The role of endothelial dysfunction for thromboembolic risk of patients with atrial fibrillation

Background and Objectives: Thromboembolism (TE) is a common complication of atrial fibrillation (AF). Although several serum markers for TE in AF patients have been reported, the mechanisms for TE have not been completely determined. Subjects and Methods: Seventy four patients with persistent or permanent AF (M: F=39 : 35, mean age: 53±18 years) were enrolled. The epidemiologic risk factors for TE, including old age (≥65 years), diabetes, hypertension, heart failure (HF), valvular heart disease, left ventricular (LV) dysfunction, and a history of TE were investigated. Serum markers for the endothelial function [von-Willebrand factor (vWF) and thrombomodulin (TM)], inflammation [quantitative and high sensitive C-reactive protein (CRP) and interleukin (IL)-6], coagulation [fibrinogen, fibrinogen degradation product (FDP), d-dimer] and platelet activity (p-selectin), and the echocardiographic parameters were measured. Results: The vWF was increased in patients with old age, hypertension, HF and a history of TE, and the vWF was positively correlated with age and the left atrium dimension (LAD), respectively. TM was also increased in the patients with old age and a history of TE and the LV dysfunction, and it was positively correlated with age and the LAD. The quantitative CRP was increased with old age, hypertension and LV dysfunction, and it was positively correlated with age and the LAD. High sensitive CRP was increased with old age and LV dysfunction, and it was positively correlated with age and the LAD. IL-6 was increased in diabetic patients. Fibrinogen was increased with old age and hypertension, and it was positively correlated with age and the LAD. FDP and d-dimer were increased in the patients with a history of TE and LV dysfunction. P-selectin was neither increased nor correlated with any other parameters. All the analyzed serum markers, except the markers for coagulation and platelet activity, were correlated with age and the LAD. Conclusions: It was shown that endothelial dysfunction plays an important role for the TE in AF patients. The serum markers for endothelial function may be used to screen the AF patients who are at a high risk for TE.