FREE NEJM E-TOC    HOME   |   SUBSCRIBE   |   CURRENT ISSUE   |   PAST ISSUES   |   COLLECTIONS   |   Search Term  Advanced Search

Sign in | Get NEJM's E-Mail Table of Contents — Free | Subscribe

Previous Volume 352:146-153 January 13, 2005 Number 2 Next

	Full Text PDF PDA Full Text PowerPoint Slide Set Perspective by Ellegala, D. B. Add to Personal Archive Add to Citation Manager Notify a Friend E-mail When Cited E-mail When Letters Appear PubMed Citation

ABSTRACT

Background Angiography shows that stereotactic radiosurgery obliterates most cerebral arteriovenous malformations after a latency period of a few years. However, the effect of this procedure on the risk of hemorrhage is poorly understood.

Methods We performed a retrospective observational study of 500 patients with malformations who were treated with radiosurgery with use of a gamma knife. The rates of hemorrhage were assessed during three periods: before radiosurgery, between radiosurgery and the angiographic documentation of obliteration of the malformation (latency period), and after angiographic obliteration.

Results Forty-two hemorrhages were documented before radiosurgery (median follow-up, 0.4 year), 23 during the latency period (median follow-up, 2.0 years), and 6 after obliteration (median follow-up, 5.4 years). As compared with the period between diagnosis and radiosurgery, the risk of hemorrhage decreased by 54 percent during the latency period (hazard ratio, 0.46; 95 percent confidence interval, 0.26 to 0.80; P=0.006) and by 88 percent after obliteration (hazard ratio, 0.12; 95 percent confidence interval, 0.05 to 0.29; P<0.001). The risk was significantly reduced during the period after obliteration, as compared with the latency period (hazard ratio, 0.26; 95 percent confidence interval, 0.10 to 0.68; P=0.006). The reduction was greater among patients who presented with hemorrhage than among those without hemorrhage at presentation and similar in analyses that took into account the delay in confirming obliteration by means of angiography and analyses that excluded data obtained during the first year after diagnosis.

Conclusions Radiosurgery significantly decreases the risk of hemorrhage in patients with cerebral arteriovenous malformations, even before there is angiographic evidence of obliteration. The risk of hemorrhage is further reduced, although not eliminated, after obliteration.

Source Information

From the Departments of Neurosurgery (K.M., N.K., M.S., H.K., S.K., A.M., T.K.), Radiology (M.T.), and Clinical Bioinformatics (J.K.), University of Tokyo Hospital, Tokyo.

Address reprint requests to Dr. Maruyama at the Department of Neurosurgery, University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan, or at kskmaru-tky{at}umin.ac.jp.

Full Text of this Article

This article has been cited by other articles:

• Friedlander, R. M. (2007). Arteriovenous Malformations of the Brain. NEJM 356: 2704-2712 [Full Text]  
• Pollock, B. E., Brown, R. D. Jr (2006). Use of the Modified Rankin Scale to assess outcome after arteriovenous malformation radiosurgery.. Neurology 67: 1630-1634 [Abstract] [Full Text]  
• Al-Shahi, R, Warlow, C (2005). Arteriovenous malformations of the brain: ready to randomise?. J. Neurol. Neurosurg. Psychiatry 76: 1327-1329 [Full Text]