Determinants of plasma levels of brain natriuretic peptide after acute ischemic stroke or TIA.

Plasma levels of brain natriuretic peptide (BNP) are frequently elevated after an acute stroke and have been shown to be an independent predictor of mortality. However, the relationships between stroke and BNP concentrations have not yet been systematically investigated. Plasma BNP assay and echocardiography were performed in 48 patients with ischemic stroke or TIA with a mean delay of 12.7 h after onset. Median BNP concentration was 88.6 pg/mL (range 5-1270). Older age, chronic heart failure, atrial fibrillation, stroke severity, lower hemoglobin levels, lower left ventricular ejection fraction, and abnormalities of left atrium or appendage (LA/LAA) were univariately associated with increased BNP levels. At multivariable analysis, the presence of at least one LA/LAA abnormality (atrial dilatation, low flow velocity, spontaneous echocontrast or thrombus) had the strongest association with BNP, explaining 38.9% of the variance in the whole sample and 28.5% in patients without atrial fibrillation. In acute ischemic stroke patients, elevated plasma BNP levels have multiple determinants, among which left atrial disease appears to be the stronger, even in patients without atrial fibrillation. These results encourage further investigation of plasma BNP concentration as a potential marker of the presence of left atrial sources of emboli.