title: Cryptogenic stroke: clinical consideration of a heterogeneous ischemic subtype.
abstract: BACKGROUND
  Cryptogenic stroke can be subdivided into 3 distinct categories: stroke of no determined cause (CyNC), stroke due to multiple etiologies (Cy >1), and stroke etiology unclear due to incomplete evaluation. Although these subdivisions may be very different from one another with respect to baseline features and outcomes, they are often reported as a composite group in clinical trials.
  
  
  METHODS
  Patients treated at our academic institution between July 2008 and June 2013 for acute ischemic stroke were retrospectively assessed in our prospective registry. CyNC and Cy >1 patients were compared to other Trial of Org 10172 in Acute Stroke Treatment (TOAST) stroke subtypes and to each other using univariate analyses and multivariate logistic regression. The primary outcome of interest was good functional outcome, defined as a discharge modified Rankin Scale score of 0-2.
  
  
  RESULTS
  Of the 1311 included patients, 260 (19.8%) experienced a CyNC and 49 (3.7%) experienced a Cy >1. Cy >1 classification was associated with history of atrial fibrillation (odds ratio [OR], 3.17; 95% confidence interval [CI], 1.16-6.12; P = .001). In comparison to other TOAST classifications, CyNC strokes were more likely to have good functional outcome (OR, 1.97; 95% CI, 1.38-2.82; P < .001) after adjusting for baseline National Institutes of Health Stroke Scale, admission glucose, age, and intravenous tissue plasminogen activator (IV tPA).
  
  
  CONCLUSIONS
  Even after adjusting for higher IV tPA treatment rates, ischemic stroke patients with no identified cause had better outcomes than other TOAST groups. Conversely, patients coded as cryptogenic with more than 1 likely cause represent a different patient subpopulation. These data argue against the consolidation of cryptogenic stroke subcategories in future investigations.
authors: Stroke Program, Department of Neurology, Tulane University School of Medicine, New Orleans, Los Angeles.
authors: Tyler A
authors: TA
authors: Scullen
authors: Stroke Program, Department of Neurology, Tulane University School of Medicine, New Orleans, Los Angeles.
authors: Dominique J
authors: DJ
authors: Monlezun
authors: Stroke Program, Department of Neurology, Tulane University School of Medicine, New Orleans, Los Angeles.
authors: James E
authors: JE
authors: Siegler
authors: Stroke Program, Department of Neurology, Tulane University School of Medicine, New Orleans, Los Angeles.
authors: Alexander J
authors: AJ
authors: George
authors: Stroke Program, Department of Neurology, Tulane University School of Medicine, New Orleans, Los Angeles.
authors: Melissa
authors: M
authors: Schwickrath
authors: Stroke Program, Department of Neurology, Tulane University School of Medicine, New Orleans, Los Angeles.
authors: Ramy
authors: R
authors: El Khoury
authors: Stroke Program, Department of Neurology, Tulane University School of Medicine, New Orleans, Los Angeles.
authors: Min Chan
authors: MC
authors: Cho
authors: Stroke Program, Department of Neurology, Tulane University School of Medicine, New Orleans, Los Angeles. Electronic address: smartin2@tulane.edu.
authors: Sheryl
authors: S
authors: Martin-Schild
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000150:complications*; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging; D012189:Retrospective Studies; D020521:Stroke / Q000145:classification / Q000209:etiology* / Q000628:therapy; D016896:Treatment Outcome
chemical_list: D005343:Fibrinolytic Agents
keywords: Ischemic stroke; TOAST; atrial fibrillation; cost; cryptogenic stroke; management