Does hemorrhagic presentation in cerebral arteriovenous malformations affect obliteration rate after gamma knife radiosurgery?

Objectives: Radiosurgery has been widely adopted for the treatment of cerebral AVMs. However radiosurgical treatment of patients with hemorrhagic presentation is fraught with risk of rebleed during latency period. The present study intends to analyze the obliteration rate, time to obliteration and chances of rebleed in patients with hemorrhagic versus non-hemorrhagic clinical presentation in cerebral arteriovenous malformations (AVMs) treated with gamma knife radiosurgery (GKS).

Patients And Methods: Of all the patients with cerebral AVMs treated from May 1997 to June 2006, 157 patients with neuroimaging follow up with digital subtraction angiography harboring 160 AVM nidii formed the study group. The mean age of presentation was 28 years (range, 6-58 years); mean nidus volume being 3.64 cm3 (range, 0.011-36.6 cm3). The mean follow up period was 70 months (range, 13-121 months). All the patients were treated predominantly by primary GKS with use of adjunctive pre-GKS embolization in selected patients.

Results: A total of 103 (64%) patients presented with hemorrhage. There was no difference in the obliteration rate (69% versus 67%, p=0.672), mean latency period to obliteration (30 months versus 32 months, p=0.1989) and chances of hemorrhage (4.8% versus 3.5%, p=0.690) in patients with hemorrhagic as compared to non-hemorrhagic presentation.

Conclusion: Prior hemorrhage does not affect the outcome after GKS in terms of obliteration rate, latency to obliteration as well as chances of hemorrhage during latency period. Gamma knife appears equally efficacious irrespective of the mode of clinical presentation in the management of cerebral AVMs; a concomitant use of pre-GKS embolization/surgery may be needed in patients with hemorrhagic presentation in selected cases, however.