Relation of interleukin-6,C-reactive protein, and the prothrombotic state to transesophageal echocardiographic findings in atrial fibrillation

Atrial fibrillation (AF) is a major cause of morbidity and mortality from stroke due to thromboembolism from the fibrillating left atrium, including its appendage. We hypothesized that indexes of inflammation (as indicated by C-reactive protein and interleukin-6) and indexes of the prothrombotic state in,AF that represent platelet activation (soluble P-selectin levels), endothelial damage or dysfunction (von Willebrand factor), coagulation (tissue factor and fibrinogen), and hemorrheology (plasma viscosity and hematocrit) would be related to the presence of thromboembolic Predictors on transesophageal echocardiography in patients with long-term AF. To test this hypothesis, we recruited 37 patients with long-term AF who were receiving warfarin therapy with an international normalized ratio of greater than or equal to2.0 for greater than or equal to 3 weeks before transesophageal echocardiography. twenty-two patients had dense spontaneous echo contrast (SEC) visible in the left atrium or left atrial appendage, 10 had complex atheromatous plaque in the descending aorta, 11 had peak left atrial appendage velocities less than or equal to0.2 m/s, and 3 had thrombus visible in the left atrial appendage. Twenty-eight patients had greater than or equal to1 transesophageal echocardiographic (TEE) risk factor for thromboembolism. Plasma levels of C-reactive protein (p = 0 . 03) and soluble P-selectin (P = 0.04) and hematocrit (p = 0.004) were higher among patients with AF with dense SEC than among those without. No significant associations were found for other TEE risk factors. Hematocrit was the only variable significantly associated with the presence of greater than or equal to 1 TEE risk factor among patients with AF (p = 0.007) and the only independent associate of dense SEC after multivariate analysis (relative risk 1.4, 95% confidence interval 1.1 to 1.6) per 1% increase in hematocrit (p = 0.003, r(2) = 0.22). Although hematocrit was the only independent associate of dense SEC and greater than or equal to I TEE risk factor, significant associations between dense SEC and the 2 indexes, C-reactive protein and soluble P-selectin, may indicate that mechanisms other than stasis are present with dense SEC. These observations support an "inflammatory hypothesis" in the pathogenesis of SEC that may have implications for thrombogenesis in AF. (C) 2004 by Excerpta Medica, Inc.