Brain natriuretic peptide as a surrogate marker for cardioembolic stroke with paroxysmal atrial fibrillation

Background: Cardioembolic stroke generally results in severer disability, since it typically has a larger ischemic area than the other types of ischemic stroke. However, it is difficult to differentiate cardioembolic from noncardioembolic stroke (atherothrombotic and lacunar stroke), whenever ischemic stroke patients have sinus rhythm at the time of presentation. Methods: In this study, we evaluated the levels of plasma brain natriuretic peptide in acute ischemic stroke patients with cardioembolic or noncardioembolic stroke and assessed whether this could provide a basis for differentiating cardioembolic stroke (especially due to paroxysmal atrial fibrillation) from noncardioembolic stroke. Our patient cohort consisted of 99 consecutive patients with acute cerebral infarction who were admitted to Kagawa University School of Medicine Hospital from January 1, 2005, to December 31, 2006. We excluded 23 patients with valve disease, heart failure, myocardial infarction or chronic renal failure. The mean age of the remaining 76 patients (51 males, 25 females) was 70.0 ± 10.1 years. Results: Thirty-six patients had cardioembolic stroke with atrial fibrillation (including permanent and paroxysmal atrial fibrillation); the remaining 40 had noncardioembolic stroke. The plasma brain natriuretic peptide was evaluated on the first morning after admission in all patients. In cardioembolic stroke with atrial fibrillation (permanent and paroxysmal atrial fibrillation), the plasma brain natriuretic peptide, ratio of peak early filling velocity to peak atrial systolic velocity (E/A) and left atrial diameter were significantly increased (p < 0.001), and the left atrial appendage flow was significantly decreased (p < 0.001), compared with noncardioembolic stroke. Analyzed in those 4 factors, cardioembolic stroke was strongly predicted with >95% accuracy assessed by plasma brain natriuretic peptide and left atrial appendage flow. Conclusion: From our results, it was suggested that the first-day brain natriuretic peptide and left atrial appendage flow measurements would be helpful in differentiating cardioembolic stroke with atrial fibrillation from noncardioembolic stroke.