Left Ventricular Injury Detected by Cardiac MRI and Incident Ischemic Stroke and Dementia Risk: The Multi-Ethnic...

Left ventricular injury (LVI) can be detected by cardiac magnetic resonance (CMR) imaging with high sensitivity; however, the implication of these findings on brain health longitudinally is uncertain. We aimed to evaluate the association between LVI biomarkers detected by CMR and the risk of developing ischemic stroke and dementia.

We analyzed the prospective, observational cohort of participants in the Multi-Ethnic Study of Atherosclerosis (MESA) study (median follow-up of 8.7 years). MESA is a population-based cohort recruited from 6 communities. The complete case analysis (CCA) sample included stroke-free participants who underwent CMR at Exam 5 (2010-2012). The multiple imputation (MI) sample consisted of stroke-free participants at Exam 5, irrespective of CMR collection. Missing CMR variables were imputed because of the nonrandom missingness of CMR data. The primary exposure was LVI defined by LV ejection fraction < 50% or circumferential strain ≥ -10 in any LV apical wall. Secondary exposures were left ventricular ejection fraction (LVEF) and strain as continuous measures. Primary outcomes were (1) incident ischemic stroke and (2) newly diagnosed all-cause dementia. Cox proportional hazard models were adjusted for demographic and clinical covariates.

There were 2,584 (11.7% with LVI [mean age 71, 65% male], 88.3% without LVI [mean age 69, 44% male]) and 4,594 participants in the CCA and MI cohorts, respectively. Incident ischemic stroke occurred in 18 (6%) participants with and 65 (3%) without LVI in the CCA sample (302 or 12% with and 18 or 6% without LVI in the MI sample). Both groups had similar rates of cardiovascular disease (6% vs 4%, p = 0.143). LVI was significantly associated with incident ischemic stroke in the MI cohort (adjusted hazard ratio [HR] 1.82, 95% CI 1.08-3.09), but not in the CCA cohort. LV apical peak strain was significantly associated with newly diagnosed dementia only in the MI cohort (adjusted HR 1.06, 95% CI 1.01-1.12). LVEF per 10% was significantly associated with newly diagnosed dementia in both cohorts (adjusted HR in MI cohort 0.73, 95% 0.59-0.90).

CMR-detected LVI is associated with incident ischemic stroke and newly diagnosed dementia. Further studies are needed to validate CMR biomarkers of brain injury risk.