Abstract
BACKGROUND: Various measures of abnormal left atrial (LA) structure or function (LA myopathy) are associated with a higher risk of ischemic stroke and dementia, independent of atrial fibrillation. However, limited data exist on their prognostic usefulness. Therefore, we aimed to assess the ability of markers of LA myopathy to improve the prediction of ischemic stroke and dementia. METHODS: The ARIC study (Atherosclerosis Risk in Communities) is a prospective community-based cohort study. For this analysis, we included participants who attended visit 5 (2011-2013) without a history of stroke or atrial fibrillation and had a 12-lead ECG and a transthoracic echocardiogram. Markers of LA myopathy included P wave abnormalities from 12-lead ECG, NT-proBNP (N-terminal pro-B-type natriuretic peptide), and LA volume and strain parameters from the echocardiogram. The primary composite outcome comprised ischemic stroke and dementia, which were ascertained through hospital surveillance, cohort follow-up, and death registries. To determine improvement in risk prediction of the composite outcome, each marker was individually added to a model that included CHA(2)DS(2)-VASc variables, and Akaike information criterion, C statistic, and its change were computed. Cox proportional hazards models were used to assess the independent association of LA myopathy markers with the outcome. RESULTS: Among 4712 participants (59% female; mean age, 74 years), 193 ischemic strokes and 769 dementia cases were ascertained over a median follow-up of 8.3 years. Of LA myopathy markers, only LA reservoir strain and NT-proBNP significantly improved C statistic when added to the CHA(2)DS(2)-VASc model (base C statistic, 0.677) for the prediction of the composite outcome. Adding the LA reservoir yielded the highest increase in C statistic (0.010 [95% CI, 0.003-0.017]), and the model including the LA reservoir showed the lowest Akaike information criterion. In multivariable regression models, LA volume index, NT-proBNP, and LA strain parameters were significantly associated with the composite outcome. CONCLUSIONS: Of various LA myopathy markers, LA reservoir yields the greatest improvement in the prediction of ischemic stroke and dementia, supporting its use to identify people at high risk of cerebrovascular events and dementia.