Aim    To study the role of blood concentration of growth differentiation factor 15 (GDF-15) as a predictor of left atrial/left atrial appendage (LA/LAA) thrombosis in patients with nonvalvular atrial fibrillation (AF).Material and methods    538 patients with nonvalvular AF were admitted to the Tyumen Cardiology Research Center in 2019–2020 for radiofrequency ablation and elective cardioversion. According to findings of transesophageal echocardiography (EcoCG), 42 (7.8%) of these patients had LA/LAA thrombosis and 79 (14.7%) of them had the effect of spontaneous echo contrast (SEC). This comparative, cross-sectional, cohort study included at the initial stage 158 successively hospitalized patients with nonvalvular AF: group 1 (with LA/LAA thrombosis, n=42) and group 2 (without LA/LAA thrombosis and without SEC, n=116). To eliminate significant differences in age between the groups, an additional inclusion criterium was introduced, age from 45 to 75 years. Finally, 144 patients were included into the study: group 1 (with LA/LAA thrombosis, n=42, mean age 60.9±7.2 years) and group 2 (without LA/LAA thrombosis and without SEC, n=116, mean age 59.5±6.0 years). 93 (91%) patients in group 1 and 40 (95%) patients in group 2 had arterial hypertension (p=0.4168); 53 (52%) and 29 (^(%), respectively, had ischemic heart disease (p=0.0611). The groups did not differ in sex, profile of major cardiovascular diseases, or frequency and range of oral anticoagulant treatment. General clinical evaluation, EchoCG, and laboratory tests, including measurements of blood concentrations of GDF-15 and NT-proBNP, were performed.Results    In the group with LA/LAA thrombosis, 1) persistent AF prevailed whereas paroxysmal AF was more frequently observed in patients without thrombosis; 2) a tendency toward more pronounced chronic heart failure was observed; 3) tendencies toward a high median CHA2DS2‑VASc score and toward a greater proportion of patients with scores ≥3 were observed. According to EchoCG findings, group 1 had higher values of sizes and volumes of both atria and the right ventricle, left ventricular (LV) end-systolic volume and size, pulmonary artery systolic blood pressure, and LV myocardial mass index. LV ejection fraction (EF) was in the normal range in both groups but it was significantly lower for patients with LA/LAA thrombosis, 59.1±5.1 and 64.0±7.3, respectively (p=0.00006). Concentrations of GDF-15 (p=0.00025) and NT-proBNP were significantly higher in group 1 than in group 2 (p=0.000001). After determining the threshold values for both biomarkers using the ROC analysis, two independent predictors of LA/LAA thrombosis were obtained by the stepwise multiple regression analysis: GDF-15 >935.0 pg/ml (OR=4.132, 95 % CI 1.305–13.084) and LV EF (OR=0.859, 95 % CI 0.776–0.951). The ROC analysis assessed the model quality as good: AUC=0.776 (p<0.001), sensitivity 78.3 %, specificity 78.3 %.Conclusion    For patients with nonvalvular AF, both increased GDF-15 (>935.0 pg/ml) and LV EF are independent predictors for LA/LAA thrombosis.

Aim: To test the previously developed predictive model on a test set, including patients with non-valvular atrial fibrillation (AF).Material and Methods. A predictive model was previously developed on a training set of 638 patients with non-valvular AF. The test set included 175 randomly selected patients with non-valvular AF hospitalized at the Tyumen Cardiology Research Center for radiofrequency ablation (RFA) or electrical cardioversion in 2018-2021. The quality of the predictive model was assessed using ROC analysis.Results. Arterial hypertension, coronary heart disease, congestive chronic heart failure, and persistent AF were more common in patients of both sets with left atrial appendage (LAA) thrombosis. Patients of the training and test sets with LAA thrombus had more pronounced structural changes in the heart cavities and similar changes in the geometry of the heart: normal left ventricle (LV) geometry was less common and eccentric LV hypertrophy was more common. According to the results of a previous retrospective analysis of the data, independent predictors of LAA thrombosis were persistent type of AF, left atrium size, and eccentric LV hypertrophy. Based on the data gathered, a predictive model LAA thrombosis was developed as an equation that includes 3 variables. The cut-off point for calculating the probability of LAA thrombosis is 0.07. Applying this model on a test set showed the good quality of the model: the area under the curve obtained using ROC analysis was 0.750 (p < 0.001). At the same time, the sensitivity and specificity of this model for the detection of LAA thrombosis were 72.3% and 71%, respectively.Conclusion. The evaluation of the quality of the LAA thrombosis predictive model developed on the training set confirmed its good quality on a similar test set of patients with non-valvular AF hospitalized for RFA or electrical cardioversion.

Aim. To identify predictors of spontaneous echo contrast (SEC) and/or left atrial appendage (LAA) thrombosis in patients with nonvalvular atrial fibrillation (AF) who are referred for elective cardioversion or catheter ablation (CA).Material and methods. A retrospective analysis of data from 638 patients with nonvalvular AF who were hospitalized from 2014 to 2017 for cardioversion or CA was performed. All patients underwent diagnostic tests, including transthoracic and transesophageal echocardiography (TEE).Results. According to the TEE results, two groups of patients were formed: group 1 — 95 patients (14,9%) with signs of SEC and/or thrombosis in LAA; group 2 — 543 patients (85,1%) without SEC or thrombosis in LAA. Patients with the phenomenon of SEC and/or LAA thrombosis were older, had a higher risk on the CHA2DS2-VASc score. These patients were more likely to have coronary heart disease (CAD), hypertension, stage IIA chronic heart failure, obese class >II, persistent or permanent AF Patients in both groups did not differ in anticoagulant therapy. Patients in group 1 had a larger size of the left and right atria, right ventricle, left ventricular (LV) end-systolic and end-diastolic diameters, higher LV mass index, lower values of LV ejection fraction and blood flow velocity in LAA. Logistic regression revealed following independent predictors of SEC and/or LAA thrombosis: CAD (odds ratio (OR) 2,289; 95% confidence interval (CI) 1,313-3,990; p=0,003), persistent or permanent AF (OR 2,071; 95% CI 1,222-3,510; p=0,007), LA diameter >43 mm (OR 3,569; 95% CI 2,0822-6,117; p<0,001), concentric or eccentric LV hypertrophy (OR 2,230; 95% CI 1,302-3,819; p=0,003).Conclusion. As the result, all patients referring for CA or cardioversion, regardless of the CHA2DS2-VASc score, should underwent LAA. According to this study, the presence of CAD, persistent or permanent AF, LA diameter >43 mm, concentric or eccentric LV hypertrophy are independent predictors of SEC and/or LAA thrombosis.