title: CT angiography predicts use of tertiary interventional services in acute ischemic stroke patients.
abstract: BACKGROUND
  Patients with acute stroke are often transferred to tertiary care centers for advanced interventional services. We hypothesized that the presence of a proximal cerebral artery occlusion on CT angiography (CTA) is an independent predictor of the use of these services.
  
  
  METHODS
  We performed a historical cohort study of consecutive ischemic stroke patients presenting within 24 h of symptom onset to an academic emergency department who underwent emergent CTA. Use of tertiary care interventions including intra-arterial (IA) thrombolysis, mechanical clot retrieval, and neurosurgery were captured.
  
  
  RESULTS
  During the study period, 207/290 (71%) of patients with acute ischemic stroke underwent emergent CTA. Of the patients, 74/207 (36%) showed evidence of a proximal cerebral artery occlusion, and 22/207 (11%) underwent an interventional procedure. Those with proximal occlusions were more likely to receive a neurointervention (26% vs. 2%, p < 0.001). They were more likely to undergo IA thrombolysis (9% vs. 0%, p = 0.001) or a mechanical intervention (19% vs. 0%, p < 0.0001), but not more likely to undergo neurosurgery (5% vs. 2%, p = 0.2). After controlling for the initial NIH stroke scale (NIHSS) score, proximal occlusion remained an independent predictor of the use of neurointerventional services (OR 8.5, 95% CI 2.2-33). Evidence of proximal occlusion on CTA predicted use of neurointervention with sensitivity of 82% (95% CI 59-94%), specificity of 71% (95% CI 64%-77%), positive predictive value (PPV) of 25% (95% CI 16%-37%), and negative predictive value (NPV) of 97% (95% CI 92%-99%).
  
  
  CONCLUSIONS
  Proximal cerebral artery occlusion on CTA predicts the need for advanced neurointerventional services.
authors.affiliation: Department of Emergency Medicine, Massachusetts General Hospital, Boston, MA, USA. jgoldstein@partners.org.
authors.forename: Lisa E
authors.initials: LE
authors.lastname: Thomas
authors.forename: Joshua N
authors.initials: JN
authors.lastname: Goldstein
authors.forename: Reza
authors.initials: R
authors.lastname: Hakimelahi
authors.forename: Yuchiao
authors.initials: Y
authors.lastname: Chang
authors.forename: Albert J
authors.initials: AJ
authors.lastname: Yoo
authors.forename: Lee H
authors.initials: LH
authors.lastname: Schwamm
authors.forename: R Gilberto
authors.initials: RG
authors.lastname: Gonzalez