Risk Factors for Silent Brain Infarction in Nonvalvular Atrial Fibrillation Patients with Low CHA₂DS₂-VASc Score

Silent Brain Infarction (SBI) has been found to be linked to an increased risk of cognitive impairment and future symptomatic stroke. Atrial fibrillation is a significant risk factor for SBI. Even in low-risk atrial fibrillation patients, the incidence of SBI remains high. This study aims to investigate the risk factors for SBI in nonvalvular atrial fibrillation (NVAF) patients with a CHA₂DS₂-VASc score of 0 to 1.

A total of 301 consecutive low-risk NVAF patients (male: CHA₂DS₂-VASc=0, female: CHA₂DS₂-VASc=1) were enrolled. According to brain Magnetic Resonance Imaging (MRI), patients were divided into SBI (n=90) and non-SBI (n=211) groups. Baseline characteristics, blood parameters, and echocardiography results were analyzed. Multivariate logistic regression was performed to identify independent predictors. Receiver Operating Characteristic (ROC) curve analysis was used to evaluate the diagnostic power of the relevant risk factors.

The study revealed that neutrophil count, monocyte count, Platelet-To-Lymphocyte Ratio (PLR), neutrophil-to-high density lipoprotein cholesterol ratio (NHR), and left atrial diameter (LAD) were significantly higher in the SBI group than non-SBI group (p <0.05). Multivariate logistic regression analysis identified PLR (OR, 1.004; 95%CI 1.001-1.007; p =0.026) and LAD (OR 1.092; 95%CI 1.054-1.130; p <0.001) as the independent risk factors associated with SBI. The ROC showed that the Area Under the Curve (AUC) of PLR is 0.589 (95%CI 0.515- 0.662; p =0.015) with an optimal cut-off point of 151 (sensitivity 43.3%, specificity 74.6%). The AUC of LAD is 0.676 (95%CI 0.606-0.746; p <0.001) with an optimal cut-off point of 39 mm (sensitivity 61.1%, specificity 72.0%). The AUC of PLR combined with LAD is 0.711 (95%CI 0.646-0.777; p <0.001) with a sensitivity of 63.3% and specificity of 73.5% for SBI.

PLR and LAD can be independent risk factors for SBI in NVAF patients with low CHA₂DS₂-VASc scores. The combination of the two factors can enhance the predictive ability of SBI in these patients.