Plasma concentrations of atrial natriuretic peptide in cardioembolic stroke with atrial fibrillation

The aim of the present study was to determine whether the level of plasma atrial natriuretic peptide (ANP), an indicator of atrial stretching, correlates with the formation of a thrombus in the left atrium during cardioembolic stroke with atrial fibrillation. Plasma concentrations of immunoreactive ANP and thrombin-antithrombin III complex (TAT) were measured in five age-matched groups including: 16 patients with acute cardioembolic stroke and atrial fibrillation (group 1), 26 patients with chronic cardioembolic stroke and atrial fibrillation (group 2), 27 patients with atrial fibrillation without previous stroke (group 3), 21 patients with acute lacunar stroke (group 4), and 27 healthy controls. The plasma ANP levels were higher in group 1, regardless of the stage, than those estimated at chronic stage in group 4 and in healthy controls. There were no stage-related differences between groups 1, 2 and 3. Plasma levels of ANP in group 2, a high risk group of cardioembolic stroke, were higher than in group 3, a low risk group. There was no correlation between plasma levels of ANP and mean blood pressure, pulse rate or plasma levels of TAT in any group. These results indicate that the determination of plasma ANP concentration is useful to distinguish a high risk patient from a low risk patient and also a cardioembolic stroke patient from a lacunar stroke patient. They also underscore the difficulties in recognizing left atrial thrombus formation by determining the plasma ANP concentration in cardioembolic stroke.