title: Treatment of brain arteriovenous malformations: a systematic review and meta-analysis.
abstract: BACKGROUND
  Outcomes following treatment of brain arteriovenous malformations (AVMs) with microsurgery, embolization, stereotactic radiosurgery (SRS), or combinations vary greatly between studies.
  
  
  OBJECTIVE
  To assess rates of case fatality, long-term risk of hemorrhage, complications, and successful obliteration of brain AVMs after interventional treatment and to assess determinants of these outcomes.
  
  
  METHODS
  We searched PubMed and EMBASE to March 1, 2011, and hand-searched 6 journals from January 2000 until March 2011.
  
  
  METHODS
  We identified studies fulfilling predefined inclusion criteria. We used Poisson regression analyses to explore associations of patient and study characteristics with case fatality, complications, long-term risk of hemorrhage, and successful brain AVM obliteration.
  
  
  RESULTS
  We identified 137 observational studies including 142 cohorts, totaling 13,698 patients and 46,314 patient-years of follow-up. Case fatality was 0.68 (95% CI, 0.61-0.76) per 100 person-years overall, 1.1 (95% CI, 0.87-1.3; n = 2549) after microsurgery, 0.50 (95% CI, 0.43-0.58; n = 9436) after SRS, and 0.96 (95% CI, 0.67-1.4; n = 1019) after embolization. Intracranial hemorrhage rates were 1.4 (95% CI, 1.3-1.5) per 100 person-years overall, 0.18 (95% CI, 0.10-0.30) after microsurgery, 1.7 (95% CI, 1.5-1.8) after SRS, and 1.7 (95% CI, 1.3-2.3) after embolization. More recent studies were associated with lower case-fatality rates (rate ratio [RR], 0.972; 95% CI, 0.955-0.989) but increased rates of hemorrhage (RR, 1.02; 95% CI, 1.00-1.03). Male sex (RR, 0.964; 95% CI, 0.945-0.984), small brain AVMs (RR, 0.988; 95% CI, 0.981-0.995), and those with strictly deep venous drainage (RR, 0.975; 95% CI, 0.960-0.990) were associated with lower case fatality. Lower hemorrhage rates were associated with male sex (RR, 0.976, 95% CI, 0.964-0.988), small brain AVMs (RR, 0.988, 95% CI, 0.980-0.996), and brain AVMs with deep venous drainage (0.982, 95% CI, 0.969-0.996). Complications leading to permanent neurological deficits or death occurred in a median 7.4% (range, 0%-40%) of patients after microsurgery, 5.1% (range, 0%-21%) after SRS, and 6.6% (range, 0%-28%) after embolization. Successful brain AVM obliteration was achieved in 96% (range, 0%-100%) of patients after microsurgery, 38% (range, 0%-75%) after SRS, and 13% (range, 0%-94%) after embolization.
  
  
  CONCLUSIONS
  Although case fatality after treatment has decreased over time, treatment of brain AVM remains associated with considerable risks and incomplete efficacy. Randomized controlled trials comparing different treatment modalities appear justified.
authors: Department of Neurology and Neurosurgery, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, The Netherlands. j.vanbeijnum@gmail.com
authors: Janneke
authors: J
authors: van Beijnum
authors: H Bart
authors: HB
authors: van der Worp
authors: Dennis R
authors: DR
authors: Buis
authors: Rustam
authors: R
authors: Al-Shahi Salman
authors: L Jaap
authors: LJ
authors: Kappelle
authors: Gabriël J E
authors: GJ
authors: Rinkel
authors: Jan Willem Berkelbach
authors: JW
authors: van der Sprenkel
authors: W Peter
authors: WP
authors: Vandertop
authors: Ale
authors: A
authors: Algra
authors: Catharina J M
authors: CJ
authors: Klijn
mesh_terms: D002543:Cerebral Hemorrhage / Q000209:etiology; D004621:Embolization, Therapeutic; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000401:mortality / Q000601:surgery* / Q000628:therapy; D008297:Male; D008866:Microsurgery; D011183:Postoperative Complications; D012306:Risk; D016896:Treatment Outcome