Background Plasma brain natriuretic peptide (BNP) is used as a marker of congestive heart failure. Moreover, plasma BNP levels are increased in patients with acute ischemic stroke, in particular, cardioembolic stroke. We investigated whether the plasma BNP level can also be used as a biological marker to differentiate specific stroke subtype, in particular cardioembolic stroke from the other ischemic stroke subtypes.
Methods Consecutive patients (total 200; 124 males, 76 females; mean age, 71.4 years) with acute ischemic stroke within 24 hours of onset were prospectively enrolled. We measured plasma BNP on admission. Patients were divided into four groups according to the TOAST classification: large-vessel disease (LVD), cardioembolism (CE), small-vessel disease (SVD), and other stroke. Correlation between plasma BNP level and stroke subtype was then examined.
Results Cardioembolism (41%) was the most frequent stroke subtype, followed by other stroke (34%), SVD (16%), and LVD (9%). Age, female, atrial fibrillation, NIHSS score ≥7 on admission and mRS score ≥3 at discharge were significantly higher in CE than in the other stroke subtypes. The mean plasma BNP level of the CE group was significantly higher than that of the other 3 subtypes (409.6 pg/mL for CE, 94.0 pg/mL for LVD, 37.4 pg/mL for SVD, and 156.9 pg/mL for others, p<0.001). The optimal cut-off concentration, sensitivity, and specificity of plasma BNP levels to distinguish CE from other stroke subtypes were 140.0 pg/mL, 80.5% and 80.5%, respectively.
Conclusion Plasma BNP level is significantly higher in CE patients than in other stroke subtypes, and thus physicians should strongly consider CE when the plasma BNP level is over 140.0 pg/mL in patients with acute ischemic stroke.