title: Brain natriuretic peptide is associated with worsening and mortality in acute stroke patients but adds no prognostic value to clinical predictors of outcome.
abstract: BACKGROUND
  At the present time, the determination of the outcome of stroke patients is based on the analysis of clinical and neuroimaging data. The use of prognostic blood biomarkers could aid in decision-making processes, e.g. admitting patients to specialized stroke units. Although the prognostic role of natriuretic peptides has been studied in heart failure and coronary diseases, the value of brain natriuretic peptide (BNP) is less known within the field of strokes.
  
  
  OBJECTIVE
  We aimed to study the relationship between plasma levels of BNP and acute neurological worsening or mortality after stroke in a large cohort of patients (investigating both ischemic and hemorrhagic disease).
  
  
  METHODS
  Consecutive stroke patients (ischemic and hemorrhagic) admitted to the Stroke Unit of our University Hospital within 24 h of the onset of symptoms were included. Stroke severity was assessed according to the National Institutes of Health Stroke Scale (NIHSS) at admission and at discharge. Neurological worsening was defined as an increase of 4 or more points in the NIHSS score or death during the patient's stay at the Stroke Unit. Blood samples were drawn upon admission to measure plasma levels of BNP (Biosite Inc., San Diego, Calif., USA). Statistical analysis was performed using SPSS 15.0 and R software.
  
  
  RESULTS
  Altogether, 896 patients were included in the study. BNP plasma levels were higher among patients who deteriorated the most over time (n = 112; 90.5 vs. 61.2 ng/l; p = 0.006) or died (n = 83; 118.2 vs. 60.9 ng/l; p < 0.001). Multivariate logistic regression analysis indicated that plasma BNP level was an independent predictor of neurological worsening [BNP >56.7 ng/l; odds ratio (OR) = 1.64; p = 0.04] and death after stroke (BNP >65.3 ng/l; OR = 1.97; p = 0.034). Adding BNP level to other well-known clinical predictors of bad outcome did not significantly increase the predictive value.
  
  
  CONCLUSIONS
  Plasma levels of BNP measured during the acute phase of stroke are associated both with early neurological worsening and mortality. However, this biological information does not supply prognostic information which would add to clinical variables, which limits its use as a biomarker. Further investigation and systematic reviews are needed to clarify the role of natriuretic peptides in stroke outcome.
authors.affiliation: Neurovascular Research Laboratory, Vall d'Hebron University Hospital Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain. 31862jmv@comb.cat
authors.forename: J
authors.initials: J
authors.lastname: Montaner
authors.forename: T
authors.initials: T
authors.lastname: García-Berrocoso
authors.forename: M
authors.initials: M
authors.lastname: Mendioroz
authors.forename: M
authors.initials: M
authors.lastname: Palacios
authors.forename: M
authors.initials: M
authors.lastname: Perea-Gainza
authors.forename: P
authors.initials: P
authors.lastname: Delgado
authors.forename: A
authors.initials: A
authors.lastname: Rosell
authors.forename: M
authors.initials: M
authors.lastname: Slevin
authors.forename: M
authors.initials: M
authors.lastname: Ribó
authors.forename: C A
authors.initials: CA
authors.lastname: Molina
authors.forename: J
authors.initials: J
authors.lastname: Alvarez-Sabín
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012189:Retrospective Studies; D012720:Severity of Illness Index; D020521:Stroke / Q000097:blood / Q000175:diagnosis* / Q000401:mortality*; D015996:Survival Rate
chemical_list: D015415:Biomarkers; D020097:Natriuretic Peptide, Brain