Risk factors and localization of silent cerebral infarction in patients with atrial fibrillation

Background: It is important to identify the risk factors and localization of silent cerebral infarction (SCI), especially in younger patients with atrial fibrillation (AF). Objective: The purpose of this study was to examine the characteristics and risk factors for SCI in AF patients, with particular attention to localization of SCI. Methods: The study enrolled 286 consecutive neurologically asymptomatic patients who underwent AF ablation from January 2014 to July 2017 (age 61.7 ± 10.2 [SD] years; 208 male and 78 female). All patients underwent magnetic resonance imaging (MRI) before ablation. Results: SCIs were classified independently by 2 radiologists as follows: cardiogenic SCI in 19 (10.6%), lacunar SCI in 13 (8.9%), undetermined causes in 6 (1.6%), and no SCI in 248 (controls, 78.7%). Importantly, no patients with CHA₂DS₂-VASc score 0 had SCI on MRI. In univariable analysis, significant risk factors for lacunar SCI included age (P = .007), hypertension (P = .037), congestive heart failure (P = .040), left atrial (LA) diameter (P = .013), and cardio-ankle vascular index (P = .004). In multivariable analysis, significant risk factors for cardiogenic SCI were AF duration (odds ratio [OR] 1.01; 95% confidence interval [CI] 1.00–1.02; P = .038), ankle-brachial pressure index (OR 0.002; 95% CI 0–0.68; P = .030), and LA abnormality (OR 8.99; 95% CI 2.78–31.00; P <.001), defined by the presence of spontaneous echo contrast and/or decreased LA appendage emptying velocity. Conclusion: The study results indicate that among AF patients, SCIs localized in the cerebral cortex and cerebellum are frequently noted, for which cardiogenic mechanisms may be mainly involved; CHA₂DS₂-VASc score could be useful for screening SCI; and LA abnormality is the specific marker for cardiogenic SCI, providing useful information for risk stratification of SCI.