Abstract: Objective To explore the risk factors of atrial thrombosis in patients with nonvalvular atrial fibrillation (NVAF) with low CHA2DS2-VASc scores at admission (≤1 for male and ≤2 for female patients). Methods We retrospectively analyzed the clinical data of 10 382 patients with NVAF undergoing transesophageal echocardiography in our hospital from 2009 to 2019, and enrolled 48 NVAF patients with thrombosis as the observation group and another 240 NVAF patients without thrombosis as the control group. The baseline characteristics, biochemical indicators, and echocardiographic findings of the patients were analyzed using univariate analysis, multivariate logistic regression analysis and Pearson correlation analysis. Results The baseline data did not differ significantly between the two groups (P>0.05). Compared with those in the control group, the patients with atrial thrombosis had an increased left atrial diameter (LAD; P<0.001), a greater likelihood of hypertrophic cardiomyopathy (HCM; P<0.001), significantly higher levels of C-reactive protein (CRP; P<0.05) and uric acid (P<0.001) , and greater standard deviation of red blood cell distribution width (RDW-SD; P<0.001). LAD (P<0.001), HCM (P<0.05) and CRP (P< 0.05) were identified as the independent factors affecting the occurrence of atrial thrombosis in patients with low CHA2DS2-VASc scores. Conclusions LAD enlargement, HCM, and an elevated CRP level are independent risk factors for atrial thrombosis in NVAF patients with low CHA2DS2-VASc scores. Active anticoagulation therapy should be administered for these patients once these risk factors are detected to prevent the occurrence of stroke.

Key words: atrial fibrillation; low CHA2DS2-VASc score; atrial thrombosis; risk factors