Markers of Thrombin and Platelet Activity in Patients With Atrial Fibrillation

Abstract

Background and Purpose —Markers of thrombin generation and platelet activation are often elevated in patients with nonvalvular atrial fibrillation, but it is unclear whether such markers usefully predict stroke. Therefore, we undertook the present study to assess the relationship between prothrombin fragment F1.2 (F1.2), β-thromboglobulin (BTG), fibrinogen, and the factor V Leiden mutation with stroke in atrial fibrillation. Methods —Specimens were obtained from 1531 participants in the Stroke Prevention in Atrial Fibrillation III study. The results were correlated with patient features, antithrombotic therapy, and subsequent thromboembolism (ischemic stroke and systemic embolism) by multivariate analysis. Results —Increased F1.2 levels were associated with age ( P P P =0.006), and heart failure ( P =0.001). F1.2 were not affected by aspirin use and were not associated with thromboembolism after adjustment for age ( P =0.18). BTG levels were higher with advanced age ( P =0.006), coronary artery disease ( P =0.05), carotid disease ( P =0.005), and heart failure ( P P =0.05), and not significantly associated with thromboembolism. Fibrinogen levels were not significantly related to thromboembolism but were associated with elevated BTG levels ( P Conclusions —Elevated F1.2 levels were associated with clinical risk factors for stroke in atrial fibrillation, whereas increased BTG levels were linked to manifestations of atherosclerosis. In this large cohort of patients with atrial fibrillation who were receiving aspirin, F1.2, BTG, fibrinogen, and factor V Leiden were not independent, clinically useful predictors of stroke.