Prothrombotic activity is increased in patients with nonvalvular atrial fibrillation and risk factors for embolism

Study objectives: The aim of this study was to investigate whether risk factors for embolism would promote thrombus formation in patients with nonvalvular atrial fibrillation (NVAF). Methods: Hemostatic markers for platelet activity (ie, platelet factor-4 and beta-thromboglobulin [TG]) thrombotic status (ie, prothombin fragments 1 and 2), and fibrinolytic status (ie, d-dimer) were determined in 246 patients with NVAF (mean age, 66.1 years) and 111 control subjects without NVAF (68.3 years). Results: The beta-TG level was higher in NVAF patients than in control subjects. D-dimer levels were higher in NVAF patients having risk factors (mean [+/- SE] d-dimer level, 158.6 +/- 9.2 ng/mL) than in those without risk factors (mean d-dimer level, 92.1 +/- 6.7 ng/mL; p < 0.01) and in control subjects (mean d-dimer level: control subjects with risk factors, 79.1 +/- 10.3 ng/mL; control subjects without risk factors, 31.0 +/- 7.4 ng/mL; p < 0.01). NVAF (odds ratio [OR], 3.94; 95% confidence interval [CI], 1.87 to 8.30; p = 0.0003) and age of greater than or equal to 75 years (OR, 5.68; 95% CI, 2.87 to 11.23; p < 0.0001) emerged as predictors of elevated levels of d-dimer, and only NVAF (OR, 10.30; 95% CI, 5.67 to 18.72; p < 0.0001) emerged as a predictor of elevated levels of beta-TG. Conclusions: NVAF patients whose conditions were complicated with risk factors for embolism could be in the prothrombotic state. Advanced age is a strong predictor of the prothrombotic state in NVAF patients.