title: Threshold for NIH stroke scale in predicting vessel occlusion and functional outcome after stroke thrombolysis.
abstract: BACKGROUND
  Data are limited on optimal threshold for baseline National Institutes of Health Stroke Scale in predicting outcome after stroke thrombolysis (intravenous thrombolysis).
  
  
  OBJECTIVE
  Finding thresholds for baseline National Institutes of Health Stroke Scale scores that predict functional outcome and baseline vessel occlusion.
  
  
  METHODS
  We analyzed 44 331 patients with available modified Rankin Scale score at three-months and 11 632 patients with computed tomography/magnetic resonance angiography documented vessel occlusion at baseline in the SITS-International Stroke Thrombolysis Register. Main outcomes were functional independency (modified Rankin Scale 0-2) at three-months and baseline vessel occlusion. We obtained area under the curves by receiver operating characteristic analysis and calculated multivariately adjusted odds ratio for the outcomes of interest based on baseline National Institutes of Health Stroke Scale scores.
  
  
  RESULTS
  For functional independency, National Institutes of Health Stroke Scale scores of 12 (area under the curve 0·775) and for baseline vessel occlusion, scores of 11 (area under the curve 0·678) were optimal threshold values. For functional independency, adjusted odds ratio decreased to 0·07 (95% CI 0·05-0·11), and for presence of baseline occlusion, aOR increased to 3·28 (95% CI 3·04-3·58) for National Institutes of Health Stroke Scale scores 12 and 11, respectively, compared with National Institutes of Health Stroke Scale score 0. National Institutes of Health Stroke Scale thresholds decreased with time from stroke onset to imaging, with 2-3 points, respectively, if time to imaging exceeded three-hours.
  
  
  CONCLUSIONS
  Ideally, all acute stroke patients should have immediate access to multimodal imaging. In reality these services are limited. Baseline National Institutes of Health Stroke Scale scores of 11 and 12 were identified as markers of baseline vessel occlusion and functional independency after intravenous thrombolysis, respectively. These values are time dependent; therefore, a threshold of National Institutes of Health Stroke Scale 9 or 10 points may be considered in the prehospital selection of patients for immediate transfer to centers with multimodal imaging and availability of highly specialized treatments.
authors.affiliation: Department of Clinical Neurosciences, Karolinska Institutet, Solna, Sweden.|and Department of Neurology Karolinska University Hospital, Solna, Sweden.
authors.forename: Charith
authors.initials: C
authors.lastname: Cooray
authors.affiliation: Department of Neurology, University of Debrecen, Debrecen, Hungary.
authors.forename: Klara
authors.initials: K
authors.lastname: Fekete
authors.affiliation: International Clinical Research Center, Department of Neurology, St. Anne's Hospital and Masaryk University, Brno, Czech Republic.
authors.forename: Robert
authors.initials: R
authors.lastname: Mikulik
authors.affiliation: Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK.
authors.forename: Kennedy R
authors.initials: KR
authors.lastname: Lees
authors.affiliation: Department of Clinical Neurosciences, Karolinska Institutet, Solna, Sweden.|and Department of Neurology Karolinska University Hospital, Solna, Sweden.
authors.forename: Nils
authors.initials: N
authors.lastname: Wahlgren
authors.affiliation: Department of Clinical Neurosciences, Karolinska Institutet, Solna, Sweden.|and Department of Neurology Karolinska University Hospital, Solna, Sweden.
authors.forename: Niaz
authors.initials: N
authors.lastname: Ahmed
mesh_terms: D061605:Administration, Intravenous; D000368:Aged; D001921:Brain / Q000187:drug effects* / Q000473:pathology*; D002545:Brain Ischemia / Q000175:diagnosis / Q000188:drug therapy / Q000473:pathology; D002533:Cerebral Angiography; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D064847:Multimodal Imaging; D009316:National Institutes of Health (U.S.); D011446:Prospective Studies; D012042:Registries; D012720:Severity of Illness Index; D020521:Stroke / Q000175:diagnosis* / Q000188:drug therapy* / Q000473:pathology; D015912:Thrombolytic Therapy / Q000379:methods; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014481:United States
chemical_list: D005343:Fibrinolytic Agents; D010959:Tissue Plasminogen Activator
keywords: acute stroke therapy; stroke; thrombolysis