[Value of D-dimer and left atrial size combined with CHA2DS2-VASc score in excluding left atrial thrombosis in patients with non-valvular atrial fibrillation].

Objective: To investigate the related factors of thrombosis in patients with non-valvular atrial fibrillation (NVAF), and whether the combination of D-dimer, left atrial anteroposterior diameter and CHA2DS2-VASc score can be used to exclude left atrial thrombosis. Methods: A total of 75 NVAF patients with left atrial thrombosis confirmed by transesophageal echocardiography in Peking University People's Hospital from January 1, 2015 to December 31, 2019 were enrolled as the thrombus group. From January 1 to October 31, 2019, 80 patients with NVAF without left atrial thrombosis were enrolled as the control group. The clinical data, CHA2DS2-VASc score, hematological biomarkers, ultrasound data of two groups were compared. The independent factors associated with left atrial thrombosis were screened by univariate analysis and multivariate logistic regression analysis. The positive predictive value and negative predictive value for the diagnosis of left atrial thrombosis were gained by the score calculated based on the independent related factors. Results: There were no significant differences in age, gender, proportion of persistent atrial fibrillation and duration of atrial fibrillation between the two groups. The CHA2DS2-VASc score [M (Q1, Q3)] of the thrombus group was higher than that of the control group [2.5 (1.0, 3.0) vs 1.8 (1.0, 3.0), P=0.012]. The prothrombin time activity [M (Q1, Q3)] of the thrombus group was 81.1 (72.0, 93.0)%, which was lower than that of the control group 88.8 (83.0,96.0)% (P=0.008). The activated partial thromboplastin time (APTT) of the thrombus group was longer than that of the control group [(32.1±4.8) s vs (30.2±3.7) s, P=0.006]. D-dimer [M (Q1, Q3)] of the thrombus group was 231.0 (71.5, 272.2) ng/ml, which was higher than that of the control group 121.7 (49.0, 140.0) ng/ml (P<0.001). The left atrial anteroposterior diameter in thrombus group was larger [(44.6±6.6) mm vs (38.9±5.3) mm, P<0.001], the proportion of mitral regurgitation was higher (58.1% vs 26.8%, P<0.001). The left ventricular ejection fraction [M (Q1, Q3)] of the thrombus group was 56.7% (45.8%, 66.3%), which was lower than that of the control group 63.3% (60.5%, 70.2%) (P=0.003). Multivariate logistic regression analysis showed that the factor related to left atrial thrombosis was left atrial anteroposterior diameter (OR=4.480, 95%CI: 1.616-12.423). The negative predictive value of the new scoring system combined with D-dimer, left atrial anteroposterior diameter and CHA2DS2-VASc score for left atrial thrombosis was 100%. Conclusions: In NVAF patients, the factor independently associating with left atrial thrombosis is left atrial anteroposterior diameter. The combination of D-dimer, left atrial anteroposterior diameter, and CHA2DS2-VASc score can help exclude left atrial thrombosis before ablation of NVAF.