Objective To investigate the value and correlation of biomarker B-type brain natriuretic peptide (BNP) level and left atrial appendage function in predicting the cardiogenic stroke risk in patients with non-valvular atrial fibrillation (NVAF).

Methods A total of 80 patients with NVAF who were going to receive catheter ablation or electrical cardioversion for atrial fibrillation were selected.The clinical and echocardiographic data of patients were collected, including demographic information, blood BNP level, preoperative transthoracic and transesophageal echocardiography parameters.The ultrasound acquisition parameters included left ventricular end diastolic volume (LVEDV), left ventricular ejection fraction (LVEF), left atrial volume index (LAVI) and left atrial appendage emptying velocity (PEV).According to whether there was thrombus in left atrial appendage (LAA) or spontaneous echo contrast of left atrial (SEC), they were divided into stroke risk group and normal group.The differences of parameters between the two groups were compared.The correlation between each parameter and stroke risk was analyzed by multivariate logistic regression and receiver operating characteristic (ROC) curve.The correlation between BNP and LAA function and LAVI was analyzed.

Results Among the 80 patients with NVAF, there were 44 cases in the stroke risk group (9 cases of atrial thrombus and 35 cases of left atrial SEC) and 36 cases in the normal group.There was no significant difference in the age, sex, blood pressure, blood glucose, blood lipid and vascular diseases between the two groups (P>0.05).In the stroke risk group, the levels of BNP and LAVI were significantly higher than those in the normal group, LVEF and PEV were significantly lower than those in the normal group (P < 0.01).There was no significant difference in LEDV (P>0.05).Multivariate logistic regression analysis showed that LAVI, PEV and BNP were independent risk factors for stroke risk (OR=1.270, 1.291, 1.016, P < 0.01).Further correlation analysis showed that BNP was significantly negatively correlated with PEV (r=-0.549, P < 0.01) and positively correlated with LAVI (r=0.497, P < 0.01).ROC curve analysis showed that the best cut-off value of PEV for predicting the risk of cardiogenic stroke was 26.5 cm/s, the sensitivity was 61.4%, the specificity was 97.2%, and the area under the curve was 0.87.The areas under the ROC curve predicted by LAVI and BNP were 0.86 and 0.78, respectively.

Conclusions LAVI, PEV and BNP are independent risk factors for stroke risk in NVAF patients.PEV has greater value in predicting stroke risk, and BNP has significant correlation with PEV and LAVI, which can be used as a valuable index to guide clinical anticoagulant therapy.