title: N-terminal probrain natriuretic peptide as a biomarker of cardioembolic stroke.
abstract: BACKGROUND
  and purpose N-terminal probrain natriuretic peptide, which is mainly produced by the heart, is increased in acute stroke. We aimed to determine if N-terminal probrain natriuretic peptide could be a biomarker for ischemic stroke with a cardioembolic cause.
  
  
  METHODS
  Consecutive sample of acute stroke patients admitted to a Stroke Unit. Ischemic stroke subtype was classified using the TOAST classification. Blood samples were drawn within 72 h after stroke onset. Serum N-terminal probrain natriuretic peptide concentration was measured using an electrochemiluminescence immunoassay. Mean values of N-terminal probrain natriuretic peptide were compared between patients with hemorrhagic stroke vs. ischemic stroke, cardioembolic stroke vs. noncardioembolic stroke, cardioembolic stroke with atrial fibrillation vs. noncardioembolic stroke using t-test. Receiver operating characteristic curves were used to test the ability of N-terminal probrain natriuretic peptide values to identify cardioembolic stroke and cardioembolic stroke with atrial fibrillation.
  
  
  RESULTS
  Ninety-two patients were included (66 with ischemic stroke) with a mean age of 58·6 years. Twenty-eight (42·4%) ischemic strokes had a cardioembolic cause. Mean N-terminal probrain natriuretic peptide values for cardioembolic stroke were significantly higher (P<0·001) (491·6; 95% confidence interval 283·7-852·0 pg/ml) than for noncardioembolic ischemic stroke (124·7; 86·3-180·2 pg/ml). The area under the receiver operating characteristic curve for N-terminal probrain natriuretic peptide in cardioembolic stroke was 0·77. The cut-off point with the highest sensitivity and specificity was set at 265·5 pg/ml (71·4% and 73·7% respectively). The area under the curve of N-terminal probrain natriuretic peptide for cardioembolic stroke related to atrial fibrillation was 0·92, cut-off was set at 265·5 pg/ml (sensitivity 94·4%, specificity 72·9%).
  
  
  CONCLUSIONS
  N-terminal probrain natriuretic peptide is a biomarker with a good accuracy to predict ischemic stroke of cardioembolic cause, namely associated with atrial fibrillation.
authors.affiliation: Department of Neurology, Hospital de Santa Maria, University of Lisbon, Lisboa, Portugal. catarinagfonseca@gmail.com
authors.forename: Ana Catarina
authors.initials: AC
authors.lastname: Fonseca
authors.forename: Joaquim Sampaio
authors.initials: JS
authors.lastname: Matias
authors.forename: Teresa
authors.initials: T
authors.lastname: Pinho e Melo
authors.forename: Filipa
authors.initials: F
authors.lastname: Falcão
authors.forename: Patrícia
authors.initials: P
authors.lastname: Canhão
authors.forename: José M
authors.initials: JM
authors.lastname: Ferro
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D001281:Atrial Fibrillation / Q000097:blood* / Q000150:complications / Q000000981:diagnostic imaging; D015415:Biomarkers / Q000097:blood; D002545:Brain Ischemia / Q000097:blood* / Q000145:classification / Q000209:etiology; D002543:Cerebral Hemorrhage / Q000097:blood / Q000150:complications; D005260:Female; D006331:Heart Diseases / Q000097:blood* / Q000150:complications / Q000000981:diagnostic imaging; D006801:Humans; D020766:Intracranial Embolism / Q000097:blood* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D012372:ROC Curve; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014463:Ultrasonography
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain