Cerebral amyloid angiopathy and its co-occurrence with Alzheimer's disease and other cerebrovascular neuropathologic changes.

We examined the relationship between cerebral amyloid angiopathy (CAA), Alzheimer's disease neuropathologic changes, other vascular brain pathologies, and cognition in a large multicenter autopsy sample. Data were obtained from the National Alzheimer's Coordinating Center on autopsied subjects (N = 3976) who died between 2002 and 2012. Descriptive statistics and multivariable regression models estimated the associations between CAA and other pathologies, and between CAA severity and cognitive test scores proximal to death. CAA tended to co-occur with Alzheimer's disease neuropathologic changes but a minority of cases were discrepant. CAA was absent in 22% (n = 520) of subjects with frequent neuritic plaques but present in 20.9% (n = 91) of subjects with no neuritic plaques. In subjects with no/sparse neuritic plaques, nonhemorrhagic brain infarcts were more common in those with CAA pathology than without (p = 0.007). In subjects without the APOE ε4 allele, CAA severity was associated with lower cognition proximal to death, factoring in other pathologies. The presence of CAA in patients without Alzheimer's disease may indicate a distinct cerebrovascular condition.