Left Atrial Enlargement Linked to Vascular Brain Injury
Investigators recommend further studies to determine whether patients with LA enlargement can reduce risk for incident brain infarcts with anticoagulant use.
Left atrial diameter (LAD) has been shown to be independently associated with prevalent brain infarcts, in particular nonlacunar infarcts, but not with leukoaraiosis (ie, white matter disease), according to an analysis of data from the prospective Cardiovascular Health Study (CHS). Results of the study were published in Neurology.
The investigators sought to determine the relationship between LAD and vascular brain injury on brain magnetic resonance imaging (MRI). They evaluated data from the CHS: a prospective cohort of community-dwelling adults age 65 and older were randomly selected from Medicare eligibility lists in 4 counties from California, Maryland, North Carolina, and Pennsylvania. A total of 5888 participants were enrolled in 2 waves. The first cohort was enrolled from 1989 to 1990 and the second cohort, which comprised predominantly black individuals, was enrolled from 1992 to 1993. All participants were followed through 1998 to 1999 via yearly clinic visits and semi-annual telephone calls.
In all participants, LAD was measured using 2-dimensional transthoracic echocardiograms. Of CHS participants who underwent brain MRIs, the association between LAD and brain infarcts and between LAD and leukoaraiosis was explored. Primary study outcomes (ie, number for analysis) included prevalent infarcts (2327) and degree of leukoaraiosis on initial brain MRI (2315). Secondary outcomes included prevalent nonlacunar infarcts, incident infarcts, incident nonlacunar infarcts, and level of leukoaraiosis on follow-up brain MRI adjusted for initial MRI.
Of the 2335 participants with initial brain MRIs, 38.7% were men, mean age was 72.0±4.8, and 29.0% had prevalent infarcts. Per multivariable, fully adjusted models, LAD was significantly associated with prevalent infarcts (risk ratio [RR] 1.20; 95% CI, 1.08-1.34; P <.001) and with prevalent nonlacunar infarcts (RR 1.28; 95% CI, 1.06-1.54; P = .01). In contrast, there was no significant association between LAD and leukoaraiosis (RR –0.08; 95% CI, –0.17 to 0.01), incident infarcts (RR 1.00; 95% CI, 0.78-1.29), nonlacunar infarcts (RR 0.98; 95% CI, 0.67-1.42), or worsening leukoaraiosis (RR –0.04; 95% CI, –0.10 to 0.02).
The investigators concluded that larger studies are warranted in order to determine the association between LAD and the risk for incident brain infarcts and whether this risk can be reduced in patients with left atrial enlargement through the use of anticoagulant agents.
Yaghi S, Bartz TM, Kronmal R, et al. Left atrial diameter and vascular brain injury on MRI: the Cardiovascular Health Study. Neurology. 2018;91:e1237-e1244.