Predictors of ischemic stroke for low-risk patients with atrial fibrillation: A matched case-control study

BACKGROUND: The predictors of ischemic stroke in 'low-risk' patients with atrial fibrillation (AF) (CHA2 DS2 -VASc score 0 in men or 1 in women) are debated.

OBJECTIVE: This study aimed to investigate the factors associated with ischemic stroke in 'low-risk' AF patients. Imaging characteristics of their ischemic strokes were also evaluated.

METHODS: This was a matched case-control study conducted at a single tertiary institution. We identified 44 patients with de novo ischemic stroke, and incidentally found AF with low-risk CHA2 DS2 -VASc scores. A 1:5 age- and sex-matched control group was selected for AF patients with a low-risk CHA2 DS2 -VASc score but without ischemic stroke and oral anticoagulant therapy. Conditional multivariate logistic regression analysis was performed to identify the predictors.

RESULTS: There were no significant differences in age, sex, body-mass index, comorbidities, size of the left atrium, and left ventricular ejection fraction. Smokers were more prevalent in the stroke group than in the non-stroke group (24/44 [54.5%] versus 22/220 [10.0%], p-value <0.001). Additionally, mean white blood cell count was significantly higher in the stroke group (p-value =0.019). In conditional univariate logistic regression analysis, smoking, and white blood cell count were significant predictors of stroke. In multivariate analysis, smoking was the only significantly associated factors (matched odds ratio [95% confidence interval] =9.10 [2.48-33.42]). In the stroke group, 14/44 (31.8%) patients had multiple vascular territory infarcts.

CONCLUSION: Smoking was the predictor associated with ischemic stroke in AF patients with low-risk CHA2 DS2 -VASc scores.