Angioarchitecture determines obliteration rate after radiosurgery in brain arteriovenous malformations

Radiosurgery as a potential treatment modality for brain arteriovenous malformations (AVM) has 60% to 90% obliteration rates.

To test whether AVM angioarchitecture determines obliteration rate after radiosurgery.

This study was a retrospective analysis of 139 patients with AVM who underwent radiosurgery. Multiple angioarchitectural characteristics were reviewed on conventional angiogram on the day of radiosurgery: enlargement of feeding arteries, flow-related or intranidal aneurysms, perinidal angiogenesis, arteriovenous transit time, nidus type, venous ectasia, focal pouches, venous rerouting, and presence of a pseudophlebitic pattern. The radiation plan was reviewed for nidus volume and eloquence of AVM location. A chart review was performed to determine clinical presentation and previous treatment. Outcome was dichotomized into complete/incomplete obliteration, and various statistics were performed, examining whether outcome status was associated with the investigated factors.

Marginal dose ranged from 15 to 25 Gy (mean, 18.8 Gy), with lower doses prescribed in eloquent locations. Sizes of AVMs ranged from 0.08 to 21 cm (mean, 3.78 ± 4.19 cm). Complete AVM obliteration was achieved in 92 patients (66%) and was related to these independent factors: noneloquent location (odds ratio [OR], 3.20), size (OR, 0.88), low flow (OR, 3.47), no or mild arterial enlargement (OR, 3.32), and absence of perinidal angiogenesis (OR, 2.61). Concerning the 3 last angioarchitectural characteristics, if no or only a single factor was present in an individual patient (n = 92 patients), obliteration was observed in 74 (80%); if 2 or 3 factors were present (n = 47), obliteration was observed in 18 patients (38%; OR, 6.62).

Angioarchitectural factors that indicate high flow are associated with a lower rate of AVM obliteration after radiosurgery.