title: Angioarchitectural factors present in brain arteriovenous malformations associated with hemorrhagic presentation.
abstract: OBJECTIVE
  Associations between clinical presentation of brain arteriovenous malformations (AVMs) and their angioarchitecture have been described. This study aims to identify significant factors related to the initial hemorrhagic event through multivariate statistical methodology.
  
  
  METHODS
  The authors studied the initial clinical presentation of 390 consecutive patients with brain AVMs at the University of Toronto Vascular Malformation Study Group. Angiographic features present at that time, such as location, size, and blood supply, were recorded following a standard protocol and associated, through multivariate analysis techniques, with type of presentation.
  
  
  RESULTS
  Patients had hemorrhagic presentation in 146 cases (37.4%). Hemorrhage was the initial presentation in 59.5% of the deep-seated AVMs (odds ratio [OR]=3.26; 95% CI=1.15 to 9.2; P=0.03). A single draining vein was associated with bleeding at presentation in 57.6% AVMs (OR=1.78; 95% CI=1.12 to 2.82; P=0.01), and 72.8% of the patients with venous ectasia had bleeding as initial evidence (OR=3.9; 95% CI=1.63 to 9.28; P=0.002). Hemorrhage was the initial presentation in 47.6% (111/233) of AVMs <3 cm, 22.5% (32/142) in sizes between 3 and 6 cm, and 20% in malformations >6 cm (3/15), but these differences were not significant in multivariate analyses.
  
  
  CONCLUSIONS
  For initial hemorrhagic presentation, a small number of draining veins, deep location, and the presence of venous ectasias were significant associated factors. In contrast with many previous reports, AVM size was not associated with hemorrhage at presentation in adjusted analyses.
authors.affiliation: University of Toronto Brain Vascular Malformation Study Group, Toronto, Ontario, Canada.
authors.forename: Marco A
authors.initials: MA
authors.lastname: Stefani
authors.forename: Phillip J
authors.initials: PJ
authors.lastname: Porter
authors.forename: Karel G
authors.initials: KG
authors.lastname: terBrugge
authors.forename: Walter
authors.initials: W
authors.lastname: Montanera
authors.forename: Robert A
authors.initials: RA
authors.lastname: Willinsky
authors.forename: M Christopher
authors.initials: MC
authors.lastname: Wallace
mesh_terms: D000328:Adult; D002170:Canada / Q000453:epidemiology; D002533:Cerebral Angiography / Q000706:statistics & numerical data*; D002543:Cerebral Hemorrhage / Q000145:classification* / Q000000981:diagnostic imaging / Q000453:epidemiology; D002550:Cerebral Veins / Q000002:abnormalities / Q000000981:diagnostic imaging; D015897:Comorbidity; D016208:Databases, Factual / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D002538:Intracranial Arteriovenous Malformations / Q000145:classification* / Q000000981:diagnostic imaging / Q000453:epidemiology; D008297:Male; D015999:Multivariate Analysis; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D017678:Sex Distribution