title: Collateral score complements clot location in predicting the outcome of intravenous thrombolysis.
abstract: OBJECTIVE
  Collateral circulation is an important determinant of stroke outcome. We studied the impact of leptomeningeal collateral circulation with respect to the location of the thrombus in predicting the clinical outcome of patients treated with intravenous thrombolytic therapy (<3 hours) in a retrospective cohort.
  
  
  METHODS
  Anterior circulation thrombus was detected with CT angiography in 105 patients. Baseline clinical and imaging information was collected, and the site of the occlusion was recorded. Collaterals were assessed by using a 5-grade collateral score and were entered into logistic regression analysis to predict favorable clinical outcome (3-month modified Rankin Scale score of 0-2).
  
  
  RESULTS
  Two-thirds of patients with a proximal occlusion displayed poor collateral filling (collateral score 0-1), whereas in more distal clot locations, approximately one-third had poor collaterals. Only 36% of patients with a proximal occlusion and good collaterals experienced favorable clinical outcome. In multivariate analysis, both clot location and collateral score were highly significant (P = .003 and P = .001) and independent predictors of favorable clinical outcome. Good collateral status increased the odds of favorable clinical outcome about 9-fold (OR = 9.3; 95% CI, 2.4-35.8). After dichotomization, a distal clot location had a larger odds ratio (OR = 13.3; 95% CI, 3.0-60.0) compared with the odds ratio of good collaterals (OR = 5.9; 95% CI, 1.8-19.0).
  
  
  CONCLUSIONS
  A proximal occlusion in the anterior circulation is associated with poorer collateral status compared with a more distal occlusion. Both the clot location and collateral score are important and independent predictors of favorable clinical outcome of hyperacute stroke treated with intravenous thrombolysis. The location of the clot is a stronger determinant of the outcome than the collateral score.
authors.affiliation: From the Department of Neurology (J.T.S.), University of Tampere, Tampere and Vaasa Central Hospital, Vaasa, Finland.
authors.forename: J T
authors.initials: JT
authors.lastname: Saarinen
authors.affiliation: Department of Neurology (H.R.), Oulu University Hospital, Oulu, Finland.
authors.forename: H
authors.initials: H
authors.lastname: Rusanen
authors.affiliation: Medical Imaging Center (N.S.), Tampere University Hospital, Tampere, Finland. niko.sillanpaa@pshp.fi.
authors.forename: N
authors.initials: N
authors.lastname: Sillanpää
mesh_terms: D000368:Aged; D002533:Cerebral Angiography; D015331:Cohort Studies; D003097:Collateral Circulation / Q000502:physiology*; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008578:Meninges / Q000098:blood supply*; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D012189:Retrospective Studies; D020521:Stroke / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy*; D015912:Thrombolytic Therapy / Q000379:methods*; D013927:Thrombosis / Q000000981:diagnostic imaging; D016896:Treatment Outcome
chemical_list: D005343:Fibrinolytic Agents