Thromboembolic risk factors determined in patients with atrial fibrillation
MedWire News: Advanced age, low left atrial appendage velocity (LAAV), and variation in the Factor (F) V gene predict left atrial thrombosis (LAT) in patients with non-valvular atrial fibrillation (AF), researchers report.
"Atrial fibrillation renders individual patients at risk for development of an atrial thrombus," explain Dimitry Chistiakov (National Research Center GosNIIgenetika, Moscow, Russia) and colleagues.
The thrombi tend to form in the left atrial appendage because of its shape and the presence of rod-shaped trabeculations, they add.
To determine clinical, echocardiographic and genetic factors influencing the risk for LAT in patients with persistent nonvalvular AF, Chistiakov and team studied 212 patients (62.2% male) that had AF for between 48 hours and 90 days.
The researchers genotyped the patients for the polymorphisms 4G/5G in the plasminogen activator inhibitor 1 gene (SERPINE-1), G(-455)A in the fibrinogen ß chain gene (FGB), C(-224)T in the FV gene (F5), and R506Q in F5 using a polymerase chain reaction-restriction fragment length polymorphism approach.
Transesophageal echocardiography revealed that LAT was present in 44 (21%) patients.
LAT was observed significantly more frequently in patients older than 75 years, and in those who had a left ventricular ejection fraction (LVEF) below 40% and a LAAV below 20 cm/s.
In addition, a significantly higher proportion of patients with LAT had the T/T (vs C/C) genotype at F5 C(-224)T than patients with no LAT. No other genetic associations were observed.
Logistic regression analysis revealed that advanced age, LVEF below 40%, LAAV below 20 cm/s, and TT genotype at F5 C(-224)T were independently associated with a significantly increased risk for LAT.
"Our results suggest that the thromboembolic risk in AF could be genetically modulated," conclude Chistiakov and co-authors in the Journal of Thrombosis and Thrombolysis.
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By Laura Dean