Fibroblast growth factor 23 as a predictor of left atrial appendage thrombosis in patients with nonvalvular atrial fibrillation and various risk of stroke

Aim. To study the role of fibroblast growth factor 23 (FGF-23) as a predictor of left atrial appendage (LAA) thrombosisin patients (pts) with non-valvular atrial fibrillation (AF) and different risk levels of thromboembolic complications (TEC) according to the CHA2DS2-VASc score.Methods. The study included 250 pts with non-valvular AF hospitalized for radiofrequency ablation, divided into 2 groups: group (gr.) 1 - with 0-1 points (n=79) and gr.2 - with ≥2 points on the CHA2DS2-VASc scale (n=171). According to the results of transesophageal echocardiography, pts of each group were divided into subgroups depending on the presence of LAA thrombosis, which was found in 19 pts of gr.1 and 72 of gr.2. Patients underwent transthoracic echocardiography, determination of blood biomarkers: NT-proBNP (pg/ml), GDF-15 (pg/ml), FGF-23 (pmol/l), highly sensitive C-reactive protein (mg/l), cystatin C (mg/l).Results. Pts with LAA thrombosis in both groups had in common: a longer history of arterial hypertension, a greater proportion of coronary artery disease and persistent AF, lower GFR, higher values of atrial volume indices, left ventricle myocardial mass, systolic pressure in the pulmonary artery, median NT-proBNP, FGF-23 and GDF-15. Logistic regression analysis performed separately in the groups revealed the same independent predictors of LAA thrombosis in both groups: LA volume index (LAVI) and the level of FGF-23 in the blood. At the same time, the threshold value of FGF-23, separating pts by the presence of LAA thrombosis, was higher in gr.1 (≥0.85 and ≥0.5 pmol/l, respectively), and the area under the AUC curve for FGF-23 in gr.1 was greater: 0.964 vs 0.865 in gr.2 (p=0.026).Conclusion. The serum level of FGF-23, along with the LAVI, is an independent predictor of LAA thrombosis in pts with AF and various risk of TEC according to CHA2DS2-VASc; the threshold level of FGF-23 for pts at low risk of TEC is significantly higher than for high risk pts, and allows more accurate prediction of the presence of LAA thrombosis.