectives: Stereotactic radiosurgery (SRS) with neoadjuvant embolization is a treatment strategy for brain arteriovenous malformations (AVMs), especially for those with large nidal volume or concomitant aneurysms. The aim of this study was to assess the effects of pre-SRS embolization in AVMs with an associated intracranial aneurysm (IA).

Methods: The International Radiosurgery Research Foundation AVM database from 1987 to 2018 was retrospectively reviewed. SRS-treated AVMs with IAs were included. Patients were categorized into those treated with upfront embolization (E + SRS) vs stand-alone SRS (SRS). Primary end point was a favorable outcome (AVM obliteration + no permanent radiation-induced changes or post-SRS hemorrhage). Secondary outcomes included AVM obliteration, mortality, follow-up modified Rankin Scale, post-SRS hemorrhage, and radiation-induced changes.

Results: Forty four AVM patients with associated IAs were included, of which 23 (52.3%) underwent pre-SRS embolization and 21 (47.7%) SRS only. Significant differences between the E + SRS vs SRS groups were found for AVM maximum diameter (1.5 ± 0.5 vs 1.1 ± 0.4 cm 3 , P = .019) and SRS treatment volume (9.3 ± 8.3 vs 4.3 ± 3.3 cm 3 , P = .025). A favorable outcome was achieved in 45.4% of patients in the E + SRS group and 38.1% in the SRS group ( P = .625). Obliteration rates were comparable (56.5% for E + SRS vs 47.6% for SRS, P = .555), whereas a higher mortality rate was found in the SRS group (19.1% vs 0%, P = .048). After adjusting for AVM maximum diameter, SRS treatment volume, and maximum radiation dose, the likelihood of achieving favorable outcome and AVM obliteration did not differ between groups ( P = .475 and P = .820, respectively).

Conclusion: The likelihood of a favorable outcome and AVM obliteration after SRS with neoadjuvant embolization in AVMs with concomitant IA seems to be comparable with stand-alone SRS, even after adjusting for AVM volume and SRS maximum dose. However, the increased mortality among the stand-alone SRS group and relatively low risk of embolization-related complications suggest that these patients may benefit from a combined treatment approach.