Atrial fibrillation and atherosclerosis cause different vascular brain lesions on magnetic resonance imaging.

Background And Aims Atrial fibrillation (AF) and atherosclerosis pre-dispose to the occurrence of vascular brain lesions compared with the general population, yet direct comparisons of brain lesion patterns between these two cardiovascular patient groups are lacking. This study sought to compare the prevalence and distribution of vascular brain lesions on cerebral magnetic resonance imaging (MRI) between patients with AF and those with atherosclerosis.Methods Baseline clinical data and standardized brain MRI scans from the Swiss Atrial Fibrillation cohort study (Swiss-AF; representing patients with AF) and the COMPASS MRI sub-study (COMPASS MIND; representing patients with atherosclerosis without AF) were used to compare the prevalence of lacunar and non-lacunar infarcts, periventricular and deep white matter hyperintensities (WMH), and cerebral micro-bleeds (CMB) between groups.Results Overall, 3508 patients were included (AF: n = 1748; atherosclerosis: n = 1760). Mean age was 73 (±8) years in the AF cohort and 71 (±6) years in the atherosclerosis cohort, 28% and 23% were female, 90% of the AF patients took oral anti-coagulation, 93% of the atherosclerosis patients took anti-platelet therapy. AF patients were more likely to have non-lacunar infarcts (22% vs 10%; P < .001), and atherosclerosis patients were more likely to have lacunar infarcts (21% vs 26%; P = .001). A higher grade of periventricular WMH was seen in AF patients (49% vs 37%; P < .001). The presence of CMB were more common in atherosclerosis patients (22% vs 29%; P < .001). In multi-variable analyses, AF patients had a higher odds ratio (OR) of non-lacunar infarcts (OR 2.28, 95% confidence interval [CI] 1.86-2.81; P < .001), lower odds of lacunar infarcts (OR 0.66, 95% CI 0.56-0.79; P < .001), and higher odds of severe periventricular WMH (OR 1.42, 95% CI 1.22-1.67; P < .001) compared with atherosclerosis patients.Conclusions Patients with AF had a higher rate of non-lacunar infarcts, multi-infarct patterns and more severe periventricular white matter disease compared with patients with atherosclerosis. These findings support disease-specific mechanisms in the development of vascular brain lesions in patients with cardiovascular disease.