Brain natriuretic peptide is associated with worsening and mortality in acute stroke patients but adds no prognostic value to clinical predictors of outcome

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.

The gender gap in stroke: a meta-analysis

Several studies have indicated that gender differences might exist in stroke.

OBJECTIVES AND METHODS

Our goal was to perform a comprehensive meta-analysis in order to evaluate and quantify stroke gender disparities through a systematic search of relevant articles published up to October 2009 and addressing gender related differences in ischemic stroke risk factors, stroke subtype and severity, diagnostic tests, and acute phase and secondary prevention treatments.

RESULTS

Forty-five articles were included in the analysis, representing a total of 673,935 patients. Women were globally older than men (+5.2 years) and suffered more hypertension (P = 0.017) and atrial fibrillation (P < 0.001), although they were less likely to drink alcohol (P < 0.001), smoke cigarettes (P < 0.001), present hyperlipidemia (P = 0.033) or diabetes (P = 0.003) than men. Baseline stroke severity was not different between genders. Women suffered more cardioembolic strokes, while men had more atherothrombotic strokes. Moreover, women were less likely to receive stroke-related treatments, such as antiplatelets (P < 0.001), statins (P < 0.001), and tPA (P < 0.001) than men. Although meta-regression did not identify age or stroke etiology as sources of heterogeneity, caution should be taken as that analysis was possible only for gender differences in secondary prevention with antiplatelets because of limited data for other end points.

CONCLUSIONS

Gender differences have been identified on the risk factors profile and diagnostic and therapeutic management of patients with ischemic stroke. Active measures should thus be taken to avoid bias in clinical practice.