title: Collateral flow predicts outcome after basilar artery occlusion: The posterior circulation collateral score.
abstract: Our aim was to assess the prognostic value of a semiquantitative computed tomography angiography-based grading system, for the prediction of outcome in patients with acute basilar artery occlusion, based on the presence of potential collateral pathways on computed tomography angiography: the posterior circulation collateral score (PC-CS).
  
  
  
  One hundred forty-nine patients with acute basilar artery occlusion from the Basilar Artery International Cooperation Study were included. We related poor outcome at one month, defined as a modified Rankin scale score of 4 or 5, or death to collateral flow with Poisson regression. We used a 10 points grading system to quantify the potential for collateral flow in the posterior communicating arteries and the cerebellar arteries. Additionally, the relation between the presence and size of posterior communicating arteries and outcome was analyzed.
  
  
  
  Thirty-six patients had poor (PC-CS: 0-3), 59 patients intermediate (PC-CS: 4-5), and 54 patients good (PC-CS: 6-10) collaterals. Multivariable analyses showed a statistically significant lower risk of poor outcome in patients with a good PC-CS than in patients with a poor PC-CS (risk ratio (RR): 0.74, 95% confidence interval (CI): 0.58-0.96), but not for patients with an intermediate PC-CS compared with patients with a poor PC-CS (RR: 0.95, 95% CI: 0.78-1.15). Multivariable analyses showed a statistically significant lower risk of poor outcome for the presence of at least one posterior communicating artery and for larger caliber of posterior communicating arteries (RR: 0.79, 95% CI: 0.66-0.95 and 0.76, 95% CI: 0.61-0.96, respectively).
  
  
  
  The PC-CS predicted poor outcome at one month. In a separate analysis, both the absence and smaller caliber of posterior communicating arteries predicted poor outcome.
authors.affiliation: Department of Radiology, St. Antonius Hospital, Nieuwegein, the Netherlands e.van.der.hoeven@antoniusziekenhuis.nl.
authors.forename: Erik Jrj
authors.initials: EJ
authors.lastname: van der Hoeven
authors.affiliation: Department of Neurology, Altnagelvin Area Hospital, Derry, Northern Ireland.
authors.forename: Ferghal
authors.initials: F
authors.lastname: McVerry
authors.affiliation: Department of Radiology, St. Antonius Hospital, Nieuwegein, the Netherlands.
authors.forename: Jan Albert
authors.initials: JA
authors.lastname: Vos
authors.affiliation: Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands Julius Center for Health Sciences and Patient Care, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Ale
authors.initials: A
authors.lastname: Algra
authors.affiliation: Department of Neurology, Dresden University Stroke Center, University Clinics Carl Gustav Carus, Technical University Dresden, Dresden, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Puetz
authors.affiliation: Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: L Jaap
authors.initials: LJ
authors.lastname: Kappelle
authors.affiliation: Department of Neurology, Sint Antonius Hospital, Nieuwegein, the Netherlands.
authors.forename: Wouter J
authors.initials: WJ
authors.lastname: Schonewille
mesh_terms: D000368:Aged; D001488:Basilar Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002533:Cerebral Angiography; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D011446:Prospective Studies; D012042:Registries; D012044:Regression Analysis; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014715:Vertebrobasilar Insufficiency / Q000000981:diagnostic imaging* / Q000401:mortality / Q000503:physiopathology
keywords: Acute ischemic stroke; basilar artery; basilar artery occlusion; collateral circulation; computed tomographic angiography; imaging; posterior circulation