N-terminal probrain natriuretic peptide as a biomarker of cardioembolic stroke

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 pep-tide 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%). Conclusion N-terminal probrain natriuretic peptide is a biomarker with a good accuracy to predict ischemic stroke of cardioembolic cause, namely associated with atrial fibrillation.