title: Hemorrhage rate in patients with Spetzler-Martin grades IV and V arteriovenous malformations: is treatment justified?
abstract: OBJECTIVE
  We sought to examine the prospective annual risk of hemorrhage in patients harboring Spetzler-Martin grades IV and V arteriovenous malformations (AVMs) before and after initiation of treatment.
  
  
  METHODS
  Medical records of 61 consecutive patients presenting with Spetzler-Martin grades IV and V AVMs were retrospectively reviewed for demographics, angiographic features, presenting symptom(s), and time of all hemorrhage events, before or after treatment initiation. Pretreatment hemorrhage rates (excluding hemorrhages at presentation) and posttreatment rates were subsequently calculated. Modified Rankin Scale (mRS) scores before and after treatment were recorded.
  
  
  RESULTS
  The annual pretreatment hemorrhage rate for all patients was 10.4% per year (95% CI, 2.2 to 15.4%), 13.9% (95% CI, 3.5 to 22.1%) in patients with hemorrhagic presentation and 7.3% (2.6 to 14.3%) in patients with nonhemorrhagic presentation. Posttreatment hemorrhage rates were 6.1% per year (95% CI, 2.5 to 13.2%) for all patients, 5.6% (95% CI, 2.1 to 11.8%) for patients presenting with hemorrhage and 6.4% (95% CI, 1.6 to 10.1%) in patients with nonhemorrhagic presentation. A noninferiority test showed that the posttreatment hemorrhage rate was less than or equal to the pretreatment hemorrhage rate (P<0.0001), with some indication that the reduction was greatest in patients with hemorrhagic presentation. Of the 62 patients, 51 (82%) had an mRS score of 0 to 2 before treatment, and 47 (76%) had an mRS score of 0 to 2 at the last follow-up after treatment.
  
  
  CONCLUSIONS
  The annual rate of hemorrhage in grades IV and V AVMs is higher in this series than reported for all AVMs, which may reflect some referral bias in this single-center study. Nevertheless, initiation of treatment does not appear to increase the rate of subsequent hemorrhage. Treatment for these lesions may be warranted, given their poor natural history.
authors.affiliation: Department of Radiology, Stanford University Medical Center, Room S-047, 300 Pasteur Dr, Stanford, CA 94305-5105, USA.
authors.forename: Mahesh V
authors.initials: MV
authors.lastname: Jayaraman
authors.forename: Mary L
authors.initials: ML
authors.lastname: Marcellus
authors.forename: Huy M
authors.initials: HM
authors.lastname: Do
authors.forename: Steven D
authors.initials: SD
authors.lastname: Chang
authors.forename: Jarrett K
authors.initials: JK
authors.lastname: Rosenberg
authors.forename: Gary K
authors.initials: GK
authors.lastname: Steinberg
authors.forename: Michael P
authors.initials: MP
authors.lastname: Marks
mesh_terms: D000293:Adolescent; D000328:Adult; D002543:Cerebral Hemorrhage / Q000150:complications / Q000453:epidemiology* / Q000628:therapy*; D002648:Child; D004621:Embolization, Therapeutic / Q000009:adverse effects; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000150:complications / Q000453:epidemiology* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012189:Retrospective Studies