title: The effect of basilar artery bifurcation angle on rates of initial occlusion, recanalization, and retreatment of basilar artery apex aneurysms following coil embolization.
abstract: BACKGROUND
  Arterial bifurcations are common locations for aneurysm development given the altered hemodynamic forces and shear stress variations present at these locations. Recent reports indicate that a wide basilar artery bifurcation angle is an independent predictor of aneurysm development, growth, and subsequent rupture.
  
  
  METHODS
  To determine the effect of basilar artery bifurcation angle on rates of initial occlusion, recanalization, and retreatment of basilar artery apex aneurysms following coil embolization, the records of 46 patients with basilar artery apex aneurysms treated with endovascular coil embolization from 2007 to 2013 were analyzed.
  
  
  RESULTS
  A wide basilar artery bifurcation angle was associated with a Raymond-Roy Occlusion Classification (RROC) III occlusion in univariate analysis, but was not a statistically significant factor in multivariate modeling. An increasing basilar artery bifurcation angle was not associated with aneurysm recanalization or retreatment following coil embolization. Increasing packing density (p < .01) was the only statistically significant predictor of a RROC I or II closure. The initial RROC designation was the most powerful predictor of both eventual aneurysm recanalization (p = .01) and retreatment (p = .02). While increasing aneurysm size (p < .01), increasing aneurysm volume (p < .01), and increasing neck size (p < .01) were associated with wide basilar artery bifurcation angles, neck size (p = .03) was the only statistically significant predictor of basilar artery bifurcation angle on multivariate analyses.
  
  
  CONCLUSIONS
  Basilar artery bifurcation angle fails to predict rates of initial occlusion, recanalization, and retreatment on multivariate modeling in our series. Basilar artery apex aneurysm neck size independently correlates with basilar artery bifurcation angle.
authors.affiliation: Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, USA Neuroendovascular Program, Massachusetts General Hospital and Harvard Medical School, Boston, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Stapleton
authors.affiliation: Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, USA.
authors.forename: Jay I
authors.initials: JI
authors.lastname: Kumar
authors.affiliation: Department of Neurological Surgery, University of California, San Francisco, USA.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Walcott
authors.affiliation: Neuroendovascular Program, Massachusetts General Hospital and Harvard Medical School, Boston, USA.
authors.forename: Collin M
authors.initials: CM
authors.lastname: Torok
authors.affiliation: Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, USA.
authors.forename: Pankaj K
authors.initials: PK
authors.lastname: Agarwalla
authors.affiliation: Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Koch
authors.affiliation: Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, USA Neuroendovascular Program, Massachusetts General Hospital and Harvard Medical School, Boston, USA abpatel@mgh.harvard.edu.
authors.forename: Aman B
authors.initials: AB
authors.lastname: Patel
mesh_terms: D001488:Basilar Artery / Q000033:anatomy & histology*; D004621:Embolization, Therapeutic / Q000379:methods*; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D019233:Retreatment; D012189:Retrospective Studies; D016896:Treatment Outcome
keywords: Arterial bifurcation angles; basilar artery; endovascular coil embolization; intracranial aneurysm; subarachnoid hemorrhage