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To assess the predictive value of the strain rate of left atrial appendage (LAA), brain natriuretic peptide (BNP), D-dimer for thedetection of LAA thrombus in patients with nonvalvular atrial fibrillation(NVAF).
44 patients with NVAF were evaluated by transthoracic and transesophageal echocardiography(TEE). Each segment systolic strain rate (SRS) was measured by strain rate imaging. The parameters of SRI are performed with offline analysis in 5 segments of LAA wall. And all patients immediately underwent fluorescence immunoassay to detect the plasma D-D and BNP. According to with or without thrombotic events, the patients were divided into thrombotic events positive group (n=20) and thrombotic events negative group (n=24). The comparison of strain rate and the levels of D-D and BNP between thrombotic events positive group and thrombotic events negative group. The evaluation of diagnostic value for the independent risk factors of thrombotic events in patients with AF.
Ssr taken from the tip of the LAA were negatively correlated with left atrium dimension (r=-0.547, P<0.01). Patients with LAA thrombus showed a significantly lower the tip strain rate values (0.84 ± 0.49 vs 2.42 ± 1.68, P < 0.01, respectively) than those without LAA thrombi. The Person product-moment correlation coefficient was used to evaluate the associations of the tip Ssr with the plasma D-dimer level and BNP level. The SSr was negatively associated with the D-dimer level (R2=0.30, P<0.05) and BNP level (R2=0.25, P<0.05). ROC curve analysts showed that, the top SSr curve had certain diagnostic accuracy for LAA thrombotic. The best diagnostic cut-off point of it was 1.66.BNP, D-dimmer have predictive value as therisk assessment of thrombotic events in patients with atrial fibrillation; the best critical points of BNP and D-D were 312pg/ml, 0.9μg/l.
The application of strain rate imaging can detect LAA function dysfunction. The LAA Ssr may be helpful for predicting the incidence of LAA thrombus. Ssr is clinically useful for the risk stratification of systemic thromboembolism in patients with unanticoagulated NVAF. LAA strain rate, D- dimer and BNP have a high diagnostic value.