O4‐02‐05: The relationship of cerebral vessel pathology to brain microinfarcts

The relationship of cerebral vessel pathology to brain microinfarcts is not fully understood. We examined the association of atherosclerosis, arteriolosclerosis, and amyloid angiopathy in cerebral vessels postmortem with the odds of having one or more brain microinfarcts among older, community-dwelling persons who came to autopsy. Brain specimens, and clinical and pathologic data, were derived from 1,125 deceased subjects (mean age-at-death = 88 years, 65% women) who were participating in one of two cohort studies of aging (Rush Memory and Aging Project; Religious Orders Study) and had agreed to brain autopsy. Brain infarcts were identified on gross and microscopic examinations, and rated as present and not present, and classified by number (single vs. multiple), age (chronic vs. not), and location (cortical vs. subcortical). Severities of cerebral vessel pathologies including atherosclerosis, arteriolosclerosis, and amyloid angiopathy, were graded. A third of subjects (n=322; 29%) had at least one microinfarct, including 133 with cortical microinfarcts only, 127 with subcortical microinfarcts only, and 48 with both. Moderate-to-severe atherosclerosis was present in 452 (41%) subjects, arteriolosclerosis in 400 (36%), and amyloid angiopathy in 379 (35%). In a proportional odds model adjusted for age and sex, the odds of a presence of one or multiple (more than one) microinfarct(s) was increased for more severe atherosclerosis (OR =1.22; 95%CI: 1.03-1.45), arteriolosclerosis (OR =1.18; 95%CI: 1.02-1.37), and amyloid angiopathy (OR =1.13; 95%CI: 1.00-1.28). In two similar models but with separate microinfarct outcomes in cortical and in subcortical regions, the odds of a presence of one or multiple subcortical microinfarct(s) was increased for more severe atherosclerosis (OR =1.49; 95%CI: 1.20-1.84) and arteriolosclerosis (OR =1.39; 95%CI: 1.16-1.67), and the odds of a presence of one or multiple cortical microinfarct(s) was increased for amyloid angiopathy (OR =1.26; 95%CI: 1.09-1.46). Cerebral vessel pathologies are associated with increased brain microinfarct burden. Specifically, atherosclerosis and arteriolosclerosis are associated with subcortical microinfarcts, and amyloid angiopathy with cortical microinfarcts.